CA2081921C - Improvements in or relating to electrostatic coating of substrates of medicinal products - Google Patents
Improvements in or relating to electrostatic coating of substrates of medicinal products Download PDFInfo
- Publication number
- CA2081921C CA2081921C CA002081921A CA2081921A CA2081921C CA 2081921 C CA2081921 C CA 2081921C CA 002081921 A CA002081921 A CA 002081921A CA 2081921 A CA2081921 A CA 2081921A CA 2081921 C CA2081921 C CA 2081921C
- Authority
- CA
- Canada
- Prior art keywords
- cores
- conveying means
- powder
- dry powder
- coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
- B05D1/04—Processes for applying liquids or other fluent materials performed by spraying involving the use of an electrostatic field
- B05D1/06—Applying particulate materials
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K9/00—Medicinal preparations characterised by special physical form
- A61K9/20—Pills, tablets, discs, rods
- A61K9/28—Dragees; Coated pills or tablets, e.g. with film or compression coating
- A61K9/2893—Tablet coating processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B16/00—Spray booths
- B05B16/90—Spray booths comprising conveying means for moving objects or other work to be sprayed in and out of the booth, e.g. through the booth
- B05B16/95—Spray booths comprising conveying means for moving objects or other work to be sprayed in and out of the booth, e.g. through the booth the objects or other work to be sprayed lying on, or being held above the conveying means, i.e. not hanging from the conveying means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
- B05B5/08—Plant for applying liquids or other fluent materials to objects
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
- B05B5/08—Plant for applying liquids or other fluent materials to objects
- B05B5/087—Arrangements of electrodes, e.g. of charging, shielding, collecting electrodes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
- B05B5/08—Plant for applying liquids or other fluent materials to objects
- B05B5/082—Plant for applying liquids or other fluent materials to objects characterised by means for supporting, holding or conveying the objects
- B05B5/084—Plant for applying liquids or other fluent materials to objects characterised by means for supporting, holding or conveying the objects the objects lying on, or being supported above conveying means, e.g. conveyor belts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2258/00—Small objects (e.g. screws)
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
- B05D3/0254—After-treatment
Abstract
A method of coating substrates of medicinal products with a dry powder includes the following steps; feeding the medicinal substrates onto a conveying means (1); supplying the dry powder to a region (5) through which the substrates are to be conveyed;
conveying the medicinal substrates on the conveying means (1) through the region (5) with the conveying means and or the substrates maintained at a different electric potential from the dry powder, whereby the dry powder is attracted to the exposed surfaces of the substrates but is unable to reach the coated surfaces of the substrates in contact with the conveying means, and treating the dry powder coatings to convert the powder into a fused film secured to the substrates.
conveying the medicinal substrates on the conveying means (1) through the region (5) with the conveying means and or the substrates maintained at a different electric potential from the dry powder, whereby the dry powder is attracted to the exposed surfaces of the substrates but is unable to reach the coated surfaces of the substrates in contact with the conveying means, and treating the dry powder coatings to convert the powder into a fused film secured to the substrates.
Description
WO 92/14451 PC1'/GB92/(D~323 .. ~~8~~~~
Improvements in or r.elatinct to Electrostatic Coating of Substrates of Medicinal Products The present invention relates to a method and apparatus for electrostatic coating of substrates of medicinal products. The invention is particularly, but not exclusioely, concerned pith the coating of pharma-ceutical :ablet cores saiLh a dry powder.
Proposals ror electrostatic coating of tablets have been made f or at leas t vise las t t:~i~y years or so . For example, GB-1075404 (published in 1967) proposes an apparatus far coating tablets in which a liquid is sprayed onto one face of each tablet core as the tablet cores are conveyed below a first stage sprayer having an associated high voltage grid, the coating is dried, the coat~ei cores are then conveyed below a second stage sprayer having an associated high voltage grid with the other side of the tablets uppermost, and then that coating is dried again.
Various paper proposals for electrostatically coating tablet cores with a liquid ar a dry powder have been made but as yet at least in the case of pharma°
ceutical'table~s there is no recognized electrostatic coating method or apparatus that has proved sufficiently successful to be 'applied commercially on a reasonable scale. while there are rotary tablst presses capable of producing pharmaceutical tablet cores continuously at a rate of fox example 5;000 tableLS tier minute, the i~'O 92/l~t~l ~ PCT/~892/00323 subsequent coating of the tablet cores is most commonly carried out as a batch process by applying a liquid coating in a revolving drum.
In order to provide a commercially viable apparatus or method for coating medicinal products various problems must be overcome. It is in many ways easier '~o apply a liquid rather than a dry powder as the coari:-:g material and therefore, although both options haze beep. cor.sidere in research , workers have f avour ed the ~a sa o _ '.. l ~~~ l ms's .
l0 If a dry powder is applied then ~,. is harder to obtain adhesion of the coating to the substrate, r;~_c._ l s no=
itself likely to be sufficiently electrically conducting, even when the powder is electrostatically charged. In order to provide a lasting bond between the substrate and the powder, the powder must be transferred into a film, for example by melting, but in the case of a medicinal product, which iw many cases will include organic materials, must not be damaged. furthermore an even coating is required and it is very difficult to obtain an even coating of powder on an electrically insulating medicinal substrate, even when the powder is electro-statically charged.
When liquid coating is used, the coating must be dried. Theoretically such drying could in some circum-stances be carxied out at room temperature but in commercial practice it is important, for example because of the rate at which the process m:a t be carried out, to heat the tablets and that is exoensi~re because of the iV~ 92/1:451 ~ y~ PCT/G339?/OiD323 large input of energy required to vapourize the solvent used in the liquid coating. Another disadvantage of liquid coating is that it cannot be used for coating materials that are not soluble or suitably dispersible in a usable liquid, preferably water.
It is an object of the invention to provide an improved method and apparatus for coating substrates of medicinal. products.
According to the invention there is orovide~-1 a method of coating substrates of ~~,edicinal prec:'~'c'ws jai t'~ a dry powder, the method includi~:: t'~°_ fcll,o~.~in~; st=w feeding the medicinal substrates onto a conveying means;
supplying the dry powder to a region through which the medicinal substrates are to be conveyed on the conveying means;
conveying the medicinal substrates on the conveying means through the region with the conveying means and/or the substrates maintained at a different electric potential from the dry powder, whereby the dry powder is at~.racted to the exposed surfaces of the substrates but is unable to reach the surfaces of the substrates in contact with the conveying means, and treating the dry powder coatings to convert the powder into a fused film securAd to the substrates.
Hy placing the substrates on a conveying means during the charging process, __ is found t'.:at a satisfac--Cory spread of powder over the substrate can be obtained.
d~~ 92/ 14-l51 PC: f/C~3~2/00323 ~~
It is also found that some unevenness of distribution is not necessarily serious, even if it is important for the final tablet to have a coating of substantially constant thickness, because further levelling can take place when the powder is converted into a fused film. Thus the present invention enables a desired thickness of coating to be applied uniformly over a surface of a substrate.
The thic.'cness o~ t;:e coating gill typically be greater than 10 sm . A? ti. ougn the present in~rer.ti on as def fined :above s~ci 11 i.~.~roives the input of energy to convert the ~O~dd~?= '_:'.:O ~ fl;S°~ film, the amount Of energy r2qulred can be substanLiall;y less than that involved in the case where a liquid coating comprising a coating substance dissolved in a suitable solvent is applied and the solvent has to be vapourised after application of the coating. The method also removes the necessity for solvent handling and disposal and for batch processing.
The medicinal products will usually be pharma-ceutical tablets ("tablets°' being as defined below) but ~O they may also be implants that are not administered orally.
While reference is made throughout the specification to ''tablets" and the invention is of particular applica~
tion to pharmaceutical tablets of conventional shape, it should be understood that the term is to be interpreted in a broad sense as covering also, far example, pellets, capsules or spherules.
While the method of the invention will generally be W() 92/ 14~~ 1 ~ ~ ~ ~ ~ ~ -~ P~/~ ~'~2/00323 applied to the coating of tablet cores (or substrates of the medicinal products) which have not received any coating since being formed in a press, it may be used to apply a coating on top of an already coated or partly coated tablet core.
The method othe present invention may be carried out as a cen~-~inuous process. An practice there are con-sideraol~ advantac,'es in being able to operate the coating "'O~~~SS CCri=_n110L;S1 y =at::0~ t.'13~, aS 3 batch prOCeSS.
While there are certain applications, which will be Z'2ae'r're.C:,' =O la'~.'.~=, ~a7i'1~~°_ i°.'. iv'~.,.: be desirad t0 Coat tile medicinal substrate on one side only or with at least one discontinuity in the coating, it will generally be desirable to coat all of the exterior of the tablet core.
Accordingly the ~netYaod preferably comprises the following further subsequent steps:
feeding the medicinal substrates onto a conveying means with the treated powder coatings of the substrates in contact with the conveying means and with that surface of the substrate that was in contact with the conveying means during the above-mentioned conveying step exposed;
supplying the dry powder caith which the substrates are to be coated to a region through which the conveying means passes;
conveying the substrates ;n the conveying means through the region with the ccnveying means and/or the substrates maintained at a di_'erant electric potential frpm'the dry powder whereby t::e cry powder is attracted WO 92/151 ~ PC.'T/G892/~~323 -to the exposed surfaces of the substrates but is unable to reach the coated surfaces of the substrates in contact with the conveying means, and treating the dry powder coatings to convert the newly applied powder into a fused film secured to the substrates.
For practical convenience the conveyia.g means used during the second coating stage is prrws=ab'_yr r.ot =.a one used during the first coating stage but it vs possible to use the same conveying means for both coac~.ng stages.
The powder applied during each coating st~c~ viill usually be the same but it is of course possible to apply different powders at each stager similarly the same thickness of coating will usually be applied at each stage but different thicknesses may be applied, if desired.
If desired still further coating stages may be employed for example to apply powder to sides of the products, if the sides have not already been coated.
Preferably the conveying means comprises a conveyor belt. The conveying means may however comprise an inclined static surface_.or a vibrated surface along which the substrates slide. The friction between the sub strafes and the inclined surface may be reduced by passing air through the inclined surface from the underside.
Canverting the powder.into a =used fi':.~ may advant-ageously comprise converting the powder into the liquid dJ0 92/1~~51 PCT/~k392/00323 _ 7 _ phase after which it returns to the solid phase.
We have found 'that the conversion of the dry powder into a fused film not only serves to secure the coar.ing to the substrate but also provides a means by which the distribution of the coating material over the substrate may be made more even. In some cases 'the coating material may have such a low viscosity when fused that the coating will distribute i°tselv evenly over a sub-strate but in most cases the coating material wii'~ be more viscous and the method thareo« prefe_ably includes the further mechanical treatment o.L the coa-v_:~..~ ~.o even out the depth of the coating over the surface of the substrate. The evening out step may be carried out by passing the substrates under a vibrating plate or a rotating roller, the plate or roller contacting and evening out the coating on the substrate. Alternatively the evening out step may be carried out by passing the substrates under a jet of air, for example an air knife, the curtain of air generated as the air knife evening out the coating on the substrate; the air may be heated in order to avoid. premature solidifying of the coating.
The dry powder coating is preferably converted into a fused film by heating, preferably by infra red radia-tion; but other forms of electromagnetic radiation may be used: Also the conversion into a fused file may be achieved partly or wholly by reducing 'the pressure of the region. Usually the change ir, the coating upon.
heating will simply be a physical change from a powder to ~C.'"f/C ~9~/~D03~.~
W O 9'2 / 1:h851 : ,' .' g _ a liquid and then, on coo7.ing, to a continuous solid coating, but there are other possibilities: for example, the powder coating may comprise a polymer which is cured during the treating step, for example by irradiation with energy in the gamma, ultra violet or radio frequency bands, to form a continuous cross-linked polyzuer coating.
It is preferable to charge the powder to an approp-r~at° eleCrriC '~O-W_'~1'Cla' , ~:ahlCh nay be poSltlV'e or negative. The no~ader is preferably charged as it is supplied to ~L.he region through which the conveying means passes . The c~~_ay gi ng may be carried out using a corona charging apparatus; another possibility is to charge the powder triboelectrically. One or more electrodes maintained at a selected potential which would normally be of the same sign as that of the powder (i:e. a positive potential if the powder is positively charged and a negative potential if the powder is negatively charged) are preferably provided above the conveying means in the region to which the powder is supplied. The positioning of the electrodes and the potentials) at which they are maintained influences the electric field zn the region and therefore the path of the powder through the region:
The conveying means is preferably maintained at a potential which is either earth potential or of opposite sign to the potential to which the powder is charged.
The conveying means may have gr. electrically conducting uppex surface on which the medicinal substrates rest. .In dV0 92/la~t91 ~ ~ ~ ~ 9 2 ~ PCT/~~92/00323 most. cases the substrates will be made of an electri-cally insulating material; they may be treated prior to application of the powder. to make them more electrically conducting, for example by moistening the exterior of the substrate. Such moistening facilitates the maintenance of the exterior of the substrate at earth potential and thus facilitates the application of the powder to the COre.
The method of the invention is not restricted to the 1C use of a..~.y parvic~ular form of coming material. On the other hand, for good results, the dry powder preferably has the following physical properties:
(1) A particle size in the range of 1 ~m to 1000 ~m and preferably in the range of 30 ~m to 80 Vim:
7:5 a small particle sire enables the powder to be evenly dispersed in the region to which it is supplied and through which the conveyor belt passes.
Improvements in or r.elatinct to Electrostatic Coating of Substrates of Medicinal Products The present invention relates to a method and apparatus for electrostatic coating of substrates of medicinal products. The invention is particularly, but not exclusioely, concerned pith the coating of pharma-ceutical :ablet cores saiLh a dry powder.
Proposals ror electrostatic coating of tablets have been made f or at leas t vise las t t:~i~y years or so . For example, GB-1075404 (published in 1967) proposes an apparatus far coating tablets in which a liquid is sprayed onto one face of each tablet core as the tablet cores are conveyed below a first stage sprayer having an associated high voltage grid, the coating is dried, the coat~ei cores are then conveyed below a second stage sprayer having an associated high voltage grid with the other side of the tablets uppermost, and then that coating is dried again.
Various paper proposals for electrostatically coating tablet cores with a liquid ar a dry powder have been made but as yet at least in the case of pharma°
ceutical'table~s there is no recognized electrostatic coating method or apparatus that has proved sufficiently successful to be 'applied commercially on a reasonable scale. while there are rotary tablst presses capable of producing pharmaceutical tablet cores continuously at a rate of fox example 5;000 tableLS tier minute, the i~'O 92/l~t~l ~ PCT/~892/00323 subsequent coating of the tablet cores is most commonly carried out as a batch process by applying a liquid coating in a revolving drum.
In order to provide a commercially viable apparatus or method for coating medicinal products various problems must be overcome. It is in many ways easier '~o apply a liquid rather than a dry powder as the coari:-:g material and therefore, although both options haze beep. cor.sidere in research , workers have f avour ed the ~a sa o _ '.. l ~~~ l ms's .
l0 If a dry powder is applied then ~,. is harder to obtain adhesion of the coating to the substrate, r;~_c._ l s no=
itself likely to be sufficiently electrically conducting, even when the powder is electrostatically charged. In order to provide a lasting bond between the substrate and the powder, the powder must be transferred into a film, for example by melting, but in the case of a medicinal product, which iw many cases will include organic materials, must not be damaged. furthermore an even coating is required and it is very difficult to obtain an even coating of powder on an electrically insulating medicinal substrate, even when the powder is electro-statically charged.
When liquid coating is used, the coating must be dried. Theoretically such drying could in some circum-stances be carxied out at room temperature but in commercial practice it is important, for example because of the rate at which the process m:a t be carried out, to heat the tablets and that is exoensi~re because of the iV~ 92/1:451 ~ y~ PCT/G339?/OiD323 large input of energy required to vapourize the solvent used in the liquid coating. Another disadvantage of liquid coating is that it cannot be used for coating materials that are not soluble or suitably dispersible in a usable liquid, preferably water.
It is an object of the invention to provide an improved method and apparatus for coating substrates of medicinal. products.
According to the invention there is orovide~-1 a method of coating substrates of ~~,edicinal prec:'~'c'ws jai t'~ a dry powder, the method includi~:: t'~°_ fcll,o~.~in~; st=w feeding the medicinal substrates onto a conveying means;
supplying the dry powder to a region through which the medicinal substrates are to be conveyed on the conveying means;
conveying the medicinal substrates on the conveying means through the region with the conveying means and/or the substrates maintained at a different electric potential from the dry powder, whereby the dry powder is at~.racted to the exposed surfaces of the substrates but is unable to reach the surfaces of the substrates in contact with the conveying means, and treating the dry powder coatings to convert the powder into a fused film securAd to the substrates.
Hy placing the substrates on a conveying means during the charging process, __ is found t'.:at a satisfac--Cory spread of powder over the substrate can be obtained.
d~~ 92/ 14-l51 PC: f/C~3~2/00323 ~~
It is also found that some unevenness of distribution is not necessarily serious, even if it is important for the final tablet to have a coating of substantially constant thickness, because further levelling can take place when the powder is converted into a fused film. Thus the present invention enables a desired thickness of coating to be applied uniformly over a surface of a substrate.
The thic.'cness o~ t;:e coating gill typically be greater than 10 sm . A? ti. ougn the present in~rer.ti on as def fined :above s~ci 11 i.~.~roives the input of energy to convert the ~O~dd~?= '_:'.:O ~ fl;S°~ film, the amount Of energy r2qulred can be substanLiall;y less than that involved in the case where a liquid coating comprising a coating substance dissolved in a suitable solvent is applied and the solvent has to be vapourised after application of the coating. The method also removes the necessity for solvent handling and disposal and for batch processing.
The medicinal products will usually be pharma-ceutical tablets ("tablets°' being as defined below) but ~O they may also be implants that are not administered orally.
While reference is made throughout the specification to ''tablets" and the invention is of particular applica~
tion to pharmaceutical tablets of conventional shape, it should be understood that the term is to be interpreted in a broad sense as covering also, far example, pellets, capsules or spherules.
While the method of the invention will generally be W() 92/ 14~~ 1 ~ ~ ~ ~ ~ ~ -~ P~/~ ~'~2/00323 applied to the coating of tablet cores (or substrates of the medicinal products) which have not received any coating since being formed in a press, it may be used to apply a coating on top of an already coated or partly coated tablet core.
The method othe present invention may be carried out as a cen~-~inuous process. An practice there are con-sideraol~ advantac,'es in being able to operate the coating "'O~~~SS CCri=_n110L;S1 y =at::0~ t.'13~, aS 3 batch prOCeSS.
While there are certain applications, which will be Z'2ae'r're.C:,' =O la'~.'.~=, ~a7i'1~~°_ i°.'. iv'~.,.: be desirad t0 Coat tile medicinal substrate on one side only or with at least one discontinuity in the coating, it will generally be desirable to coat all of the exterior of the tablet core.
Accordingly the ~netYaod preferably comprises the following further subsequent steps:
feeding the medicinal substrates onto a conveying means with the treated powder coatings of the substrates in contact with the conveying means and with that surface of the substrate that was in contact with the conveying means during the above-mentioned conveying step exposed;
supplying the dry powder caith which the substrates are to be coated to a region through which the conveying means passes;
conveying the substrates ;n the conveying means through the region with the ccnveying means and/or the substrates maintained at a di_'erant electric potential frpm'the dry powder whereby t::e cry powder is attracted WO 92/151 ~ PC.'T/G892/~~323 -to the exposed surfaces of the substrates but is unable to reach the coated surfaces of the substrates in contact with the conveying means, and treating the dry powder coatings to convert the newly applied powder into a fused film secured to the substrates.
For practical convenience the conveyia.g means used during the second coating stage is prrws=ab'_yr r.ot =.a one used during the first coating stage but it vs possible to use the same conveying means for both coac~.ng stages.
The powder applied during each coating st~c~ viill usually be the same but it is of course possible to apply different powders at each stager similarly the same thickness of coating will usually be applied at each stage but different thicknesses may be applied, if desired.
If desired still further coating stages may be employed for example to apply powder to sides of the products, if the sides have not already been coated.
Preferably the conveying means comprises a conveyor belt. The conveying means may however comprise an inclined static surface_.or a vibrated surface along which the substrates slide. The friction between the sub strafes and the inclined surface may be reduced by passing air through the inclined surface from the underside.
Canverting the powder.into a =used fi':.~ may advant-ageously comprise converting the powder into the liquid dJ0 92/1~~51 PCT/~k392/00323 _ 7 _ phase after which it returns to the solid phase.
We have found 'that the conversion of the dry powder into a fused film not only serves to secure the coar.ing to the substrate but also provides a means by which the distribution of the coating material over the substrate may be made more even. In some cases 'the coating material may have such a low viscosity when fused that the coating will distribute i°tselv evenly over a sub-strate but in most cases the coating material wii'~ be more viscous and the method thareo« prefe_ably includes the further mechanical treatment o.L the coa-v_:~..~ ~.o even out the depth of the coating over the surface of the substrate. The evening out step may be carried out by passing the substrates under a vibrating plate or a rotating roller, the plate or roller contacting and evening out the coating on the substrate. Alternatively the evening out step may be carried out by passing the substrates under a jet of air, for example an air knife, the curtain of air generated as the air knife evening out the coating on the substrate; the air may be heated in order to avoid. premature solidifying of the coating.
The dry powder coating is preferably converted into a fused film by heating, preferably by infra red radia-tion; but other forms of electromagnetic radiation may be used: Also the conversion into a fused file may be achieved partly or wholly by reducing 'the pressure of the region. Usually the change ir, the coating upon.
heating will simply be a physical change from a powder to ~C.'"f/C ~9~/~D03~.~
W O 9'2 / 1:h851 : ,' .' g _ a liquid and then, on coo7.ing, to a continuous solid coating, but there are other possibilities: for example, the powder coating may comprise a polymer which is cured during the treating step, for example by irradiation with energy in the gamma, ultra violet or radio frequency bands, to form a continuous cross-linked polyzuer coating.
It is preferable to charge the powder to an approp-r~at° eleCrriC '~O-W_'~1'Cla' , ~:ahlCh nay be poSltlV'e or negative. The no~ader is preferably charged as it is supplied to ~L.he region through which the conveying means passes . The c~~_ay gi ng may be carried out using a corona charging apparatus; another possibility is to charge the powder triboelectrically. One or more electrodes maintained at a selected potential which would normally be of the same sign as that of the powder (i:e. a positive potential if the powder is positively charged and a negative potential if the powder is negatively charged) are preferably provided above the conveying means in the region to which the powder is supplied. The positioning of the electrodes and the potentials) at which they are maintained influences the electric field zn the region and therefore the path of the powder through the region:
The conveying means is preferably maintained at a potential which is either earth potential or of opposite sign to the potential to which the powder is charged.
The conveying means may have gr. electrically conducting uppex surface on which the medicinal substrates rest. .In dV0 92/la~t91 ~ ~ ~ ~ 9 2 ~ PCT/~~92/00323 most. cases the substrates will be made of an electri-cally insulating material; they may be treated prior to application of the powder. to make them more electrically conducting, for example by moistening the exterior of the substrate. Such moistening facilitates the maintenance of the exterior of the substrate at earth potential and thus facilitates the application of the powder to the COre.
The method of the invention is not restricted to the 1C use of a..~.y parvic~ular form of coming material. On the other hand, for good results, the dry powder preferably has the following physical properties:
(1) A particle size in the range of 1 ~m to 1000 ~m and preferably in the range of 30 ~m to 80 Vim:
7:5 a small particle sire enables the powder to be evenly dispersed in the region to which it is supplied and through which the conveyor belt passes.
(2) A relatively high resistivity in the range of 20 106 flm to 1024 ilm and preferably in the range of 101 fpm to 1014 tim; a high resistivity facilitates maintenance of the powder charge beat makes it harder to charge the powder.
(3) A viscosity when in the liquid phase of less 25 khan 500 Pas and preferably less than 75 Pas;
a low viscosity facil~.tates even spreading of the coating over the sur=ace of the tablet core.
w~ ~zm~~~n 2,,~ ~ ~. ~9 '~ ~. ~c~ri~a~~ioo3z~
,.
- ~o -. (4) After conversion to a fused film, a tensile strength of more than 0.5 N/m2 and preferably more than 3.a N/m~; a reasonably strong and tough coating is required in order to protect.
the tablet during subsequent hancxiing up to the administration of the tablet.
(5) A melting point which lies in the range o~ 50'C
to 180°C and preferably 60'C to '~v~'C. ~rii~:~
relatively low melting point less ener~~v is 1.~ reau~red to convert t:le 'p70::id.~_.r iiW v vi~c: iiGl.lud phase and the r. isk or damage to the table= .~.or. a from heating is reduced. The latter point is of special importance when the drug in the tablet core is liable to be damaged if its temperature is increased substantially above room temperature.
Examples of materials which, alone or when blended with other materials, meet same or all of the five preferred properties listed above can be found in:
2n polyamides, polyalkenes, waxes, oils, polyesters, sugar alcohols, sugars, polyoxyethylenes and ethylene vinyl acetate copolymer. Examples of suitable sugar alcohols are: sorbitol and xy1lto1. Examples of suitable sugars are sucxose and lactose. A polyester having properties especially suitable for the method of the invention is polycaprolactone.
The materials indicated above may be modified b.r blending other materials with them so as to improve their wo ~~itaa~t ~ ~ ~ ~. ~..~. t'~-rics9aioo3z3 physical properties to match more closely the properties indicated above. One or more opacifiers, for' example titanium dioxide, and/or col.ourants, for example alumin-ium lakes or dyes, may also be added to the formulation of the coating material.
The materials listed above fall into two categories:
the water soluble materials (polyoxyethylenes, sugars, sugar alcohols) and the poorly sol a ble or ir.sol~.:b~_e polymeric materials. If a coating is re;:uired to dissolve quickly following administration, :.~~n a =.a~t°-r soluble material will genes ally be pr ef crr e~ -ar°_= °_as =_ a delayed, controlled or modulated release of the drug is required a poorly soluble or insoluble polymeric material is lil~2ly to be advantageous.
1.5 An especially preferred sugar alcohol is xylitol, while an especially pref erred polymeric material is a polyester, such as, for exaanple polycaprolactone. In both cases, however, it may be desirable to add small quantities of other substances to improve the physical properties of the material.
In another aspect the present invention is not concerned exclusively with coating a substrate with a dry ~aowder and provides a method of coating substrates of medicinal products including the following steps:
feeding the substrates onto a conveying means, providing an electrode spaced above the conveying means and extending along and across the conveying means to define a box-like region between the electrode and the ~~c~ ~~~ir~i:s~r p~-r'm~~~~ioroz~
conveying means, and maintaining the electrode at a first electric potential, supplying coating material to the bo~c-like region and electrically charging the coating material to a second electric potential, conveying the substrates on the conveying means through the region with the conveying means and/or the subsrrat~~s maintained at a dirferent electric potential from the coating material and the electrode, whereby the COatli~C Wat2ridi iS at4raCtdCi t0 tYl~ eXpOSed SurZaCeS Of the substrates.
The invention may be used to apply a coating of controlled thickness and may be employed for a medicinal product containing a drug that is to be instantaneously 15 released when administered or that is to be the subject of controlled or modulated release, such control or modulation being achieved from the nature of the coating and/or from the nature of the core. Where the desired form of release is to be achieved by characteristics of 20 the coating, it may be preferred to leave one portion of the product uncoated or coated with a different material In the case of a tablet having faces at opposite ends connected by a cylindrical side wall, the portion that is uncoated or coated with a different material may be one 2a of the faces of the tablet, a smal'_ portion of one of the faces or a side wall of the tablet.
As has already been made c'_ea:-, the methods des-cribed above have the advantage thaw they can be carried CVO 92/l~i5l ~ ~ ~ ~ ~ ~ PC T/G~9~/~V0323 out~continuously. They can therefore be employed as part of a continuous process for producing coated medicinal products, especially pharmaceutical tablets.
Thus, the present invention provides a continuous process for producing coated tablets comprising the steps of continuously forming pharmaceutical tablet cores on a rotary pr°SS, ariG' continuously coating the tablet cores by a method as def ir.e,~'. move .
'~hP ~= og°?'! ~ ' ~~leilt lon al S~v prOVl.deS an appar atus f Qr coating medicinal substrates of medicinal products with a dry powder, the apparatus including:
a conveying means, means for feeding substrates onto the conveying means, a feed for supplying dry powder to a region through which the conveying means passes, electric charging means for electrically charging the powder and/or the conveying means and/or the sub-strates such that the potential of the powder supplied to the region through which the conveying means passes is different from the potential of the substrates on the conveying means, ~5 means for treating dry pcwder coatings on the substrates to convert the powder into a fused film secured to the substrates.
The present invention alsa provides a medicinal 4-'ijl ~ c ~ ~ - PCT/t~B92/~0323 -- l~ -product when coated by a method as described above and a medicinal product when produced by a method as described above.
A method and apparatus for electrostatic coating of tablet cores will now be described by way o~ example witr~
reference to the accompanying drawings cf ~.~nich:
Fig. 1 is a schematic side vie~~~ or an apparatus for coating tablets cv one ~_~e, Fig. 2 is a bloc,{ diagra:.~. c' a co-a=-~~uc~a p-l0 for manufacturing coated tablets employing the apparatus of __°ig. ', aid Fig. 3 is a side view of a coated tablet.
The apparatus shown in Fig. 1 includes a conveyor belt 1 which is guided around three idler rollers 2 and a drive roller 3 driven by a motor 4 in the direction shown by an arrow in Fig. 1. A booth 5 is provided enclosing most of the upper run of the conveyor belt 1.
Apparatus for feeding tablet cores to the upstream end (the left hand end as seen in Fig. 1) of the conveyor belt 1 outside the booth 5 is provided, but is not shown in the drawing. The form of such apparatus is nat part of the present invention. A feed 6 for supplying dry powder to the interior of the booth above the conveyor belt is also provided. In the example of the invention illustrated the feed 6 comprises an electrostatic powder gun employincJ a single fixed corona electrode 7 mounted at the end of the gun barrel 8 and connected to a voltage supply 9. A mixture of powder and air is fed to the gun dvo ~2iaa~s~ ~ ~ ~ .~ ~ ~ ~ ~c-ri~~~zioo3z~
barrel from a venturi powder feed 10.
Suspended from the top of the booth is an electrode 11 which is rectangular in plan view and extends across the whole width of the conveyor belt 1 and a portion of its length. The electrode 11 is connected to a voltage supply 12. Immediately below a..~.d s~~pperting t a con veyo~
belt 1 in the region below t2~~2 elecvrod° 1' is anot:~.°r rectangular electrode 18 which is connected to earth.
The conveyor belt 1 is made of a lar,~ina~.a o_ poly;ir.y_-chloride and aluminium foil with the aluminium foil forming the outer layers of the belt and one belt is connected to earth.
An infra red heater 13 and a vibrating plate 14 are provided over the downstream end of the conveyor belt.
1~ In use of the apparatus, pharz~aceutical tablet cores are fed onto the upstream end of the belt 1 by a feed 6 and pass along the conveyor with one face of the core resting on the belt and the other facing upwards.
Dry powder with which the tablet cores are to be coated is sprayed into the booth 5 by the spray gun 1 which charges the powder to a suitable potential (for this example it will. be assumed that the.powder ~a charged to a persitive potential ) . Powder sprayed from the g~an 1 enters the region between the electrode 11, which is 2g maintained at a positive potential, and the conveyor belt l and electrode l8 both of which are earthed. Thus powder is directed downwardly away from the electrode 11 towards the conveyor belt 1 and the electrode 18. A
bd(~ 92/~4~9~1 ~ . PCT/GB9'?/00323 coating of powder is therefore laid over the conveyor belt and the tablet cores on the conveyor belt.
The tablet cares are then passed under the infra red heater 13 which heats the coating of powder on the tablets sufficiently to cause the coating to melt and form a film coating over 'the upper side of the 'tablet core. As the tablets are carried beyond the heater 13 they are contacted by the vibrating plate 14 which evens o:a t:~e ccav=n5. Thereafter, the film coating solid-ifies.
Tn crdwr to provide a coating on the other side of the tablet core (if one is desired), the tablets are laid the other way up on a further conveyor arrangement simi-lar to that shown in Fig. 1 arid the process described above with respect to Fig. 1 is repeated. Apparatus for transferring tablets from one conveyor to another and for turning them over in the course of the transfer is already known (see for example Figs. 2 and 3 of GB 1 0°75 404).
Referring now to Fig. 2, it will be seen that with the apparatus and method just described a continuous production of coated tablets can be provided, Tablet cores produced for example from a high speed rotary press are fed directly to the apparatus of Fig. 1 where their upper faces are coated with electrically charged dry 2~ powder; The dry powder coating is then melted by heating; the partially coated tablets allowed to cool and fed to another apparatus of the mind shown in Fig. 1 but with their izncoated faces now upper:~ost. mhose uncoated CVO 9z~lA~s1 ~ p ~-~ ~ ~ ~ PL'fiGS9zio~3z3 - m -faces are coated with electrically charged dry powder, the dry powder coating is melted by heating and the coated tablet allowed to cool and then .fed to appropriate packaging machinery. Such a process can operate continously.
Fig. 3 s:-~ows a tablet having an upper face 15, a lower face 16, and a cylindrical side wall 17. In the first coating stage, one oz the faces, say the face 15, is coated gully and the side wall 17 receives some powder coating but not a full coating. In the second coating stage the other fat' 16 is coated fully and the remainder of the coating to the side walls 17 is applied.
a low viscosity facil~.tates even spreading of the coating over the sur=ace of the tablet core.
w~ ~zm~~~n 2,,~ ~ ~. ~9 '~ ~. ~c~ri~a~~ioo3z~
,.
- ~o -. (4) After conversion to a fused film, a tensile strength of more than 0.5 N/m2 and preferably more than 3.a N/m~; a reasonably strong and tough coating is required in order to protect.
the tablet during subsequent hancxiing up to the administration of the tablet.
(5) A melting point which lies in the range o~ 50'C
to 180°C and preferably 60'C to '~v~'C. ~rii~:~
relatively low melting point less ener~~v is 1.~ reau~red to convert t:le 'p70::id.~_.r iiW v vi~c: iiGl.lud phase and the r. isk or damage to the table= .~.or. a from heating is reduced. The latter point is of special importance when the drug in the tablet core is liable to be damaged if its temperature is increased substantially above room temperature.
Examples of materials which, alone or when blended with other materials, meet same or all of the five preferred properties listed above can be found in:
2n polyamides, polyalkenes, waxes, oils, polyesters, sugar alcohols, sugars, polyoxyethylenes and ethylene vinyl acetate copolymer. Examples of suitable sugar alcohols are: sorbitol and xy1lto1. Examples of suitable sugars are sucxose and lactose. A polyester having properties especially suitable for the method of the invention is polycaprolactone.
The materials indicated above may be modified b.r blending other materials with them so as to improve their wo ~~itaa~t ~ ~ ~ ~. ~..~. t'~-rics9aioo3z3 physical properties to match more closely the properties indicated above. One or more opacifiers, for' example titanium dioxide, and/or col.ourants, for example alumin-ium lakes or dyes, may also be added to the formulation of the coating material.
The materials listed above fall into two categories:
the water soluble materials (polyoxyethylenes, sugars, sugar alcohols) and the poorly sol a ble or ir.sol~.:b~_e polymeric materials. If a coating is re;:uired to dissolve quickly following administration, :.~~n a =.a~t°-r soluble material will genes ally be pr ef crr e~ -ar°_= °_as =_ a delayed, controlled or modulated release of the drug is required a poorly soluble or insoluble polymeric material is lil~2ly to be advantageous.
1.5 An especially preferred sugar alcohol is xylitol, while an especially pref erred polymeric material is a polyester, such as, for exaanple polycaprolactone. In both cases, however, it may be desirable to add small quantities of other substances to improve the physical properties of the material.
In another aspect the present invention is not concerned exclusively with coating a substrate with a dry ~aowder and provides a method of coating substrates of medicinal products including the following steps:
feeding the substrates onto a conveying means, providing an electrode spaced above the conveying means and extending along and across the conveying means to define a box-like region between the electrode and the ~~c~ ~~~ir~i:s~r p~-r'm~~~~ioroz~
conveying means, and maintaining the electrode at a first electric potential, supplying coating material to the bo~c-like region and electrically charging the coating material to a second electric potential, conveying the substrates on the conveying means through the region with the conveying means and/or the subsrrat~~s maintained at a dirferent electric potential from the coating material and the electrode, whereby the COatli~C Wat2ridi iS at4raCtdCi t0 tYl~ eXpOSed SurZaCeS Of the substrates.
The invention may be used to apply a coating of controlled thickness and may be employed for a medicinal product containing a drug that is to be instantaneously 15 released when administered or that is to be the subject of controlled or modulated release, such control or modulation being achieved from the nature of the coating and/or from the nature of the core. Where the desired form of release is to be achieved by characteristics of 20 the coating, it may be preferred to leave one portion of the product uncoated or coated with a different material In the case of a tablet having faces at opposite ends connected by a cylindrical side wall, the portion that is uncoated or coated with a different material may be one 2a of the faces of the tablet, a smal'_ portion of one of the faces or a side wall of the tablet.
As has already been made c'_ea:-, the methods des-cribed above have the advantage thaw they can be carried CVO 92/l~i5l ~ ~ ~ ~ ~ ~ PC T/G~9~/~V0323 out~continuously. They can therefore be employed as part of a continuous process for producing coated medicinal products, especially pharmaceutical tablets.
Thus, the present invention provides a continuous process for producing coated tablets comprising the steps of continuously forming pharmaceutical tablet cores on a rotary pr°SS, ariG' continuously coating the tablet cores by a method as def ir.e,~'. move .
'~hP ~= og°?'! ~ ' ~~leilt lon al S~v prOVl.deS an appar atus f Qr coating medicinal substrates of medicinal products with a dry powder, the apparatus including:
a conveying means, means for feeding substrates onto the conveying means, a feed for supplying dry powder to a region through which the conveying means passes, electric charging means for electrically charging the powder and/or the conveying means and/or the sub-strates such that the potential of the powder supplied to the region through which the conveying means passes is different from the potential of the substrates on the conveying means, ~5 means for treating dry pcwder coatings on the substrates to convert the powder into a fused film secured to the substrates.
The present invention alsa provides a medicinal 4-'ijl ~ c ~ ~ - PCT/t~B92/~0323 -- l~ -product when coated by a method as described above and a medicinal product when produced by a method as described above.
A method and apparatus for electrostatic coating of tablet cores will now be described by way o~ example witr~
reference to the accompanying drawings cf ~.~nich:
Fig. 1 is a schematic side vie~~~ or an apparatus for coating tablets cv one ~_~e, Fig. 2 is a bloc,{ diagra:.~. c' a co-a=-~~uc~a p-l0 for manufacturing coated tablets employing the apparatus of __°ig. ', aid Fig. 3 is a side view of a coated tablet.
The apparatus shown in Fig. 1 includes a conveyor belt 1 which is guided around three idler rollers 2 and a drive roller 3 driven by a motor 4 in the direction shown by an arrow in Fig. 1. A booth 5 is provided enclosing most of the upper run of the conveyor belt 1.
Apparatus for feeding tablet cores to the upstream end (the left hand end as seen in Fig. 1) of the conveyor belt 1 outside the booth 5 is provided, but is not shown in the drawing. The form of such apparatus is nat part of the present invention. A feed 6 for supplying dry powder to the interior of the booth above the conveyor belt is also provided. In the example of the invention illustrated the feed 6 comprises an electrostatic powder gun employincJ a single fixed corona electrode 7 mounted at the end of the gun barrel 8 and connected to a voltage supply 9. A mixture of powder and air is fed to the gun dvo ~2iaa~s~ ~ ~ ~ .~ ~ ~ ~ ~c-ri~~~zioo3z~
barrel from a venturi powder feed 10.
Suspended from the top of the booth is an electrode 11 which is rectangular in plan view and extends across the whole width of the conveyor belt 1 and a portion of its length. The electrode 11 is connected to a voltage supply 12. Immediately below a..~.d s~~pperting t a con veyo~
belt 1 in the region below t2~~2 elecvrod° 1' is anot:~.°r rectangular electrode 18 which is connected to earth.
The conveyor belt 1 is made of a lar,~ina~.a o_ poly;ir.y_-chloride and aluminium foil with the aluminium foil forming the outer layers of the belt and one belt is connected to earth.
An infra red heater 13 and a vibrating plate 14 are provided over the downstream end of the conveyor belt.
1~ In use of the apparatus, pharz~aceutical tablet cores are fed onto the upstream end of the belt 1 by a feed 6 and pass along the conveyor with one face of the core resting on the belt and the other facing upwards.
Dry powder with which the tablet cores are to be coated is sprayed into the booth 5 by the spray gun 1 which charges the powder to a suitable potential (for this example it will. be assumed that the.powder ~a charged to a persitive potential ) . Powder sprayed from the g~an 1 enters the region between the electrode 11, which is 2g maintained at a positive potential, and the conveyor belt l and electrode l8 both of which are earthed. Thus powder is directed downwardly away from the electrode 11 towards the conveyor belt 1 and the electrode 18. A
bd(~ 92/~4~9~1 ~ . PCT/GB9'?/00323 coating of powder is therefore laid over the conveyor belt and the tablet cores on the conveyor belt.
The tablet cares are then passed under the infra red heater 13 which heats the coating of powder on the tablets sufficiently to cause the coating to melt and form a film coating over 'the upper side of the 'tablet core. As the tablets are carried beyond the heater 13 they are contacted by the vibrating plate 14 which evens o:a t:~e ccav=n5. Thereafter, the film coating solid-ifies.
Tn crdwr to provide a coating on the other side of the tablet core (if one is desired), the tablets are laid the other way up on a further conveyor arrangement simi-lar to that shown in Fig. 1 arid the process described above with respect to Fig. 1 is repeated. Apparatus for transferring tablets from one conveyor to another and for turning them over in the course of the transfer is already known (see for example Figs. 2 and 3 of GB 1 0°75 404).
Referring now to Fig. 2, it will be seen that with the apparatus and method just described a continuous production of coated tablets can be provided, Tablet cores produced for example from a high speed rotary press are fed directly to the apparatus of Fig. 1 where their upper faces are coated with electrically charged dry 2~ powder; The dry powder coating is then melted by heating; the partially coated tablets allowed to cool and fed to another apparatus of the mind shown in Fig. 1 but with their izncoated faces now upper:~ost. mhose uncoated CVO 9z~lA~s1 ~ p ~-~ ~ ~ ~ PL'fiGS9zio~3z3 - m -faces are coated with electrically charged dry powder, the dry powder coating is melted by heating and the coated tablet allowed to cool and then .fed to appropriate packaging machinery. Such a process can operate continously.
Fig. 3 s:-~ows a tablet having an upper face 15, a lower face 16, and a cylindrical side wall 17. In the first coating stage, one oz the faces, say the face 15, is coated gully and the side wall 17 receives some powder coating but not a full coating. In the second coating stage the other fat' 16 is coated fully and the remainder of the coating to the side walls 17 is applied.
Claims (31)
1. A method of coating cores of pharmaceutical tablets with a coating material, the method including the following steps:
feeding the cores onto a conveying means;
supplying coating material to a region through which the cores are to be conveyed on the conveying means; and conveying the cores on the conveying means through the region with the cores maintained at a different electric potential from the coating material, whereby the coating material is attracted to the exposed surfaces of the cores to form coatings thereon, wherein the coating material is a dry powder and after the dry powder is attracted to the exposed surfaces of the cores to form coatings thereon the dry powder is treated to convert the powder into fused film coatings secured to the cores.
feeding the cores onto a conveying means;
supplying coating material to a region through which the cores are to be conveyed on the conveying means; and conveying the cores on the conveying means through the region with the cores maintained at a different electric potential from the coating material, whereby the coating material is attracted to the exposed surfaces of the cores to form coatings thereon, wherein the coating material is a dry powder and after the dry powder is attracted to the exposed surfaces of the cores to form coatings thereon the dry powder is treated to convert the powder into fused film coatings secured to the cores.
2. A method according to claim 1, in which the method is carried out as a continuous process.
3. A method according to claim 1 or 2, including the following further subsequent steps:
feeding the tablet cores onto a conveying means with the fused film coatings of the cores in contact with the conveying means and with that surface of the core that was in contact with the conveying means during the above-mentioned conveying step exposed;
supplying the dry powder with which the cores are to be coated to a region through which the conveying means passes;
conveying the cores on the conveying means through the region with the conveying means and/or the cores maintained at a different electric potential from the dry powder whereby the dry powder is attracted to the exposed surfaces of the cores, and melting the dry powder coatings to convert the newly applied powder into fused film coatings secured to the cores.
feeding the tablet cores onto a conveying means with the fused film coatings of the cores in contact with the conveying means and with that surface of the core that was in contact with the conveying means during the above-mentioned conveying step exposed;
supplying the dry powder with which the cores are to be coated to a region through which the conveying means passes;
conveying the cores on the conveying means through the region with the conveying means and/or the cores maintained at a different electric potential from the dry powder whereby the dry powder is attracted to the exposed surfaces of the cores, and melting the dry powder coatings to convert the newly applied powder into fused film coatings secured to the cores.
4. A method according to claim 3, in which the conveying means used during the second coating stage is not the one used during the first coating steps.
5. A method according to any one of claims 1 to 4, in which the conveying means comprises a conveyor belt.
6. A method according to any one of claims 1 to 5, in which the dry powder coating is converted into a fused film by heating.
7. A method according to any one of claims 1 to 6, in which the powder is electrically charged.
8. A method according to claim 7, in which the powder is charged as it is supplied to the region through which the conveying means passes.
9. A method according to claim 7 or 8, in which the charging is carried out using a corona charging apparatus.
10. A method according to any one of claims 1 to 9, in which one or more electrodes maintained at a selected potential are provided above the conveying means in the region to which the powder is supplied.
11. A method according to any one of claims 1 to 10, in which the powder has a particle size in the range of 1µm to 1000µm.
12. A method according to any one of claims 1 to 11, in which the powder has a relatively high resistivity in the range of 10 6 to 10 24 .OMEGA.2m.
13. A method according to any one of claims 1 to 12, in which the powder has a viscosity when in the liquid phase of less than 500 Pas.
14. A method according to any one of claims 1 to 13, in which the powder has, after returning to the solid phase, a tensile strength of more than 0.5 N/m2.
15. A method according to any one of claims 1 to 14, in which the powder has a melting point which lies in the range of 50°C to 180°C.
16. A method according to claim 15, in which the powder has a melting point in the range of 60°C to 100°C.
17. A method according to any one of claims 1 to 16, in which the dry powder consists wholly or substantially of one or more of the materials in the group comprising:
polyamides, polyalkenes, waxes, oils, polyesters, polyoxyethylenes, sugars, sugar alcohols and ethylene vinyl acetate copolymer.
polyamides, polyalkenes, waxes, oils, polyesters, polyoxyethylenes, sugars, sugar alcohols and ethylene vinyl acetate copolymer.
18. A method according to claim 17, in which the dry powder consists wholly or substantially of xylitol.
19. A method according to any one of claims 1 to 17, in which the dry powder consists wholly or substantially of polycaprolactone.
20. A method according to any one of claims 1 to 19, in which the tablet cores are treated prior to application of the powder to make them more electrically conducting.
21. A method according to claim 20, in which the treatment comprises moistening the exterior of the tablet cores.
22. A continuous process for producing coated tablets comprising the steps of:
continuously forming pharmaceutical tablet cores on a rotary press, and continuously coating the tablet cores by a method according to any one of claims 1 to 21.
continuously forming pharmaceutical tablet cores on a rotary press, and continuously coating the tablet cores by a method according to any one of claims 1 to 21.
23. An apparatus for carrying out a method according to any of claims 1 to 21, the apparatus including:
a conveying means, means for feeding the cores onto the conveying means, a feed for supplying dry powder coating material to a region through which the conveying means passes, electric charging means for electrically charging the coating material and/or the conveying means and/or the cores such that the potential of the coating material supplied to the region through which the conveying means passes is different from the potential of the cores on the conveying means, whereby the coating material is attracted to the exposed surfaces of the cores to form coatings thereon, and means for treating the dry powder attracted to the cores to convert the powder into fused film coatings secured to the cores.
a conveying means, means for feeding the cores onto the conveying means, a feed for supplying dry powder coating material to a region through which the conveying means passes, electric charging means for electrically charging the coating material and/or the conveying means and/or the cores such that the potential of the coating material supplied to the region through which the conveying means passes is different from the potential of the cores on the conveying means, whereby the coating material is attracted to the exposed surfaces of the cores to form coatings thereon, and means for treating the dry powder attracted to the cores to convert the powder into fused film coatings secured to the cores.
24. An apparatus according to claim 23, the apparatus further including a rotary press, wherein the feeding means is operative to feed the cores from the press onto the conveying means.
25. An apparatus according to claim 23 or claim 24, wherein the conveying means comprises an inclined static surface.
26. A pharmaceutical tablet when coated by a method according to any one of claims 1 to 21
27. A tablet when produced by a method according to claim 22.
28. The use of a dry powder having a melting point which lies in the range of 50°C to 180°C in a method as claimed in any one of claims 1 to 21.
29. The use of a dry powder consisting wholly or substantially of one or more of the materials in the group comprising: polyamides, polyalkene, waxes, oils, polyesters, polyoxyethylenes, sugars, sugar alcohols and ethylene vinyl acetate copolymer in a method as claimed in any one of claims 1 to 21.
30. The use according to claim 29 of a dry powder consisting wholly or substantially of ethylene vinyl acetate copolymer.
31. The use according to claim 29 of a dry powder consisting wholly or substantially of a sugar alcohol selected from sorbitol and xylitol.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9103711.9 | 1991-02-22 | ||
| GB9103711A GB2253164B (en) | 1991-02-22 | 1991-02-22 | Improvements in or relating to electrostatic coating of substrates of medicinal products |
| PCT/GB1992/000323 WO1992014451A1 (en) | 1991-02-22 | 1992-02-21 | Improvements in or relating to electrostatic coating of substrates of medicinal products |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2081921A1 CA2081921A1 (en) | 1992-08-23 |
| CA2081921C true CA2081921C (en) | 2004-01-27 |
Family
ID=10690391
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002081921A Expired - Lifetime CA2081921C (en) | 1991-02-22 | 1992-02-21 | Improvements in or relating to electrostatic coating of substrates of medicinal products |
Country Status (15)
| Country | Link |
|---|---|
| US (2) | US5470603A (en) |
| EP (1) | EP0526606B1 (en) |
| JP (1) | JP2919971B2 (en) |
| AT (1) | ATE126431T1 (en) |
| AU (1) | AU653989B2 (en) |
| CA (1) | CA2081921C (en) |
| CZ (1) | CZ343492A3 (en) |
| DE (1) | DE69204127T2 (en) |
| DK (1) | DK0526606T3 (en) |
| ES (1) | ES2078036T3 (en) |
| GB (1) | GB2253164B (en) |
| GR (1) | GR3018080T3 (en) |
| HU (1) | HU215907B (en) |
| PL (1) | PL166928B1 (en) |
| WO (1) | WO1992014451A1 (en) |
Families Citing this family (95)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2164344C (en) * | 1993-08-30 | 2004-06-29 | Stanley Lech | Tablet coating based on a melt-spun mixture of a saccharide and a polymer |
| US5567238A (en) * | 1994-12-06 | 1996-10-22 | Coating Machinery Systems, Inc. | Oscillating bed seed coating machine for particulate material |
| US7008668B2 (en) * | 1995-05-09 | 2006-03-07 | Phoqus Pharmaceuticals Limited | Powder coating composition for electrostatic coating of pharmaceutical substrates |
| GB2316342B (en) * | 1995-05-09 | 2000-01-12 | Colorcon Ltd | Electrostatic coating |
| GB2316086B (en) * | 1995-05-09 | 2000-01-12 | Colorcon Ltd | Method and powder coating composition for electrostatic coating of pharmaceutical substrates |
| KR19990008431A (en) * | 1995-05-09 | 1999-01-25 | 피터 존스 팔슨즈 | Electrostatic coating |
| US5714007A (en) * | 1995-06-06 | 1998-02-03 | David Sarnoff Research Center, Inc. | Apparatus for electrostatically depositing a medicament powder upon predefined regions of a substrate |
| SE505906C2 (en) * | 1996-02-19 | 1997-10-20 | Hanian Hb | Electrostatic coating of small, non-grounded objects |
| US5861191A (en) * | 1996-02-26 | 1999-01-19 | Technology Licensing Company | Bacteriostatic coating of polymeric conduit |
| DE19758730B4 (en) * | 1996-04-09 | 2004-03-04 | Delsys Pharmaceutical Corp. | Electrostatic chuck for manufacturing pharmaceutical products e.g. tablets, inhaler substrate |
| US5858099A (en) | 1996-04-09 | 1999-01-12 | Sarnoff Corporation | Electrostatic chucks and a particle deposition apparatus therefor |
| FI111816B (en) * | 1996-09-19 | 2003-09-30 | Metso Paper Inc | A method and apparatus for transferring additional material to the surface of a moving web of material |
| GB9623634D0 (en) | 1996-11-13 | 1997-01-08 | Bpsi Holdings Inc | Method and apparatus for the coating of substrates for pharmaceutical use |
| US6004752A (en) * | 1997-07-29 | 1999-12-21 | Sarnoff Corporation | Solid support with attached molecules |
| US6045753A (en) * | 1997-07-29 | 2000-04-04 | Sarnoff Corporation | Deposited reagents for chemical processes |
| GB9720061D0 (en) * | 1997-09-19 | 1997-11-19 | Crosfield Joseph & Sons | Metal compounds as phosphate binders |
| US6395345B1 (en) | 1997-11-13 | 2002-05-28 | Soerensen Frede | Coating material and application methods therefor |
| US6974598B2 (en) | 1999-05-14 | 2005-12-13 | Coors Worldwide Inc. | Method of cooling a beverage |
| CO5070568A1 (en) * | 1998-05-22 | 2001-08-28 | Eurand Internatrional Spa | LAYER AND APPLIANCE APPLICATION PROCESS FOR EFFECT |
| JP2935697B1 (en) * | 1998-07-01 | 1999-08-16 | 勲 菅井 | Substrate coating method |
| US6652903B2 (en) | 1998-07-09 | 2003-11-25 | Lts Lohmann Therapie-Systeme Ag | Dry-copying method for producing flat, individually dosed preparations of active agents |
| DE19830650C1 (en) * | 1998-07-09 | 1999-08-12 | Lohmann Therapie Syst Lts | Dry copying to give bonded active ingredients at a substrate surface for transdermal therapy |
| US6146685A (en) * | 1998-11-05 | 2000-11-14 | Delsys Pharmaceutical Corporation | Method of deposition a dry powder and dispensing device |
| US6120832A (en) * | 1998-11-25 | 2000-09-19 | The Lubrizol Corporation | Method and apparatus for measuring the transfer efficiency of a coating material |
| US6372246B1 (en) | 1998-12-16 | 2002-04-16 | Ortho-Mcneil Pharmaceutical, Inc. | Polyethylene glycol coating for electrostatic dry deposition of pharmaceuticals |
| US6432448B1 (en) | 1999-02-08 | 2002-08-13 | Fmc Corporation | Edible coating composition |
| US6723342B1 (en) | 1999-02-08 | 2004-04-20 | Fmc Corporation | Edible coating composition |
| US6923979B2 (en) * | 1999-04-27 | 2005-08-02 | Microdose Technologies, Inc. | Method for depositing particles onto a substrate using an alternating electric field |
| US6500462B1 (en) | 1999-10-29 | 2002-12-31 | Fmc Corporation | Edible MCC/PGA coating composition |
| GB9929946D0 (en) * | 1999-12-17 | 2000-02-09 | Phoqus Limited | Electrostatic application of powder material to solid dosage forms |
| US6806017B2 (en) | 1999-12-17 | 2004-10-19 | Phoqus Limited | Electrostatic application of powder material to solid dosage forms |
| GB0002305D0 (en) | 2000-02-01 | 2000-03-22 | Phoqus Limited | Power material for electrostatic application |
| HUP0301415A2 (en) * | 2000-07-06 | 2003-09-29 | Delsys Pharmaceutical Corporation | Method for formulating healthcare products with enhanced stability |
| TR200300731T2 (en) | 2000-11-28 | 2004-08-23 | Fmc Corporation | Composition of edible PGA coating |
| GB2370243B (en) * | 2000-12-21 | 2004-06-16 | Phoqus Ltd | Electrostatic application of powder material to solid dosage forms in an elect ric field |
| US6511541B2 (en) | 2001-02-27 | 2003-01-28 | Spray Dynamics, Ltd. | Powder applicator for particulate material coating |
| GB0117618D0 (en) * | 2001-07-19 | 2001-09-12 | Phoqus Ltd | Pharmaceutical dosage form |
| GB0117619D0 (en) * | 2001-07-19 | 2001-09-12 | Phoqus Ltd | Pharmaceutical dosage form |
| GB0204772D0 (en) * | 2002-02-28 | 2002-04-17 | Phoqus Ltd | Pharmaceutical dosage forms |
| GB2402895B (en) * | 2003-06-18 | 2006-08-23 | Phoqus Pharmaceuticals Ltd | Method and apparatus for the application of powder material to substrates |
| GB0318353D0 (en) * | 2003-08-05 | 2003-09-10 | Phoqus Pharmaceuticals Ltd | Coating of surgical devices |
| US7198675B2 (en) | 2003-09-30 | 2007-04-03 | Advanced Cardiovascular Systems | Stent mandrel fixture and method for selectively coating surfaces of a stent |
| US6907913B1 (en) | 2003-11-12 | 2005-06-21 | C & J Industries, Inc. | Tire mounting device and method |
| GB0330171D0 (en) * | 2003-12-30 | 2004-02-04 | Phoqus Pharmaceuticals Ltd | Method and apparatus for the application of powder material to substrates |
| GB0407312D0 (en) | 2004-03-31 | 2004-05-05 | Phoqus Pharmaceuticals Ltd | Method and apparatus for the application of powder material to substrates |
| US7553377B1 (en) * | 2004-04-27 | 2009-06-30 | Advanced Cardiovascular Systems, Inc. | Apparatus and method for electrostatic coating of an abluminal stent surface |
| US7390524B1 (en) | 2004-05-20 | 2008-06-24 | Advanced Cardiovascular Systems, Inc. | Method for electrostatic spraying of an abluminal stent surface |
| TWI356036B (en) * | 2004-06-09 | 2012-01-11 | Smithkline Beecham Corp | Apparatus and method for pharmaceutical production |
| US8101244B2 (en) * | 2004-06-09 | 2012-01-24 | Smithkline Beecham Corporation | Apparatus and method for producing or processing a product or sample |
| US7205027B2 (en) * | 2004-09-27 | 2007-04-17 | Brandyn Brosemer | Powder coating method providing enhanced finish characteristics |
| KR101406415B1 (en) | 2005-07-15 | 2014-06-19 | 미셀 테크놀로지즈, 인코포레이티드 | Polymer coatings containing drug powder of controlled morphology |
| WO2007011708A2 (en) | 2005-07-15 | 2007-01-25 | Micell Technologies, Inc. | Stent with polymer coating containing amorphous rapamycin |
| US7862848B2 (en) * | 2005-08-03 | 2011-01-04 | The University Of Western Ontario | Direct coating solid dosage forms using powdered materials |
| US7867547B2 (en) | 2005-12-19 | 2011-01-11 | Advanced Cardiovascular Systems, Inc. | Selectively coating luminal surfaces of stents |
| MY157620A (en) * | 2006-01-31 | 2016-06-30 | Cytochroma Dev Inc | A granular material of a solid water-soluble mixed metal compound capable of binding phosphate |
| AU2007243268B2 (en) | 2006-04-26 | 2013-06-13 | Micell Technologies, Inc. | Coatings containing multiple drugs |
| US8069814B2 (en) | 2006-05-04 | 2011-12-06 | Advanced Cardiovascular Systems, Inc. | Stent support devices |
| CA2651852C (en) | 2006-05-12 | 2016-08-16 | Mars Incorporated | Use of powders for creating images on objects, webs or sheets |
| US8603530B2 (en) | 2006-06-14 | 2013-12-10 | Abbott Cardiovascular Systems Inc. | Nanoshell therapy |
| US8048448B2 (en) | 2006-06-15 | 2011-11-01 | Abbott Cardiovascular Systems Inc. | Nanoshells for drug delivery |
| US8017237B2 (en) | 2006-06-23 | 2011-09-13 | Abbott Cardiovascular Systems, Inc. | Nanoshells on polymers |
| US7976872B2 (en) * | 2006-07-24 | 2011-07-12 | L. Perrigo Company | Method for distributing a pharmaceutically active compound in an excipient |
| WO2008042909A2 (en) | 2006-10-02 | 2008-04-10 | Micell Technologies Inc. | Surgical sutures having increased strength |
| WO2008052000A2 (en) | 2006-10-23 | 2008-05-02 | Micell Technologies, Inc. | Holder for electrically charging a substrate during coating |
| US11426494B2 (en) | 2007-01-08 | 2022-08-30 | MT Acquisition Holdings LLC | Stents having biodegradable layers |
| JP5603598B2 (en) | 2007-01-08 | 2014-10-08 | ミセル テクノロジーズ、インコーポレイテッド | Stent with biodegradable layer |
| AU2008246717B2 (en) * | 2007-04-26 | 2013-02-28 | Eisai R & D Management Co., Ltd. | Method for production of tablet |
| WO2008148013A1 (en) | 2007-05-25 | 2008-12-04 | Micell Technologies, Inc. | Polymer films for medical device coating |
| US8048441B2 (en) | 2007-06-25 | 2011-11-01 | Abbott Cardiovascular Systems, Inc. | Nanobead releasing medical devices |
| GB0714670D0 (en) * | 2007-07-27 | 2007-09-05 | Ineos Healthcare Ltd | Use |
| GB0720220D0 (en) * | 2007-10-16 | 2007-11-28 | Ineos Healthcare Ltd | Compound |
| BRPI0910969B8 (en) | 2008-04-17 | 2021-06-22 | Micell Technologies Inc | device |
| JP2011528275A (en) | 2008-07-17 | 2011-11-17 | ミセル テクノロジーズ，インク． | Drug delivery medical device |
| US8834913B2 (en) | 2008-12-26 | 2014-09-16 | Battelle Memorial Institute | Medical implants and methods of making medical implants |
| US20100239635A1 (en) | 2009-03-23 | 2010-09-23 | Micell Technologies, Inc. | Drug delivery medical device |
| JP2012522589A (en) | 2009-04-01 | 2012-09-27 | ミシェル テクノロジーズ，インコーポレイテッド | Covered stent |
| EP3366326A1 (en) | 2009-04-17 | 2018-08-29 | Micell Technologies, Inc. | Stents having controlled elution |
| EP2453834A4 (en) | 2009-07-16 | 2014-04-16 | Micell Technologies Inc | Drug delivery medical device |
| GB0913525D0 (en) | 2009-08-03 | 2009-09-16 | Ineos Healthcare Ltd | Method |
| EP2531140B1 (en) | 2010-02-02 | 2017-11-01 | Micell Technologies, Inc. | Stent and stent delivery system with improved deliverability |
| GB201001779D0 (en) | 2010-02-04 | 2010-03-24 | Ineos Healthcare Ltd | Composition |
| US8795762B2 (en) | 2010-03-26 | 2014-08-05 | Battelle Memorial Institute | System and method for enhanced electrostatic deposition and surface coatings |
| EP2560576B1 (en) | 2010-04-22 | 2018-07-18 | Micell Technologies, Inc. | Stents and other devices having extracellular matrix coating |
| WO2012009684A2 (en) | 2010-07-16 | 2012-01-19 | Micell Technologies, Inc. | Drug delivery medical device |
| CA2810842C (en) | 2010-09-09 | 2018-06-26 | Micell Technologies, Inc. | Macrolide dosage forms |
| US20120177742A1 (en) | 2010-12-30 | 2012-07-12 | Micell Technologies, Inc. | Nanoparticle and surface-modified particulate coatings, coated balloons, and methods therefore |
| WO2012166819A1 (en) | 2011-05-31 | 2012-12-06 | Micell Technologies, Inc. | System and process for formation of a time-released, drug-eluting transferable coating |
| WO2013012689A1 (en) | 2011-07-15 | 2013-01-24 | Micell Technologies, Inc. | Drug delivery medical device |
| US10188772B2 (en) | 2011-10-18 | 2019-01-29 | Micell Technologies, Inc. | Drug delivery medical device |
| CA2852260C (en) | 2011-10-18 | 2020-09-22 | Micell Technologies, Inc. | Drug delivery medical device |
| EP2967803B1 (en) | 2013-03-12 | 2023-12-27 | Micell Technologies, Inc. | Bioabsorbable biomedical implants |
| KR102079613B1 (en) | 2013-05-15 | 2020-02-20 | 미셀 테크놀로지즈, 인코포레이티드 | Bioabsorbable biomedical implants |
| CN106944292A (en) * | 2017-02-20 | 2017-07-14 | 陈婷 | A kind of precision part paint spraying machine of anti-lost paint |
| CN107028765A (en) * | 2017-05-05 | 2017-08-11 | 盐城卫生职业技术学院 | Pharmaceutical process plant and drug handling device |
| CN113600386B (en) * | 2021-09-02 | 2022-11-01 | 滁州学院 | Coating spraying equipment for civil engineering construction professional decorative plates |
Family Cites Families (33)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE522840A (en) * | ||||
| US50097A (en) * | 1865-09-26 | Improved machine for making drain-tiles | ||
| US1226824A (en) * | 1916-10-30 | 1917-05-22 | Dale G Steely | Method and apparatus for coating chocolates. |
| US2421801A (en) * | 1941-09-22 | 1947-06-10 | Gromiller Inc | Apparatus for fusing the coating on tablets |
| US2555519A (en) * | 1947-03-11 | 1951-06-05 | Gen Motors Corp | Method of painting electrostatically nonconducting articles |
| US2685537A (en) * | 1948-03-05 | 1954-08-03 | Dunmire Russell Paul | Apparatus for the coating of pellets |
| NL294399A (en) * | 1962-06-22 | |||
| NL6406815A (en) * | 1963-06-19 | 1964-12-21 | ||
| GB1123517A (en) * | 1967-04-10 | 1968-08-14 | Samuel Phillip Lipoma | Method and apparatus for applying a particulate material to a food product |
| US3536034A (en) * | 1968-01-29 | 1970-10-27 | Dawn Donut Co Inc | Apparatus for coating edibles |
| GB1449993A (en) * | 1973-10-01 | 1976-09-15 | American Can Co | Method and apparatus for distributing plastics on an irregular wokpiece surface |
| US4209550A (en) * | 1976-01-19 | 1980-06-24 | Xerox Corporation | Coating carrier materials by electrostatic process |
| DE2636152C2 (en) * | 1976-08-11 | 1980-11-06 | Arcana Chem.-Pharm. Fabrik Gmbh, Spittal, Drau (Oesterreich) | Process for the production of coated tablets |
| FR2447794A1 (en) * | 1979-02-05 | 1980-08-29 | Valentine Cie Vernis | PROCESS FOR COATING THERMOSETTING PLASTIC MATERIALS AND PRODUCTS OBTAINED ACCORDING TO THIS PROCESS |
| GB2056885A (en) * | 1979-08-08 | 1981-03-25 | Blundell Permoglaze Ltd | Powder coating cellulose fibre substrates |
| JPS6045806B2 (en) * | 1979-08-22 | 1985-10-12 | 株式会社日立製作所 | Air flow meter using heating resistor |
| IT1149716B (en) * | 1982-02-02 | 1986-12-10 | Edt Spa | PROCEDURE AND APPARATUS FOR THE ELECTROSTATIC APPLICATION OF LIQUIDS OR POWDERS ON SUBSTANCES AND OBJECTS |
| US4495217A (en) | 1982-04-19 | 1985-01-22 | Schrum Timothy J | Method for applying powdered coatings |
| GB8314025D0 (en) * | 1983-05-20 | 1983-06-29 | Pharmaindev Ltd | Electrostatic coating of materials |
| IT1163548B (en) * | 1983-06-21 | 1987-04-08 | Pirelli Cavi Spa | MULTI-POLE CABLE WITH FLUID OIL |
| GB8400562D0 (en) * | 1984-01-10 | 1984-02-15 | Pharmindey Ltd | Electrostatic coating materials |
| DE3500988C1 (en) * | 1985-01-09 | 1986-02-13 | Roland 6231 Schwalbach Sommer | Probe for measuring gaseous or liquid flows with respect to direction and strength |
| JPH0675692B2 (en) * | 1985-05-16 | 1994-09-28 | 小野田セメント株式会社 | Electrostatic powder coating method and coating equipment |
| GB8514915D0 (en) * | 1985-06-12 | 1985-07-17 | Vincent Processes Ltd | Coating apparatus |
| US4774102A (en) | 1986-06-09 | 1988-09-27 | Morton Thiokol, Inc. | Method of electrostatic powder spray coating |
| EP0265376A1 (en) * | 1986-10-01 | 1988-04-27 | Ciba-Geigy Ag | Coating of small objects |
| SE463541B (en) * | 1987-08-31 | 1990-12-10 | Lejus Medical Ab | GRANULATED PRODUCT TRANSFER OF A MELT OF ITSELF AND THE PROCEDURE FOR ITS PREPARATION |
| GB8819002D0 (en) * | 1988-08-10 | 1988-09-14 | Johnson H C | Coating apparatus |
| DE3839440C1 (en) * | 1988-11-23 | 1989-11-23 | Sollich Gmbh & Co Kg, 4902 Bad Salzuflen, De | |
| DE3903235A1 (en) * | 1989-02-03 | 1990-08-09 | Hoechst Ag | METHOD AND DEVICE FOR THE SURFACE PRE-TREATMENT OF SURFACE BODIES WITH ELECTRIC CORONA DISCHARGE |
| US5000978A (en) * | 1989-06-29 | 1991-03-19 | The Procter & Gamble Company | Electrostatic coating of detergent granules |
| US5178874A (en) * | 1989-06-30 | 1993-01-12 | Smithkline Beechman Corporation | Intermittent release dosage form |
| US5132142A (en) * | 1991-03-19 | 1992-07-21 | Glatt Gmbh | Apparatus and method for producing pellets by layering power onto particles |
-
1991
- 1991-02-22 GB GB9103711A patent/GB2253164B/en not_active Expired - Fee Related
-
1992
- 1992-02-21 DE DE69204127T patent/DE69204127T2/en not_active Expired - Lifetime
- 1992-02-21 WO PCT/GB1992/000323 patent/WO1992014451A1/en not_active Application Discontinuation
- 1992-02-21 ES ES92905114T patent/ES2078036T3/en not_active Expired - Lifetime
- 1992-02-21 AU AU12084/92A patent/AU653989B2/en not_active Expired
- 1992-02-21 EP EP92905114A patent/EP0526606B1/en not_active Expired - Lifetime
- 1992-02-21 DK DK92905114.2T patent/DK0526606T3/en active
- 1992-02-21 HU HU9203652A patent/HU215907B/en unknown
- 1992-02-21 CA CA002081921A patent/CA2081921C/en not_active Expired - Lifetime
- 1992-02-21 PL PL92296624A patent/PL166928B1/en not_active IP Right Cessation
- 1992-02-21 JP JP4504620A patent/JP2919971B2/en not_active Expired - Fee Related
- 1992-02-21 US US07/937,870 patent/US5470603A/en not_active Expired - Lifetime
- 1992-02-21 AT AT92905114T patent/ATE126431T1/en not_active IP Right Cessation
- 1992-11-19 CZ CS923434A patent/CZ343492A3/en unknown
-
1995
- 1995-08-15 US US08/515,210 patent/US5656080A/en not_active Expired - Lifetime
- 1995-11-15 GR GR950403198T patent/GR3018080T3/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| GB2253164B (en) | 1994-10-05 |
| JP2919971B2 (en) | 1999-07-19 |
| AU653989B2 (en) | 1994-10-20 |
| ATE126431T1 (en) | 1995-09-15 |
| GB9103711D0 (en) | 1991-04-10 |
| HU9203652D0 (en) | 1994-04-28 |
| HUT66848A (en) | 1995-01-30 |
| GB2253164A (en) | 1992-09-02 |
| US5470603A (en) | 1995-11-28 |
| US5656080A (en) | 1997-08-12 |
| AU1208492A (en) | 1992-09-15 |
| PL296624A1 (en) | 1993-11-02 |
| EP0526606A1 (en) | 1993-02-10 |
| PL166928B1 (en) | 1995-07-31 |
| CZ343492A3 (en) | 1993-08-11 |
| ES2078036T3 (en) | 1995-12-01 |
| JPH05508337A (en) | 1993-11-25 |
| EP0526606B1 (en) | 1995-08-16 |
| DE69204127T2 (en) | 1996-04-04 |
| HU215907B (en) | 1999-03-29 |
| CA2081921A1 (en) | 1992-08-23 |
| DK0526606T3 (en) | 1995-12-27 |
| WO1992014451A1 (en) | 1992-09-03 |
| GR3018080T3 (en) | 1996-02-29 |
| DE69204127D1 (en) | 1995-09-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2081921C (en) | Improvements in or relating to electrostatic coating of substrates of medicinal products | |
| CN101237846B (en) | Direct coating solid dosage forms using powdered materials | |
| CA2279841C (en) | Method and apparatus for the coating of substrates for pharmaceutical use | |
| EP0869847B1 (en) | Electrostatic coating | |
| Luo et al. | Dry coating, a novel coating technology for solid pharmaceutical dosage forms | |
| Yang et al. | An update on electrostatic powder coating for pharmaceuticals | |
| JP2004531610A5 (en) | ||
| NZ509086A (en) | Electrostatic layering process and coated units obtained thereby | |
| US6045855A (en) | Electrostatic coating of small falling objects | |
| KR970070062A (en) | Method and apparatus for manufacturing plastic web by coating | |
| GB2356587A (en) | Coating of substrates for pharmaceutical use | |
| WO1990014950A1 (en) | Method and apparatus of applying hot melt adhesive to paper products | |
| Jaimini et al. | Solventless coating for Tablets: An alternative to conventional coating technique | |
| JPS61200880A (en) | Production of resin coated wooden board |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |