US 2947415 A
Description (OCR text may contain errors)
Aug. 2, 1960 E. D. G. GARTH STERILE PACKAGE AND METHOD OF MAKING SAME 2 Sheets-Sheet 1 Filed owns. 195? cAaaoxi DE Aug. 2; 1960 E. D. G. GARTH STBRILE PACKAGE AND METHOD OF MAKING SAME 2 Sheeis-Sheet 2 Filed Oct. 5, 1957 REL-VALVE GAUQQ nsn' CARBOYIDE s UPPLY INVEN TOR. BY 9. qua M MTTORNEYS iinited States hatengt STERILE PACKAGE AgID METHOD OF MAKING Ernest D. G. Garth, Summit, N.J., assignor to C. R. Bard, Inc., Summit, NJ., a corporation of New Jersey Filed Oct. 3, 1957, Ser. No. 688,048
Claims. (Cl. 20663.2)
This invention relates to a sterile package, with particular reference to the packaging of medical and surgical articles or implements.
It is an object of the invention to provide a package composed wholly or partially of transparent plastic sheet material, which package is securely sealed so that it can be opened readily only at a predetermined point or points and in such a manner that its contents can be removed from the package without touching any non-sterile surface or can be used directly from the package without handling, thus avoiding contamination.
A further object is to provide such a package which is capable of being sterilized by gas after being sealed, and which is composed largely of a gas-impermeable material for protection of the contents, at least the inner surfaces of the package being of a material which is non-reactive with the latex or vinyl plastic compounds of which the packaged items may be made.
Another object is to provide a pack-age which has a relatively long shelf lifee.g., two years or more.
A further object is to provide certain improvements in the form, construction, arrangement and material of the package, by which the above named and other objects may effectively be attained.
A practical embodiment of the invention is shown in the accompanying drawings, in which:
Fig. 1 represents a perspective view of a piece of laminated plastic sheeting, on an enlarged scale and parts being broken away; v
Fig. 2 represents a perspective view of a complete package containing, for instance, a catheter, parts being broken away to show approximately a transverse section;
Fig. 3 represents a detail view on an enlarged scale, partly in perspective and partly in section on the line -II-IIII of Fig. 2, parts being broken away;
Fig. 4 represents a detail elevation of a segment of a catheter showing how it is releasably secured to a supporting card;
Fig. 5 represents a detail elevation of the engaging parts of a pair of sealing rollers;
Fig. 6 represents, diagrammatically, an assembly of apparatus for effecting sterilization of the packages;
Figs. 7, 8 and 9 represent detail perspective views illustrating the manner of opening the package and making its contents available for use. I
Referring to the drawings, the package is made from laminated plastic sheeting, and preferably from sheeting comprising a layer 1 of polyethylene on which is bonded a thinner layer 2 of Mylar polyester film (Du Pont brand of polyethylene terephthalate resin). In actual practice it has been found that a layer 1 having a thickness of about 2 to 3 mils, bonded to a layer 2 having a thickness of about /2 to 1 mil, constitutes a satisfactory sheet for the intended purpose. To form the package, two such sheets are assembled with their polyethylene faces toward each other and with the desired contents (e.g., a catheter A and supporting card B) between them. The side edges of the package are heat-sealed together 2,947,415 Patented Aug. 2, 1960 Free bar designed to seal the faces together along spaced parallel lines 4 having substantially the same appearance and eitect as the seal-lines 3 and extending across them at each corner of the package, as shown at 5.
The characteristics of the plastic materials constituting the layers 1 and 2, as they have special significance in the present case, are that both materials are strong, chemically inert and not subject to deterioration with time under normal conditions. The polyethylene (layerv 1) is permeable to gas under pressure and is thermoplastic. The Mylar (layer 2) is impervious to gas and has thermal stability at temperatures where the polyethylene layers can be sealed together. In addition to the gas permeability of the polyethylene, it is desirable to provide a gas window in the form of a strip 4 of microporous material (narrow dental tape having proven satisfactory) sealed between the two films and extending from the interior of the package to an edge or end thereof, as shown in Fig. 2.
When apackage has been made as described above it contains not only such articles as the catheter A and card B, but also a certain amount of air, since packaging in the absence of air is diflicult and awkward. To
efiect sterilization, the package is placed in a vacuum chamber, indicated at 6 (Fig. 6) and is subjected to a full vacuum (27 in.) for about 5 minutes. During this period the air in the package is substantially exhausted as some of it permeates outwardly through the sealed lines 3 and 4, which are narrow walls of polyethylene having a thickness slightly less than the sum of thepolyethylene layers, while most of it flows quite rapidly out through the microporous strip 4'. Following this air exhaustion step the package is subjected (normally in the same chamber) to an atmosphere of sterilizing gas under pressure, a suitable gas being Carboxide" (10% ethylene oxide and CO at a pressure of one or more atmospheres. A sufiicient amount of the gas permeates into the more or less collapsed pac'kage, mostly through the strip 4', as well as through the polyethylene walls of the seal-lines, to serve the purpose of sterilization of the contents. The duration of the pressure treatment depends somewhat on the pressure used and on the temperature of the gas, which passes through the polyethylene more rapidly with an increase in temperature.
It is important to attain full vacuum as quickly as possible in order to prevent the spores of any bacteria which may be present from drying out; it has been found that the ethylene oxide cannot readily penetrate and kill a dry spore, while it is highly effective in the treatment of those which are not too dry. Since the strip 4' is microporous, it eifeotively filters out air-borne bacteria and the like.
While the foregoing description refers generally to a package, it will be understood that the packages and their contents are normally assembled in. a continuous production line, and that many such packages are subjec-ted simultaneously to the sterilization operation. In the course of continuous assembly in the lengthwise direction of the package the strips 4' (twice as long as shown) may conveniently be inserted across alternate areas where the packages are to be cut apart after end sealing; thus, after cutting, one such strip will form a gas window at the rear end of one package while the other strip forms the window in the front end of the next package.
As an additional feature of great practical importance, a package of the nature shown herein is provided with a short cut 7 in one side edge near the end where the tip of the catheter A is located and inward from the seal-lines 4 at that end. In order to open the package, one need only tear ofif the end, starting with the cut 7 and tearing straight across; then placethepackage on a flat surfacev and peel back the upper sheet 8 (Fig. 7) while; holding down, the lower sheet 9; then turn back both sheets (Fig. 8) and remove the card B, leaving the tip. of the catheter exposed (Fig. 9) and ready for insertion, while the catheter has not been, and still need not be, touched by either hand of the operator. Since some users prefer to open the package at the opposite end and remove the contents entirely before use, a cut 7 is provided also adjacent said, opposite end. Accidental contamination of the contents 'is readily avoided in either case.
To the extent that internal pressures may be developed within the package, during sterilization or subsequently, it will be noted that they act evenly against the continuous straight seal-lines around the whole periphery of the package and can never become strong enough at any localized point to separate the upper and-lower sheets. While the seal-lines resist strongly such forces, the packages can be opened easily as described above since the peeling action is resistedonly at the four or five, points on each side where the line of separation intersects, more or less at right; angles, the several seal-lines.
Catheters and the like, particularly those of the Foley latex type, are very flexible and non-self-supporting. For this reason it is necessary that they be mounted on a supporting card-such as that indicated at B (Figs. 2 and 4); w The particular manner of mounting shown in Fig. 4 ishighly' advantageous because of its simplicity and effectiveness; the cardis X cut at two, or preferably three, pointsand isthen laid in a jig where the side edges oppositqeach'c-ut can beldepressed to makethe triangular fingers B B stand up and separate enough so that the catheter-A can be dropped between them, the jig then being released and the fingers closing down on the catheter; The card is preferably scored longitudinally, as'indicated at B", between the outer ends of adjacent cutsbutnotbetween the endsof any single cut, so that the parts of the card adjacent each finger B remain somewhator the likewithno-possibility of the catheter coming incontact' with any supportingsurfiace otherthan the card itself, particularlysince the bent down edgesjust mentioned also act as legs on which the card is at least partially-supported; The catheter isheld firmly enough by-the fingers B, B so that it will not-drop on the card iuthecourseof normal handling but it .canbe readilyremoved' whenever desired.
Although the package and method described above were devised'primarily for use in connection with catheters and the-like, it will be evident that the invention is useful in connection with numerous other devices which require sterile packaging and adaptation to such devices,
within obvious limits, is intended to be regarded as within the scope of the invention.
If desired, a laminated cover sheet could be affixed to an impervious backing sheet, laminated or not. In any case the thickness of the? permeable layer and the permeahility rate through. the. strip 4 (whenpresent) are factors to be considered andcorelated' with the duration and degree of the vacuum and pressure treatments. As a further variant, apluralityof separatecover sheets, eachforming a package,'can be afli'xed to a single backing sheet either as. mintermediate stepin, the. formation of separate packages or as the definitive step in making a unit having articles-in individual sealedzcornpartments.
What I claim is:
1. A package for the protection of articles requiring sterilization and the maintenance of, sterility comprising, a backing sheet, a cover sheet fixed to, said backing sheet along at least one continuous line adjacent to the periphery of the cover sheet, at least the cover sheet being made of. laminated plastic, sheet material the inner layer of which is elfectively' gas permeable and an outer layer of which is gas impervious at least the edge of said inner layer being exposed on the outside of the package, and a narrow strip of microporous material lying between said sheets and extending from the interior of the package to an outer edge thereof.
2. Apackage according to claim 1 in which the inner layer of gas permeable material is, substantially thicker than the outer layer of gasimpervious material.
3 A package according; to claim 1 in which. the backing sheet is made of laminated plastic sheet material the inner layer of which is gas permeableand an outer layer of which is gas impervious, at least the edge of said inner layer of the backing sheet being'exposed' on the outside of the package.
4. A package according to claim 3 in which the backing sheet and the cover sheet are substantially coextensive.
5; A package accordingto claim,4' in which the gas permeable layers of the sheets are, sealed, together, along a plurality of continuous lines adjacent to the periphery of the sheets.
References Cited in the file of this patent UNITED STATES PATENTS Haddad Sept. 24, 1957