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AN INHALATION DEVICE AND METHOD HAVING A VARIABLY RESTRICT ABLE AIR INLET THAT ALLOWS THE INHALATION FORCE REQUIRED TO OVERCOME A LOCKING 5 ELEMENT TO BE CHANGED
The invention belongs to the field of medicine technology and relates to a method and device for dosing and nebulizing a preparation for inhalation by means of 10 which, for example, pharmaceutical products such as antiasthmatic drugs can be inhaled in a dosed manner.
Inhalation is a known method of administering medicines, for example, for absorption into the airways and lungs. Various inhalation devices are commercially 15 available for this purpose, with which liquid or powdered preparations are introduced, finely distributed, into the buccal cavity. The inhalation devices are so conceived that with each application a specified dose of the preparation is released. In order that the prepara- 20 tion, finely distributed by nebulization, can pass from the buccal cavity, through the throat into the airways and lungs, it is inevitable that the patient must inhale simultaneously whilst introducing the nebulized preparation into the buccal cavity by means of the inhalation 25 device. If he or she does not do so, or does so insufficiently, the medicine remains wholly or partly in the buccal cavity and in the throat, and the desired effect is not achieved. Even if the medicine can be precisely dosed with the inhalation device, the dose of medicine 30 which is actually effective is dependent on the strength of the actual inhalation, i.e. on the strength of simultaneous inhalation. The part of the dose remaining on the walls of the buccal cavity and throat is substantially swallowed and remains virtually ineffective. In the case 35 of only weak inhalation, the effective dose is only a fraction of the dose released by the inhalation device. Every inhaler user is familiar with this failure of the effect of inhalation and is inclined to achieve the desired effect with a further dose. 40
Inhalation devices have also been developed which only permit a dose and nebulization if inhalation takes place at the same time. Such devices are described, for example, in U.S. Pat. Nos. 3,565,070, 3,789,843 and 3,598,294 or in French Patent 40542. All these devices 45 must be brought into an active state before inhalation by a separate lever. In this active state, an automatic dose is released by inhalation. All these devices include, in addition to a supply vessel for the inhalation preparation, a complex mechanism consisting of a lever and 50 spring system and are therefore elaborate and, in particular, prone to malfunctioning.
Such disadvantages do not affect the inhalation device described in European Pat. 0 147 028, in which dosing is actuated manually, but a corresponding lock- 55 ing device ensures that this is only possible when the patient inhales. This device also comprises a mechanism, albeit less complex, which consists of a plurality of levers, but which is located partly in the region of the spray to be inhaled and is therefore exposed to contami- 60 nation which may jeopardise its perfect functioning.
All existing devices comprise, for dosing and nebulizing, a reservoir, which contains the preparation and a propellant gas and which is provided with a dosing valve, with which a specified dose of the preparation is 65 nebulized per stroke. Different dosages for different patients, for example adults and children, are achieved by inhalation of a different number of individual doses.
If the device, as mentioned above, has to be actuated again in between individual doses, operation seems complicated. As they are intended to be applicable for patients with different constitutions, the devices are also adapted for the weakest patients, i.e. children for example, who according to their smaller lung capacity can only produce a slight inhalation power, which is however sufficient for a good effect in their own case. In other words, if for example an adult uses the same device, although he or she must inhale to release or unlock the dose, this does not have to be carried out with sufficient strength for optimum inhalation according to his or her lung capacity. Therefore, whilst all existing devices remove from the patient the synchronization of dosing and inhalation, only in the minority of cases do they force the patient to produce adequate inhalation power for an optimum effect of the preparation.
The object of the invention, therefore, is to indicate a method of dosing and nebulizing inhalation preparations whereby each dose released is also an effective dose, the patient being forced to inhale upon dosing and with a strength corresponding to his or her constitution. In the method according to the invention, the patient is not only to be forced to inhale sufficiently, but should also be given the opportunity to train his or her lung power by inhaling in order to help improve his or her inhalation. In emergencies, however, it should also be possible to administer the dose with insufficient inhalation. The preparation is to be dosed and nebulized according to known methods and be so prepared by appropriate pretreatment after being discharged from the nebulizing nozzle that, if possible, it only contains particles or drops of an optimum size for inhalation and is present in the inhaled air, if possible, in the form of a stable aerosol.
The configuration of the inhalation device for carrying out the method is to be adaptable for different users and adjustable for training the lung power. It should be as small as possible and simple to operate. It should comprise simple, reliably operating mechanical parts which are not prone to contamination. It should allow the patient absolute control over the administration of a dose. The device should be usable for the nebulization and dosing of standard commercial inhalation preparations or active substances in standard commercial aerosol containers with a dosing valve, but especially in devices with mechanical dosing and nebulising pumps which operate without propellant gas.
The method and device are described in detail with the aid of the following Figures, which show:
FIG. 1 (a and b), a comparison of the released and active doses in the use of a non-inhalation-dependent method and of the inhalation-dependent method according to the invention, and a diagram for the training effect of the method according to the invention,
FIG. 2 (a and b), sections through an embodiment, given by way of example, of the inhalation device according to the invention to illustrate its operation,
FIG. 3, a plan view towards the nozzle of the embodiment, according to FIG. 2,
FIG. 4 (a to d), respective details from the section and plan view in FIGS. 2 and 3 for two embodiments with an adjustable inhalation strength,
FIG. 5 (a to c), three embodiments, by way of example, of the mouthpiece of the device according to the invention,
FIG. 6 (a and b), a further embodiment of the device according to the invention,