MXPA99011752A

MXPA99011752A - Valve for aerosol container

Info

Publication number: MXPA99011752A
Application number: MXPA/A/1999/011752A
Authority: MX
Inventors: Colin Weston Burt Peter
Original assignee: Glaxo Group Limited
Priority date: 1997-06-26
Filing date: 1999-12-15
Publication date: 2000-06-01

Abstract

There is provided a valve for an aerosol container for dispensing a suspension or solution of a substance in a liquid propellant contained therein. The valve comprises a valve body (1) definingan aperture, a seal (9) mounted at the aperture, and a valve stem (7) having a dispensing passage (11), the valve stem (7) being slideably moveable through the seal (9) such that in a first position the valve is closed to prevent the substance to be dispensed from entering the dispensing passage (11) and in a second position the valve is open to allow the substance to be dispensed throu gh the dispensing passage (11). The valve stem (7) is made froma material comprising lubricant.

Description

AND VALVE FOR AEROSOL CONTAINER This invention is applied to a valve for an aerosol container with the aid of which a quantity of the contents thereof can be supplied. The invention has particular application for the supply of regulated doses of drugs, although it is applicable to the supply of aerosols, generally. The continuous use of aerosol formulations Tr, i comprising conventional chlorofluorocarbon propellants is being discussed due to the suspicious role of such propellants in atmospheric depletion ----- of ozone. Accordingly, formulations based on alternative propellants such as HFA-134a (1,1,1,2-tetrafluoroethane) and HFA-227 (1,1,1,2,3,3,3-heptafluoropropane) are being developed to replace conventional propellants designed to contribute to the depletion of ozone in the atmosphere. --_ Containers for aerosol formulations commonly comprise a bottle body coupled to a valve. The valve comprises a valve stem through which the formulations are supplied. In general, the valve includes a rubber seal of the proposed valve to allow reciprocal movement REF: 032286 of valve stem while preventing leakage -T -% of the container's propellant. It has been found that some conventional devices for supplying aerosols suffer from a ------ - *. "decreased performance when used in connection with - = -fc the ÌFA-134a or HFA-227. The selection of materials - 5 - Suitable for use in valves to contain aerosol fornplations based on these alternative propellants is complicated for the interactions between the components of the valve components and the components of the formulation, including the propellant. In conventional devices, particularly with some drug formulations, the valve rod tends to stick, stop, or offer resistance during the operating cycle with the result that the user perceives a cut 'when the valve stem is depressed and released. . This * can be caused in part by -the drug to be delivered from the container that is sedimented or precipitated out of the drug-propellant suspension or solution formulation and is deposited in the internal components of the valve, the presttency of the drug in the_ sliding contact surface creates increased friction during operation S "International patent application No. PCT /? JS94 / 06900 describes an aerosol valve wherein the" rubber seal of the valve is made of a specially composed composition. selected to minimize propellant leakage through the contact surface between the valve seal and the valve stem in the firing action. The uniformity of the operation is also improved with some formulations compared to devices that involve thermosetting, conventional rubber seals. However, although such seal compositions can improve the performance of the valve, they do not prevent the increase of the deposit in the valve components, and the problem of "cutting may persist. ~ It is an objective to provide a valve with a uniformity of Improved operation, which mitigates the problem of valve adhesion. According to one aspect of the present invention there is provided a valve for an aerosol container for supplying a suspension of a substance in a liquid propellant contained therein. same, the valve comprising a valve body that ** defines an opening, a seal mounted to the opening, and a valve stem having a supply passage, the valve stem that is slidably movable through the valve body. ~ of the seal such that in a first position the valve closes to prevent the substance from being supplied- from the entrance to the supply passage, and in a second position the valve is opened to "allow the substance to be supplied through the supply passage, characterized in that the valve stem is made of a material comprising lubricant. According to another aspect of the present invention there is provided a valve stem made of a material comprising lubricant. According to a further aspect of the present invention, there is provided an aerosol container comprising a valve as described herein. - The incorporation of the lubricant in the material of the valve stem ensures that the lubricant is included within the maximum area of the stem / seal contact surface, thus providing the improved lubrication and uniformity of operation for the life of the valve. The term "lubricant" means any material which reduces the friction between the rod and the valve seal. 5 Suitably, the lubricant comprises a fluorine-containing polymer such as polytetrafluoroethane (PTFE ~) ethylenetetrafluoroethylene (EXAMPLE), peroxyaloxyalkane (PFA), "" ethylene propylene fluoride (----- Fi, vindildionfluride (PUDF) and ethylene In the preferred form, the lubricant contains polytetrafluoroethane (PTFE). Preferably, the lubricant consists of . polytetrafluoroethane (PTFE) "The 2 FE has found that __ is particularly advantageous with a lubricant due to its low coefficient of friction.In addition, the PTFE significantly reduces the problem of drug deposition on the valve stem, eliminating of this mace one of the causes of ^ the adhesion of the valve. _ Z1 Properly, the valve stem • A - A - • - '"r: - ~, -i" -. - ---- - - - '". It comprises up to 20% by weight of PTF-E In preferred form, the valve rod comprises 5 to 10% by weight of PTFE. _ ~ - _ Y PTFE can be molded plastic and can - to be "" used effectively in small quantities which constitute of the order of 5% by weight of the material of the valve stem. PTFE is also non-toxic, an important consideration for aerosol devices for drug delivery. . And "In one respect, the valve stem is free of any silicone material, such as silicone oil, either as a component thereof or as a coating therein.A suitably, the valve is a dosing valve. comprising a metering chamber, a transfer passage through which a quantity of the substance to be delivered can pass from the container in the metering chamber, where in the first position the supply passage is isolated from the metering chamber. and the metering chamber is in communication with the container via the transfer passage, and in the second position the supply passage is in communication with the metering chamber and the transfer passage is isolated from the 5-? dosing chamber. - ZZ Suitably, the substance to be administered is a medicine supplied in HFA-134a or 'HFA-227 liquified.' The drugs suitable for this purpose are, for example, for the treatment of respiratory disorders such as asthma, bronchitis, pulmonary, obstructive diseases, chronic and infections of the peSho. The additional drugs can be selected from any other suitable drug useful in inhalation therapy and which can be presented as a suspension. The appropriate medicaments can be selected in this manner from, for example, analgesics, for example codeine, dihydromorphine, ergotamine, fentanyl or morphine; anginal preparations, for example diltiazem; ant? allergic, ~ for example Y ^ w crombglicate, cetotifen or neodocromil; anti-infectives, for example cephalosporins, penicillins, streptomycin, sulfonamides, tetracyclines and pentamidine; antihistamines, for example meta-pyrilalene anti-inflammatories, for example, fluticasone propionate, beclomethasone dipropionate, flunisolide, budesonide or triamcinolone acetonide; antitussives, for example noscapine; bronchodilators, for example salmeterol, salbutamol, ephedrine, edrenaline, fenoterol, formoterol, isoprenaline, metaprotenol, phenylephrine, phenylpropanolamine, pirbutero, reproterol, ri iterol, terbutaline, isoetarin, tulobuterol orciprenaline, or (-) -4-amino-3, 5 -dichloro- - [[[6- [2- (2-pyridinyl) ethoxy] -hexyl] amino] methyl] benzenemethanol; diuretics, for example amoride; anticholinergics, for example ipratropium, atropine or oxitropium; hormones, for example, cortisone, hid ocortisone or prednisolone; xanthines for example to ihofilin, choline theophyllinate, lysine theophyllinate or theophylline and therapeutic proteins and peptides, for example, insulin or glucagon. It will be clear to a person skilled in the art that, where appropriate, well known. The container is filled with a suspension of salmeterol xinafoate in a liquid propellant of HFA 134a. The body of the valve 1 is formed in its lower part with a metering chamber 4, and its upper part with a sampling chamber 5 which also acts as a housing for a return spring 6. The upper "words" "e" lower "are used for the container when in an orientation of use with the neck of the container and the valve at the lower end of the container which corresponds to the orientation of the valve as shown in Figure 1. Center of the valve stem 1 is disposed a valve stem 7, a part 8 of which extends from the valve through the lower stem seal 9 and the metal lining 2. The part of the rod 8 is formed with an axial or longitudinal channel, interior 10 that opens at the end of the rod and in communication with a radial passage 11. The upper portion of the rod 7 has a diameter such that it can pass slidably through an opening in a seal of the upper rod 12 and the periphery of that opening sufficient to "'provide a seal. The rod is made of HOSTAFORM X329MR (Hoechst), which is molded in a conventional manner. Significantly, the HOSTAFORM comprises 5% PTFE, which has the effect of reducing the friction between the valve stem and the seals of the rod 9 and 12 during operation, as explained below. The PTFE also has the effect of reducing any increase in deposition of the drug on the surface of the valve stem, the presence of which on the surface of the slip contact between the valve stem and the seal could otherwise cause increased friction. during the operation. The seal of the upper rod 12 is held in position against a step 13 formed in the body of the valve 1 between the lower and upper parts by a sleeve 14 which defines the metering chamber 4 between the seal of the lower rod 9 and the seal of the piston rod. upper stem 12. The stem of the valve 7 has a passage 15 which, when the rod is in the inoperative position shown, provides a "communication between the dosing chamber 4 and the sampling chamber 5, which itself communicates with the interior of the container by means of a hole 16 formed in the side of the valve body 1. * The valve stem 7 is decentered downward to the inoperative position by the return spring 6 and is provided with a shoulder 17 which it rests against the seal of the lower rod 9. In the inoperative position as shown in Figure 1, the shoulder 17 bears against the seal of the lower rod 9 and the radial passage 11 opens downwardly to the lower rod. seal of the lower rod 9 so that the metering chamber 4 is isolated from the channel 10 and the suspension inside can not escape. A ring 18 having a "U" shaped cross section that "extends in a radial direction is placed around the valve body below the hole 16 to form a channel 9 around the valve body. Figure 1, the ring "is formed as a separate component having an annular, inner contact protrusion of a suitable diameter to provide a friction assembly on the upper part of the valve body 1, the annulus against the step 13 below the orifice 16. However, the ring 18 can be formed "alternatively as an integrally molded part of the valve body 1. To use the device, the container is first agitated to homogenize the suspension within the container. "" then squeezes the stem of the valve 7 against the force of the spring 6. When the valve * of the valve is tightened, both ends of the passage 15 come to rest "on the side of the seal of the upper rod 12 remote from the dosing chamber 4. In this way, a dose is regulated inside the dosing chamber. Continuous depression of the valve stem will move the radial passage 11 within the dosing chamber 4, while the seal of the upper rod 12 is sealed against the valve stem body. In this way, the regulated dose can exit through a radial passage 11 and the outlet channel 10. The release of the valve stem causes it to return to the position illustrated under the force of the spring 6. The passage 15 then provides again the communication between the dosing chamber 4 and "the sample chamber 5. Accordingly, in this step, the liquid passes under pressure from the container through the orifice 16, through the passage 15 and therefore inside the dosing chamber 4 to fill it. ^ __-- It will be understood that the present description is for. the purpose of illustration only and the invention extends to modifications, variations and improvements thereto.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, property is claimed as contained in the following:

Claims

1 1. A valve for an aerosol container for the supply of a suspension or solution of a substance in a liquid propellant contained therein, the valve comprising a valve body defining an opening, a seal mounted on the opening, and a valve stem having a supply passage, the valve rod that is movably slidable through the seal such that in a first position the valve closes to prevent the substance to be delivered from entering. supply passage, and in a second position the valve is opened to allow the substance to be supplied through the supply passage ", characterized in that the valve stem is made of a material comprising lubricant.

2. The valve according to claim 1, characterized in that the lubricant comprises a fluorocarbon copolymer.

3. The valve according to claim 2, characterized in that the lubricant comprises PTFE.

4. The valve according to claim 3, characterized in that it comprises 5 to 10% by weight of PTFE.

5. The valve according to any of claims 1 to 4, characterized in that the valve rod is free of silicone material.

6. The valve according to any of claims 1 to 5, characterized in that the valve is a metering valve comprising a metering chamber, a transfer passage through which a quantity of the substance to be delivered from the container in the chamber can pass. of adjustment, wherein in the first position the delivery passage is isolated from the dosing chamber and the dosing chamber is in communication with the container via the transfer passage, and in the second position the delivery passage is in communication with the delivery passage. Dosing chamber and the transfer passage is isolated from the dosing chamber.

7. The valve according to claim 6, characterized in that the substance to be "supplied is a medicament suspended in HFA134a or liquified HFA-227.

8. The valve according to claim 7, characterized in that the medicament is salmeterol, xinafoate, fluticasone propionate or a combination thereof.

9. A valve stem, characterized in that it comprises a lubricant material.

10. An aerosol container, characterized in that it comprises a valve according to any of claims 1 to 8.