Non-chlorofluorocarbon aerosol formulations

Abstract: An aerosol formulation comprises (a) an effective amount of a medicament comprising albuterol, beclomethasone dipropionate or a salt or clathrate thereof, (b) 1,1,1,2,333-heptafluoropropane, and (c) optionally, one or more components selected from preservatives, buffers, antioxidants, sweeteners, and taste masking agents. Use of said formulation in treatment of asthma.

Description: INTRODUCTION TO THE INVENTION The present invention is directed at aerosol formulations which are substantially free of chlorofluorocarbons (CFC's). More specifically, the present invention is directed at formulations substantially free of CFC's and having particular utility in medicinal applications, especially in metered dose pressurized inhalators (MDI's). Metered dose inhalators have proven to be an effective method for delivering medicaments orally and nasally. They have been used extensively for delivering bronchodilating and steroidal compounds to asthmatics and may also be useful for delivering other compounds such as pentamidine and non-bronchodilator antiinflammatory drugs. The rapid onset of activity of compounds administered in this manner and the absence of any significant side effects have resulted in a large number of compounds being formulated for administration via this route. Typically, the drug is delivered to the patient by a propellant system generally comprising one or more propellants which have the appropriate vapor pressure and which are suitable for oral or nasal administration. The more preferred propellant systems typically comprise propellant 11, propellant 12, propellant 114 or mixtures thereof. Often the vapor pressure of the propellant systems is adjusted by admixing a liquid excipient with the propellant. However, propellants 11, 12 and 114 belong to a class of compounds known as chlorofluorocarbons, which have been linked to the depletion of ozone in the atmosphere. It has been postulated that ozone blocks certain harmful UV rays and that a decrease in the atmospheric ozone content will result in an increase in the incidence of skin cancer. In the 1970's certain steps were taken to reduce the CFC emissions from aerosols. Other propellants, such as hydrocarbons, were used, or the product was delivered in a different manner. Because CFC usage in medicinal applications is relatively low i.e. less than 1% of total CFC emissions, and because of the health benefits associated with metered dose inhalators, steps were not taken at that time to restrict the use of CFC propellants in metered dose inhalators. However, continuing and more sophisticated ozone measurements have indicated that the earlier restrictions in CFC usage were insufficient and that additional, significant steps should be taken to drastically reduce CFC emissions. Recently, recommendations have been made that CFC production be virtually discontinued by the end of this century. As a result, it may not be possible to continue to use CFC propellants in the intermediate and long term. While some efforts have been made to use non-pressurized metered dose inhalators, many of these devices have not been completely successful. Many do not deliver uniform doses, are mechanically complex, do not provide the 100-200 doses per unit of current aerosol containers, are difficult for individuals to utilize, and are bulky and/or cumbersome for the patients to use, particularly when they have an acute need for the medication. As a result, there is a need for aerosol formulations which are substantially free of CFC's. Non-CFC propellants systems must meet several criteria for pressurized metered dose inhalators. They must be non-toxic, stable and non-reactive with the medicament and the other major components in the valve/actuator. One propellant which has been found to be suitable is CF 3 -CH 2 F-CF 3 , also known as Freon 227, HFA 227, HFC 227 or 1,1,1,2,3,3,3 heptafluoropropane. However, certain physical properties, i.e., polarity and solubility, of HFC 227 differ from those of commonly used CFC propellants. Commonly used surfactants may be insoluble in HFA 227. Moreover, where the medicament is to be delivered as a solution, the medicament may not be readily soluble in this propellant. The polarity difference between HFC 227 and the previously used CFC propellants may result in a different delivery of the medicament when HFC 227 replaces a CFC propellant. The medicament may cream, settle or agglomerate in the non-CFC propellant even though this did not occur in the CFC propellant. The use of HFA 227 previously has been disclosed for use in medicinal inhalators. European Patent Publication No. 0 384 371 is directed at the combination of propellant 227 and propane, butane, isobutane, Me 2 O and/or F 2 CHMe. Research Disclosure No. 30161, May, 1989 discloses that non-CFC propellants, such as fluorohydrocarbons may be used in pressurized medicaments delivered directly to the lungs, e.g. bronchodilators. Other publications have been directed at the use of other fluorohydrocarbons, such as HFC 134a, for aerosol propellants. European Patent Publication No. 0 372 777 is directed at medicinal aerosol formulations incorporating HFC 134a and an adjuvant having a higher polarity than the propellant. This publication lists several possible adjuvants and surfactants for use in combination with the propellant and the medicament. International patent application No. WO 91/04011 discloses the combination of HFC 134a and a powdered medicament pre-coated with a non-perfluorinated surfactant prior to dispersing the powdered medicament in the propellant. Pages 6-7 of the publication list suitable surfactants for use with the propellant. A perfluorinated adjuvant optionally could be added. However, the pre-coating of the medicament may not be advantageous, since it adds an additional, complex step to the manufacturing process. U.S. Patent No. 4,174,295 discloses the combination of HFC 134a with various chlorofluorocarbons and optionally a saturated hydrocarbon. U.S. Patent No. 2,885,427 discloses the use of HFC-134a as an aerosol propellant. U.S. Patent No. 3,261,748 discloses the use of HFC-134a for anesthesia. U.S. Patent Nos. 4,129,603, 4,311,863, 4,851,595 and European Publication No. 379,793 also disclose the use of HFC-134a as an aerosol propellant. WO 92/00062 discloses pharmaceutical suspension aerosol formulations comprising one or more perfluorinated sulfonamido alcohol phosphate esters as surface-active dispersing agents and 1,1,1,2,3,3,3-heptafluoropropane as the propellant. WO 92/00061 discloses pressurised aerosol compositions comprising a medicament, a hydrofluorocarbon propellant and a polyethoxylated surfactant. WO 91/14422 discloses pharmaceutical suspension aerosol formulations comprising one or more perfluorinated carboxylic acids or esters thereof as surface-active dispersing agents and 1,1,1,2,3,3,3-heptafluoropropane as the propellant. WO 91/11496 discloses the use of 1,1,1,2,3,3,3-heptafluoropropane in combination with other propellant gases for pharmaceutical compositions. WO 91/11173 discloses pressurised aerosol compositions comprising a liquified hydrofluorocarbon propellant containing substantially no hydrofluorocarbon solvent, having dispersed therein a medicament and a fluorinated surfactant. However, the specific combinations noted above may not provide the desired solubility, stability, low toxicity, exact dosage, correct particle size (if suspension) and/or compatibility with commonly used valve assemblies of metered dose inhalers. SUMMARY OF THE INVENTION Accordingly, the present invention is directed at a non-toxic formulation substantially free of CFC's having improved stability and compatibility with the medicament and which is relatively easily manufactured. The present invention also is directed at formulations which may be utilized in present aerosol filling equipment with only relatively minor modifications and without pre-coating the medicament. One embodiment of the present invention is directed at an aerosol formulation consisting of: A. an effective amount of a medicament selected from albuterol and salts thereof, beclomethasone dipropionate and clathrates thereof, wherein the medicament is a powder having a mean particle size of 0.5-10 microns; and B. 1,1,1,2,3,3,3-heptafluoropropane; and C. optionally, one or more components selected from one or more of the following: preservatives; sweeteners; and taste masking agents, and D. one or more excipients selected from the following: propylene glycol diester of a C 6 -C 12 fatty acid; tryglyceride ester of a C 6 -C 12 fatty acid; perfluorodimethylcyclobutane; perfluorocyclobutane; polyethylene glycol; menthol; lauroglycol; diefhylene glycol monoethylether; polyglycolized glyceride of a C 6 -C 12 fatty acid; alcohols; eucalyptus oil; C 4 -C 8 fatty acids; and combinations thereof. The preferred liquid excipients are diethylene glycol monethyether, propyleneglycol diesters of medium chain fatty acids, perfluorodimethylcyclobutane and polyethylene glycol. The invention is of particular utility where the medicament is albuterol, or beclomethasone dipropionate, and salts and clathrates thereof. A useful formulation range comprises A. 1,1,1,2,3,3,3 heptafluoropropane 25 - 99.99 wt % B. medicament 0.01 -1 wt % C. excipient up to 75 wt% D. surfactant 0 wt % The aerosol formulations of the invention are for use in treating asthma. DETAILED DESCRIPTION OF THE INVENTION The formulations of the present invention all utilize propellant 227 in combination with the medicament, and a liquid excipient. The excipient facilitates the compatibility of the medicament with the propellant and also lowers the discharge pressure to an acceptable range i.e. about 2.76- 5.52 x 10 5 newton/meter 2 absolute (40 to 80 psia), preferably 3.45 - 4.83 x 10 5 newton/meter 2 absolute (50 to 70 psia). The excipient chosen must be non-reactive with the medicament, relatively non-toxic, and should have a vapor pressure below about 3.45 x 10 5 newton/meter 2 absolute (50 psia). As used hereinafter the term "medium chain fatty acids" refers to chains of alkyl groups terminating in a -COOH group and having 6-12 carbon atoms, preferably 8-10 carbon atoms. The term "short chain fatty acids" refers to chains of alkyl groups terminating in a -COOH group and having 4-8 carbon atoms. The term "alcohol" includes C 1 -C 3 alcohols, such as methanol, ethanol and isopropanol. Among the preferred excipients are: propylene glycol diesters of medium chain fatty acids available under the tradename Miglyol 840 (from Hüls America, Inc. Piscataway, N.J.); triglyceride esters of medium chain fatty adds available under the tradename Miglyol 812 (from Hüls); perfluorodimethylcyclobutane available under the tradename Vertrel 245 (from E.I DuPont de Nemours and Co. Inc. Wilmington, Delaware); perfluorocyclobutane available under the tradename octafluorocyclobutane (from PCR Gainsville, Florida); polyethylene glycol available under the tradename PEG 400 (from BASF Parsippany, N.J.); menthol (from Pluess-Stauffer International Stanford, Connecticut); propylene glycol monolaurate available under the tradename lauroglycol (from Gattefossé Elmsford, N.Y.); diethylene glycol monoethylether available under the tradename Transcutol (from Gattefossé); polyglycolized glyceride of medium chain fatty acids available under the tradename Labrafac Hydro WL 1219 (from Gattefossé); alcohols, such as ethanol, methanol and isopropanol; eucalyptus oil available (from Pluess-Stauffer International); and mixtures thereof. The medicaments of the present invention include albuterol, and beclomethasone dipropionate. These compounds may be utilized either as the free base, as a salt, or as a clathrate, depending upon the stability and solubility of the active compound in the specific formulation. When clathrates are utilized, P-11 and hexane clathrates are particularly preferred. Where the active compound forms a suspension, the particle size should be relatively uniform, with substantially all the particles ranging between 0.5-10 microns, preferably 1-5 microns. Particles larger than 25 microns may be held up in the. oropharyngeal cavity, while particles smaller than about 0.5 micron preferably are not utilized, since they would be more likely to be exhaled and, therefore, not reach the lungs of the patient. The formulations of the present invention may be filled into the aerosol containers using conventional filling equipment. Since propellant 227 may not be compatible with all elastomeric compounds currently utilized in present aerosol valve assemblies, it may be necessary to substitute other materials, such as white buna rubber, or to utilize excipients and optionally surfactants which mitigate the adverse effects of propellant 227 on the valve components. To assure uniform dispersion of the active ingredient, the formulations typically will include the following components: Range (wt %) Preferred Range (wt%) Most Preferred Range (wt%) Medicament 0.01 - 1 0.03 - 0.7 0.05 - 0.5 Propellant 25 - 99.99 50 - 99.97 50 - 99.95 Excipient(s) up to 75 up to 50 up to 50 Surfactant(s) 0 0 0 Depending on the particular application, the container may be charged with a predetermined quantity of formulation for single or multiple dosing. Typically, the container is sized for multiple-dosing, and, therefore, it is very important that the formulation delivered is substantially uniform for each dosing. For example, where the formulation is for bronchodilation, the container typically is charged with a sufficient quantity of the formulation for 200 charges. Suitable suspensions may be screened in part by observing several physical properties of the formulation, i.e. the rate of particle agglomeration, the size of the agglomerates and the rate of particulate creaming/settling and comparing these to an acceptable standard. Suitable solutions may be screened by observing the solubility of the medicament over the entire recommended storage temperature range. Suspensions of the present invention preferably may be prepared by either the pressure filling or cold filling procedures well-known in the art. For metered dose inhalators, suspensions may be particularly preferred for efficacy and stability considerations. Those skilled in the art may choose to add one or more preservative, buffer, antioxidant, sweetener and/or flavors or other taste masking agents depending upon the characteristics of the formulation. Examples I - XXXIII below further describe the present invention. For several of the examples, alternative formulations denoted as A and B are provided. Component Wt% EXAMPLE I A B Albuterol 0.5 0.1 Miglyol 812 10.0 1.0 HFC-227 89.5 98.9 EXAMPLE II Albuterol 0.1 Transcutol 25.0 HFC-227 74.9 EXAMPLE III A B Albuterol 0.5 0.1 Miglyol 840 10.0 1.0 HFC-227 89.5 98.9 EXAMPLE IV Albuterol 0.1 PEG 400 1.0 HFC-227 98.9 EXAMPLE V Albuterol 0.1 Menthol 0.5 HFC 227 98.9 EXAMPLE VI A B Albuterol 0.1 0.1 Lauroglycol 0.1 0.5 HFC 227 99.8 99.4 EXAMPLE VII A B Albuterol 0.1 0.5 Vertrel 245 10.0 49.6 HFC 227 89.9 49.9 EXAMPLE VIII Albuterol 0.1 Labrafac Hydro WL 1219 0.5 HFC 227 99.4 EXAMPLE IX A B Albuterol 0.1 0.5 Perfluorocyclobutane 10.0 49.6 HFC 227 89.9 49.9 EXAMPLE X A B Beclomethasone Dipropionate 0.1 0.1 Miglyol 812 1.0 10.0 HFC 227 98.9 89.9 EXAMPLE XI A B Beclomethasone Dipropionate 0.1 0.1 PEG 400 1.0 10.0 HFC 227 98.9 89.9 EXAMPLE XII Beclomethasone Dipropionate 0.1 Ethanol 5 HFC 227 94.9

Claims: An aerosol formulation consisting of: A. an effective amount of a medicament selected from albuterol and salts thereof, beclomethasone dipropionate and clathrates thereof, wherein the medicament is a powder having a mean particle size of 0.5-10 microns; and B. 1,1,1,2,3,3,3-heptafluoropropane; and C. optionally, one or more components selected from one or more of the following: preservatives; sweeteners; and taste masking agents, and D. one or more excipients selected from the following: propylene glycol diester of a C 6 -C 12 fatty acid; triglyceride ester of a C 6 -C 12 fatty acid; perfluorodimethylcyclobutane; perfluorocyclobutane; polyethylene glycol; menthol; lauroglycol; diethylene glycol monoethylether; polyglycolized glyceride of a C 6 -C 12 fatty acid; alcohols; eucalyptus oil; C 4 -C 8 fatty acids; and combinations thereof. A formulation according to Claim 1 containing 0.01 to 1 percent by weight medicament. A formulation according to Claim 2 containing 0.03 to 0.7 percent by weight medicament. A formulation according to Claim 3 containing 0.05 to 0.5 percent by weight medicament. A formulation according to any preceding claim wherein the medicament is a powder having a mean particle size of 1-5 microns. A formulation according to any of Claims 1 to 5, comprising an excipient selected from propylene glycol diester of a C 6 -C 12 fatty acid and a triglyceride ester of a C 6 -C 12 fatty acid. A formulation according to any of Claims 1 to 6 for the treatment of asthma. Use of albuterol or a salt thereof in association with 1,1,1,2,3,3,3, heptafluoropropane and an excipient in the manufacture of a surfactant-free medicament for oral and/or nasal administration to a patient suffering from asthma, wherein said medicament is a powder having a mean particle size of 0.5-10 microns and wherein the excipient is selected from:- propylene glycol diester of a C 6 -C 12 fatty acid; triglyceride ester of a C 6 -C 12 fatty acid; perfluorodimethylcyclobutane; perfluorocyclobutane; polyethylene glycol; menthol; lauroglycol; diethylene glycol monoethylether; polyglycolized glyceride of a C 6 -C 12 fatty acid; alcohols; eucalyptus oil; C 4 -C 8 fatty acids; and combinations thereof. Use of beclomethasone dipropionate or a clathrate thereof in association with 1,1,1,2,3,3,3, heptafluoropropane and an excipient in the manufacture of a surfactant-free medicament for oral and/or nasal administration to a patient suffering from asthma, wherein said medicament is a powder having a mean particle size of 0.5-10 microns and wherein the excipient is selected from:- propylene glycol diester of a C 6 -C 12 fatty acid; triglyceride ester of a C 6 -C 12 fatty acid; perfluorodimethylcyclobutane; perfluorocyclobutane; polyethylene glycol; menthol; lauroglycol; diethylene glycol monoethylether; polyglycolized glyceride of a C 6 -C 12 fatty acid; alcohols; eucalyptus oil; C 4 -C 8 fatty acids; and combinations thereof. Use of albuterol or a salt thereof in the manufacture of a surfactant-free aerosol pharmaceutical composition, said composition comprising 1,1,1,2,3,3,3 heptafluoropropane as propellant for the treatment of asthma by oral and/or nasal administration, wherein said albuterol or salt thereof is a powder having a mean particle size of 0.5-10 microns and wherein said composition also comprises an excipient selected from:- propylene glycol diester of a C 6 -C 12 fatty acid; triglyceride ester of a C 6 -C 12 fatty acid; perfluorodimethylcyclobutane; perfluorocyclobutane; polyethylene glycol; menthol; lauroglycol; diethylene glycol monoethylether; polyglycolized glyceride of a C 6 -C 12 fatty acid; alcohols; eucalyptus oil; C 4 -C 8 fatty acids; and combinations thereof. Use of beclomethasone dipropionate or a clathrate thereof in the manufacture of a surfactant-free aerosol pharmaceutical composition, said composition comprising 1,1,1,2,3,3,3 heptafluoropropane as propellant for the treatment of asthma by oral and/or nasal administration, wherein said beclomethasone diproprionate or a clathrate thereof is a powder having a mean particle size of 0.5-10 microns and wherein said composition also comprises an excipient selected from:- propylene glycol diester of a C 6 -C 12 fatty acid; triglyceride ester of a C 6 -C 12 fatty acid; perfluorodimethylcyclobutane; perfluorocyclobutane; polyethylene glycol; menthol; lauroglycol; diethylene glycol monoethylether; polyglycolized glycerides of a C 6 -C 12 fatty acid; alcohols; eucalyptus oil; C 4 -C 8 fatty acids; and combinations thereof.

Inventors: BERRY JULIANNE, CHAUDRY IMTIAZ A, KOPCHA MICHAEL, SEQUEIRA JOEL A, BERRY, JULIANNE, CHAUDRY, IMTIAZ A., KOPCHA, MICHAEL, SEQUEIRA, JOEL A.
Applicants: SCHERING CORP, SCHERING CORPORATION
Application year: 1992
Main classification: A61K9
IPC codes: A61K9, A61K31, A61P9, A61K47, A61P11, A61P43, A61P29, C09K3