US3456052A - Aerosol composition containing butoxymonoether of a polyoxyalkylene glycol - Google Patents

Description

United States Patent 3,456,052 AEROSOL COMPOSITION CONTAINING BU- TOXYMONOETHER OF A POLYOXYAL- KYLENE GLYCOL Marvin Gordon, Baltimore, Md., assignor to Garrett Laboratories, Inc., a corporation of Maryland No Drawing. Filed Sept. 28, 1965, Ser. No. 491,030 Int. Cl. A61k 9/06, 21/00 U.S. Cl. 42445 7 Claims ABSTRACT OF THE DISCLOSURE An improved pharmaceutical aerosol ointment base system which consists essentially of a propellant, an ointment base and an efiective amount of a medicament. The ointment base consists essentially of a butoxymonoether of a polyoxyalkylene glycol which is substantially completely soluble in the propellant.

This invention relates to improvements in self-propelling medicinal compositions and methods of their use and relates more particularly to an improved pharmaceutical aerosol ointment base system.

There have been various self-propelling therapeutic preparations suggested heretofore which provide for the topical application of a selected pharmaceutically active material to an injured or infected area of the human body. Many of the prior art materials merely dispense the medicament in the form of a spray form a dispersion or solution of the same in a propellant maintained under pressure in an aerosol container. Such systems suffer numerous disadvantages, perhaps the most significant of which is their inability to maintain the active ingredient in contact with a limited area of the body for a time sufficient to allow the same to provide its healing properties. Generally, the spray resulting from such a composition has an extremely low viscosity, frequently on the order of water, whereby the material has a tendency to run from the area onto which it is dispensed causing great inconvenience to the patient as well as a substantial loss of medicament. Moreover, these materials are generally cold in use because of the rapid evaporation of the propellant which forms the major constituent of the composition. In view of the fact that the area being treated is normally quite sensitive, such a characteristic is extremely undesirable.

An additional difficulty frequently encountered with spray materials of this type is their inability to provide, especially in a reproducible manner, a uniform application of the medically active ingredient throughout the use of the entire aerosol container. This is particularly due to the fact that the active material is frequently merely dispersed in the propellant whereby it will have a tendency to settle to the bottom. Further, the dispersed material will sometimes clog the spray dispensing valve whereby the pattern of the atomized particles will vary with the use of the container, substantially decreasing the likelihood that a consistent quantity of medicament can be dispensed in a particular time.

It has been proposed to overcome certain of the above disadvantages by topically applying the medicament in the form of an ointment spray. However, the attempt to self-propellant ointment base causes many difficulties of its own. Although the ointment systems suggested to date may improve the healing capabilities of a self-propelling medicinal composition by providing a non-runny film for maintaining the active ingredient in contact with the afiected bmly area, there are many problems with which these prior art materials have not been able to deal effectively.

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In the first place, While the ointment base systems currently in use do provide a means for applying a film of a somewhat stable material to the bodily area being treated whereby prolonged contact with a medicament may be realized, it has been found that they do not permit sufliciently rapid release of the active component of the composition to effect the proper healing characteristics. Moreover, the nature of such prior art systems is such that, for the most part, they are water insoluble and produce a greasy film on the skin surface. Thus, in addition to the obvious cosmetic problems resulting from the use of such materials, they are difficult to remove whereby it sometimes becomes necessary to contact a sensitive body area with an irritating solvent or to apply undesirable pressure to the area to cleanse the same. Further, the oily nature of the ointment base in some such systems has a tendency to soil clothing with which it comes in contact. Also, dust and dirt from the environment have a great tendency to stick to these ointment bases and the difiiculty in removing the same will frequently result in the presence of a contaminating film in contact with the body area being treated whereby the therapeutic value of the composition may be defeated.

Further, the difiiculty in substantially uniform applications referred to hereinabove is even more prevalent in materials of this type since the ointment base and certain of the additional materials included therewith are generally merely dispersed in the propellant whereby an even greater tendency to clog the spray dispensing head results.

In an attempt to improve the properties of the applied materials while limiting the area to be covered to a desired degree, it has been suggested that self-propelling compositons in the nature of a foam in contrast to an atomized spray be utilized. However, in order to provide a foam which will be quick-breaking so that proper use of the same is feasible, it is necessary to include a substantial quantity of extraneous materials such as surface active agents and the like thereby increasing the expense of manufacture as well as toxicity problems encountered with a medicinal composition. Moreover, a foam cannot provide the distribution and substantially uniform film which is realized with a properly atomized spray. Further, in pharmaceutical applications, such foams suffer from relatively poor medicament release whereby their healing properties are substantially diminished.

Another significant disadvantage of foams, when considered in contrast with sprays, particularly for medicinal compositions, is their inability to penetrate into the various crevices which are usually present in an injured or infected area of the human body. Although a spray is capable of providing suflicient dispensing power to uniformly cover the entire affected area, it is still an ideal method of application from the standpoint of gentleness and comfort to the patient.

Generally, sprayable ointment compositions utilized in the past have had as the major component of their ointment base, an oil, such as mineral oil, either by itself or in combination with other oils and thixotropic agents. Additionally, mineral oil bases including fibrous or other forms of various resinous materials such as polyethylene or the like, have been utilized in an attempt to improve some of the characteristics of the ointment base. However, all of these compositions have suifered from the various disadvantages mentioned hereinabove since they are generally in the form of dispersions of a non-water soluble, greasy material having relatively poor medicament release capabilities in use. Particular obstacles to overcome with such compositions is the provision of substantially uniform and reproducible application as well as relative ease in removal from a sensitive body area.

Similarly, attempts to use such materials as Carbowax,

a trademark for a particular series of polyethylene glycols produced by Union Carbide Chemicals Company, while providing water solubility to the ultimate ointment base, still results in a greasy film and raises certain toxicity problems With respect to the aerosol application of the same. Moreover, this material is generally insoluble in many of the propellants which are most desirable for topical application to sensitive body areas, requiring either the use of a dispersion which results in non-uniform application, or the use of a propellant having various undesirable characteristics such as irritation to the skin and possible flammability.

Thus, it will be seen that although many attempts have been made to provide an ideal self-propelling composition for topical application of a pharmaceutically active material, each of the materials suggested to date has failed in one or more respects. It is to be understood that the disadvantages of prior art materials discussed hereinabove are merely illustrative and are not meant to be fully comprehensive in all respects. However, it is apparent from the above background that the production of an optimum ointment base system and method of its application has provided the industry with an intricate problem which it has been unable to satisfactorily solve even after extensive research.

It is therefore a primary object of the instant invention to provide an ointment base system and method of using the same which is free from the foregoing and other disadvantages. In this regard, it is a particular objective of the instant inventive concept to provide an aerosol ointment base which is relatively simple and inexpensive to manufacture and which results in the topical application of a pharmaceutically active material in an easily controlled, substantially uniform, water soluble, film from which the medicament is rapidly and continuously released to the area being treated.

Consistent with the above, it is a basic object of this invention to provide a self-propelling medicinal spray wherein the ointment base, and preferably the medicament or medicaments, are substantially fully soluble in the propellant in order that the application of a desired quantity of the active ingredients in a reproducible manner can be produced from a conventional pressurized aerosol container, even after extended use. Further along these lines, it is an important object of this invention, at least in its preferred form that there be complete and mutual solubility of the ingredients in order to preclude settling of any of the components of the system and clogging of the spray dispensing head.

A further object of this invention is the provision of an aerosol ointment base system which is uniquely compatible with substantially all commonly utilized therapeutic materials and which is capable of releasing the same from the ointment film to the body area under treatment in a rapid and continuous manner whereby effective healing of the injury or infection will be realized.

Yet another important objective of this invention is the provision of a self-propelling medicinal composition which is capable of penetrating the area being treated while providing for gentle application. In a similar vein, it is a special feature of at least the preferred compositions of this invention that the applied spray be uniquely warm and non-irritating to a sensitive body area on which it is used, while producing a uniform film sufliciently viscous at body temperatures to remain in place and yet water soluble so that it can be easily removed Without undesirable discomfort to the patient Other and further objects of this invention reside in the particular materials utilized, the quantitative relationship between the same and the method of applying the composition to a body area requiring treatment. Still other objects will in part be obvious and in part be pointed out as the description of the invention proceeds.

Consistent with the above background and objects of this invention, it has been found that all of the desirable characteristics for a self-propelling therapeutic material set forth in detail therein, can be provided by a sprayable ointment composition including a propellant-ointment base mixture and an effective quantity of one or more medicaments, wherein the ointment base consists essentially of a butoxymonoether of a polyoxyalkylene' glycol substantially completely soluble in the propellant in the quantities utilized. The butoxymonoether of a polyoxyalkylene glycol utilized in accordance with the instant inventive concept is preferably prepared by reacting an approximately 50/50 mixture by weight of ethylene oxide and 1,2-propylene oxide with butyl alcohol according to the detailed explanation of the production of such materials set forth, for example, in Roberts et a1. Patent No. 2,425,755 dated Aug. 18, 1947. It is pointed out in this patent that such materials are believed to be complex mixtures of glycols of various molecular weights depending on the length of the polyoxyalkylene chain, (OC H which is built up by the addition of the oxyethylene group, OC H and the oxy 1,2-propylene group, OC H -CH to the individual molecules according to the following general equation:

where y and z represent the mols of ethylene oxide and 1,2-propylene oxide respectively; n is both 2 and 3 in a single molecule, the total number of times n has a value of 2 being equal to y and the total number of times It has a value of 3 being equal to z; and x is the total number of such oxyalkylene groups, being equal to y+z. As can be seen, in the preferred starting material which i an approximately 50/50 mixture by weight of ethylene oxide and 1,2-pr0pylene oxide, z is approximately equal to y.

The preferred materials are available commercially from the Union Carbide Chemicals Company under the SO-HB series of their UCON lubricants. Basically, those materials identified as SO-HB-400, 50-HB-660, 50HB2000, 50-HB-3520 and SO-HB-SIOO and mixtures of the same have all been found to be useful although the 50-HB-5100 material provides particularly satisfactory results. These individual materials differ in certain characteristic properties, and may be generally designated by their viscosity in S.U.S. (Saybolt Universal Seconds) at F. which ranges from 400 to 5100 depending on their molecular Weight, this value forming the sufiix in their identification in the UCON 50-HB series.

For most purposes, it is preferred to limit the composition to its three basic ingredients, that is, the propellant, the ointment base and the medicaments. In this regard, it has been found that the addition of extraneous materials in any significant quantity substantially decreases the roperties of the ideal system resulting from the preferred composition.

It is particularly important to avoid the inclusion of any ingredients such as surface active, emulsifying, or foaming, agents in quantities which tend to make it difficult to produce an atomized spray. Any material proportion of such additives will result in the production of a foam in contrast to the discrete particles of a spray.

Similarly, the inclusion of extraneous materials in any substantial amount which are insoluble in the system is to be particularly avoided in order to insure the uniformity of the composition and its application over an etxended period of time from a conventional aerosol container.

While it is to be understood that the self-propelling medicinal spray of the instant invention will preferably consist essentially of the propellant-ointment base mixture and suitable medicaments, the addition of extremely small or insignificant quantities of other constituents which will not affect the basic desired characteristics of the system as specified in detail throughout this application, is acceptable, although not optimum. For example, in the use of a metallic aerosol container, it is sometimes desirable to include a small quantity of a non-toxic corrosion inhibitor. Similarly, small percentages of cosmetic or pharmaceutically active ingredients which are not fully soluble in the system may be included so long as the percentage of the same is insuflicient to overcome to any substantial degree the basic advantages of the completely soluble, three component, composition which is preferred. It is to be emphasized that the addition of such materials, while possibly acceptable in small quantities, is not preferred and therefore should be avoided except for the provision of certain special characteristics to the composition. It will be within the ordinary skill of this art to determine when such extraneous materials may be included without significantly reducing the effectiveness of the basic system.

The quantitative ratio between the primary ingredients of the composition of this invention can vary within relatively large ranges. Preferably, the propellant constitutes the major component in the composition in order that satisfactory atomization and spray characteristics may be provided. In its broadest aspects, a suitable self-propelling material may include from as little as about 0.5 to as much as about 90 percent by weight of the butoxymonoether of a polyoxyalkylene glycol in the propellant-ointment base mixture, with the propellant constituting sub stantially the remainder of the same. However, it will be obvious that the use of the minimum quantity of ointment base will result in a relatively cool, non-viscous system which would require a substantial quantity of spray to build up a thin layer of ointment. On the other hand, although a spray pattern can be produced with only percent propellant, such a composition would be extremely viscous and would provide a relatively thick ointment film which would not be as easy to control. However, by varying the quantitative ratio of propellant to ointment base within the extreme limits of about 0.5 to about 90 weight percent ointment base as indicated above, a system having selective and satisfactory characteristics for a particular application can be provided. In this regard, it has been found that a preferred ratio from all respects includes from about 10 to about 25 weight percent ointment base in the mixture.

With regard to the quantity of medicament utilized, this will of course vary depending upon the particular medically accepted range of the particular pharmaceutically active ingredient. In any event, effective quantities of common therapeutic constituents are relatively low, generally in the vicinity of 1 or 2 percent based on the weight of the ointment base in the composition.

It is to be understood that the type of medicament utilized may vary substantially since, in general, and particularly in view of the relatively small percentages of the same in the overall composition, the characteristics of the aerosol ointment system is not dependent thereon. Further, various combinations of pharmaceutically active ingredients may be utilized. For example, a common antiseptic or bactericidal material such as Merthiolate or thimerosa may be utilized as the only medicament, or may be utilized in combination with an antibiotic such as bacitracin. Similarly, an anesthetic such as benzocaine or lidocaine may be used alone or in combination with other pharmaceutically active materials such as hydrocortisone or the like. Similarly, combinations of antibiotics such as bacitracin and neomycin sulfate may be used with each other or with one or more of the steroids such as hydrocortisone or the like.

Although, as has been pointed out in the immediately preceding paragraph, the aerosol ointment system of this invention is useful as a carrier for most any pharmaceutically active material, it has been found that it provides a unique base material for bacitracin and bacitracin-including medicaments and such a combination is therefore a preferred compoistion for use with the instant inventive concept.

There are various suitable non-toxic propellants which are well known in the aerosol art. In general, these materials may be described as inert, liquefied, normally gaseous volatile materials in which the butoxymonoether of a polyoxyalkylene glycol is substantially completely soluble at the temperature normally encountered in use. Many of the well known fluorinated and chlorinated haloalkanes and mixtures of the same with each other and with n butane and isobutane are completely satisfactory in this regard. Suitable examples of individual and mixed propellants are Du Ponts Freon-22 (CHCIF Allied Chemicals Genetron 142B (CHgCClFz) mixtures of Freon-22 and Freon-114 (CHClF -CClF CCIF Genetron 142B and Freon-114 (CH CClF -CClF CClF Genetron 152A and Freon-114 (CH CHF CClF CClF Freon-l2 and Freon-11 (CCl F CCl F), and mixtures of either isobutane or butane with Genetron 142B, Genetron 152A, Freon-22 or Freon-114. The preferred propellants from the standpoint of solubility, non-irritability and non-flammability are the mixtures of Freon-12 or Freon-22 with Freon-114, but it will be understood that any of the above materials and various other well known propellants and combinations of propellants are suitable, the basic requirement being that the ointment base, and preferably all of the ingredients of the system, are soluble therein and that the propellant provide sufficient pressure to produce an atomized spray of the ointment base and medicaments while completely evacuating a conventional aerosol container.

The various compositions of the instant invention are conveniently prepared according to any conventional aerosol packing procedure. The individual ingredients may be premixed before addition to the aerosol containers, or the various constituents may be separately introduced into the containers by conventional cold fill or pressure methods. In operation, the composition is confined within the aerosol container at the vapor pressure of the propellant and on opening the spray dispensing valve, which may be of any conventional construction, the pressure is released to produce a fine ointment mist of the desired characteristics. A substantially uniform and reproducible layer of the ointment base and medicaments may be readily applied to an injured or infected body area in this manner. The resultant film is air pervious in order to provide a breathing covering which permits access of air and oxygen to the affected area thereby improving the healing characteristics. Further, an ointment film produced in this manner is found to simultaneously permit extremely fast release of the pharmaceutically active ingredient to the body area being treated.

In packing the pressurized aerosol containers, the metallic shell, the spray dispensing head and the constituents of the composition may be presterilized or handled in any medically accepted manner. The aerosol container may then be filled and maintained at a relatively cool temperature while cold propellant is added following which the container may be closed while maintained at the low temperature. Other filling cycles may be used such as mixing the ointment and the propellant and cold filling, or the composition may be pressure-filled at higher temperatures. Various such methods of packing are conventional and the present compositions may be handled by any of the known procedures thus being readily adapted for use with any of the equipment currently available. Preferably, the materials are sufliciently intermixed prior to, or during the filling procedure that a substantially uniform solution is produced thereby precluding any settling or valve clogging problems in subsequent use of the aerosol dispenser.

As mentioned hereinbefore a wide variety of active ingredients may be included in the compositions of the instant invention. In this regard, the term medicament as utilized throughout this specification and in the appended claims, is to be interpreted as one or more cosmetic or therapeutically active ingredients which are suitable for topical application in the form of a fine mist or spray. Such materials are particularly useful in the treatment of open or ulcer-ous wounds or burns and various It will now be seen that there is herein provided an improved aerosol ointment base system and method of using the same which satisfies all of the objectives of the instant invention, and others, including many advantages of great practical utility and commercial importance.

dermatological conditions where it is important to pro- What is claimed is: vide an uncontaminated coating containing therapeutic 1. An aerosol composition consisting essentially of an ingredients in a quick, gentle manner with relative ease eifective quantity of a medicament selected from the of removal for subsequent applications of additional group consisting of antiseptic, antibiotic, anesthetic and quantities of the active ingredients or merely for cleans- 1O hydrocortisone medicaments and mixtures thereof and a ing the affected area. mixture of a propellant and an ointment base, said oint- Although it is believed that the instant inventive conment base being present in from about 0.5 to 90 percent cept can be readily understood from the preceding de by weight of said mixture of propellant and ointment scription, the following table sets forth various illustrabase with the remainder of said mixture being said propeltive examples, in which percents are by weight unless 15 lant, said ointment base having a viscosity of from about otherwise noted: 400 to 5100 S.U.S. at 100 F. and consisting essentially of a TABLE 1 Ointment Example Base, Number Percent Propellant, Percent Active Ingredients 2 Comments Freon-22-114: 1a 0. 5 99.5 Satisfactory, but thin and cool. Particularly 1b excellent, spray and release characteris- 1c 25 tics. 1d 90 Satisfactory, but relatively viscous and difiicult to control. 2 Freon-22, 85 Neomycin Sulfate, 0.5 percent Good. 3 Freon-114, 80 Bacitracin, t500 units; Neomycin Sulfate, Particularly good antibiotic release. 0.5 percen Penicillin G Potassium: fig 30 1,000 units 0 2,000 units.- 4c 20 5 000 units Satisfactory 4d 20 80 10,000 units 5 10 "Genetron 152 Fr 4, 90 Tetracycline HG], 3 percen od. 6 15 Freon-12414, 85 Polymyxin B Sulfate, 10,000 units; Baci- Particularly good release.

tracin, 500 units. 7 Genetron 142B, 75 Poly-inyxin B Sulfate, 10,000 units; Neo- Particularly good.

mycin Sulfate, 0.5 percent; Bacitracin, 500 units. 15 Fre0n-22-114, 85 Bacitracin, 500 units; Neomycin Sulfate, Particularly good antibiotic release plus 0.5 percent; Bcnzocaine, 2 percent. anesthetic action. 10 Genetron 142B"Freon12, 90 Hydrocortisone, 1 percent; Neomycin Good.

Sulfate, 1.5 percent; Bacitracin, 500 units. 25 Freon-12-11, 75-.." Neomycin Sulfate, 5/10 percent; Triam- Do.

cinoloue Acetonide, 0.1 percent. n 11 15 Butane-Freon-114,85.-- Hydrocortisone, 0.5 percent; Neomycm Antunflammation,antibioticandanesthetic Sulfate, 0.5 percent; Lidocaine, 2.5 properties. percent. 12 10 Freon-22414, 90 Thirnerosal, 0.1 percent Good bacteriostat and fungistat.

1 Butoxymonoether of a polyoxyalkylene glycol. 2 U.S.P. units or percent per gram of ointment base.

Tests to date of the compositions of this invention from the standpoint of medical acceptability and toxicity in various regards have all been satisfactory. Such tests have included oral dose and inhalation studies in rats as well as skin penetration and irritation and eye injury studies in rabbits.

It is to be understood that although various specific propellants and quantitative ratios of the components of the aerosol ointment base system have been set forth in the above table, in each instance, these criteria may be varied within the broad ranges and classes of material set forth herein without substantially aifecting the characteristic properties of the ointment film resulting therefrom. However, it might be pointed out again that particularly advantageous results such as medicament release and the like are generally found with bacitracin-containing compositions. Further, comparison of the compositions of this invention with similar self-propelling ointment systems wherein the butoxymonoether of a polyoxyalkylene glycol is replaced by other ointment bases such as those using mineral oil as a major component, results in an ointment film which was unsatisfactory from the standpoint of either cosmetic or therapeutic characteristics. Moreover, the compositions of the instant invention had up to percent better medicament release than those utilizing prior art ointment bases. Similarly, the compositions of this invention were more easily and uniformly applied and more readily removed without irritating the infected or injured areas of the body being treated.

butoxymonoether of a polyoxyalkylene glycol prepared by reacting an approximately 50/50 mixture by weight of ethylene oxide and 1,2-propylene oxide with butyl alcohol, said propellant being selected from the group consisting of fluorochloroalkanes having 14 carbon atoms, and mixtures of the same with each other and with butane and isobutane, said butoxymonoether of a polyoxyalkylene glycol being soluble in said propellant in the quantities utilized.

2. The composition defined in claim 1 wherein said butoxymonoether of a polyoxyalkylene glycol constitutes from approximately 10 to 25 percent by weight of said propellant-ointment base mixture and has a viscosity of approximately 5100 S.U.S. at F.

3. The composition defined in claim 1 wherein said butoxymonoether of a polyoxyalkylene glycol constitutes from approximately 10 to 25 percent by weight of said propellant-ointment base mixture.

4. The composition defined in claim 1 wherein said butoxymonoether of a polyoxyalkylene glycol has a viscosity of approximately 5100 S.U.S. 100 F.

5. The composition defined in claim 1 wherein said medicament is selected from the group consisting of thimerosal, bacitracin, benzocaine, lidocaine, hydrocortisone, neomycin sulfate, penicillin, tetracycline, polymixin B sulfate, and mixtures thereof.

6. The compositions defined in claim 5 wherein said medicament is bacitracin and is present in an amount of from approximately 250-1000 U.S.P. units per gram of ointment base.

7. The composition defined in claim 5 wherein said medicament includes bacitracin.

References Cited UNITED STATES PATENTS 5 Roberts et a1. 260-615 Heilig 167-63 Siegal et a1 167-63 Noseworthy 167-63 Silson et a1. 167-82 10 Hellbaum 167-63 Gross et a1. 167-63 XR 10 OTHER REFERENCES Shepherd Aerosols: Science and Technology, 1961, pp.

ALBERT T. MEYERS, Primary Examiner D. R. MAHANAND, Assistant Examiner US. Cl. X.R.