GB2179249A

GB2179249A - Dispensing filled pressurised container

Info

Publication number: GB2179249A
Application number: GB08521249A
Authority: GB
Inventors: David Fitzgerald Webster; Derek Andrew Hollingsbee
Original assignee: Smith and Nephew Associated Companies PLC
Current assignee: Smith and Nephew PLC
Priority date: 1985-08-24
Filing date: 1985-08-24
Publication date: 1987-03-04
Also published as: GB8521249D0

Abstract

A filled pressurised container which on activation of a valve dispenses an emollient cream, preferably comprising an oil-in-water emulsion, which has a viscosity of 70 to 170 poise at 25 DEG C. By means of this dispensing system contamination of the emollient cream in a multi dose situation is avoided and instability on storage.

Description

SPECIFICATION Dispensing Filled Pressurised Container The present invention is concerned with a filled pressurised container which on activation of a valve dispenses an emollient cream for use on the skin.

It is often necessary to treat patients showing the symptoms of dry skin with moisturising or emollient preparations, that is a preparation which tends to reduce moisture loss from the stratum corneum and hydrates the keratin. Such preparations are used, for example, to ameliorate the effects of eczema, pzoriasis, ichthyosis and for other chronic dry skin conditions. Generally available emollient preparations are in the form of water-in-oil emulsions, oil-in water emulsions and lotions, all of which have a low viscosity and are freely flowable.

Such preparations are inconvenient to apply to a patient because they will tend to flow away from the point of application and may be contaminated by bacteria or other contaminants when used in multidose situations.

We believe that it would be desirable if the emollient preparation could be applied in the form of a thick cream, as a thick cream would not flow on the skin until dispersed by the band and the amount which was applied could be readily controlled.

However, if the cream is dispensed from a conventional tube or pot it appears to us that two problems could arise. Firstly the preparation could be contaminated in a multidose situation as at least some of the recipients of the preparation could be suffering from a transmittable disease of the skin and secondly instability during storage and between applications. We have now found that by using a non-aerosol pressurised container or barrier pressure pack it is possible to dispense the thick creams required for the emollient preparations without the risk of contamination and without encountering stability problems on storage.

Accordingly the present invention comprises a filled pressurised container which on activation on a valve dispenses an emollient cream for use on the skin, wherein the emollient cream has a viscosity of from 75 to 170 poise at 25"C.

Suitably the emollient cream for use in the present invention will be in the form of a thick oil in water emulsion which is ambiphilic, that is may be diluted by both water and oil. Suitably, the cream will contain as well as oil and water, emulsifying agents and emulsifying waxes and fatty alcohols to stabilise the oil phase.

Non-ionic surface active agents may be employed as emulsifying agents to aid in the emulsification of the oil and water phases of the emollient creams used in the present invention. Suitable non-ionic surface active agents include the polyoxyethylated sorbitan fatty acid esters and the sorbitan fatty acid esters. Normally the non-ionic surface active agent will comprise a mixture of the two types of agent in proportions which will provide a hydrophilelipophile balance number of between 8 and 18 which will provide a particularly stable cream.

Preferably the non-ionic surface active agent is a mixture of sorbitan monopalmitate and polyoxyethylated sorbitan monopalminate. Suitably the cream will comprise from 1 to 10% by weight of non-ionic surface active agent, more suitably 2 to 8% of non-ionic surface active agent and preferably 3 to 6%, for example 3%, 4% and 5%.

Suitable fatty alcohols for use in the emollient creams used in the present invention will be water insoluble and will form part of the oil phase of the cream. Suitable alcohols include stearyl alcohol, cetyl alcohol, lauryl alcohol, myristyl alcohol and cetostearyl alcohol. Suitably the cream will comprise from 1 to 10% by weight of fatty alcohol, more suitably from 2 to 8% of fatty alcohol and preferably 2 to 5%, for example 2%, 3% and 4%.

Suitably the emollient cream employed in the present invention will contain a second emulsifying agent. Suitable emulsifying agents include the glyceryl fatty acid esters of which glyceryl monostearate is preferred. Suitably the cream will contain from 1 to 12% by weight of emulsifying agent, more suitably 2 to 6% and preferably 2 to 4%, for example 2%, 2.5% and 3%.

An emulsifying wax, which may be used in place of part of both of the fatty alcohol and non-ionic surface active agent may be present in the emollient creams employed in the invention. The presence of the wax which is soluble in the oil in the cream improves the consistency of the oil thereby contributing to the stability and high viscosity of the cream. Preferably the emulsifying wax replaces 1 to 2% by weight of the cream of each of the non-ionic surface active agent and fatty alcohol. The cream will suitably contain from 0 to 10% by weight of emulsifying wax and preferably 2 to 6% by weight, for example 2% and 3%.

Suitably the emollient cream will contain a humectant to facilitate the moisturising effect of the cream. Suitable humectants include polyhydric alcohols such as propylene glycol, sorbitol or glycerol or mixtures thereof. Suitably the emollient cream will contain from 5 to 25% by weight of a humectant, more suitably 6 to 20% by weight and preferably 7 to 15% by weight Aptly the oil phase of the emollient cream used in the invention comprises a pharmaceutically acceptable oil or a mixture of such oils. Suitable oils include vegetable oils, mineral oils and synthetic oils such as paraffin oil, white soft paraffin, white oil, arachis oil. A preferred oil phase is a mixture of white soft paraffin and white oil. Suitably the cream will contain from 30 to 50% by weight of oil, more suitably from 32 to 45% and preferably 35 to 42%.

Normally the emollient creams employed in the present invention will contain preservative. Suitable preservatives will be those which are compatible with the other components of the cream and are not inactivated by them Suitable preservatives include 2-phenoxyethanol (phenoxetol), sorbic acid and Dowicil 200 (Registered trade mark). Each preservative has a range of concentration at which it is effective in the cream, therefore the cream may contain from 0.3 to 0.5% 2-phenoxyethanol, for example 0.4%, from 0.1 to 0.3% of sorbic acid, for example 0.2% and from 0.05 to 0.2% of Dowicil 200, for example 0.1%.

The creams for use in the present invention may be prepared by mixing together and warming to 80"C the water and water soluble components. The oil and oil soluble components are similarly mixed together and warmed to 75"C. The oil components may be placed in a large mixing vessel and the aqueous components, at 80"C, added with stirring.

The mixture is stirred and allowed lo cool when a thick cream is formed.

Alternatively the mixture may be allowed to cool to 40"C and then be passed through a conventional colloid mill to produce a smoother cream.

The cream once formed may be filled into the barrier pack containers by conventional filling equipment.

Suitably the pressurised container comprises a cylindrical seamless aluminium container body. The container body has a concave base with a hole through which a gas may be introduced under pressure. The top of the body is closed by a cone which has an opening to accommodate a conventional valve. A shaped pouch of aluminium is attached at rim between the container body and cone. A gas impermeable stopper closes the hole at the bottom of the container. Preparation of the filled container is accomplished by filling the cream into the aluminium pouch which had previously been attached between cone and body. The cone is then closed by the valve. A pressure medium, for example nitrogen, dried filtered compressed air or other suitable gas is introduced through the hole in the bottom of the container and the hole closed by an impermeable rubber bung.Activation of the valve mechanism by finger pressure causes cream to be expelled from the container through the nozzle on the valve.

In use the valve on the container is activated to dispense the emollient cream.

The viscosity of the emollient creams suitable for use in this invention were measured using a Ferranti-Shirley Cone and Plate Viscometer with the following parameters: cone 7cm spring 600 g/cm- sweep time 120 seconds maximum rate of shear 172.2 sec.

temperature 25"C I Suitably the emollient creams used in the present invention will have a viscosity when measured under these parameters of 70 to 175 poise and more suitably will have a viscosity of 80 to 120 poise and preferably from 85 to 110 poise, for example 90 poise, 92 poise.

Optionally, though not preferably, the emollient cream may additionally contain a pharmacologically active agent. Suitable pharmacological agents include steroids such as hydrocortisone and betamethasone and their salts, antibiotics and antibacterials such as tetracycline and chlorhexidine gluconate and antipsoriatics.

EXAMPLE 1 Emollient Cream Formulation Non-ionic surface active agent 4.0% Glyceryl monostearate 2.5% Stearyl alcohol 2.5% Emulsifying wax 3.0% Oils 36.0% Isopropyl myristate 3.0% Propylene glycol 7.0% Sorbic acid 0.2% Distilled water to 100% The aqueous phase containing distilied water, sorbic acid, non-ionic surface active agents and propylene glycol were mixed together and warmed to 80"C. The remaining components comprising the oil phase were mixed together and warmed to 75" and then transferred to a planetary mixer bowl. The aqueous phase, at 80"C, was added to the oil phase with mixing.Mixing was continued until the emulsion became viscous, this occurred at approximately 40"C. This emulsion was then passed through a 125 um gap on a colloidal mill to produce a smooth white emulsion.

This emulsion was then filled into the pouch of a pressurisable container. The container sealed by a valve mechanism and the container pressurised. In use, activation of the valve mechanism permitted controlled dispensing of the emollient cream.

EXAMPLE 2 Emollient Cream Formulation An emollient cream was formulated as follows: *Non-ionic surface active agents 3.0% Glyceryl monostearate 2.0% Cetostearyl alcohol 2.0% Emulsifying wax 2.0% Mineral oils 29.0% Isopropyl myristate 2.5% Propylene glycol 5.5% Sorbic acid 0.3% Distilled water to 100% *a mixture of polyoxyethylated sorbitan monopal mate and polyoxyethylated sorbitan fatty acid ester, saturated.

The cream was prepared und packaged in a similar mannerto that of Example 1.

Claims

1. A filled pressurised container which on activation or a valve dispenses an emollient cream for use on the skin wherein the emollient cream has a viscosity of from 70 to 170 poise at 25"C.

2. A container as claimed in claim 1 in which the emollient cream comprisesfrom 1 to 10% by weight of non-ionic surface active agent.

3. A container as claimed in claim 2 in which the non-ionic surface active agent comprises a mixture of polyoxyethylated sorbitan fatty acid esters and sorbitan fatty acid esters which provide a hydrophile-lipophile balance number of between 8 and 18.

4. A container as claimed in claim 3 in which the non-ionic surface active agent comprises sorbitan monopalmate and polyoxyethylated sorbitan monopalmitate.

5. A container as claimed in any one of claims 1 to 4 in which the emollient cream comprises from 1 to 12% by weight of an emulsifying agent.

6. A container as claimed in claim 5 in which the emulsifying agent is glyceryl monostearate.

7. A container as claimed in any one of claims 1 to 6 in which the emollient cream comprises from 1 to 10% by weight of fatty alcohol.

8. A container as claimed in claim 7 in which the fatty alcohol is stearyl alcohol.

9. A container as claimed in any one of claims 1 to 8 in which the emollient cream comprises from 5 to 25% of a humectant.

10. A container as claimed in claim 10 in which the humectant is propylene glycol.

11. A container as claimed in any one of claims 1 to 10 in which the emollient cream comprises from 30 to 50% by weight of a pharmaceutically acceptable oil.

12. A container as claimed in claim 11 in which the pharmaceutically acceptable oil is a mixture of white soft paraffin and white oil.

13. A container as claimed in any one of claims 1 to 12 in which the emollient cream comprises from 2 to 6% by weight of an emulsifying wax.

14. A container as claimed in any one of claims 1 to 13 in which the emollient cream contains from 0.1 to 0.5% by weight of a pharmaceutically acceptable preservative.

15. A container as claimed in claim 14 in which the emollient cream contains from 0.1 to 0.3% of sorbic acid.

16. A container as claimed in claim 14 in which the emollient cream comprises from 0.3 to 0.5% by weight of 2-phenoxyethanol.