Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Phosphorus containing other than solely as part of an...
Patent
1996-04-08
2000-04-18
Lovering, Richard D.
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Phosphorus containing other than solely as part of an...
424401, 524521, 524522, 524523, 516 67, 516 73, A01N 5708, A61K 740, C08J 303
Patent
active
060515627
DESCRIPTION:
BRIEF SUMMARY
This application is filed under 35 U.S.C. 371 and based on PCT/GB 94/02014, filed Sep. 15, 1994.
This invention relates to compositions that are generally referred to as oil-in-water emulsions. These are; storage-stable, heterogeneous, liquid compositions comprising a continuous aqueous phase (the "water") and a discontinuous dispersed phase of a hydrophobic liquid (the "oil") which is immiscible in the water. Instead of the dispersed phase being a liquid, it can be a solid obtained by providing an emulsion in the water of a solution in the oil of potentially solid material, and then converting this solution to a solid phase while it is emulsified in the water.
BACKGROUND OF THE INVENTION
It is standard practice to include various additives in such emulsions in order to facilitate their initial formation and to promote stability, in particular by reducing coalescence. Thus it is conventional to include one or more emulsifiers or surfactants. The use of combinations of emulsifiers of different HLB values is conventional. The use of two surfactants that are intended to react with one another is described in U.S. Pat. No. 4,472,291. The particle size in this is below 0.5 .mu.m.
Conventional emulsifiers consist of a single hydrophobic moiety and a single hydrophilic moiety (for instance an ethoxylated fatty alcohol consists of a fatty alkyl hydrophobic group and a hydroxy-terminated polyoxy ethylene hydrophilic group). However emulsifiers that have a more complex structure are known for specialised purposes.
For instance it is known from GB 2,001,083, GB 2,002,400 and EP 333501 to provide an oil-soluble emulsifier by condensing hydroxy stearic acid with itself and on to polyethylene glycol or polyethylene imine. The resultant product may contain molecules having a polyoxyethylene or polyethylene imine backbone terminated at each end by an end group containing a stearic group or a condensate of several stearic groups, thus providing terminal hydrophobes and a central hydrophilic chain. We have used these oil-soluble materials dissolved in the continuous phase of water-in-oil emulsions and suspensions.
It is also to known to use block copolymers of ethylene oxide and propylene oxide and/or butylene oxide as emulsifiers. We believe that existing emulsification systems always require, as an essential ingredient, the use of a conventional emulsifier of the type having a single hydrophobic moiety and a single hydrophilic moiety. Such emulsifiers are thought to be effective at promoting stability as a result of this single hydrophobic moiety being physically attracted into the oil phase and a single hydrophilic moiety being physically attracted into the water phase.
The emulsifiers and surfactants concentrate at the interface between the two phases, but it is also known that emulsion properties can be altered by viscosifying the water phase. Thus a water-soluble polymer that is wholly hydrophilic, for instance high molecular weight polyacrylic acid, can be distributed throughout the water phase in order to viscosity it.
It is known from, for instance, EP 126528 to provide an emulsion in oil of aqueous polymer droplets (i.e., a water-in-oil emulsion) wherein the formation of the emulsion is promoted by the use of a conventional water-in-oil emulsifier (e.g., sorbitan mono oleate) and the stability of the emulsion is promoted by an oil-soluble stabilising polymer dissolved in the continuous oil phase. This polymer can be formed by copolymerisation of water insoluble ethylenically unsaturated monomer (for instance stearyl methacrylate) with ethylenically unsaturated carboxylic acid (for instance methacrylic acid) or it can be, for instance, a polyethylene glycol-polyhydroxy stearic acid condensation product as mentioned above.
It is also known to make water-in-oil-in-water emulsions using different polymers having different solubilities. For instance an oil-soluble material described as a Polaxamer surfactant of high molecular weight is incorporated in the oil phase and a water-soluble polymer such as polyacrylic aci
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Chamberlain Peter
Harden Eleanor
Ciba Specialty Chemical Water Treatment Limited
Crichton David R.
Lovering Richard D.
Metzmaier Daniel S.
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