Stable emulsions of p-hydroxybenzoic acid esters and method of preparation
AssigneeMallinckrodt Inc.
InventorsThomas E. Haag, Steven R. Freebersyser, Donald F. Loncrini
Life of this patent
Estimating the term…
Abstract
A heat and freeze-thaw stable, oil-in-water emulsion is comprised of from approximately 10% to 60% by weight of a eutectic oil containing a mixture of three or more lower alkyl esters of p-hydroxybenzoic acid, from approximately 1.5% to 5.0% by weight of an emulsifying agent which may be gelatin, casein, collagen, glyceryl oleate, the ammonium or sodium salt of sulfated nonylphenoxypoly(ethyleneoxy) ethanol or mixtures thereof, from approximately 3% to 10% by weight of sorbitol and the balance water. The method of preparing such emulsions is also disclosed.
Claims20
A stable, oil-in-water emulsion comprising from approximately 10% to 60% by weight of a eutectic oil containing a mixture of three or more lower alkyl esters of p-hydroxybenzoic acid, from approximately 1.5% to 5.0% by weight of an emulsifying agent selected from the group consisting of gelatin, casein, collagen, glyceryl oleate and the ammonium or sodium salt of sulfated nonylphenoxypoly(ethyleneoxy) ethanol and mixtures thereof, from approximately 3% to 10% by weight of sorbitol and the balance water.
The method of preparing a stable, oil-in-water emulsion comprising from approximately 10% to 60% by weight of a eutectic oil containing a mixture of three or more lower alkyl esters of p-hydroxybenzoic acid, from approximately 1.5% to 5.0% by weight of an emulsifying agent selected from the group consisting of gelatin, casein, collagen, glyceryl oleate and the ammonium or sodium salt of sulfated nonylphenoxypoly(ethyleneoxy) ethanol and mixtures thereof, from approximately 3% to 10% by weight of sorbitol and the balance water, which method comprises the steps of heating said eutectic oil to a temperature of approximately 50.degree. C. to 70.degree. C., heating an aqueous solution of said emulsifying agent and sorbitol to a temperature of approximately 50.degree. C. to 70.degree. C., adding said heated eutectic oil to said heated aqueous solution, and thereafter mixing and homogenizing the resulting mixture to form said emulsion.
Dependencies are inferred from the claim text.