Membrane lipid compositions
A composition in the form of a dry powder and which comprises: a) at least one membrane lipid, and b) at least one biologically active compound comprising a xanthine and/or a carboxylic acid, and which forms structured lipid assemblies when dispersed/dissolved in an aqueous medium. A method of preparing such a composition is also provided, together with a dispersion of structured lipid assemblies suspended in a solution of at least one biologically active compound and a method of preparing the same. The compositions and dispersions are suitable for use in creams and lotions for skin care.
1. A composition in the form of a homogenous dry powder mixture wherein the mean particle size of the powder composition is between 0.1 to 5 mm in diameter consisting essentially of:
a) at least one membrane lipid in an amount of from 5% to 70% by weight,
b) at least one biologically active compound that is a carboxylic acid selected from the group consisting of an α-hydroxycarboxylic acid, a β-hydroxycarboxylic acid and/or an α-ketocarboxylic acid, and
c) at least one biologically active compound that is a xanthine selected from the group consisting of caffeine, aminophilline, theophylline and theobromine,
and which is prepared by mixing or milling together said components to obtain the dry powder mixture,
and which forms structured lipid assemblies when dispersed/dissolved in an aqueous medium.
2. The composition as claimed in claim 1 , wherein said membrane lipid comprises a phospholipid or mixture of phospholipids.
3. The composition as claimed in claim 1 , wherein said biologically active compound is salicylic acid or a pharmaceutically acceptable salt thereof in an amount of from 10% to 50% by weight.
4. The composition as claimed in claim 1 , wherein the xanthine is caffeine and is present in an amount of from 10% to 80% by weight.
5. The composition as claimed in claim 1 , wherein the proportion of said membrane lipid to said biologically active compounds is from 1:20 to 20:1 by weight.
6. A method of preparing a composition in the form of a homogenous dry powder mixture the mean particle size of the composition being between 0.1 to 5 mm and which composition consisting essentially of:
a) at least one membrane lipid in an amount of from 5% to 70% by weight, b) at least one biologically active compound that is a carboxylic acid selected from the group consisting of an α-hydroxycarboxylic acid, a β-hydroxycarboxylic acid and/or an α-ketocarboxylic acid, and
c) at least one biologically active compound that is a xanthine selected from the group consisting of caffeine, aminophilline, theophylline and theobromine, and which forms structured lipid assemblies when dispersed/dissolved in an aqueous medium, which method comprises mixing or milling together the components to produce a homogeneous dry powder mixture.
7. A composition in the form of a homogeneous dry powder mixture which is prepared according to the method of claim 6 .
8. The composition as claimed in claim 1 , wherein the xanthine is caffeine.