Abstract: A matrix for containing drugs for transdermal delivery systems is disclosed. The matrix, formed of a skin-adhesive acrylate copolymer, attains high rates of drug delivery without the addition of drug delivery rate enhancers. In preferred embodiments the matrix is used to administer steroids, in particular estradiol. Water-soluble polymers may be added as well.

Abstract: A method of forming liposomes with a uniform size distribution, and an average size of about 300 nm or less. Vesicles-forming lipids are dissolved in a water-miscible solvent, such as ethanol, and an aqueous medium is added to a water:solvent ratio at which lipid assembly first occurs. The water:solvent ratio is raised, under conditions which maintain the volume of the mixture substantially constant, until uniform-size liposomes are formed. The average size of the liposomes can be selectively varied by changing the ionic strength and lipid composition of the mixture. In one embodiment, the method is used to produce small unilamellar vesicles. Also disclosed are suspensions of liposomes which have a narrow, substantially symmetrical size distribution in a selected size range.

Abstract: A method of forming lipid structures, such as liposomes is disclosed. Lipids are dissolved in a solvent system containing a water-miscible solvent, such as ethanol, and an aqueous medium. The water:solvent ratio is raised by removing water and solvent in a reverse osmosis system, and replacing lost solvent with added aqueous medium, preferably at a rate which just balances volume loss by reverse osmosis. In one embodiment, the method is used to produce uniform-size liposomes.