In vitro evaluation of the simultaneous transport of medroxyprogesterone acetate and equilin through different membranes and their uptake and release through polymers

The transdermal delivery of medroxyprogesterone acetate and equilin was studied using gel-like formulations and solid patches. To develop a gel-like formulation, it was required that study the solubility of these two drugs in different vehicles be studied. The behavior of these drugs was almost the same using the same solutions with or without a surfactant. The solubility of medroxyprogesterone acetate was studied further. Bearing in mind the solubility values of medroxyprogesterone acetate, we could make conclusions for the solubility of equilin in different solutions. The use of a surfactant increases the solubility of these two drugs. The drugs' solubility value was increased by increasing the lipophilicity of a solution that does not have surfactant. The solubility studies for medroxyprogesterone acetate proved that there isn't any binding between the solvent system and the drug. Van der Walls are the only interactions that can be considered between the drug and the solvent system. When the surfactant was used in the solution, the increase of the drugs' solubility was caused only by the micelles.;The release of equilin and medroxyprogesterone acetate was observed through different membranes. The diffusion coefficients of the drugs were calculated by using a mathematical model that does not count the initial lag times. The fitting was relatively successful and the mathematical model predicted the diffusion coefficients of the drugs successfully. The diffusion coefficients are useful to determine the changes that a patch must go through. These changes are necessary to achieve therapeutic levels of the drugs in the blood stream.;The release of equilin and medroxyprogesterone acetate was studied by using solid dispersion formulations (patches). These patches were formulated by mixing two different polymers and a resin. Polyisobutylene and polymethylmethacrylate were used in different proportions for the formulation of the patches. The resin was used for mixing these two polymers. The drugs' release profiles were different when different patches were used. The release profile depends on the composition of the patch and on the resin. Release experiments using patches without resin showed that resin alters the drugs' release profiles tremendously.