PERMEABILITY OF PROGESTERONE AND A SYNTHETIC PROGESTIN THROUGH METHACRYLIC FILMS

The permeation for progesterone and a synthetic progestin was determined through films prepared from a hydrophilic acrylate-methacrylate copolymer (Eudragit(R)). Steroid permeabilities allow us to evaluate a partition coefficient between films and water which is 5 times lower for the synthetic progestin: this difference is due to the higher aqueous solubility of this molecule despite the presence of a hydroxyl group which may interact with the polymer cation content. The values of partition coefficients show that both steroids are dissolved into the polymer films. From permeation experiments, diffusion coefficients are also calculated and different mechanisms of diffusion are presented which are 'pore' and 'solution diffusion'. The values of the diffusion coefficients show that the main mechanism is solution diffusion according to the steroid solubilities in the polymer films.