Design of ethylene vinyl acetate intravaginal rings releasing progesterone for contraception therapies during lactation

I.M. HELBLING; J.C.D. IBARRA; J.A. LUNA

Congreso; 3rd Annual Symposium of Drug Delivery Systems (SDDS); 2013

To date, only one intravaginal ring, named Progering®, is commercialized for application in contraception therapies during lactation. This ring is made of silicone and release progesterone through the vaginal walls of about 10 mg day-1. However, some drawbacks are related to the use of silicone. For this reason, ethylene vinyl acetate copolymer (EVA) was studied as material support to replace silicone in rings fabrication. Ring-shaped matrices made of EVA and containing progesterone were fabricated by a hot-melt extrusion procedure. Swelling and degradation assays to characterize these matrices and the commercial ring Progering® were performed. The in vitro release of progesterone from EVA rings and from Progering® was studied and a mathematical model was employed to determine the effect of design parameters over release rate. Theoretical simulations were made in the software Matlab®. Comparisons between the experimental data obtained and the theoretical prediction were realized, and the f 1 and f factors were used to quantitatively measure the model prediction. In addition, the solubility of  rogesterone in several liquids and in EVA matrices were determined. 2 Once the model was validated and the effect of parameters over release process was studied, the equation was applied to design a particular controlled release device. The focus was to design an EVA ring that releases the hormone at specific rate for its use in contraception during lactation. The initial load of progesterone in the ring was optimized using a Matlab® routine, and the release rate from Progering® and from the optimized EVA ring were compared.