A multi-compartment vaginal ring system for independently adjustable release of contraceptive steroids

Abstract

A multi-compartment contraceptive vaginal ring system has been designed for the simultaneous zero-order release of contraceptive steroids, the rates of which can be programmed independently. This vaginal ring system consists of two or more drug-containing Silastic R tubes with an outer diameter of 5 mm. The tubes with different lengths, with a total length of 16.5 cm are connected with specially-shaped glass stoppers to obtain a ring with an outer diameter of 60 mm. The stopper prevents migration of the steroids from one compartment to the other and guarantees optimal release characteristics of both steroids even after long-term storage. An additional advantage of glass is the good adherence to Silastic R, enabling construction of systems with sufficient tensile strength. The release characteristics have been followed in vitro and can be programmed independently by changing the wall thickness of the tube (membrane thickness) and/or the length of each individual steroid-containing compartment. Multi-compartment vaginal rings were made and tested with 3-keto-desogestrel and ethinylestradiol. The rings had an outer diameter of 60 mm, and were fabricated with independent in vitro release rates ranging from 75 to 300 ug/day and 10 to 30 ug/day for, respectively, 3-keto-desogestrel and ethinylestradiol. Using the multi-compartment vaginal ring system, contraceptive devices can be fabricated relatively simply with pre-programmed release rates for a progestogen and an estrogen to investigate the optimal daily doses for vaginal hormonal contraception.