Biodegradation and biocompatibility of contraceptive-steroid-loaded poly (DL-lactide-co-glycolide) injectable microspheres: in vitro and in vivo study.

Purpose: A controlled-release drug delivery of contraceptive steroids levonorgestrel (LNG) and ethinyl estradiol (EE) has been developed by successful encapsulation of LNG and EE in poly (lactide-co-glycolide) (PLG) microspheres.

Materials And Methods: Smooth, spherical, steroid-loaded PLG microspheres with a mean size of 10-25 microm were prepared by using the water/oil/water double-emulsion solvent evaporation method.

Results: In vitro release profiles showed an increased burst release of LNG/EE on Week 1; thereafter, the release was sustained.