title: Preparation and evaluation in vitro and vivo of copoly (lactic/glycolic) acid microspheres containing norethisterone.
abstract: Poly (lactic/glycolic) acid (PLGA) microspheres containing 20% norethisterone (NET) were prepared and the preparation methodology was optimised. The microspheres showed a slow and steady release pattern up to more than 96 hours in 27.5 wt% ethanol solution. In vivo performance of the microspheres indicated that a single intramuscular injection of 80 mg of microspheres could significantly prolong the duration of estrus suppression up to 45 days in rats. In addition, the studies on the stability of microspheres showed that there was no significant change both in the NET content of microspheres and the NET release rate in vitro after storage for one year.
authors: Institute of Materia Medica, Zhejiang Academy of Medicine, Hangzhou, P.R. China.
authors: Z
authors: Z
authors: Zhou
authors: M
authors: M
authors: Zhou
authors: S
authors: S
authors: Wang
authors: F
authors: F
authors: Lin
authors: W
authors: W
authors: Shan
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D003267:Contraception / Q000379:methods*; D003692:Delayed-Action Preparations; D004353:Drug Evaluation, Preclinical; D004971:Estrus / Q000187:drug effects*; D005260:Female; D007273:Injections, Intramuscular; D019344:Lactic Acid; D008863:Microspheres; D009640:Norethindrone / Q000008:administration & dosage* / Q000494:pharmacology; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000008:administration & dosage* / Q000138:chemical synthesis; D051381:Rats
chemical_list: D001672:Biocompatible Materials; D003692:Delayed-Action Preparations; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D009640:Norethindrone