Poly (DL- Lactide-co-glycol ide)/Noreth isterone Microcapsules: An Injectable Biodegradable Contraceptive
| Autor: | Thomas R. Tice, Richard M. Gilley, Richard L. Dunn, Donald R. Cowsar, Lee R. Beck, Danny Harvey Gardendale Alabama Us Lewis, Charles E. Flowers, V. Z. Pope, Alfred B. Moore |
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| Rok vydání: | 1983 |
| Předmět: |
Time Factors
Norethisterone Polymers Excipient Capsules Pharmacology Biology Injections Intramuscular In vivo Injection site Contraceptive Agents Female medicine Animals Polyglactin 910 Chromatography Rats Inbred Strains Radioimmunoassay Cell Biology General Medicine Biodegradation Serum samples Rats Biodegradation Environmental Reproductive Medicine Delayed-Action Preparations Female Norethindrone Poly dl lactide co glycolide Papio medicine.drug |
| Zdroj: | Biology of Reproduction. 28:186-195 |
| ISSN: | 1529-7268 0006-3363 |
| DOI: | 10.1095/biolreprod28.1.186 |
| Popis: | Microcapsules made from a biocompatible, biodegradable polymeric excipient, poly(DL-lactide-co-glycolide) (DL-PLGA) that contained 22 weight percent (wt %) norethisterone (NET), were prepared by a solvent-evaporation microencapsulation process. The effects of changing both the lactide-to-glycolide ratio of the DL-PLGA and the size of the microcapsules on the rate of NET release and the rate of excipient biodegradation were determined in vivo. NET release rates were determined in baboons after injecting the microcapsule formulations intramuscularly. Serum samples obtained at various times following treatment were analyzed for NET, progesterone, and estrogen by radioimmunoassay (RIA). Biodegradation kinetics were determined by injecting NET microcapsules made from radiolabeled DL-PLGA intramuscularly into the hind legs of rats. Residual radioactivity at the injection site was determined at various times after treatment by combustion analysis of the muscle tissue. Changing the ratio of the comonomers to include more glycolide (DL-lactide:glycolide-96:4, 92:8, 87:13, 74:26) increased the rate of NET release and accelerated the biodegradation of the copolymer excipient. Decreasing the size of the microcapsules increased the rate of NET release. On the basis of these studies a NET microcapsule formulation has been identified for clinical testing which releases NET for 3 months and biodegrades completely within 6 months. |
| Databáze: | OpenAIRE |
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