Sustained-release of oxytetracycline from chitosan micro spheresprepared by interfacial acylation and spray hardening methods

Abstract

Chitosan micro spherescontaining oxytetracycline (OTC)an antibiotic agentwere prepared by spray hardening and interfacial acylation methods., The object of this study was to prepare oxytetracycline-containing micro spheresfor oral administration and injection using different molecular weight (Mw 70 000 ∼ 2 000 000) of chitosan., By the spray hardening methodmicro sphereswith particle sizes between 5 and 30 μm could be obtained and might be suitable for intramuscular injection., On the other handchitosan micro sphereswith the ability to extend the dissolution period of oxytetracycline in low pH medium were also prepared by the interfacial acylation method., The result indicated that the releasing of oxytetracycline from various acylated chitosan micro sphereswas decreased with increasing the molecular weight of chitosan and would show well sustained-release property., Besidesthe morphology of various micro spheresand crystalline form transition of oxytetracycline were also studied using electron scanning microscope and X-ray analysis.