Formulation and evaluation of chitosan-gellan based methotrexate implants

An implant controlled-release system for methotrexate delivery based on a polyion complex composed of chitosan and gellan was investigated. Multi-layered implant was prepared by using poly(vinyl alcohol), gellan and chitosan. Two chitosan layers sandwiched the poly(vinyl alcohol)-gellan layer, which acted as a methotrexate reservoir. The prepared implant was evaluated for swellability, in vitro and in vivo release and biodegradation studies. The equilibrium swelling and methotrexate release was found to depend on a concentration of calcium chloride, which was used as a crosslinking agent for gellan. Drug-loaded implants were subcutaneously implanted in the back of Wistar rats. The in vivo studies showed that methotrexate was released slowly for a period over 30 days and also there was no fibrous capsule formation around the implant indicating the biocompatibility of the implant.