Biocompatible and Biodegradable Chitosan / Clay Nanocomposites as New Carriers for Theophylline Controlled Release

Abstract

Aims: Carrier polymeric materials based on chitosan and chitosan / montmorillonite crosslinked with glutaraldehyde were prepared and studied for their biocompatibility, nontoxicity, and biodegradability aiming their application in drug delivery.Study Design: Polymeric materials based on chitosan and chitosan/ montmorillonite crosslinked with glutaraldehyde were prepared as new carriers for theophylline release.Methodology: The matrices of chitosan / glutaraldehyde and chitosan / montmorillonite / glutaraldehyde were prepared, purified and lyophilized to obtain porous materials. The biocompatibility and toxicity of the samples were tested by means of specific tests determining the life rate of white Swiss mice after intraperitoneal injection of the polymeric matrices prepared as suspensions; hemocompatibility was evaluated by hemolysis test with human blood and cell viability tests were performed by chemiluminescence assay. The matrices loaded and unloaded with theophylline were characterized in terms of structural changes, thermal stability, chemical and enzymatic degradation, distribution of the active substance, etc. In order to demonstrate the drug carrier ability of these matrices, theophylline release studies were performed both by in vitro and in vivo tests.Results: The in vivo release profiles showed the sustained release of theophylline proved by the drug presence recorded up to 50 h from administration time.Conclusion: An improvement of the half-release time (t1/2) from 12 to 14 hours was obtained in vivo in the case of the matrix containing montmorillonite, indicating the possibility of reduced dosing frequency, but with a prolonged action time, which is beneficial to the patient.