Application of chitosan as release rate-controlling membrane in isosorbide dinitrate transdermal patch

Abstract

The application of chitosan as component in release rate-controlling membrane in isosorbide dinitrate (ISDN) transdermal drug delivery system (TDDs) was investigated. Chitosan was blended with various amount of other polymers, PVA PVP K90 HPM15 MC15 or corn starch, and crosslinked with two levels of glutaraldehyde to form transparent crosslinked chitosan-polymer membranes by solvent-casting technique. Plasticizer, triacetin or PEG1450, was selectively added. These membranes were characterized by SEM, DSC, IR, water sorption ability and tensile testing. In-vitro skin permeation studies were also evaluated on shed snake skin. The physical, thermal and mechanical properties were affected by the amount and type of blended polymer, type of plasticizer and the amount of crosslinking agent, thus in turn affected the drug permeation through the membranes. Increasing the amount of crosslinking agent obviously increased the ultimate tensile strength and decreased both the water sorption ability and percent elongation at break. Plasticizers apparently increased flexibility or reduced brittleness of the membranes. These crosslinked chitosan-polymer membranes were microporous in structure wherein pore mechanism was likely to predominate over permeation of ISDN. ISDN transdermal patches containing satisfactory crosslinked chitosan-polymer membranes as release rate-controlling membranes showed a sustained profile throughout 24 hours.