Physical stability of different chitosan salts in matrix tablet formulations

Abstract

This study aimed to evaluate the physical stability of chitosan (CS) and its salt forms, including chitosan glycolate (CGY) and chitosan lactate (CL), as diluent in matrix tablets for the modified-release dosage form. Caffeine, theophylline, and theobromine were selected as model drugs in this study because of its similarity in chemical structure but difference in solubility. In vitro drug release, hardness, and tablet weight of the drug-loaded matrix tablets made of CS or CS salts were assessed after preparation and 6 months of storage for physical stability monitoring. After 6 months under the accelerated storage condition, the hardness of the CS and CS salt matrix tablets without drug increased, whereas the hardness of the drug-loaded matrix tablets decreased. After 6 months, the weight gain of the CS matrix tablets was approximately 2.63% to 4.97%. In addition, storage of the CGY and CL matrix tablets for 6 months significantly caused rapid drug release. Results show that the application of CS as tablet excipient should be closely monitored and evaluated because of its low stability and hygroscopic property.