Biodegradable in situ Gel for Subcutaneous Administration of Simvastatin for Osteoporosis

Abstract

Many observational studies and animal research has revealed that statins appear to enhance osteoblastic activity and diminish osteoclast activity, hence increasing bone density. This study was aimed to prepare and characterize biodegradable in situ gel for subcutaneous administration of simvastatin for the treatment of osteoporosis. Biodegradable in situ gel was prepared using chitosan as biodegradable polymer and β-glycerol phosphate disodium salt hydrate as a buffering agent to achieve in situ gelation at physiological pH and temperature. In situ gel was characterized in terms of pH, gelling capacity, drug content, sedimentation volume, resuspendability, syringeability, in vitro drug release, particle size and zeta potential. The optimized formulation, containing 1.25 % w/v chitosan and 1 % β-glycerol phosphate disodium salt hydrate, had good gelling capacity at physiological temperature and pH. It had a pH of 5.85±0.5, drug content of 97.1±1.2 % and sedimentation volume of 0.42±0.04. In vitro drug release was found to be 98.7±1.5 % in 7 days. Particle size, zeta potential and viscosity were found to be 7.07±0.3 μm, 12.5±1.5 mV and 22.66±1.8 cp, respectively. Hence, the developed biodegradable in situ gel administered subcutaneously can prove to be an effective alternative drug delivery system for the treatment of osteoporosis.