DEVELOPMENT AND INVESTIGATION OF THERMO-SENSITIVE ORGANOGEL OF DICLOFENAC SODIUM FOR IN-SITU IMPLANTATION

The aim of the present study was to develop and evaluate thermo-sensitive in-situ implant forming injectable organogel systems of diclofenac sodium for prolonged drug effects. The formulations were prepared by separately dissolving fatty acids such as arachidic acid, stearic acid or palmitic acid in injectable soybean oil. The organogels were evaluated for physicochemical parameters as well as for in-vitro, ex-vivo release and in-vivo fluorescence imaging. All the formulations showed gelation temperature and gelation time in the range of 36.6 to 37.1 ºC and 38 to 61 sec respectively. The pH of the formulation was found to be in the range of 6.67 to 7.14. All the formulations appeared opaque, off white and free from aggregates during the study and passed the test for syringeability and injectability. The drug content of the formulations was found in the range of 89.5 to 93.5 percent. The in-vitro drug release study showed that the release followed zero-order kinetics and ex-vivo drug release was slower when compared to in-vitro drug release. In-vivo fluorescence imaging and histological studies showed that the formulation F1 was able to form a depot at the injection site at body temperature and was able to retain the depot for about 4 days without any signs of inflammation or necrosis. The formulations can be considered promising in the sustained delivery of diclofenac sodium as an alternative to the oral formulations which are associated with several GI-related risks on long term use of the drug.