Design and Development of Deflazacort pH Transition Injectable in-situ Implant for Rheumatoid Arthritis

Introduction: Rheumatoid arthritis is a chronic inflammatory disorder causing painful swelling and damaging various body systems. Deflazacort is a drug of choice for treatment, but it exhibits lower mineral corticoid activity and lower bioavailability when administered orally. The novel formulation is required to achieve a successful release rate in a well-controlled manner and facilitate the drug's uptake. Materials and Methods: The in situ injectable implants are developed as a solution using a cold technique and the ingredients carbopol 934P, hydroxypropyl methyl cellulose K4M, and hydroxypropyl methyl cellulose K15M were utilized. When exposed to external stimuli, like as pH, the solution begins to shift into a gel state. The developed formulations was subjected to pH, rheology, drug content, gelling ability, in vitro permeability, and release kinetics studies. Results: Among all the batch formulations, F14, F17, and F18 exhibited good gelling properties and optimum viscosity. In vitro permeation studies of F14 showed drug release of 95.45% in 24 hr. Further, the drug diffusion data of F14 revealed that it followed the Higuchi model, which suggests that the drug release occurred followed Non-Fickian diffusion kinetics which is ideal for injectable in situ implant formulations. Conclusion: The present study concluded that deflazacort injectable in situ implant formulations inhibit the initial burst release and sustain the drug delivery for 24 hr when administered intramuscularly or subcutaneously.