A Novel Natural Polymers Based Nanoparticles Gel Formulation for the Treatment of Rheumatoid Arthritis: Optimization and In-vivo Evaluation

Background: In 1988, the US Food and Drug Administration permitted low dose methotrexate for the treatment of rheumatoid arthritis that would change the progression of the disease. Methotrexate is a folic acid antagonist and its systemic use causes numerous side effects; including hepatic toxicity. It would be preferable to deliver methotrexate by the topical route to reduce side-effects along with ease of administration and reduced dosing frequency. So, nanoparticle gel is a hopeful approach to treat rheumatoid arthritis. Objective: The study aims to develop a nanoparticles gel containing novel natural polymer-based methotrexate nanoparticles and evaluate its therapeutic potential on Complete Freund’s Adjuvant– Induced Arthritis rat model and compare it to methotrexate and dexamethasone gel. Materials and Methods: The five batches of methotrexate nanoparticles gel were prepared viz. F1W2, F2W2, F3W2, F4W2 and methotrexate gel for the topical application by using different concentrations of Carbopol 934 base and characterized for their evaluation parameters: homogeneity, grittiness, pH, spread-ability, viscosity determination, and drug content studies. The arthritic potential of methotrexate-nanoparticles gel was evaluated by Complete Freund’s Adjuvant–Induced Arthritis rats model based on percent inhibition oedema and arthritic score. Result and Discussion: Methotrexate nanoparticles gel significantly reduced the percentage inhibition of oedema compared to methotrexate and dexamethasone gel. The therapeutic activity of nanoparticles gel was found to be F3W2 ≥ F2W2 ≥ F1W2 ≥ F4W2 ≥ MTX gel. So, the optimized nanoparticle gel formulation F3W2 can be effective in the treatment of rheumatoid arthritis. Conclusion: The developed novel nanoparticles gel formulation can be a promising alternative to existing methotrexate and dexamethasone gel.