In Vivo Evaluation of a Novel Topical Formulation of Naproxen and Betamethasone Nanogel for Osteoarthritis

Abstract

A novel topical nanogel formulation combining naproxen and betamethasone was developed and evaluated for its therapeutic potential in treating osteoarthritis (OA) using an in vivo rat model. The nanogel’s pH was optimized to ensure it was suitable for skin application without causing irritation. Uniformity tests confirmed the formulation’s homogeneity, with no aggregates observed. The nanogel demonstrated favorable spreadability and extrudability, crucial for effective skin application and patient compliance. The viscosity of the formulation was also assessed, revealing ideal properties for stable and consistent use. Rats were induced with OA via intra-articular injection of monosodium iodoacetate (MIA), leading to joint pain, inflammation, and reduced mobility. A significant decrease in motor coordination was observed using a rotarod apparatus, highlighting the detrimental effects of OA on joint function. The weight-bearing distribution between the affected and healthy limbs was evaluated using an in-capacitance tester, revealing improvements in the nanogel-treated groups. Additionally, the arthritis index (AI) score, which accounted for swelling and limping, showed a steady decline over time in nanogel-treated rats. Inflammatory cytokine levels were measured in the serum, showing a reduction in inflammation in treated groups. In vivo skin safety evaluations indicated that the nanogel caused no significant skin irritation. Paw volumes were also monitored throughout the study, demonstrating decreased inflammation in the nanogel-treated group compared to controls. The novel naproxen and betamethasone nanogel exhibited promising therapeutic benefits in reducing OA symptoms, including pain, inflammation, and impaired mobility, while maintaining a favorable safety profile for topical use. This formulation holds potential for further development as an effective topical treatment for osteoarthritis.