Comparison of the effect of in situ gel formulation of ibuprofen with classical formulations on experimental osteoarthritis in rats

Osteoarthritis (OA), also known as degenerative joint disease, is a musculoskeletal disorder. Non-steroidal anti-inflammatory drugs (NSAIDs) are frequently preferred in the treatment of OA due to their significant effects in managing pain and inflammation by controlling the development of inflammation. However, despite their beneficial effects in OA treatment, NSAIDs have a short retention time in the joint area, necessitating frequent administration at high doses. This increases the risk of serious side effects such as gastrointestinal, cardiovascular, allergic reactions, rash, hepatotoxicity, and nephrotoxicity. These adverse effects can weaken patient compliance, thereby reducing the success rate of treatment. Thus, the development of novel analgesic applications to effectively treat OA pain is of great importance. In this study, injectable ibuprofen in situ gel formulations for intraarticular use in OA treatment were developed and characterized. In an experimental osteoarthritis model induced in rats, intra-articular injections were administered to compare the effects of ibuprofen in situ gel formulations with those of classical ibuprofen formulations. Following intraarticular administration, antinociceptive effects were evaluated using the Hot Plate (HP) and Tail-Flick (TF) tests, complemented by body temperature and knee joint circumference measurements. Additionally, histological analyses of the rats' knee joints were conducted to examine the histopathological changes resulting from both formulations. The results of the study demonstrated that ibuprofen in situ gel formulations exhibited greater antinociceptive effects compared to classical formulations. Furthermore, the intraarticular administration of ibuprofen in situ gel formulations is considered to hold potential for future studies aimed at OA treatment, contributing to a better understanding of its effects.