Design, optimization, and evaluation of topical gel of Cardiospermum halicacabum and Ricinus communis L. leaves extract for the treatment of rheumatoid arthritis

This research aims to develop and assess the anti-arthritic properties of a topically herbal gel including leaf extracts from Cardiospermum halicacabum and Ricinus communis L. in rats. Utilizing gelling agents carbopol 940 (2.5, 5, 7.5 g), nine herbal gel compositions were created. Prepared formulations were then assessed for physical appearance, spreadability, viscosity, net content, pH, extrudability, in vitro diffusion profile, and main skin irritant tests. According to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) recommendations, the stability research for the topical herbal gel composition was completed, and Freund's Complete Adjuvant (FCA) induced arthritis technique was used to assess the anti-arthritic efficacy. Additional procedures included measuring the body weight, paw volume, biochemical and hematological variables, histological analysis, and in vitro serum biomarker detection. The prepared gels followed the instructions and were uniform and stable. F5 performed better than the other compositions in terms of release kinetics (97.20%). The gel proved safe and non-toxic since no erythema or edema was seen during the skin irritation test. Comparing the herbal gel F5 comprising carbopol 940 to rats with arthritis, the topical treatment showed considerable (p < .001) anti-arthritic effect. The anti-arthritic action of the gel formulations was confirmed by decreased paw volume, absence of agglutination in reacting protein and rheumatic factor, a decline in TNFα level, restoration to baseline biochemical and hematological characteristics, decrease in thymus and spleen weight, and histopathological study.