Figure 2: (a, b) Effect of compounds 1– 9 (12.5 and 25 mg/kg, intraperitoneal) on acetic acid-induced writhing. Swiss albino mice were injected with compounds 1– 9 (12.5 mg/kg, intraperitoneal) and diclofenac sodium (12.5 mg/kg, intraperitoneal), which was used as the reference standard (D), or vehicle (control) (a), or with compounds 1– 9 (25 mg/ kg, intraperitoneal) and diclofenac sodium (25 mg/kg, intraperitoneal) or vehicle (b), 30 min before the intraperitoneal injection of freshly prepared acetic acid [2% (w/v) in saline] at 10 ml/kg body weight. The mice were individually separated and were observed for 30 min. Each value represents the mean of the number of writhes ± SEM. *Significant difference from control at P < 0.05; #significant different from diclofenac sodium at P < 0.0 5.