Pharmacological screening of glycine amino acid prodrug of acetaminophen

OBJECTIVE: To develop an amino acid prodrug of acetaminophen with comparable therapeutic profile and less hepatotoxicity than acetaminophen. MATERIALS AND METHODS: Acetaminophen prodrug was synthesized by esterification between the carboxyl group of amino acid glycine and hydroxyl group of acetaminophen. Analgesic, antipyretic, ulcer healing, and hepatotoxic activities were performed on Wistar rats in this study. RESULTS: Prodrug showed a 44% inhibition in writhings as compared to 53.3% of acetaminophen. Acetaminophen also offered highest antipyretic activity. Prodrug showed gastroprotective and hepatoprotective effects as it reduced the gastric lesions by 32.1% (P < 0.01) and significantly prevented the rise in liver enzymes (serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase and bilirubin). The most notable effect of prodrug was in preventing the depletion of hepatic glutathione (GSH), which is reduced by acetaminophen. CONCLUSION: Prodrug showed hepatoprotective and gastroprotective effects, although the therapeutic efficacy was compromised. Prodrug was successful in preventing a decrease in GSH, thereby exhibiting promising results in the field of prodrug designing to avoid the toxic effects of acetaminophen.