The antinociceptive and anti-inflammatory effects of a long-acting depot formulated ketorolac in rats

• Published in: Acta anaesthesiologica Taiwanica Vol. 43; no. 1; p. 17
• Main Authors: Tzeng, Jann-Inn, Chu, Chin-Chen, Feng, Ping-Hsun, Hou, Chia-Hui, Shieh, Ja-Ping, Ho, Shung-Tai, Wang, Jhi-Joung
• Format: Journal Article
• Language: English
• Published: China (Republic : 1949- ) 01.03.2005
• Subjects: Analgesics - administration & dosage; Animals; Anti-Inflammatory Agents, Non-Steroidal - administration & dosage; Chemistry, Pharmaceutical; Dose-Response Relationship, Drug; Ketorolac - administration & dosage; Ketorolac Tromethamine - administration & dosage; Male; Rats; Rats, Sprague-Dawley
• ISSN: 1875-4597

Currently, no long-acting nonsteroidal anti-inflammatory drug is available clinically for the treatment of long-lasting pain. The aim of the study was to evaluate the antinociceptive and anti-inflammatory effects and duration of action of a novel depot formulation of ketorolac benzyl ester in sesame oil. Two studies in Sprague-Dawley rats were carried out. In study 1, the antinociceptive and anti-inflammatory effects of intramuscular ketorolac tromethamine were evaluated. In study 2, the antinociceptive and anti-inflammatory effects of intramuscular ketorolac benzyl ester were evaluated. The antinociceptive effect was evaluated using the paw pressure test, whereas the anti-inflammatory effect was evaluated by the paw edema test. Intramuscular ketorolac tromethamine at 24, 80, and 240 micromol/kg (in saline) produced significant antinociceptive and anti-inflammatory effects with duration of action around 6 to 8 h. Ketorolac benzyl ester at a dose of 240 micromol/kg (in oil) produced significant long-acting antinociceptive and anti-inflammatory effects with duration of action of 56 h. Intramuscular injection of ketorolac benzyl ester (in sesame oil) in rats produced antinociceptive and anti-inflammatory effects which were 7-fold longer in duration of action than ketorolac tromethamine (in saline).