The antinociceptive and anti-inflammatory effects of a long-acting depot formulated ketorolac in rats
Tzeng, J.-I.; Chu, C.-C.; Feng, P.-H.; Hou, C.-H.; Shieh, J.-P.; Ho, S.-T.; Wang, J.-J.
Acta Anaesthesiologica Taiwanica Official Journal of the Taiwan Society of Anesthesiologists 43(1): 17-22
2005
ISSN/ISBN: 1875-4597 PMID: 15869000 Document Number: 587926
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).