Bioavailability of ketoprofen in horses after rectal administration.
Six healthy mares ranging in age from 6 to 12 years and weighing from 415 to 540 kg were used to determine the rectal bioavailability of ketoprofen. For the rectal administration, three different formulations, each containing 1 g of ketoprofen, were administered in a fatty and a hydrophilic suppository base and as a liquid suspension. An average elimination half-life of 1.3 h (+/-1.2) was found. The average value for the total plasma clearance (ClT) was 131.9mL/ min.kg (range 95-183.5). The volume of distribution Vd(area) was 255 mL/kg and the mean residence time (MRT) value was 0.47 h. After rectal administration, the mean maximal plasma ketoprofen concentrations were 1.6(+/-0.8), 1.1(+/-0.7) and 1.6(+/-0.2) micrograms/mL for the fatty suppository, the hydrophilic suppository and the liquid suspension respectively. The absolute bioavailability of ketoprofen in horses after rectal administration of the three formulations was relatively low, with a large interindividual variability (24.5 +/- 9.5%, 28.7 +/- 18% and 31.3 +/- 6.8% for the fatty suppository, the hydrophilic suppository and the liquid suspension respectively). These values were not significantly different (P = 0.05; Friedman test). Despite the low rectal bioavailability obtained in this study, there was some evidence for the clinical effectiveness of the rectal formulations.
Corveleyn
S
S
Laboratory of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Universiteit Gent, Belgium.
Deprez
P
P
Van der Weken
G
G
Baeyens
W
W
Remon
J P
JP
D000285:Administration, Rectal; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D004305:Dose-Response Relationship, Drug; D006207:Half-Life; D006736:Horses / Q000378:metabolism*; D007660:Ketoprofen / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male; D013488:Suppositories; D013535:Suspensions
D000894:Anti-Inflammatory Agents, Non-Steroidal; D013488:Suppositories; D013535:Suspensions; D007660:Ketoprofen