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.
Laboratory of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Universiteit Gent, Belgium.
S
S
Corveleyn
P
P
Deprez
G
G
Van der Weken
W
W
Baeyens
J P
JP
Remon
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