Sustained-release theophylline pharmacokinetics in the cat.
Theophylline was administered in a three-way crossover design study to six cats intravenously (Aminophylline USP, Invenex Laboratories, Chagrin Falls, OH) and orally as two sustained-release formulations (Slo-bid Gyrocaps (SB), William H. Rorer, Inc., Fort Washington, PA; Theo-Dur Tablets (TD), Key Pharmaceuticals, Miami, FL). Values were determined for mean residence time (SB = 19.4 +/- 3.2 h; TD = 15.8 +/- 4.8 h), mean absorption time (SB = 8.0 +/- 2.3 h; TD = 4.8 +/- 2.3 h), absolute bioavailability (SB = 82 +/- 27%; TD = 76 +/- 38%), and time to peak plasma concentrations (SB = 8 h; TD = 8 h). After normalization to a dose of 25 mg/kg, the average peak plasma concentrations were also predicted (SB = 10.5 +/- 3.4 micrograms/ml; TD = 14.3 +/- 6.7 micrograms/ml). Slo-bid was predicted to provide the least peak:trough fluctuation in theophylline concentrations. Slo-bid and Theo-Dur appear to have pharmacokinetic characteristics which, if given once-daily, would maintain plasma theophylline concentrations of 5-20 micrograms/ml in the cat.
Dye
J A
JA
Department of Veterinary Clinical Medicine, University of Illinois, Urbana 61801.
McKiernan
B C
BC
Jones
S D
SD
Neff-Davis
C A
CA
Koritz
G D
GD
D000818:Animals; D001682:Biological Availability; D002415:Cats / Q000378:metabolism*; D003692:Delayed-Action Preparations; D007275:Injections, Intravenous; D008297:Male; D013806:Theophylline / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D013997:Time Factors
D003692:Delayed-Action Preparations; D013806:Theophylline