Pharmacokinetics of prethcamide following rapid intravenous injection and oral administration in rabbits.
A simple gas chromatographic method for the quantitative determination of ethyl butamide and propyl butamide, the active constituents of the analeptic drug "Prethcamide", in whole blood and tissues has been developed. The method was used to study the disposition of the compounds after iv and po administration to rabbits. The course of changes of ethyl butamide and propyl butamide concentration following rapid intravenous injection and oral administration was described by the two-compartment and one-compartment open models, respectively. The mean half-life (t1/2 beta, min), the body clearance (Clb, 1/min), the mean absorption rate constant (ka, min1-) and tmax (min) values were, respectively: 43.07 +/- 10.54, 0.05 +/- 0.0125, 0.033 +/- 0.0073 and 30.0 +/- 5.0 for ethyl butamide and 30.0 +/- 4.13, 0.0962 +/- 0.0269, 0.0512 +/- 0.0328 and 30.0 +/- 5.0 for propyl butamide. The low bioavailability (F) of the compounds, in the range 24-32%, may be attributed to low absorption of the drugs from the gastro-intestinal tract, or the first-pass effect, or both. The drugs accumulate predominantly in the liver. The faster metabolism and elimination of propyl butamide is postulated.
D000284:Administration, Oral; D000613:Aminobutyrates / Q000008:administration & dosage / Q000378:metabolism*; D000818:Animals; D001711:Biotransformation; D003437:Crotonates / Q000097:blood; D006207:Half-Life; D007275:Injections, Intravenous; D007700:Kinetics; D008297:Male; D011817:Rabbits; D014018:Tissue Distribution
D000613:Aminobutyrates; D003437:Crotonates; C100196:prethcamide; C015090:crotetamide; C015089:cropropamide