Pseudoephedrine pharmacokinetics in the rat using a microanalysis technique.

A microanalytical procedure was developed using a gas chromatographic-electron capture technique which is capable of detecting 2 ng pseudoephedrine in 20 microliter plasma samples. Standard curves for pseudoephedrine are linear over the concentration range 0.1--1.6 microgram/ml. Plasma and urine concentrations of pseudoephedrine were followed in 3 rats after intravenous dosing. Derived pharmacokinetics parameters exhibited little inter-animal variation. Average plasma clearance was 67.6 ml/min/kg, with renal clearance averaging 30.3 ml/min/kg. This latter value is approximately 4X the glomerular filtration rate in the rat.