N-nitrosoephedrine and N-nitrosopseudoephedrine: their dissolution, absorption, blood clearance and elimination studies.

Abstract Dissolution and absorption rates (in vitro); clearance from blood and elimination rates of N -nitrosoephedrine (NEP) and N -nitrosopseudophedrine (NPEP) in mice were determined. The two isomers obeyed first-order kinetics and from the slope of the regression line, the rate constant for each study was obtained. These constants were 0.023, 0.038 min −1 (dissolution); 0.192, 0.225 h −1 (stomach absorption); 2.898, 1.980 h −1 (intestinal absorption); 0.33, 0.55 h −1 (blood clearance) and 0.373, 0.393 h −1 (elimination from whole animal) of NEP and NPEP, respectively, and were tested by Student's t -test. Significant differences in the dissolution, absorption and blood clearance rates of NPEP from those of NEP have been observed ( P