Pharmacokinetics of papaverine HCl upon intravenous route of administration in old and young beagle dogs.

This in vivo study was designed to compare the pharmacokinetics of papaverine HCl in young and old Beagle dogs following intravenous (i.v.) administration of papaverine HCl. Blood samples were analyzed by high performance liquid chromatography. The pharmacokinetic parameters were first determined using a curve fitting program (RESID), and then evaluated by SAS statistics. The plasma concentration-time profiles show that papaverine HCl pharmacokinetics is best described by an open two-compartment model. The only age-dependent significant difference in pharmacokinetic behavior between young and old Beagle dogs was found concerning the distribution rate constants.