A kinetic model of benzoylecgonine disposition after cocaine administration in humans.

Cocaine (C) and benzoylecgonine (BZ) plasma levels and urinary excretion rate data from a series of intravenous cocaine studies were used to develop a kinetic model for C and BZ, with the main objective of characterizing BZ disposition. Kinetic analyses were made with the CONSAM 30 computer program. Under assumptions of the model, calculated parameters indicated a BZ distribution volume of 50 L, a half-time for BZ formation of 1.9 h and a BZ excretion half-time of 4.7 h. The model may eventually provide a basis for interpretation of analytical data on isolated samples of plasma or urine.