Dn. Bailey, EFFECT OF DRUGS AND COCAINE METABOLITES ON COCAINE AND COCAETHYLENE BINDING TO HUMAN SERUM IN-VITRO, Therapeutic drug monitoring, 19(4), 1997, pp. 427-430
The effect of amphetamine (AMPH), codeine (COD), methamphetamine (MEPH
), morphine (MORP), and benzoylecgonine (BE) on the binding of cocaeth
ylene (CE) and cocaine (COC) to human serum in vitro was investigated
by equilibrium dialysis at 4 degrees C. Each compound was added indivi
dually at concentrations of 500, 1,000, or 2,000 nM to pooled human se
rum containing COC or CE at 500 nM concentration. For COC, the additio
n of COD, MEPH, and CE enhanced serum binding whereas MORP and BE decr
eased it. Variable effects on COC binding were noted for AMPH. For CE,
the addition of COD and COC generally increased binding whereas MORP
decreased it. No appreciable effect on CE binding was observed after a
dding AMPH, MEPH, and BE. Except for CE, AMPH, and MEPH in the presenc
e of COC, the binding of COC and CE tended to be less with 2,000 nM of
each added drug than at lower concentrations of them, presumably beca
use of mass-action displacement of COC and CE at the higher concentrat
ion. These findings should be clinically important because these drugs
are frequently found together in patients.