Determination of quinacrine (mepacrine) in plasma by high-performance liquid chromatography with fluorimetric detection.

Quinacrine (mepacrine, Atebrine) is an antiparasitic acridine derivative that is currently used as an intrapleural sclerosing agent. It was determined in plasma by reversed-phase high-performance liquid chromatography of a dichloroethane extract. The mobile phase was methanol-phosphate buffer (65:35) with 0.1 mM decylammonium hydrochloride and 8 mM ethanolammonium hydrochloride. Strong base was added post-column, and the detection of quinacrine was by fluorescence at 270/495 nm. Use of ethacridine lactate as internal standard was feasible but without significant advantage. The coefficient of variation for eight determinations of quinacrine was 4% at 3.4 ng/ml and 5% at 17 ng/ml. The stability of quinacrine in blood, plasma, water and dichloroethane solution was satisfactory for practical work. The usefulness of the analytical procedure for pharmacokinetic studies could be demonstrated.