Simultaneous Quantification of Ciprofloxacin, Quinine and 3-hyrdoxyquinine in Human Plasma using a HPLC Method

Malaria has been shown to strongly predispose patients in areas of malaria endemicity to bacteremia with severe outcomes, thus justifying the use of antibiotics in combination with antimalarial therapy in patients with severe malaria. This study describes a High-Performance Liquid Chromatographic (HPLC) method for simultaneous determinations of Ciprofloxacin (CPN), Quinine (QN), and its major metabolite, 3-Hydroxyquinine (3-HQN), in human plasma. Following a simple precipitation with acetonitrile, chromatographic separation was achieved on a reversed-phase Agilent Zorbax (CN) column (5 μm, 150 X 4.6 mm i.d) using a mobile phase consisting of acetonitrile: potassium dihydrogen phosphate (pH = 2.8; 0.02 M) (42:58, v/v). Retention times for CPN, 3-HQN, IS and QN were 2.7, 3.3, 3.6 and 4.9 minutes respectively. The limits of detection and validated lower limits of quantitation were 30 and 70 ng/ml for both QN and 3-HQN while the corresponding values were 50 and 100 ng/ml for CPN, respectively. The new HPLC method here developed, when compared with previous methods for the analysis of either or both drugs is simple, rapid, selective, reproducible and costeffective. It is also suitable for conducting a simultaneous therapeutic monitoring of quinine and ciprofloxacin in patients when concomittantly administered as demonstrated in five healthy volunteers.