Kenya Medical Research Institute (KEMRI)/Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), P.O. Box 230-80108, Kilifi, Kenya; Department of Pharmaceutics and Pharmacy Practice, School of Pharmacy, University of Nairobi, P.O. Box 19676-00202 (KNH), Nairobi, Kenya; African Centre for Clinical Trials, P.O. Box 2288-00202 (KNH), Nairobi, Kenya; Consortium for National Health Research, P.O. Box 29832-00202 (KNH), Nairobi, Kenya; Department of Paediatrics, Faculty of Medicine and The Wellcome Trust Centre for Clinical Tropical Medicine, Imperial College, Norfolk Place, London, W2 1PG, United Kingdom
Muchohi, S.N., Kenya Medical Research Institute (KEMRI)/Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), P.O. Box 230-80108, Kilifi, Kenya; Thuo, N., Kenya Medical Research Institute (KEMRI)/Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), P.O. Box 230-80108, Kilifi, Kenya; Karisa, J., Kenya Medical Research Institute (KEMRI)/Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), P.O. Box 230-80108, Kilifi, Kenya; Muturi, A., Kenya Medical Research Institute (KEMRI)/Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), P.O. Box 230-80108, Kilifi, Kenya; Kokwaro, G.O., Kenya Medical Research Institute (KEMRI)/Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), P.O. Box 230-80108, Kilifi, Kenya, Department of Pharmaceutics and Pharmacy Practice, School of Pharmacy, University of Nairobi, P.O. Box 19676-00202 (KNH), Nairobi, Kenya, African Centre for Clinical Trials, P.O. Box 2288-00202 (KNH), Nairobi, Kenya, Consortium for National Health Research, P.O. Box 29832-00202 (KNH), Nairobi, Kenya; Maitland, K., Kenya Medical Research Institute (KEMRI)/Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), P.O. Box 230-80108, Kilifi, Kenya, Department of Paediatrics, Faculty of Medicine and The Wellcome Trust Centre for Clinical Tropical Medicine, Imperial College, Norfolk Place, London, W2 1PG, United Kingdom
Clinical pharmacokinetic studies of ciprofloxacin require accurate and precise measurement of plasma drug concentrations. We describe a rapid, selective and sensitive HPLC method coupled with fluorescence detection for determination of ciprofloxacin in human plasma. Internal standard (IS; sarafloxacin) was added to plasma aliquots (200μL) prior to protein precipitation with acetonitrile. Ciprofloxacin and IS were eluted on a Synergi Max-RP analytical column (150mm×4.6mm i.d., 5μm particle size) maintained at 40°C. The mobile phase comprised a mixture of aqueous orthophosphoric acid (0.025M)/methanol/acetonitrile (75/13/12%, v/v/v); the pH was adjusted to 3.0 with triethylamine. A fluorescence detector (excitation/emission wavelength of 278/450nm) was used. Retention times for ciprofloxacin and IS were approximately 3.6 and 7.0min, respectively. Calibration curves of ciprofloxacin were linear over the concentration range of 0.02-4μg/mL, with correlation coefficients (r2)≥0.998. Intra- and inter-assay relative standard deviations (SD) were <8.0% and accuracy values ranged from 93% to 105% for quality control samples (0.2, 1.8 and 3.6μg/mL). The mean (SD) extraction recoveries for ciprofloxacin from spiked plasma at 0.08, 1.8 and 3.6μg/mL were 72.8±12.5% (n=5), 83.5±5.2% and 77.7±2.0%, respectively (n=8 in both cases). The recovery for IS was 94.5±7.9% (n=15). The limits of detection and quantification were 10ng/mL and 20ng/mL, respectively. Ciprofloxacin was stable in plasma for at least one month when stored at -15°C to -25°C and -70°C to -90°C. This method was successfully applied to measure plasma ciprofloxacin concentrations in a population pharmacokinetics study of ciprofloxacin in malnourished children. © 2010 Elsevier B.V.
