title: Validation and pharmacokinetic application of a high-performance liquid chromatographic technique for determining the concentrations of amodiaquine and its metabolite in plasma of patients treated with oral fixed-dose amodiaquine-artesunate combination in areas of malaria endemicity.
abstract: Artemisinin-based combination therapies (ACTs) have been adopted by most African countries, including Nigeria, as first-line treatments for uncomplicated falciparum malaria. Fixed-dose combinations of these ACTs, amodiaquine-artesunate (FDC AQAS) and artemether-lumefantrine (AL), were introduced in Nigeria to improve compliance and achieve positive outcomes of malaria treatment. In order to achieve clinical success with AQAS, we developed and validated a simple and sensitive high-performance liquid chromatography (HPLC) method with UV detection for determination of amodiaquine (AQ) and desethylamodiaquine (DAQ) in plasma using liquid-liquid extraction of the drugs with diethyl ether following protein precipitation with acetonitrile. Chromatographic separation was achieved using an Agilent Zorbax C18 column and a mobile phase consisting of distilled water-methanol (80:20 [vol/vol]) with 2% (vol/vol) triethylamine, pH 2.2, at a flow rate of 1 ml/min. Calibration curves in spiked plasma were linear from 100 to 1,000 ng/ml (r > 0.99) for both AQ and DAQ. The limit of detection was 1 ng (sample size, 20 μl). The intra- and interday coefficients of variation at 150, 300, and 900 ng/ml ranged from 1.3 to 4.8%, and the biases were between 6.4 and 9.5%. The mean extraction recoveries of AQ and DAQ were 80.0% and 68.9%, respectively. The results for the pharmacokinetic parameters of DAQ following oral administration of FDC AQAS (612/200 mg) for 3 days in female and male patients with uncomplicated falciparum malaria showed that the maximum plasma concentrations (C max) (740 ± 197 versus 767 ± 185 ng/ml), areas under the plasma concentration-time curve (AUC) (185,080 ± 20,813 versus 184,940 ± 16,370 h · ng/ml), and elimination half-life values (T 1/2) (212 ± 1.14 versus 214 ± 0.84 h) were similar (P > 0.05).
authors.affiliation: Department of Pharmacology and Therapeutics, Faculty of Basic Medical Sciences, University of Ibadan, Ibadan, Nigeria Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria.
authors.forename: Olumuyiwa N
authors.initials: ON
authors.lastname: Adedeji
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria.
authors.forename: Oluseye O
authors.initials: OO
authors.lastname: Bolaji
authors.affiliation: Department of Pharmacology and Therapeutics, Faculty of Basic Medical Sciences, University of Ibadan, Ibadan, Nigeria Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria.
authors.forename: Catherine O
authors.initials: CO
authors.lastname: Falade
authors.affiliation: Olabisi Onabanjo University, Department of Pharmacology, College of Health Sciences, Sagamu, Nigeria.
authors.forename: Odusoga A
authors.initials: OA
authors.lastname: Osonuga
authors.affiliation: Department of Pharmacology and Therapeutics, Faculty of Basic Medical Sciences, University of Ibadan, Ibadan, Nigeria Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria ademowo_g@yahoo.com.
authors.forename: Olusegun G
authors.initials: OG
authors.lastname: Ademowo
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000655:Amodiaquine / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D000962:Antimalarials / Q000097:blood* / Q000627:therapeutic use*; D037621:Artemisinins / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D000077332:Artesunate; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004338:Drug Combinations; D005260:Female; D006801:Humans; D008288:Malaria / Q000097:blood / Q000188:drug therapy*; D016778:Malaria, Falciparum / Q000097:blood / Q000188:drug therapy; D008297:Male; D009549:Nigeria; D055815:Young Adult
chemical_list: D000962:Antimalarials; D037621:Artemisinins; D004338:Drug Combinations; C515299:amodiaquine, artesunate drug combination; D000655:Amodiaquine; D000077332:Artesunate; C031327:artemisinin