The effects of an investigational antimalarial agent, NIPRD-AM1 on the single dose pharmacokinetics of metronidazole in healthy human volunteers

The effect of concurrent administration of a novel phytomedicine, NIPRD-AM1 used for the treatment of malaria on the pharmacokinetics of metronidazole was investigated in healthy volunteers. The study was a completely randomized one, crossover involving administration of single dose metronidazole tablets (200 mg x 2) concomitantly with NIPRD-AM1 capsules (250 mg x 2) to 11 healthy volunteers. Blood samples were collected before and at pre-determined time intervals following administration of the drugs. Serum concentrations of the unchanged metronidazole were analyzed using a modified simple and sensitive reversed phase high performance liquid chromatography (HPLC) method. The method showed good precision for metronidazole with coefficient of variation less than 10%. The Pharmacokinetic parameters (AUC, C(max), and T(max)) were generated using GraphPad Prism software version 2. The derived pharmacokinetic parameters (AUC, C(max)) following the administration of metronidazole alone and co-administration with NIP-RD-AM1 were 76.12 mu g/ml per hour, 7.94 mu g/ml and 73.52 mu g/ml per hour, 7.83 mu g/ml, respectively. This differences were not statistically significant (P < 0.05) and the relative bioavailability was found to be about 96%. The comparable relative bioavailabilty value obtained shows that there is little or no interaction between NIPRD-AM1 and metronidazole. The findings, therefore, showed that metronidazole can be administered with the phytomedicine NIPRD-AM1 without any significant effect on the pharmacokinetic profiles of metronidazole.