Background: A considerable challenge exists in the measuring of the therapeutic level of antimalarial drugs in the body. Current intensive pharmacokinetic studies often rely on determining the drug levels in blood or urine samples. Drug levels in saliva have been shown in a few studies to correlate linearly with that in the blood in adult patients and healthy volunteers. Thus, correlation between plasma and saliva drug levels in children, who bore the burden of morbidity and mortality associated with malaria requires evaluation.

Materials and Methods: Precise, accurate, rapid and cost-effective isocratic reverse-phase high performance liquid chromatographic (RP-HPLC) method was adapted, optimized and validated for the estimation of Piperaquine phosphate (PIP) in spiked plasma and saliva. The drug was estimated using Cecil C18 (250 mm x 4.6 mm i.d-5μm particle size) column. A mobile phase composed of phosphate buffer, acetonitrile, methanol in proportion of 40:30:30 v/v, at a flow rate of 1.0 mL/min was used for the separation. Detection was carried out at 340nm.

Results: The linearity range obtained was 10-80 μg/mL with retention times (t R ) of 2.347 min, 2.839 min and 2.346 min for standard, spiked plasma and spiked saliva samples of Piperaquine respectively. The correlation coefficient value was found to be 0.996 for standard sample. Precision studies showed % RSD (Relative standard deviation) values less than 2% for the drug in all the selected concentrations of the standard solution. The percentage recoveries PIP was in the range of 97.47-99.94 %. The assay results of were 97.47 % (plasma) and 99.94 % (saliva) samples of PIP. The limit of detection (LOD) and limit of quantification (LOQ) were 0.388 μg/mL and 1.174 μg/mL for PIP respectively in the standard samples.

Conclusion: This validated method was successfully used for the quantitative analysis of standard salt of piperaquine in spiked plasma and saliva.

Keywords: Piperaquine, Biological fluids, Plasma, Saliva, HPLC, Methodology development