Advanced Study on Assay of Quinine Utilizing Isocratic HPLC Solvent Conditions and Feasibility of Assay from Human Urine

The assay of quinine sulfate, a drug that is administered for the clinical treatment of Plasmodium falciparum, can be accomplished utilizing isocratic solvent conditions and with high performance liquid chromatography (HPLC). Plasmodium falciparum (P. falciparum) will cause the most severe form of human malaria and has been found to be responsible for 85% of all malaria cases. In addition, this study intends to show that quinine can be identified and assayed from raw human urine. The drug quinine is detected after elution with an ultraviolet light detector, which is set at 222 nm (or alternatively at 254 nm). The stock solution of quinine sulfate was prepared in solvent consisting of 64% ethanol (v/v) and 36% water (v/v), at a concentration of 1.3155 x 10-2 molar. The test samples injected into HPLC instrument were predominantly in a solvent that consisted of 95% (v/v) water and 5% ethanol (v/v). The column solvent can have a range from 5% ethanol to 20% ethanol (v/v), with 1% to 4% glacial acetic acid (v/v) and the remaining volume being distilled water. The limit of detection (LOD) was found to be 2.2628 x 10-5 molar and the limit of quantitation (LOQ) was found to be 7.542 x 10-5 molar. This highly sensitive methodology for analysis of quinine from water mixtures, 5% glucose, cellulose based tablets and directly from urine will be useful in determining patient compliance and regimen maintenance, as well as quality control in manufacturing.