Conductometric and indirect AAS determination of antimalarials

Two methods are described for the determination of amodiaquine hydrochloride, chloroquine phosphate and primaquine phosphate, based on the formation of their ion-associates with [Cd2+, Co2+, Mn2+ and Zn2+] thiocyanate, ammonium reineckate and/or sodium cobaltinitrite. The molar combining ratio reveal that (1:1) (drug:reagent) ion associates are formed for all reagents except for ammonium reineckate which form (1:2) ion associates with all studied drugs. The optimum conditions for the ion-association have been studied. Conductometric method was applied for the direct determination of the suggested drugs in bulk powders, whereas indirect atomic absorption spectrometric method, depending on the measurement of the excess metal ion present in supernatant solutions after precipitation of the ion associates is used to calculate the drug concentration. Optimum concentration ranges for the determination of aminoquinoline antimalarial drugs under consideration were 0.46-12.90 and 0.155-3.87 mg using conductometric and indirect atomic absorption spectral methods, respectively. The proposed procedures have been applied successfully to the analysis of these drugs in certain formulations and the results are favourably comparable to the official methods. (C) 2002 Elsevier Science B.V. All rights reserved.