Desenvolvimento e validação de métodos por eletroforese capilar para a quantificação de primaquina em comprimidos e visando a determinação de artemeter e lumefantrina em dose fixa combinada

Abstract

Malaria is a neglected and infectious tropical disease caused by the parasite of the genus Plasmodium, which is endemic in countries with poorer and more vulnerable populations and represents a serious public health problem worldwide. Currently, for uncomplicated malaria caused by P. falciparum, combined therapy with artemisinin or its derivatives is recommended, associated with other drugs, for example, the artemether-lumefantrine combination. In addition, primaquina has activity against hypnozoites and is used to prevent the recurrence of the disease. Since the dosage of these drugs is essential to ensure the quality, safety, and efficacy of the treatment, in the present study new analytical methods were developed for the determination of primaquine, artemether, and lumefantrine in tablets, using Capillary Electrophoresis with detection by ultraviolet absorption. For primaquine, two methods were optimized, considering different forms of sample injection, injection through the outlet and multiple injections, and an electrolyte formed by Tris/HCl 20/30 mmol L-1 (pH 2.0). The other electrophoretic conditions were studied and defined by implementing experimental design. The main difference between the methods is in the analytical frequency since 9 injections per hour can be performed by the outlet method versus 32 injections per hour for the multiple injection method. Both methods were validated, with an evaluation of the parameters of linearity, selectivity, precision, accuracy, detection limits, and quantification, and subsequently applied for the primaquine dosing. All the results obtained were satisfactory. In addition, the outlet injection method was applied in a qualitative study of forced degradation of primaquine, in which changes in the drug signals were observed when subjected to different stress conditions, indicating the viability of its use as a method to indicate stability. Due to the characteristics of the drugs, a method was optimized for artemether and lumefantrine using a microemulsion composed of 20 mmol L-1 sodium tetraborate (pH 8.7), 18% v/v acetonitrile, 0.8% v/v hexane, 21% v/v 1-butanol, and 1.2% v/v sodium dodecyl sulfate. In addition, sample preparation and the conditioning between runs were optimized and evaluated. Finally, a preliminary method for determining artemether and lumefantrine using Microemulsion Electrokinetic Chromatography was obtained.