Journal of Liquid Chromatography & Related Technologies, 38: 886–890, 2015 Copyright # Taylor & Francis Group, LLC ISSN: 1082-6076 print/1520-572X online DOI: 10.1080/10826076.2014.982869 Determination of Quinine, Quinidine, and Cinquinidine by Capillary Electrophoresis MARIUSZ KLUSKA, 1 ANNA MARCINIUK-KLUSKA, 2 DOROTA PRUKALA, 3 and WIESŁAW PRUKALA 3 1 Institute of Chemistry, Siedlce University of Natural Sciences and Humanities, Siedlce, Poland 2 Faculty of Management, Siedlce University of Natural Sciences and Humanities, Siedlce, Poland 3 Faculty of Chemistry, Adam Mickiewicz University, Poznan, Poland This article presents the results of the research on a newly developed methodology for the separation and determination of quinine and its two derivatives. The analyzed compounds are biologically active, which are used in the treatment of malaria. The mixture of the analyzed compounds, i.e., hydrochlorides: quinidine, quinine, and cinquinidine, was dissolved in water and then exposed to optimization of separation and determination by isotachophoresis. The analysis was conducted with a varying number of steps and varying time of analysis, different intensities and voltages of the electric current, and different high voltage limits. For the ternary mixture, the optimal time of analysis was just over 8 min. On the other hand, the determination of cinquinidine had the shortest time of analysis (less than 3 min). The conducted validation of the developed methodology indicates very good conditions for the determination of quinidine, quinine, and cinquinidine. Keywords: alkaloids, determination, isotachophoresis, malaria, quinine and its derivatives, separation Introduction In some regions of the world, mainly Africa, South-East Asia, and South America, malaria is still a major threat to human health and life. It is estimated that over 40% of the world’s population lives in areas at risk of malaria. The problem also applies to (though to a lesser extent) the European countries and other economically developed countries. Malaria is caused by parasites from the group of Plasmodium, which are character- ized by high resistance to currently available drugs. [1] There are several types of malaria, including the most dangerous and common tropical malaria, caused by Plasmodium falciparum. It is characterized by irregular attacks of fever and shivers. The incubation period of the disease varies depending on the infectious agents and ranges from several weeks to several months, or even a year in the case of infection with P. falciparum. Prevention of the spread of this dangerous disease is one of the major challenges of our times. Several research centers located throughout the world deal with this problem. [2] Infection with plasmodia occurs after a female malaria mos- quito (Anopheles maculipennis) bite. At the moment of biting, sporozoites are released into the body, which after the process of metabolism, attack red blood cells in the liver, multiply within them, and finally cause their disintegration (hemolysis). Apart from asexual erythrocytic and liver forms occurring in humans, sexual forms also develop in the mosquito body – gametocytes, and therefore an effective antimalarial drug should fight both forms. So far, attempts at isolation or synthesis of such com- pounds have failed, hence an entirely effective medicine has not yet been found. At present, there are ca. 50 antimalarial drugs and compounds still at the testing stage, including quinine and its derivatives. [3] Quinine inhibits the biosynthesis of parasite’s DNA through the formation of complexes with nucleic acids, which prevent the proper functioning of parasite cells. The main disadvantage of quinine is the extent of biological activity, which includes only forms in red blood cells, resulting in a partially successful therapy. It should be emphasized, however, that quinine is a toxic drug, i.e., causes allergic reactions and can damage the heart and blood vessels. [4–7] Administration of quinine for uncomplicated malaria cases had been temporarily reduced due to toxicity, poor compatibility, and introduction of newer and better-tolerated therapies. In recent years, however, an increasing resistance to chloroquine and antifolates has actually caused increased use of quinine in the treatment of malaria. Therefore, the tests on the role of quinine in the treatment of malaria and its impact on the human health and life are continued. Quinine is bacteriostatic, highly active toward protozoans in in vitro studies, and inhibits yeast fermentation. The mixture of quinine hydrochloride and urea is injected as a sclerosant (sclerosing agent) in the treatment of internal hemorrhoids and varicose veins. Quinine is also used to reverse a multiple drug resistance in patients with acute leukemia. Patients treated with quinine and polytherapy manifested better results of treatment compared to patients treated with chemotherapy. Despite fre- quent observations of undesirable effects, such a combination is still used in the treatment of acute leukemia. [8–11] Address correspondence to: Mariusz Kluska, Institute of Chemistry, Siedlce University of Natural Sciences and Humanities, 54 3-Maja St, 08-110 Siedlce, Poland. E-mail: kluskam@uph.edu.pl Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/ljlc.