1.Capillary electrophoresis methods for the analysis of antimalarials. Part I. Chiral separation methods.
Amin NC1, Blanchin MD, Aké M, Fabre H. J Chromatogr A. 2012 Nov 16;1264:1-12. doi: 10.1016/j.chroma.2012.09.057. Epub 2012 Sep 25.
This paper presents an overview on the current status of enantiomeric and diastereomeric separations of chiral antimalarials and derivatives by capillary electrophoresis (CE). The wide variety of chiral selectors which have been employed to resolve successfully antimalarial enantiomers: oligosaccharides (cyclodextrins, oligomaltodextrins), neutral (amylose, dextrin and dextran) and charged (chondroitin sulfate, heparin, dextran sulfate) polysaccharides and proteins are reviewed. Cyclodextrins were the most employed. Chiral additives added to the background electrolyte often facilitated separations of quinine/quinidine and cinchonine/cinchonidine diastereomers. However, in a few cases, using micellar electrokinetic capillary chromatography or non aqueous CE, resolution of diastereomers could be achieved without additives. Quantitative applications of CE to the quality control of antimalarial drugs and their analysis in biological and food matrices are presented.
2.Analysis of Cinchona alkaloids by high-performance liquid chromatography. Application to the analysis of quinidine gluconate and quinidine sulfate and their dosage forms.
Smith E. J Chromatogr. 1984 Sep 7;299(1):233-44.
The application of high-performance liquid chromatography to resolve the individual alkaloids present in marketed Cinchona alkaloids was investigated. Normal-phase and several reversed-phase systems were evaluated. The proposed procedure uses an alkylphenyl column; it adequately resolves quinidine, quinine, dihydroquinidine, dihydroquinine, cinchonine, cinchonidine, dihydrocinchonine and dihydrocinchonidine. Epiquinidine, epiquinine, quininone and quinitoxine are also resolved from quinidine and dihydroquinidine. This high degree of resolution enables the analysis of quinidine and its salts for their usual composition and establishes the absence of any cross-contamination or decomposition. The proposed procedure was applied to currently marketed samples of quinidine salts and their dosage forms. It was also applied to samples that were cross-contaminated or which contained decomposition products.
3.The multidrug resistance protein is photoaffinity labeled by a quinoline-based drug at multiple sites.
Daoud R1, Desneves J, Deady LW, Tilley L, Scheper RJ, Gros P, Georges E. Biochemistry. 2000 May 23;39(20):6094-102.
Tumor cells overcome cytotoxic drug pressure by the overexpression of either or both transmembrane proteins, the P-glycoprotein (P-gp) and the multidrug resistance protein (MRP). The MRP has been shown to mediate the transport of cytotoxic natural products, in addition to glutathione-, glucuronidate-, and sulfate-conjugated cell metabolites. However, the mechanism of MRP drug binding and transport is at present not clear. In this study, we have used a photoreactive quinoline-based drug, N-(hydrocinchonidin-8'-yl)-4-azido-2-hydroxybenzamide (IACI), to show the photoaffinity labeling of the 190 kDa protein in membranes from the drug resistant SCLC H69/AR cells. The photoaffinity labeling of the 190 kDa protein by IACI was saturable and specific. The identity of the IACI-photolabeled protein as the MRP was confirmed by immunoprecipitation with the monoclonal antibody QCRL-1. Furthermore, a molar excess of leukotriene C(4), doxorubicin, colchicine, and other quinoline-based drugs, including MK571, inhibited the photoaffinity labeling of the MRP.