betadex and quinocide

Capillary electrophoresis (CE) methods for chiral resolution of five antimalarial drugs (primaquine, tafenoquine, mefloquine, chloroquine and quinacrine) were developed by using a wide selection of neutral and anionic cyclodextrin (CD) derivatives. The use of sulfobutyl-β-CD and carboxymethyl-β-CD (CMBCD) resulted in good resolution of quinacrine and tafenoquine, respectively. New results are presented for resolutions of chloroquine and mefloquine. Application of carboxyalkyl- and sulfobutyl-CD derivatives provided improved resolution for primaquine. The impurity in primaquine sample detected by CE was identified as quinocide by MS and NMR. CMBCD provided not only the best separation of primaquine from quinocide but also the simultaneous complete resolution of both compounds.

Topics: Aminoquinolines; Anions; Antimalarials; beta-Cyclodextrins; Chloroquine; Cyclodextrins; Electrophoresis, Capillary; Humans; Magnetic Resonance Spectroscopy; Mass Spectrometry; Mefloquine; Primaquine; Stereoisomerism

The antimalarial drug primaquine (PQ) and its contaminant, the positional isomer quinocide (QC) have been successfully separated using capillary electrophoresis with either beta-cyclodextrin (beta-CD) or 18-crown-6 ether (18C6) as chiral mobile phase additive. The interactions of the drugs with cyclodextrins and 18C6 were studied by the semiempirical method (Parametric Model 3) PM3. Theoretical calculations for the inclusion complexes of PQ and QC with alpha-CD, beta-CD and 18C6 were performed. Data from the theoretical calculations are correlated and discussed with respect to the electrophoretic migration behavior. More stable complexes are predicted for the PQ-beta-CD and PQ-18C6 complexes. The coelution of PQ and QC when alpha-CD was used as buffer additive can be explained by their comparable stabilities of the inclusion complex formed, while significant differences in the complexation stabilities of the drugs with beta-CD is responsible for their separation. The stronger hydrogen bonding in PQ-18C6 system is responsible for the separation between PQ and QC when 18C6 was used as chiral mobile phase additive.

Topics: Aminoquinolines; beta-Cyclodextrins; Crown Ethers; Drug Stability; Electrophoresis, Capillary; Models, Molecular; Primaquine

A capillary zone electrophoretic method has been developed and validated for the determination of the impurity quinocide (QC) in the antimalarial drug primaquine (PQ). Different buffer additives such as native cyclodextrins and crown ethers were evaluated. Promising results were obtained when either beta-cyclodextrin (beta-CD) or 18-crown-6 ether (18C6) were used. Their separation conditions such as type of buffer and its pH, buffer additive concentration, applied voltage capillary temperature and injection time were optimized. The use of 18C6 offers slight advantages over beta-CD such as faster elution times and improved resolution. Nevertheless, migration times of less than 5 min and resolution factors (R(s)) in the range of 2-4 were obtained when both additives were used. The method was validated with respect to selectivity, linearity, limits of detection and quantitation, analytical precision (intra- and inter-day variability) and repeatability. Concentrations of 2.12 and 2.71% (w/w) of QC were found in pharmaceutical preparations of PQ from two different manufacturers. A possible mechanism for the successful separation of the isomers is also discussed.

Topics: Aminoquinolines; Antimalarials; beta-Cyclodextrins; Crown Ethers; Drug Contamination; Electrophoresis, Capillary; Humans; Hydrogen-Ion Concentration; Linear Models; Primaquine; Reference Standards; Sensitivity and Specificity; Tablets; Temperature; Time Factors