Method development in liquid chromatography with a charged cyclodextrin additive for chiral resolution of rac-amlodipine utilising a central composite design.

P K Owens; A F Fell; M W Coleman; J C Berridge

doi:10.1002/(sici)1520-636x(1996)8:7<466::aid-chir2>3.0.co;2-9

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Method development in liquid chromatography with a charged cyclodextrin additive for chiral resolution of rac-amlodipine utilising a central composite design.

P K Owens·A F Fell·M W Coleman·J C Berridge

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Abstract

A negatively charged derivative of beta-cyclodextrin, sulphobutyl ether-beta-cyclodextrin (SBE-beta-CD), was examined as a chiral mobile phase additive in reversed-phase high-performance liquid chromatography for the enantiomeric resolution of the calcium channel blocker rac-amlodipine. Theoretical and practical aspects are discussed for setting up a central composite design applicable to any analytical method. These include the correct location of factor points for maintaining orthogonality within the design and the augmentation of centrepoint experiments to allow a larger factor space by increasing the distance of axial star points. Optimised separation was achieved using a reverse-phase column with eluent comprising: acetonitrile (ACN)-potassium dihydrogen phosphate (pH 3.93) containing 2.66 mM SBE-beta-CD (26.5:73.5% v/v) at a flow rate of 1.0 ml/min. This yielded a Kaiser peak separation index, Pi = 0.96, at tR2 = 52 min with satisfactory reproducibility, relative standard deviation values: tR1, 0.39%; tR2, 0.47% (n = 5). These experimental results were in excellent agreement with those predicted by the SAS software package for a chromatographic response function model. Multiple regression analysis in four dimensions, with three response models based on Rs, Pi, and a function of Pi, produced response surfaces which revealed zones of optimum robustness and illustrated the interactions involved between the key chromatographic factors. Putative proposals for a mechanism involving the interaction of each of the positively charged enantiomers with the negatively charged cyclodextrin are also discussed. These examine the possibility of ion-pairing and inclusion phenomena to account for the excellent resolution observed.

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Amlodipine Calcium Channel Blockers Carbohydrate Sequence Chromatography, High Pressure Liquid Cyclodextrins Data Interpretation, Statistical Electrochemistry Models, Chemical Molecular Sequence Data Stereoisomerism beta-Cyclodextrins Journal Article Research Support, Non-U.S. Gov't

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P K Owens, A F Fell, M W Coleman, J C Berridge. 1996. Method development in liquid chromatography with a charged cyclodextrin additive for chiral resolution of rac-amlodipine utilising a central composite design.. https://doi.org/10.1002/(sici)1520-636x(1996)8%3A7%3C466%3A%3Aaid-chir2%3E3.0.co%3B2-9

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