Effect of derivatization of steroids on their retention behaviour in inclusion chromatography using cyclodextrin as a mobile phase additive

Effect of beta-cyclodextrin derivatives on the retention of steroidal drugs

The retention of eighteen steroid drugs was determined on a beta-cyclodextrin polymer (beta CDP)-coated silica column using methanol-water mixtures as eluents. The relative strength of inclusion formation between the drugs and hydroxypropyl-beta CD (HP beta CD) and dimethyl-beta CD was determined by charge transfer chromatography carried out on reversed-phase thin-layer chromatography plates. The retention characteristics of drugs were correlated with their physicochemical parameters and with their inclusion complex-forming capacity. Calculations indicated that the inclusion complex-forming capacity of the drugs has little impact on the retention that is due to the HP beta CD and water-insoluble beta CD polymers exposed to different retention characteristics. The hydrophilic molecular parameters of drugs significantly influenced their retention. This result suggests that the selectivity of the beta CDP-coated column may be different from that of the traditional reversed-phase columns.

Use of principal component analysis for the evaluation of the retention behaviour of monoamine oxidase inhibitory drugs on beta-cyclodextrin column

The retention of 17 monoamine oxidase inhibitory drugs (proparlgylamine derivatives) were determined on a beta-cyclodextrin polymer (beta CDP)-coated silica column using ethanol-0.05 M K2HPO4 (6:4 v/v) as the eluent. The relative strength of interaction between the drugs and a water soluble beta-cyclodextrin polymer was determined by charge-transfer chromatography carried out on reversed-phase TLC layers. The relationship between capacity factors, physicochemical parameters and inclusion complex forming capacity of the monoamine oxidase inhibitory drugs were evaluated by stepwise regression analysis and by principal component analysis (PCA) followed by two-dimensional nonlinear mapping and varimax rotation. Calculations indicated that the retention of monoamine oxidase inhibitory drugs on beta CDP column is mainly governed by their steric and lipophylic parameters. Significant linear correlations were found between the corresponding coordinates of varimax rotation and two-dimensional nonlinear maps proving the suitability of both methods for the reduction of dimensionality of complicated data matrices.