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.