Charge-transfer chromatographic study of the complex formation of some steroidal drugs with carboxymethyl-gamma-cyclodextrin.

The interaction between 15 steroidal drugs and carboxymethyl-gamma-cyclodextrin (CM-gamma-CD) was studied by reversed-phase charge-transfer thin-layer chromatography and the relative strength of interaction was calculated. CM-gamma-CD formed inclusion complexes with each compound, the complex always being less hydrophobic than the uncomplexed drug. The inclusion-forming capacity of drugs differed considerably depending on their chemical structures. The linear correlation between the hydrophobicity and specific hydrophobic surface area of anticancer drugs indicated that they can be considered as a homologous series of compounds, although their chemical structures are different. Hydrophobicity of drugs significantly influenced the strength of interaction, indicating the involvement of hydrophobic forces in the binding of drugs to CM-gamma-CD. The marked influence of CM-gamma-CD on the hydrophobicity of drugs suggests that this interaction may modify the biological properties (adsorption, uptake, half-life, etc.) of drug-CM-gamma-CD complexes drug, resulting in modified efficacy.