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

Quantitative relationship between the chemical structure of antisense nucleosides and their capacity to interact with cyclomalto-octaose

The interaction of twelve 8-substituted-2'-deoxyadenosine and seventeen 5-substituted-2'-deoxyuridine derivatives (antisense nucleosides) with cyclomalto-octaose (GCD) was determined by charge-transfer chromatography and the relative strength of the interaction was calculated. The majority of antisense nucleosides (14 deoxyuridine and 11 deoxyadenosine derivatives) interacted with GCD, which probably led to inclusion complex formation. Stepwise regression analysis proved that the strength of interaction was related to the length of the apolar alkyl chain of substituents and the bulkiness of the nucleoside ring structure. The effect of double or triple bonds in the chain was negligible.

Modification of the apparent lipophilicity of steroidal drugs with gamma-cyclodextrin

The interaction between 17 steroidal drugs and gamma-cyclo-dextrin (gamma-CD) was determined by charge-transfer chromatography and the relative strength of interaction was calculated. The relationship between the strength of interaction and the physico-chemical parameters of steroidal drugs was elucidated with principal component analysis. Gamma-CD interacted with each steroidal drug decreasing the apparent hydrophobicity of the guest molecules. Calculations indicated that the interaction between the drugs and gamma-CD is of mixed character: steric, hydrophobic and electronic forces are involved in the complex formation. The marked influence of gamma-CD on the apparent hydrophobicity of drugs suggests that this interaction may modify the biological properties (absorption, uptake, half-life etc.) of drug-gamma-CD complexes resulting in modified efficacy.