HPLC RETENTION AND INCLUSION OF IMIDAZOLE DERIVATIVES USING HYDROXYPROPYL-β-CYCLODEXTRIN AS A MOBILE PHASE ADDITIVE

Using the results of high performance liquid chromatography (HPLC), this paper investigates the separation and inclusion of a series of weakly polar imidazole derivatives, with hydroxypropylβ -cyclodextrin (HP-β-CD) in the mobile phase over a wide range of column temperatures.These compounds are used for the treatment of onychomycosis. Gibbs Helmholtz parameters (Δ(ΔH) and Δ(ΔS)) of two adjacent imidazole peak on a chromatogram were determined from the graph of the logarithm of the separation factor,α, against the reciprocal of the temperature. A temperature dependent reversal of the elution order between a pair of imidazole derivatives was studied. The results revealed that the main parameter determining interactions between imidazole derivatives and HP-β-CD increased as follows:HP-β-CD ⇔solute hydrogen bonding interaction >HP-β-CD ⇔solute complexation.