Formation of two particular structures between beta-cyclodextrin and bifonazole: beta-cyclodextrin-bifonazole and (beta-cyclodextrin)(i)-bifonazole (where 2 < i < 3)

This paper deals with inclusion compound formation between beta-cydodextrin (beta-CD) and bifonazole, an antimycotic hydrophobic imidazole derivative. High performance liquid chromatography (HPLC) was-used in order to measure the solubility of this drug as a function of the quantity of cyclodextrin in the samples. According to the classification of Higuchi and Conners, an A type solubility diagram was obtained, revealing the formation of soluble Inclusion compound(s). Differential scanning calorimetry (DSC) was used for the first time, in order to draw binary phase and Tammann diagrams between beta-cyclodextrin and bifonazole. The experimental results demonstrated th e formation of two binary compounds, beta-cyclodextrin-bifonazole and (beta -cyclodextrin)(i)-bifonazole (where 2 < i < 3). The two compounds have been characterised using solid state nuclear magnetic resonance (NMR) spectrosc opy. Different NMR spectra have been obtained, which indicate that the firs t compound is an inclusion Compound and the second may be a crystallised co mpound, in which the bifonazole is not necessarily included in the cyclodex trin internal cavity.