Study of the inclusion interaction of HP-γ-cyclodextrin with bupropion and its analytical application

•The inclusion complex between BUP and HP-γ-CD was studied by spectroscopy.•Formation of this 1:1 inclusion complex in aqueous phase has been confirmed by Job’s method of continuous variation.•The structure of the complex was investigated by FTIR and NMR analyses.•A spectrophotometric method was established to the determination of BUP in pharmaceuticals.

Inclusion complex formation between bupropion (BUP) and hydroxypropyl-γ-cyclodextrin (HP-γ-CD) was studied by Fourier transformation infrared (FT-IR), nuclear magnetic resonance (NMR) and UV spectroscopy. The main factors affecting inclusion interaction were discussed in detail. The inclusion complex of bupropion and hydroxypropyl-γ-cyclodextrin was studied at pH 5 in aqueous phase. Stoichiometry of the complex was found to be 1:1 and apparent formation constant (log K) was determined as 3.54 ± 0.01, suggesting a tendency of the drug to enter HP-γ-CD cavity. All obtained information proved the formation of BUP/HP-γ-CD inclusion complex. A significant enhancement of absorption intensity of bupropion in presence of HP-γ-CD was shown. Due to the property a sensitive spectrophotometric method was elaborated for determination of active substance in bulk solution. At optimum experimental conditions, a linear relationship between absorbance and concentration of bupropion is observed in range of 4–60 μg mL−1 with limit detection of 0.32 μg mL−1 and correlation coefficient of 0.9991. The proposed method was applied successfully to the determination of BUP in pharmaceutical preparations and the results were satisfactory in comparison to official method.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide