Citric acid crosslinked cyclodextrin/hydroxypropylmethylcellulose hydrogel films for hydrophobic drug delivery

The present communication deals with preparation of β-cyclodextrin (βCD) grafted hydroxypropylmethylcellulose (HPMC) hydrogel films using citric acid as crosslinking agent with the aim of improving the loading and achieving controlled release of hydrophobic weak base (ketoconazole). The hydrogel films were characterized by attenuated total reflectance-fourier transform infrared (ATR-FTIR) spectroscopy, solid state ¹³C-nuclear magnetic resonance (¹³C NMR) spectroscopy, thermal analysis and scanning electron microscopy (SEM). The films were evaluated for βCD content, carboxyl content, swelling ratio, drug loading, drug release and hemolytic assay. ATR-FTIR spectra indicated crosslinking via ester formation whereas ¹³C NMR, thermal analysis and SEM confirmed βCD grafting. The βCD grafted hydrogel films with high carboxyl content showed maximum swelling and high drug loading. The presence of grafted βCD helped to retard the release of ketoconazole from the hydrogel films. The hemolytic assay suggested the biocompatible nature of the hydrogel films. Altogether, βCD grafted HPMC hydrogel films were found to be suitable for delivery of poorly soluble weak bases.