Dissolution enhancement of griseofulvin from griseofulvin-sodium dodecyl sulfate discs investigated by UV imaging

The purpose of study was to investigate the dissolution rate enhancement obtained when sodium dodecyl sulfate (SDS) is co-compressed with griseofulvin into discs using a UV imaging-based flow-through dissolution testing setup. Griseofulvin dissolution rates obtained from discs containing 5.92 and 10.6% (w/w) SDS in phosphate buffer (pH 6.5) were similar to dissolution rates from pure griseofulvin discs when applying 20 and 100 mM SDS as dissolution medium, respectively. Dynamic light scattering of effluent samples revealed nanosized particles (approximately 135 nm in diameter) escaping the discs during dissolution. Scanning electron microscopy of co-compressed griseofulvin-SDS discs prior to dissolution testing showed surfaces apparently consisting of granules (100 and 200 nm in diameter) as well as particles present on the disc surfaces possibly related to the high initial dissolution rates. Material swelling or precipitation was observed for discs containing 10.6 or 15.8% (w/w) SDS. UV imaging revealed increased griseofulvin concentrations near the solid-liquid interface of griseofulvin-SDS discs, e.g., a 45-fold increase in concentration was observed for discs containing 10.6% (w/w) SDS as compared to discs without SDS, which is the likely cause of the enhanced dissolution rates found for the co-compressed griseofulvin-SDS discs.