Effect of hydrophilic diluents on the release profile of griseofulvin from tablet formulations

Studies have shown that when compressing drugs with low aqueous solubility, the solubility of diluents selected is very crucial as it influences the disintegration, dissolution and bioavailability of such drugs. Based on these reports, the present study was undertaken to investigate the effect of some commonly used hydrophilic tablet diluents (lactose, sucrose, mannitol and dextrose) on the in vitro release properties of griseofulvin from compressed tablets. Griseofulvin granules and tablets were prepared using the wet granulation method. Tablet properties evaluated as a function of the diluents used include, hardness, friability, dissolution profile and dissolution efficiency at 60 min. Results obtained indicated variability in griseofulvin release in the presence of the diluents. The relative enhanced dissolution effects of the four hydrophilic diluents is in the order of dextrose>sucrose>lactose>mannitol. All the griseofulvin tablet batches produced exhibited a better drug release (in terms of rate and extent of release) than a commercially available tablet sample of griseofulvin (Fulcin(®)). The results of the dissolution efficiency (DE60min) are 91.7, 83.5, 48.7, 35.3 and 15.6% for dextrose, sucrose, lactose, mannitol and fulcin(®), respectively. The overall results indicated that dextrose or sucrose can be utilised to improve the in vitro release profile and hence in vivo bioavailability of griseofulvin from compressed tablets.