To enhance dissolution rate of poorly water-soluble drugs: glucosamine hydrochloride as a potential carrier in solid dispersion formulations.

The solid dispersion technique is the most effective method for improving the dissolution rate of poorly water-soluble drugs, however this is reliant on a suitable carrier and solvent being selected. The work presented explores D-glucosamine HCl (G-HCl) as a potential hydrophilic carrier to improve dissolution rate of a poorly water-soluble drug, carbamazepine (CBZ), from physical mixtures and solid dispersion formulations. The effect of different solvents in the preparation of solid dispersion formulations was also investigated. Solid dispersions of the drug and G-HCl were prepared using different ratios by the conventional solvent evaporation method. Different solvents (ethanol, acetone and water) were used as second variable in the preparation of solid dispersions. Physical mixtures of CBZ and G-HCl were also prepared for comparison. The properties of all solid dispersions and physical mixtures were studied using a dissolution tester, FT-IR, SEM and DSC. These results showed that the presence of glucosamine can increase dissolution rate of CBZ compared to pure CBZ. All solid dispersions of CBZ-G-HCl showed considerably a higher dissolution rate than the corresponding physical mixtures. The presence of water during preparation of the solid dispersions reduced the dissolution rate of CBZ due to formation of carbamazepine dihydrate during the preparation of solid dispersion, as proved by DSC and FT-IR studies. To facilitate comparison, the dissolution efficiency was calculated for solid dispersions prepared with different solvents and the dissolution efficiency can generally be ranked as follows: ethanol>acetone>ethanol-water>acetone-water when the ratios of drug to carrier were 4:1 and 2:1. It has thus been shown that the use of G-HCl in solid dispersion formulations can significantly enhance the dissolution rate of poorly water-soluble drugs such as carbamazepine. This amino sugar could be used as a new carrier in solid dispersion formulations and would have significant commercial potential.