Controlled release of saccharides from matrix tablets

The aim of this study was to design site specific, controlled release tablets of N-acetyl-d-glucosamine (NAG), maltose monohydrate and maltopentaose by using hydrophobic matrix formers starch acetate (SA) and ethyl cellulose (EC). The optimized matrices, which had either low porosity and high drug load or high porosity and low drug load, released the saccharides within the desired 2–4 h. In general, it was possible to control the release rate of saccharides by altering the relative amount of hydrophobic matrix former in the tablet and tablet porosity. The release type of saccharides from these formulations varied from immediate release to sustained release. In the case of sustained release formulations, it was found that the release of maltose monohydrate and maltopentaose was biphasic and slower than the release rate of NAG from similar tablets. NAG release kinetics followed square root of time kinetics, while in the case of maltose monohydrate and maltopentaose, the release kinetics were zero order in both phases. The biphasic dissolution profile was proposed to be caused by water mediated recrystallisation of the disordered material formed during the dissolution. Both SA and EC matrices were found to represent suitable controlled oral delivery vehicles for saccharides.