Evaluation of the fluid uptake kinetics and drug release from gellan gum tablets containing metronidazole

In this study, the fluid uptake (swelling) kinetics and disintegrant properties of gellan gum in metronidazole tablets were evaluated in both simulated gastric and intestinal fluids (SGF and SIF respectively) without enzymes. The mechanical properties as well as the disintegration and dissolution profile of the tablets were also assessed and compared with those of two standard disintegrants: maize starch and sodium starch glycolate (Primogel®). Results show that, swelling was faster and higher in SIF than SGF with the minimum and maximum swelling rates of the gum being 0.365 and 6.900 mm3/min respectively in SGF, while the corresponding values in SIF were 0.277 and 7.600 mm3/min respectively. The gum was most effective as a disintegrant for metronidazole tablets at an optimum concentration of 0.2% (w/w) when incorporated extra-granularly.