THE EFFECT OF BINDER TYPE AND MAJOR DILUENT ON THE MIGRATION AND BIOAVAILABILITY OF RIBOFLAVIN SODIUM PHOSPHATE DURING TABLET MAKING

The migration of riboflavin sodium phosphate (RSP) upon drying of its wet granules was studied through the formulation of granules using different diluents (lactose monohydrate and anhydrous dibasic calcium phosphate), different binders of different concentrations; polyvinyl pyrrolidone (PVP k25), methylcellulose (MC), hydroxypropylmethyl cellulose (HPMC) and gelatin at different drying temperatures (50°C and 70°C). The prepared granules were compressed into tablets and evaluated. In vitro drug release from the formulated tablets was performed. In addition, in vivo study was conducted on some selected tablet batches. The results showed that, the granules prepared with dibasic calcium phosphate showed lower migration for the drug than those prepared with lactose. Also, drug migration decreased with increasing the binder concentration and viscosity. The degree of tablet mottling was inversely proportional to the binder concentration. Tablets prepared with 10% w/w gelatin were found to be the least mottled ones. In addition, they showed the least friability percentage, the highest hardness value and the highest disintegration time. Tablets prepared with 0.5% MC showed the highest dissolution rate, however, those prepared with 10% gelatin had the lowest dissolution rate. Generally, increasing the binder concentration resulted in slowing the in vitro drug release from tablets. The in vivo study showed that, tablets prepared with 10% w/w gelatin showed the lowest excretion rate and the highest Tmax (1.5 hours). Meanwhile, tablets prepared using 0.5% w/w MC exhibited higher excretion rate and Tmax of 0.5 hour.