Formulation and Evaluation of Ferrous Ascorbate Floating Tablets for the Treatment of Anaemia

Ferrous ascorbate (FA) is preferentially absorbed from the upper gastrointestinal (GI) track, and has low bioavailability due to less residence time of FA in upper GI track. In addition, FA has low solubility and stability at higher pH. The aim of this study was to prepare gastro-retentive tablets of FA in order to increase its gastric residence time and hence, bioavailability. Floating tablets of FA were prepared by wet granulation method using different retarding polymers, Povidone K30 as binder and sodium bicarbonate as effervescent agent. The prepared floating tablets were compared with immediate release (IR) tablets and characterized in detail for in vitro and in vivo studies. In-vitro drug release study of the optimized batch showed 96% drug release in 12 h in 0.1 N HCl. The mechanism of drug release from the floating tablets was non-fickian and release kinetics was best fit in peppas model. The gastric retention time of optimized was found to be significantly increased (6 h) in comparison with IR tablet (<1h). Further, bioavailability was also found significantly increased (>70%) in comparison with IR tablet (15-30%). X-ray studies carried on healthy rabbits suggested that the optimized batch remained buoyant in gastric contents up to 6 h and pharmacokinetic study showed sustained released behaviour of optimized batch in comparison to conventional IR tablet. Floating tablet of FA improved the bioavailability of iron by increasing its gastric residence time, hence it could be a better approach for treating iron deficiency and help in improving the patient compliance than IR tablets.