Formulation, optimization and evaluation of enteric coated tablets of Para-amino salicylate sodium

The objective of present investigation was to develop pharmaceutically elegant, stable, economic and easy to scale up enteric coated tablet formulation for intestinal delivery of highly gastric irritant and high dose drug, PAS sodium. Various capsule shaped tablet formulations were prepared using wet granulation technique. Formulations showing best flow properties were first subcoated with Opadry white, followed by enteric coating with Acryl-EZE aqueous acrylic enteric system (Eudragit L100-55 with pigment, surfactants and plasicizers). The enteric coated tablets of optimized formulation (s) exhibited best coating characteristics (measured in terms of coating uniformity and % coating process efficiency), remained intact for 120 min in 0.1 M HCl (pH 1.2) and released almost entire drug within 45 min in phosphate buffer (pH 6.8). Further, PAS exhibited excellent stability in phosphate buffer during the entire duration of dissolution. TO : T he prepared enteric coated tablets showed excellent physical and chemical stability, when subjected to accelerated stability studies for three months. Further, when compared to marketed formulation (Pasco Acri), the prepared enteric coated tablets showed excellent similarities with marketed product (with respect to disintegration time, drug release) thereby establishing bioequivalence with marketed product.