Correlation of surface characteristics with ease of production and in vitro release of sodium salicylate from various enteric coated microcapsules prepared by pan coating.

Nonpareil seeds were loaded with sodium salicylate and enteric coated with organic solvent based systems including polyvinyl acetate phthalate, cellacephate (CAP), shellac, hydroxypropylmethylcellulose phthalate, or Eudragit L as film former. Details of the pan coating procedure used were described. The CAP product showed optimum surface continuity when examined by scanning electron microscopy. The shellac product exhibited least aggregation during coating and consequently gave highest yields. Dissolution studies on the microcapsules in simulated gastric and intestinal media indicated that the CAP coated microcapsules had the most satisfactory enteric properties.