Development of Enteric Coated Flurbiprofen Tablets using Opadry/acryl-eze System—A Technical Note

Abstract

Tablet coating is perhaps one of the oldest pharmaceutical processes still in existence (1). It offers many benefits namely: improving the aesthetic qualities of the dosage form, masking unpleasant odour or taste, easing ingestion, improving product stability and modifying the release characteristics of the drug. It is widely used in enteric coating, controlled release system and osmotic pump systems (2). Enteric coated dosage forms are designed to resist the destructive action of the gastric fluid and to disintegrate in the higher pH environment of the intestinal fluid. Polymer for enteric coating can be applied to solid dosage forms (i.e. granules, pellets, or tablets) from aqueous solutions of alkali salts, or organic solvent solutions. The most commonly used pH-sensitive enteric coating polymers today include: cellulose acetate phthalate (CAP), cellulose acetate trimellitate (CAT), hydroxypropyl methyl cellulose phthalate (HPMCP) and methacrylic acid copolymers (3). In recent years, acrylic copolymers have evolved as the most preferred materials for designing enteric coating formulations in terms of performance and global acceptability (1). Aqueous enteric film coatings have been used widely in recent years. Many of these systems are pseudolatex dispersions of polymers such as CAP, latex dispersions of methacrylic acid copolymers and aqueous solutions of alkali salts (4).The advantages of an aqueous based coating system have been recognized. This is derived from the drawbacks of organic solvents including pollution, explosion hazards, and solvent toxicity. Especially there are risks for operators (5). Almost all nonsteroidal anti-inflammatory drugs irritate gastric mucosa and enhance ulceration by blocking protective action of the prostaglandins on gastric mucosa, causing ulcer formation not only in stomach but also in lower part of oesophagus and in duodenum too (6). The most important side effects of flurbiprofen include peptic ulceration, hemorrhage and perforation (7).The aim of current investigation was to develop an enteric coated flurbiprofen tablet formulation to minimize the gastric intolerance caused by flurbiprofen on long term use and to improve patient compliance by utilizing Acryl-Eze. Acryl-Eze is an optimized, one-step, pigmented, aqueous acrylic system for the application of an enteric film coating for oral solid dosage forms. Acryl-Eze combines the benefits and performance of a globally accepted enteric polymer (Eudragit® L100-55) with a fully formulated coating system, providing significant time savings in both development and production. Acryl-Eze has further been optimized for either tablet or multiparticulate applications (8). Eudragit® L100-55 is a copolymer of methacrylic acid and ethyl acrylate (1:1 ratio) which meets the USP definition for Methacrylic Acid Copolymer Type C. L100-55 is a re-dispersible powder produced by spray drying Eudragit® L30-D. Film coatings prepared from such dispersions are resistant to gastric juice but readily dissolve at a pH above 5.5 (9). EudragitL100-55 has been used as a coating polymer in several studies (10,11,12).