Eudragit Enteric Film Coating Systems Formula and Process Examples Zhion@zhion.com |
Enteric Film Coatings with Polymethacrylates Many pharmaceutical dosage forms irritate the stomach due to their chemical properties. Others undergo chemical changes in gastric acid and through the action of enzymes, thus becoming less effective. One of the widely used enteric film coating system is Eudragit. For the processing of EUDRAGIT usually some additional excipients are required. Plasticizers reduce the minimum film forming temperatures as well as the glass transition temperatures. The addition of a plasticizer like triethyl citrate increases the flexibility of the film coatings. To prevent the film coatings from getting sticky some glidants such as talc or glycerol monostearate are also necessary. EUDRAGIT polymers show very high pigment binding capacity. Pigments as much as three times the amount of EUDRAGIT can be incorporated or bound into the film coating. Various Eudragit Enteric Coating Products are summarized as follows: EUDRAGIT L 30 D-55 is pH dependent anionic aqueous polymer dispersion solubilizing above pH 5.5 for targeted drug delivery in the duodenum. EUDRAGIT L 100-55 prepared by spray-drying, can be reconstituted for aqueous formulations for targeted drug delivery in the duodenum. EUDRAGIT L 100 is pH dependent anionic polymer powder solubilizing above pH 6.0 for targeted drug delivery in the jejunum. EUDRAGIT L S 100 is pH dependent anionic polymer powder solubilizing above pH 7.0 for targeted drug delivery in the jejunum. EXAMPLES OPERATION PROCESS Pre-warm to about 30 °C, by means of an air spray gun. Adjust the spray rate, inlet air quantity and inlet air temperature such a way that spraying can be performed continuously. Maintain tablet-bed temperature of approx. 25 to 35 °C during the process. Spray at low rates initially for moisture-sensitive tablets (seal-coating). Spray at faster rates after the 30 minute-sealing coating. If twinning occurs, stop the spray and increase the pan speed. After coating is done, dry the tablets by slow down the coating pan speed. FORMULATIONS A. EUDRAGIT S 100 COATING SYSTEM EUDRAGIT® S 100 1,000 g Talc 330 g Triethyl citrate 500 g 1N NH3 (1.7% NH3) 508 g Water 6,662 g B . EUDRAGIT L 100 COATING SYSTEM EUDRAGIT® L 100 1,000 g Talc 330 g Triethyl citrate 500 g 1N NH3 (1.7% NH3) 339 g Water 6,661 g OTHER COATING SYSTEMS Ethylcellulose Disperision-Aquacoat |