Enteric coating is aimed to prevent the formulations from gastric fluid in the stomach and release the drug component in the intestinal region or once it has passed into the duodenum. One of the widely used enteric film coating system is Eudragit.

Various Eudragit for Enteric Coating Products are summarized as follows:

  • EUDRAGIT L 30 D-55 is an aqueous dispersion, pH dependent anionic aqueous polymer dispersion solubilizing above pH 5.5 for targeted drug delivery in the duodenum.
  • EUDRAGIT L 100-55 is powder, prepared by spray-drying, can be reconstituted for aqueous formulations for targeted drug delivery in the duodenum.
  • EUDRAGIT L 100 is powder, pH dependent anionic polymer powder solubilizing above pH 6.0 for targeted drug delivery in the jejunum.
  • EUDRAGIT L S 100 is powder, pH dependent anionic polymer powder solubilizing above pH 7.0 for targeted drug delivery in the ileum.
  • EUDRAGIT FS 30 D is an aqueous dispersion, pH dependent polymer soluble above pH 7.0, requires no plasticizer



FORMULA OF ENTERIC COATING SOLUTION USING EUDRAGIT

For the processing of EUDRAGIT usually some additional excipients are required:
  1. Plasticizers. Plasticizers are a group of auxiliary components that improve elasticity of the polymeric film which is generally rigid and breakable. Plasticizers reduce the minimum film forming temperature (MFFT) of the polymers, softening the polymeric film at lower temperature. This improves the spreadability of the polymer on the surface of the coating substrates and generates a smoother surface texture of the coating layer.
  2. Glidants. To prevent the film coatings from getting sticky some glidants such as talc or glycerol monostearate are also necessary.
  3. Pigment. 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.

The following formulation is calculated for a standard quantity of 1 kg spray suspension. The quantity for film coating of your substrate depends on the application and surface area of the substrate.


IngredientFunctionQuantity based on dry polymer (%)Quanity to be weighed (g)Dry substance (g)
EUDRAGIT L 30 D-55Polymer
416.7125.0
Triethyl CitratePlasticizer10.012.512.5
TalcAntitacking50.062.562.5
WaterDiluent
508.3



1000.0200.0

Preparation:
  1. Talc and Triethyl citrate are homogenized in water using as homog enizer (e.g. Ultra Turrax)for 10 minutes ---> Excipient Suspension
  2. Pour the excipient suspension slowly into the EUDRAGIT dispersion while stirring with conventional stirrer ---> Spray Suspension
  3. Pass the spray suspension through a 0.5 mm sieve

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