Coating applications, pharmaceutical enteric coatings

Cellulose can be esterifled with almost any organic acid [81,82,84], Whereas this is possible in principle with both alkyl chlorides and carboxylic anhydrides, commercial practice has focused on the anhydride option. Although many esters have been described in the literature, industrially manufactured organic esters are prepared only with aliphatic fatty acids with between 2 and 4 carbon atoms in length (i. e., acetates to butyrates, CA to CB). Exceptions are some mixed esters with phthalic acid, which are used for enteric coatings in pharmaceutical applications and a novel carboxymethyl cellulose acetate butyrate (CMCAB), which is used in water-borne coatings applications [81,84],... 

Acetyltriethyl citrate is used to plasticize polymers in formulated pharmaceutical coatings. The coating applications include capsules, tablets, beads and granules for taste masking, immediate release, sustained-release and enteric formulations. It is also used in diffusion-controlled release drug... 

Wu, S. Wyatt, D. Adams, M. Chemistry and application of ceUulosic polymers for enteric coatings. In Aqueous Polymeric Coatines for Pharmaceutical Dosage Forms-, McGinity, J., Ed. Dekker New York, 1997 pp. 385-418. 

Applications - delayed release, enteric coatings, pharmaceutical excipient, sustained release, tableting ... 

Intestinal delivery using acidic polymer coatings that dissolve at near-neutral and basic conditions, but are relatively insoluble at acidic conditions. Coatings are applied to drug-containing particles, tablets, or capsules. There are regulatory limitations on the use of many enteric materials for food or nutritional work. There may also be daily intake considerations for some in pharmaceutical applications. 

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