COMPARATIVE-STUDY OF AQUEOUS AND ORGANIC ENTERIC COATINGS OF CHLORPHENIRAMINE MALEATE TABLETS

Two acrylic polymers (Eudragit(R)L 12.5 P and L 30 D) and a cellulosic polymer (cellulose acetate trimellitate, CAT) in organic and aqueous formulations were used in order to obtain an enteric coating on tablet s containing clorpheniramine maleate as a water-soluble model drug. Th e coating of tablets was executed in a coating pan in similar conditio ns for each kind of solvent. The coated tablets were tested according to the delayed-release test of USP 23 (Method A). In our experimental conditions different amounts of polymers were needed to obtain an ente ric coating. The lowest amount was in the case ofEudragit L 30 D (aque ous), after which appeared Eudragit L 12.5 P (organic), CAT (organic), and finally, CAT (aqueous) as the polymer that needed to be ofthe hig hest amount. During the dissolution test differences in the size and a spect ofthe tablets were observed according to the polymers. Acrylic p olymers did not show changes in size and aspect, but CAT polymers show ed a notable increase in size. The different behavior of the tablets d uring the dissolution test can explain the differences observed in the adjustment of the release data. The release data were tested assuming common kinetic models. In the present study it was observed that Eudr agit L polymers release the drug in a first-order kinetic and that CAT releases it according to a zero-order kinetic.