[Thin layer chromatographic detection of emollients in gastric juice-resistant coatings. 2. The pharmaceutic technology and analysis of gastric juice-resistant dosage forms].

Softeners in enteric coatings as phthalic acid esters, citric acid esters, tartaric acid esters, glycerine esters, alcohols or surfactants can be identified by thin layer chromatography. Normally they are extracted by ether out of a phosphate buffer solution of the coating. In exceptional cases, it is necessary to extract dry isolated enteric coatings with acetone/ethanol. As developing solvents butanol and methylene-chloride are recommended. To separate similar substances as glycerine-diacetate from glycerine-triacetate it can be necessary to evaluate the results in both developing solvents. Softeners had been isolated and identified from 9 examples of commercial drugs.