DEVELOPMENT AND CHARACTERIZATION OF DEXTR AN FATTY-ACID ESTERS AS EXCIPIENTS FOR COLON-TARGETING DOSAGE FORMS

In this paper production methods of certain colon-degradable dextran f atty acid esters and their relevant properties as excipients for colon -targeting dosage forms are reported. Such dextran fatty acid esters m ust be insoluble in, resp. resistant against, gastric and small intest inal fluids. But to a certain degree they must be swellable in aqueous liquids in order to allow an enzymatic attack of the colonic microflo ra. Furthermore, they must be adequately soluble in pharmaceutically a ccepted solvents to permit the technological application of film coati ngs. Otherwise, they can only be used as embedding excipients or matri ces. As the most suitable excipients for film coatings, biodegradable by the colonic microflora, but resistant against gastric and small int estinal fluids, the dextran lauroyl esters were found. Their molecular weight have to be between 60000 and 250000, and their average degree of substitution (DS) between 0.06 and 0.2. Are the molecular weights h igher the DS must be correspondingly lower.