CROSS-LINKED DEXTRAN - A NEW CAPSULE MATERIAL FOR COLON TARGETING OF DRUGS

In the work presented here we have studied the application of glutaral dehyde crosslinked dextran as a capsule material for colon-specific dr ug delivery. A reaction mixture containing dextran, MgCl2, glutaraldeh yde and polyethyleneglycol 400 in water was applied onto molding pins of nylon producing capsule caps and bodies. The capsule materials were characterized by measuring of the mechanical strength in compression and equilibrium degree of swelling. Based on these results an optimal composition for the capsule material was selected. The dextran capsule s were loaded with hydrocortisone and subsequently, drug release was s tudied. The release was found to be about 10% during the initial 3 h i n a buffer solution. Over a period of 24 h the release was about 35%. However, when the dextran capsules were challenged with a dextranase s olution, simulating the arrival of the drug delivery system to the col on, the capsules quickly broke and the drug was released as a dose dum p. The study shows that the dextran capsules are promising candidates for providing a colon-specific drug delivery. (C) 1998 Elsevier Scienc e B.V.