In vitro evaluation of epichlorohydrin cross-linked pectins as colon-specific drug delivery carriers

Various epichlorohydrin cross-linked pectins, having degrees of methoxytation (DM) ranging from 60.5 ±0.9 to 68.0 ±0.6% and referred to as C-LP0, C-LP37, C-LP56, C-LP75, C-LP100 and C-LP250, respectively, were synthesized. Having been degraded by Pectinex Ultra SP-L (pectinolytic enzymes), the various derivatives were then used to prepare matrix tablets containing 10% w/w drugs (indomethacin or theophylline); this to evaluate their potential as specific colonic drug delivery carriers, using in vitro dissolution tests. The results obtained have shown that: (a) the kinetics of drug release, depending on the cross-linking degree of pectin, were the lowest with matrix tablets prepared from the derivative C-LP75; (b) the addition of pectinolytic enzymes in the dissolution media generally resulted in a huge acceleration of the drug release; (c) the less hydrosoluble drug, indomethacin, was released more slowly than theophylline from the different matrix tablet formulations.