Studies on amidated pectins as potential carriers in colonic drug delivery

Amidated pectins have been assessed, in-vitro, for their potential value in colonic drug delivery. The monitoring of the release of a model soluble drug, paracetamol, gives a sensitive indication of the behaviour of the pectins under simulated gastrointestinal conditions. Inclusion of calcium as a cross-linking agent increased the viscosities of amidated pectin gels to a maximum value. Further addition of calcium reduced gel viscosity and for pectin with a high extent of amidation this led to a reduction in drug release. Release was faster for pectin with less amidation in the presence of calcium; this could be related to matrix erosion. The results of the study suggest that the materials might be of value in colonic delivery either alone or in combination, possibly in the form of a coating.