Macromolecular conjugate based particulates: Preparation, characterisation and evaluation of controlled release properties

A new particulate delivery matrix based on macromolecular conjugate, chitosan–whey protein isolate ([Ch–WPI]) was found to exhibit controlled release properties. Fourier-Transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) demonstrated the formation of the conjugate. Particle formation of the conjugate was carried out by the ionic crosslinking technique using sodium tripolyphospate (STP). Catechin entrapped particles were prepared by varying the weight ratios of STP to conjugate [Ch–WPI]. Both the placebo and catechin-entrapped particles were found to be positively charged below pH 7.2, indicating their stability to aggregation and their suitability for bioadhesion in the gastrointestinal tract (GIT). The entrapment efficiencies of the particles ranged between 29% and 42% for particles prepared using different weight ratios of the conjugate to STP. There was 34–56% of catechin release in simulated GIT conditions depending on the entrapment efficiencies and the degree of crosslinking of the particles.