Formation and stability of shark liver oil loaded chitosan/calcium alginate capsules

Calcium alginate capsules containing shark liver oil were prepared by ionotropic gelation of alginate solutions. Since the capsules were permeable to the oil, they were coated with it membrane of chitosan-alginate polyelectrolyte complex to reduce permeability. Encapsulation efficiencies (expressed as the percentage of shark liver oil entrapped) greater than 87% (w/w) were obtained by using 6% (w/v) alginate solution. ne oil content in the capsules was higher than 65% (w/w) when the oil was dispersed in the alginate solution at 10% (v/v) or more. However, at the level of 15 or 20% (v/v) the oil was exuded after 48 h. Capsules were degraded in vitro by enzymes, with lipase being more effective than pancreatine. No release of oil from the capsules up to 4 h at pH 1.2 was observed, but after 4 h the capsules became very fragile when they were immersed in buffer solution at pH 7.4. (C) 2004 Elsevier Ltd. All rights reserved.