OBJECTIVETo prepare kappa-carrageenan-chitosan polyelectrolyte gel pellets and detect the effects of formulation and preparation factors on in vitro drug release from the pellets.

METHODThe K-carrageenan-chitosan polyelectrolyte gel pellets with baicalin as model drug were prepared by ionotropic gelation technique. The ratio of kappa-carrageenan/chitosan in pellets was determined with the composite of K-carrageenan and chitosan. The effects of the concentration of K-carrageenan, the ratio of drug/kappa-carrageenan, the concentration of gelling solution, gelling time and drying method on the release of pellets were determined by in vitro drug release.

RESULTThe mass ratio of K-carrageenan/chitosan in pellets was 6: 4. Release of the pellets in 0.1 mol x L(-1) HCl was about 10% for 2 hours and fast in PBS, indicating a typical sustained release property. The pellets released less with the increase in the concentration of K-carrageenan, the ratio of drug/kappa-carrageenan and the concentration of KCl. They also released less with the increase in gelling time, but showed little effect until 1 hour. The release of the pellets prepared by the freeze-drying method was much faster than those by vacuum drying and atmospheric drying methods which had little influence on drug release.

CONCLUSIONThe K-carrageenan-chitosan polyelectrolyte gel pellets had sustained release property. Their drug release rate could be regulated with different formulation and preparation factors.