Synthesis and characterization of Κ-Carrageenan-chitosan hollow capsules for the encapsulation and controlled release of 5-flourouracil

Polymer multilayer capsules are made by generating a template, coating it with alternating layers of different polymers and removing the template to make it hollow. It is considered a good drug delivery system as the capsules are very versatile and can be adjusted according to the kind of drug delivery system as the capsules are very versatile and can be adjusted according to the kind of drug being encapsulated by just changing the polymers and template used. Κ-Carrageenan and chitosan are polyelectrolytic biocompatible polymers which are widely studied and used for a variety of biomedical applications. Polymer multilayer capsule can be made with these polymers using the layer-by-layer deposition (LbL) method. The strong electrostatic attraction between these two oppositely charged polymers which males the capsules stable and their biocompatibility makes them excellent candidates for drug delivery applications. The drug to be encapsulated in this study is fluorouracil, a widely used drug for the treatment of cancerous tumors with a large variety of side effects which requires controlled and targeted delivery in the patient. The objectives of this study are the following: to synthesize κ-carrageenan-chitosan hollow capsules with 1 layer κ-carrageenan, and 5, 10, and 11 alternating layers of κ-carrageenan and chitosan, to obtain the fluorescence images and microscopy images of the hollow capsules, and to determine the encapsulation and release profile of fluorouracil as a function of time. Hollow capsules with 5 layers of alternating chitosan and κ-carrageenan have been synthesized with polystyrene as the core template, and the polystyrene removed after depositing the polymer layers by washing it with THF. The capsules were then subjected to gamma irradiation at the Philippine Nuclear Research Institute (PNRI). It was determined from the UV-Vis spectroscopy of the THF washings that five washings are needed to completely remove the polystyrene core template from the capsules. The capsules were subjected to 1 day swelling and through optical microscopy, it was found that the 5-layer diameter of 36.71 μ-m and the 11-layer hollow capsules of 33.75 μm. 5-Flourouracil drug loading was done for 1 hour, 2 hours and 6 hours with 10-layer capsules, with the 6-hour loading period showing the highest amount of drug loaded in the capsules. Flourescence images, drug loading of 1-layer, 5-layers and 11-layers, and drug release studies of the capsules are to follow. (author)