Composite Sodium Alginate and Chitosan Based Wafers for Buccal Delivery of Macromolecules

The objective of this study was to develop a composite buccal drug delivery wafer for protein drug delivery. The polymeric vehicle used in this study combined chitosan and sodium alginate with bovine serum albumin (BSA) as a model drug. The wafers were obtained by freeze-drying gels of the polymers in well plates. Prior to the lyophilisation process, differential scanning calorimetry was performed to establish a suitable freeze-drying cycle. Preliminary characterization experiments were undertaken to select the optimum composite gel containing sodium alginate and chitosan in a 4:1 ratio respectively for drug loading. A second series of characterisation tests were performed on the drug-loaded wafers prepared from gels containing 0.25 and 0.5 % w/w of BSA. The formulations were functionally characterised for swelling, mucoadhesive and drug dissolution properties. The morphology and crystallinity were investigated using a scanning electron microscope and X-ray diffractometer respectively. The results from drug dissolution studies over a two-hour period showed 66% and 31% cumulative drug release for the wafers obtained from gels containing 0.25 and 0.50 % w/w BSA respectively. These results show the feasibility of developing a sustained delivery system for macromolecules by combining chitosan and sodium alginate.