Thesis (M.Sc.)--Chulalongkorn University, 2012

The objective of this research was to increase the mucoadhesive property of chitosan and evaluate for its application in mucoadhesive hydrophobic drug delivery systems. Thiolated chitosan (pCA-HT-chitosan) was synthesized by the covalent attachment of p-coumaric acid (pCA) to increase hydrophobic part and conjugated homocysteine thiolactone (HT) to improve mucoadhesive property of chitosan. The modified chitosan was characterized by NMR, FTIR and TGA. The mucoadhesive and swelling properties were studied at the simulated gastric tract (pH 1.2, 4.0, and 6.4). The mucoadhesive properties of pCA-HT-chitosan higher than chitosan about 9.87-, 2.01- and 1.58-fold in all tested three pHs. Furthermore, the thiolated chitosan as hydrophobic drug carrier systems. This research used piperine (PIP) as hydrophobic drug that was investigated in order to increase the nutrients/drug adsorption in intestinal fluid. The microspheres were fabricated using electrospray ionization technique. The particles were nearly spherical in shape with an average size of 3 - 4 μm, entrapped piperine (PIP) over than 80% EE and the mucoadhesive properties displayed 5.72-, 1.59- and 1.55-fold stronger than the unmodified chitosan at pH 1.2, 4.0, and 6.4 respectively. Final the formulations could sustain release of piperine with % culmulative drug over within 12 h in vitro.