Thesis (M.Sc.)--Chulalongkorn University, 2007

Various chitosan derivatives were prepared by grafting of phthalimido and cinnamoyl groups onto the chitosan chain. Cinnamoyl derivatives used included cinnamic acid, 4-methoxycinnamic acid and 2,4,5-trimethoxycinnamic acid. The obtained cinnamoylphthaloylchitosan, 4-methoxycinnamoylphthaloylchitosan and 2,4,5-trimethoxycinnamoylphthaloylchitosan were induced into nanoparticles by dialysis method using DMF as solvent and water as an antisolvent. The sizes of most cinnamoylphthaloylchitosan nanoparticles were in the range of 50-150 nm. The shape of all cinnamoylphthaloyl chitosan nanoparticulates (DS of cinnamoyl of 0.01, 0.30 and 0.77) and all 4-methoxy cinnamoylphthaloylchitosan nanoparticulates (DS of 4-methoxycinnamoyl of 0.11, 0.22, 0.25 and 0.91) were spherical. The shape of nanoaprticulates from 2,4,5-trimethoxycinnamoylphthaloylchitosan with DS of 2,4,5-trimethoxycinnamoyl at 0.19 and 0.26 were spherical but with DS of 2,4,5-trimethoxycinnamoyl at 1.67 was rod-like. The particle sizes slightly increased with increasing concentrations and degrees of cinnamoyl substitution. The factors influencing the formation, size and shape of these nanoparticles are probably the relative ratio of the hydrophobic to hydrophilic (degree of substitution) segments, chemical structure of cinnamoyl moieties and the concentration to prepare nanoparticulates.