N,N-Dilauryl Chitosan: Synthesis and Surface Pressure-area Isotherm

With sodium dodecyl sulfonate(SDS) as the phase transferring catalyst, N,N-Dilauryl chitosans with a high degree of alkyl group substitution were prepared and characterized by means of FTIR, 1H NMR and elemental analyses. The results indicate that the average degree of alkyl group substitution on the chitosan increases with decreasing the molecular weight of the chitosan. The fully N,N-dilaurylated chitosan was found to be dissolvable in chloroform. The collapsed pressures of the samples derived from chitosan with 3000, 5000 and 10000 dalton are 47.6, 48.2 and 51.0 mN/m, respectively. The surface area occupied by the monomer unit(glucosamine) of all those samples is 0.6 nm2.

N,N′-双月桂酰基乙二胺二丙酸钠的制备与性能

以丙烯酸甲酯、乙二胺及月桂酸为原料制备了Gemini型阴离子表面活性剂N,N′ 双月桂酰基乙二胺二 丙酸钠,并对其相关性能进行表征。结果表明,该表面活性剂在25℃时γcmc为27.1mN/m,cmc为9.6× 10-4mol/dm3,胶束聚集数(Nm)为41.6,均小于相应的普通皂型表面活性剂;并测定了乳化、润湿、泡沫及耐 硬水洗涤等应用性能。

N,N-双十二烷基壳聚糖/胆固醇混合单分子膜及自组装囊泡性质

研究了添加胆固醇对N,N-双十二烷基壳聚糖(N,N-dilaurylchitosan,DLCS)单分子膜以及自组装囊泡性质的影响.结果表明,引入少量胆固醇会导致DLCS膜的凝聚性下降;当胆固醇含量增加到一定程度后,混合膜的凝聚性增强.添加胆固醇可显著改变DLCS载药囊泡的药物释放行为,少量胆固醇可以提高载药囊泡的释放速率和平衡药物释放百分率;而较高含量胆固醇则可抑制囊泡的释放速率和降低平衡药物释放百分率.此外,囊泡平衡药物释放率与其单分子膜压缩模量呈现一定线性关系,这说明胆固醇的引入导致囊泡分子膜凝聚性的改变,从而改变囊泡的通透性.通过调节胆固醇的加入量,可以制得药物释放行为在一定范围内可控的自组装囊泡.