Phetdee M, Polnok A, Viyoch J
Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand.
Int J Cosmet Sci. 2008 Aug;30(4):285-95. doi: 10.1111/j.1468-2494.2008.00447.x.
In this study, chitosan-coated liposomes were developed. To entrap lyophilized tamarind extract containing alpha-hydroxy acids (AHAs) together with tartaric acid, the reverse phase evaporation method was used to obtain well-formed liposomes loaded with the extract. The highest entrapment efficiency of 68.3 +/- 3.0% into the liposomes was obtained with liposomes consisting of phosphatidylcholine and cholesterol in a molar ratio of 2 : 1 after the extrusion process. The average particle size of the prepared liposomes was 158 +/- 26 nm showing a negative zeta potential of -6 mV. For the preparation of the chitosan-coated liposomes, two selected independent parameters were varied: chitosan concentrations of 0.1, 0.5 and 1.0% w/v and volumes of the chitosan solutions of 1, 2 and 3 mL, to study the effects of such parameters on the entrapment efficiency of the extract-loaded liposomes. Variation in the volumes of the chitosan solution did not affect the entrapment efficiency of the liposomes. However, the entrapment efficiency of the AHAs in the chitosan-coated liposomes significantly increased with increasing chitosan concentrations. The size of the chitosan-coated liposomes was in the range of 200-300 nm with a positive zeta potential in the range of 6-29 mV. An in vitro release study using dialysis technique was performed to evaluate the release profile of the tartaric acid from the chitosan-coated liposomes. The obtained results showed the effect of the chitosan-coated liposomes on the lower release rate and on the amount of tartaric acid in comparison with that of the uncoated liposomes. The study in an in vitro skin cell model indicated that the developed system could enhance the potential of tamarind's AHAs on the stimulation of human keratinocyte proliferation being two-fold higher than the solution of the tamarind extract.
在本研究中，制备了壳聚糖包被的脂质体。为了包封含有α-羟基酸（AHA）的冻干罗望子提取物以及酒石酸，采用反相蒸发法获得了负载提取物的形态良好的脂质体。在挤压过程后，由摩尔比为2:1的磷脂酰胆碱和胆固醇组成的脂质体对提取物的包封率最高，达到68.3±3.0%。所制备脂质体的平均粒径为158±26 nm，zeta电位为 -6 mV。对于壳聚糖包被脂质体的制备，改变了两个选定的独立参数：壳聚糖浓度为0.1%、0.5%和1.0%（w/v），壳聚糖溶液体积为1 mL、2 mL和3 mL，以研究这些参数对负载提取物脂质体包封率的影响。壳聚糖溶液体积的变化不影响脂质体的包封率。然而，壳聚糖包被脂质体中AHA的包封率随着壳聚糖浓度的增加而显著提高。壳聚糖包被脂质体的粒径在200 - 300 nm范围内，zeta电位在6 - 29 mV范围内呈正值。采用透析技术进行了体外释放研究，以评估酒石酸从壳聚糖包被脂质体中的释放情况。所得结果表明，与未包被的脂质体相比，壳聚糖包被脂质体对较低的释放速率和酒石酸的量有影响。体外皮肤细胞模型研究表明，所开发的系统可以增强罗望子AHA对人角质形成细胞增殖的刺激作用，比罗望子提取物溶液高两倍。
