Jiang M, Qureshi S A
Therapeutic Products Directorate (2202C1), Health Canada, Ottawa, ON.
J Dermatol Sci. 1998 Dec;18(3):181-8. doi: 10.1016/s0923-1811(98)00039-5.
The percutaneous absorption studies were performed using a flow-through diffusion cell system with skin specimens from 24 healthy women to assess the penetration of glycolic acid (GA). Percentages of GA, based on 14C-labelled activity, found in the skin after application of 4% GA at pH 2.0 or pH 3.8, after 24 h were as follows: stratum corneum (SC)= 2.65+/-1.80 versus 1.13+/-1.14 (P<0.05); viable skin (VS)= 13.46+/-7.44 versus 2.23+/-1.51 (P< 0.05) and effluent fraction (EF) = 12.22+/-9.03 versus 1.42+/-0.77 (P < 0.05), respectively. The applications of 4-60%, GA at their native pH resulted in an increased penetration of GA through the skin. For example, application of 20% GA, pH 1.9, resulted in the following values: SC = 2.69+/-2.26 (P > 0.05); VS = 4.88+/-4.05 (P > 0.05) and EF = 30.69+/-13.25 (P < 0.05). Duration of application also affected the extent of penetration of drug. For example, application of 20% GA, pH 1.9, for 6 h resulted in the following levels: SC = 1.16+/-0.80 (P < 0.05); VS = 4.07+/-1.78 (P > 0.05) and EF = 6.12+/-4.95 (P < 0.05).
(i) absorption of GA in human skin are pH-, strength- and time-dependent; and (ii) the in vitro method appears to provide an appropriate model to reflect in vivo absorption of GA through human skin.
采用流通扩散池系统对24名健康女性的皮肤标本进行了透皮吸收研究，以评估乙醇酸（GA）的渗透情况。在pH 2.0或pH 3.8条件下应用4% GA后24小时，基于14C标记活性在皮肤中发现的GA百分比情况如下：角质层（SC）=2.65±1.80与1.13±1.14（P<0.05）；活皮肤（VS）=13.46±7.44与2.23±1.51（P<0.05）；流出液分数（EF）=12.22±9.03与1.42±0.77（P<0.05）。在其天然pH值下应用4%-60%的GA会导致GA透过皮肤的渗透率增加。例如，应用pH 1.9的20% GA，得到以下数值：SC = 2.69±2.26（P>0.05）；VS = 4.88±4.05（P>0.05）；EF = 30.69±13.25（P<0.05）。应用持续时间也会影响药物的渗透程度。例如，应用pH 1.9的20% GA 6小时，得到以下水平：SC = 1.16±0.80（P<0.05）；VS = 4.07±1.78（P>0.05）；EF = 6.12±4.95（P<0.05）。
（i）GA在人体皮肤中的吸收呈pH值、浓度和时间依赖性；（ii）体外方法似乎能提供一个合适的模型来反映GA通过人体皮肤的体内吸收情况。
