目的制备O/W型土槿皮乙酸(PAB)微乳,并进行体外经皮渗透性能研究。方法通过绘制伪三元相图确定PAB微乳形成的区域,以微乳的体外经皮渗透速率为指标进一步优化筛选PAB微乳的处方,并对微乳的外观、形态、粒径分布等进行表征;以大鼠皮肤为渗透屏障,利用V-C扩散池比较了PAB微乳和PAB过饱和水溶液的体外经皮累积渗透量及皮肤滞留量。结果优选的PAB微乳处方为IPM-Cremophor EL-Transcutol P-水(0.2∶0.97∶1.83∶7),所制备的微乳澄清透明,透射电镜(TEM)观察结果为均匀的球形或近球形,平均粒径为(18.7±1.9)nm。PAB微乳与PAB过饱和水溶液24 h累积渗透量分别为(50.31±4.63)、(6.27±1.33)μg/cm²,皮肤滞留量分别为(6.28±0.31)、(0.51±0.13)μg/cm²,差异均具有显著性(P<0.05)。结论 PAB微乳新型给药系统可有效促进PAB的经皮渗透及提高其皮肤滞留量,为PAB皮肤给药抗真菌新制剂的设计提供了实验基础。

Objective To prepare O/W microemulsion formulation containing pseudolaric acid B (PAB) and investigate its transdermal delivery ability in vitro. Methods Pseudo-ternary phase diagrams were drawn to obtain the area of PAB microemulsion, and PAB microemulsion formulations were further optimized by the rate of transdermal permeation. The microemulsion properties including appearance, form, and particle size distribution were examined. Taking rat skin as permeability barrier, the cumulative permeation amount in 24 h and retention amount of PAB in skin were determined in vitro using V-C diffusion cell fitted with rat skin. Comparison was made between the PAB microemulsion and PAB supersaturated solution. Results The optimum PAB microemulsion formulation was composed of Isopropyl Myristate-Cremophore EL-Transcutol P-water (0.2∶0.97∶1.83∶7). The appearance of the prepared microemulsion was clear with the mean diameter of (18.7 ± 1.9) nm. The appearance of microemulsion droplets was spherical or near-spherical shape in TEM image. The permeation and retention amount after application of PAB microemulsion for 24 h was significantly increased compared with supersaturated solution of PAB [permeation amount (50.31 ± 4.63) and (6.27 ± 1.33) μg/cm²,retention amount (6.28 ± 0.31) and (0.51 ± 0.13) μg/cm²] (P < 0.05). Conclusion The new delivery system of PAB microemulsion could significantly improve the percutaneous absorption of PAB microemulsion and increase the amount of drug accumulated into the skin. This study will provide the experimental foundations for the development of a new antifungal percutaneous delivery system of PAB microemulsion.