In vivo transdermal permeation-enhancement activity and skin irritation of eucalyptus oil by using microdialysis technique / 中草药

ABSTRACT

Objective To evaluate the skin irritation of eucalyptus oil and its in vivo transdermal penetration enhancement properties by using the cutaneous microdialysis technique. Methods The CCK-8 assay was used to measure the toxicity of eucalyptus oil on HaCaT cells, and the TEWL values of the rat skin was determined to investigate the effect of eucalyptus oil on the skin integrity and irritation. Ligustrazine and geniposide were chosen as lipophilic and hydrophilic model drugs, respectively, and their microdialysis probe in vivo recoveries were determined using the retrodialysis method. After treatment with eucalyptus oil, the skin pharmacodynamics behaviors of two model drugs were investigated to evaluate its penetration-enhancement activity. Results The cytotoxicity test revealed there IC50 value of eucalyptus oil to HaCaT cells was 2.452 mmol/L, which was significantly higher than that of chemical penetration enhancer Azone (IC50, 0.266 mmol/L). Meanwhile, the eucalyptus oil had a certain impact on the rat skin TEWL values, but it was weaker than Azone, this implied that the eucalyptus oil had a mild skin irritation. The in vivo transdermal microdialysis tests revealed that the enhancement ratios (ER) of ligustrazine and geniposide were 11.40 and 13.79, respectively, indicating that eucalyptus oil could effectively facilitate the transdermal permeation of both of lipophilic and hydrophilic drugs. Although the penetration enhancement property was generally weaker than Azone, the ER value of eucalyptus oil was closely approximate to Azone. Conclusion The eucalyptus oil could promote the transdermal permeation of both lipophilic and hydrophilic drugs with mild skin irritation, which provided the data support for its application in topical preparation.