Study on in Vitro Transdermal Properties and Skin Safety Evaluation of Zhengrutie Cataplasm

OBJECTIVE To study the in vitro transdermal characteristics of Tibetan new drugs hereinafter referred to as Zhengrutie cataplasm, and to evaluate the safety of skin medication by using different species of animals(guinea pigs, New Zealand rabbits). METHODS The improved vertical Franz diffusion cell method was used for in vitro transdermal testand the skin of Bama miniature pig was used as the permeation barrier. The cumulative permeation amount and rate of geniposide methyl ester and 8-O-acetyl geniposide methyl ester, borneol and camphor in the receiving medium were determined by HPLC and GC, respectively, to investigate the in vitro transdermal characteristics of Zhengrutie cataplasm. Buehler test was used to study the sensitization of Zhengrutie cataplasm on guinea pig skin. Observed the skin irritation after single or multiple application of Zhengrutie cataplasm on intact and damaged skin of New Zealand rabbits. RESULTS The cumulative permeation amount of the sum of geniposide methyl ester and 8-O-acetyl geniposide methyl ester, borneol and camphor within 24 h were 14.14, 348.21, 490.97 μg·cm^-2, respectively. The cumulative permeation amount were 6.2%, 10.2% and 15.3%, respectively. The average permeation amount were 0.59, 14.51 and 20.46 μg·cm^-2·h^-1. No allergic reaction to guinea pig skin, no irritation to intact skin of New Zealand rabbits, mild irritation to damaged skin. CONCLUSION The in vitro transdermal performance of Zhengrutie cataplasm is good. The in vitro transdermal process conforms to the zero-order kinetic equation. It has no irritation and sensitization effect on the skin of guinea pigs and New Zealand rabbits. It is safe and reliable for skin external use and has good clinical application value.