ABSTRACT
Objective:To evaluate the irritation and hypersensitivity of Biyan black plaster with different coating process. Meth-ods:The skin irritation test was carried out on healthy New Zealand rabbits. Totally 18 rabbits were divided into 3 groups randomly, and Biyan black plaster Ⅰ, Biyan black plaster Ⅱ and Biyan black plaster Ⅲ was painted on the skin of rabbits, respectively, and blank plaster was used as the autologous negative control. Erythema and edema on the skin after the administration were evaluated and the scored. The skin hypersensitive test was carried out on health guinea pigs. Totally 50 guinea pigs were randomly divided into 5 groups:Biyan black plaster Ⅰ group, Biyan black plaster Ⅱ group, Biyan black plaster Ⅲ group, the negative control (the blank plaster) and the positive group(1% 2,4-dinitrochlorobenzene). The skin allergy at 24 h and 48 h was observed and the score was e-valuated. Results:The average score of stimulus response for Biyan black plasterⅠwas no more than 0.42 and the sensitization rate was 0,which had no differences when compared with those of the blank control group(P>0.05),suggesting no obvious irritation and sensitization. The average score of stimulus response of Biyan black plasterⅡwas no more than 0.83,which showed statistical signifi-cance when compared with that of the blank control group (P<0.05), and the sensitization rate was 10%, which had no difference when compared with that of the blank control group (P>0.05), suggesting mild irritation without obvious sensitization. The average score of stimulus response of Biyan black plasterⅢwas no more than 1.17,which showed statistical significance when compared with that of the blank control group (P<0.01),and the sensitization rate was 20%,which had no difference when compared with that of the blank control group (P>0.05),suggesting mild irritation and light sensitization. Conclusion:Biyan black plaster I without skin irritation and hypersensitivity can be externally used safely.