In vitro vitotoxicity test as an alternative to in vivo Draize test for the evaluation of cosmetic

Abstract

The procedures described by Draize are the basis of bothocular and cutaneous irritation tests and have been adoptedinternationally for in vivo evaluation of products andsubstances. However, they have been criticized for ethicalreasons, due to their cruelty towards animals. Therefore,alternative methodologies are being studied to evaluate thetoxicity of products, which have contact with human beings.Thus, a comparative study was performed between ocular,cutaneous and oral mucosa irritation tests using rabbits andin vitro tests through agar diffusion method and neutral reduptake method, both with the use of NCTC clone 929, FPCIAL and SIRC cell lines. Lipsticks, makeup base, face powder,blushes, eye shadows, mascara, pencils and eyeliners, as wellas liquid soap for children and adult use were evaluated. Thein vivo tests and the cell lines used in the agar diffusion testwere chosen according to the place where the products areused. Only the NCTC clone 929 linage was used in theevaluation of all the samples. From the 204 analyzed samples,141 were evaluated through the cutaneous irritation test andFPC-IAL lineage, 80 through the ocular irritation test and SIRClineage, and 78 through the oral mucosa irritation test andFPC-IAL lineage. Only the samples of liquid soap were alsoevaluated through the neutral red uptake method with thethree cells lines. The samples submitted to the in vitroevaluation were analyzed in different concentrations and theobserved parameter was cellular viability with the use of neutralred. The results obtained revealed that the agar diffusion testpositive samples which presented up to degree 3 zone rate,that is cellular death halo varying from 0,5 to 1,0cm from thesamples, according to USP 25, didn’t provoke ocular,cutaneous or oral mucosa irritation. The samples whichpresented degree 4 zone also showed different degrees ofocular and cutaneous irritation, except to two units of liquidsoap for children use which didn’t present in vivo reactions,although citotoxicity up to 10% concentration. This methodshowed significant correlation with the ocular irritation testand also concerning the individual values of cornea andconjunctiva. As for the neutral red uptake test, it presentedsignificant correlation in the ocular and cutaneous irritationtest, what make it possible to infer that when the liquid soapsamples present IC50 above 0,085% they won’t cause ocularand cutaneous irritations in rabbits. No relation was observedbetween the origin of the cell lines and the target tissue usedin the in vivo test, having all the cellular lines shown significantcorrelation with the NCTC clone 929 line. According to thedata, the in vitro methods are more sensitive and the diffusionagar method, using the American Pharmacopeia graduation,can be adopted as a screening procedure in the evaluation ofcosmetics. This is a result of its capacity of predicting irritation,what largely contributes for the reduction of animal using tests.