SKIN(2)(R) - AN IN-VITRO HUMAN SKIN MODEL - THE CORRELATION BETWEEN IN-VIVO AND IN-VITRO TESTING OF SURFACTANTS

The availability of an in vitro test system to replace animal testing of potential irritants is becoming more and more urgent especially in Europe as a consequence of the European Community Cosmetics Directive. To evaluate the ability of Advanced Tissue Sciences' (ATS) ZK1301 ski n model to predict the skin irritation potential of surfactants, we pe rformed a pilot validation study utilizing four different laboratories . The in vitro protocol was designed as a quantitative pre-screen for the clinical patch studies. Sixteen substances, representing various s urfactant categories and ranges of irritation potential, were tested. The [4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) a ssay was used to quantitate viability in vitro. We documented the viab ility of tissues exposed to unknown substances for specific periods. T he in vitro results were calculated as percent distilled water control s (DWC), The time required to reduce the viability of each tissue to 5 0% of the distilled water controls (T-50) was compared to mean erythem a and edema scores from the clinical studies by Pearson's correlation. The individual laboratories demonstrated coefficients of 0.72. The re sults indicated that the 30 min percent untreated control values best predicted the 24 h clinical patch scores, No statistically significant interlab variability was found, Only one false negative was seen when non/mild and moderate/severe irritant categories were assigned accord ing to the in vitro scores. These results demonstrate that the skin(2) (R) in vitro test system may serve as a good screening method prior to clinical patch studies.