A prevalidation study on the in vitro skin irritation function test (SIFT) for prediction of acute skin irritation in vivo: results and evaluation of ECVAM Phase III.

A prevalidation study sponsored by the European Centre for the Validation of Alternative Methods (ECVAM) on in vitro tests for acute skin irritation is aimed at identifying non-animal tests capable of discriminating irritants (I) from non-irritants (NI), as defined according to European Union and OECD. This paper reports on Phase III for one of the methods, the skin integrity function test (SIFT), assessing the protocol performance of the SIFT, in terms of reproducibility and predictive ability, in three laboratories. The barrier function properties of excised mouse skin were determined using a set of 20 coded chemicals (10 I, 10 NI), using the endpoints of trans-epidermal water loss (TEWL) and electrical resistance (ER). The basis of the SIFT prediction model is if the ratios of the pre- and post-application values for either TEWL or ER are greater than five-fold, then the test chemical is deemed irritant (I). If the ratio of both parameters is less than five-fold then the chemical is deemed non-irritant (NI). Analysis of variance (ANOVA) indicated that the intra-lab reproducibility was acceptable but that the inter-lab reproducibility was not. Overall, the SIFT test under-predicted the irritancy of the test chemicals chosen for Phase III with an overall accuracy of only 55%. The sensitivity value (ability to correctly predict I) was only 30%. The specificity (ability to predict NI) of the test was better at 80%. A retrospective examination of the SIFT results was undertaken using Student's t-test and a significance level of P<0.05 to predict an irritant based on changes in the TEWL ratio values. This improved the predictivity of the SIFT test, giving a specificity of 60%, a sensitivity of 80% and an overall accuracy of 70%. Appropriate modifications to the prediction model have now been made and the SIFT will be re-examined in a new validation exercise to investigate the potential of this non-animal method to predict acute skin irritation potential.

[1]  J W Green,et al.  Rapid integrity assessment of rat and human epidermal membranes for in vitro dermal regulatory testing: correlation of electrical resistance with tritiated water permeability. , 2002, Toxicology in vitro : an international journal published in association with BIBRA.

[2]  M Liebsch,et al.  The ECVAM International Validation Study on In Vitro Tests for Skin Corrosivity. 2. Results and Evaluation by the Management Team. , 1998, Toxicology in vitro : an international journal published in association with BIBRA.

[3]  J. J. van de Sandt,et al.  Alternative Methods for Skin Irritation Testing: The Current Status , 1998, Alternatives to laboratory animals : ATLA.

[4]  P. Botham,et al.  Eye irritation: Reference chemicals data bank , 1992 .

[5]  Michael Balls,et al.  The Role of Prevalidation in the Development, Validation and Acceptance of Alternative Methods , 1995 .

[6]  J. Heylings,et al.  Percutaneous absorption and metabolism of dinitrochlorobenzene in vitro , 2000, Archives of Toxicology.

[7]  J. Heylings,et al.  Comparison of tissue sources for the skin integrity function test (SIFT). , 2001, Toxicology in vitro : an international journal published in association with BIBRA.

[8]  D. Basketter,et al.  The classification of skin irritants by human patch test. , 1997, Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association.

[9]  J. Heylings,et al.  Sensitization to 2,4-dinitrochlorobenzene: influence of vehicle on absorption and lymph node activation. , 1996, Toxicology.

[10]  M. R. Simon,et al.  Methods for in vitro percutaneous absorption studies. VII: Use of excised human skin. , 1986, Journal of pharmaceutical sciences.

[11]  L. V. Zutphen,et al.  Animal Alternatives, Welfare and Ethics , 1997 .

[12]  M. Berry.  Alternatives to animal testing II , 1999 .

[13]  John H. Draize,et al.  METHODS FOR THE STUDY OF IRRITATION AND TOXICITY OF SUBSTANCES APPLIED TOPICALLY TO THE SKIN AND MUCOUS MEMBRANES , 1944 .

[14]  Valérie Zuang,et al.  Follow-up to the ECVAM Prevalidation Study on In Vitro Tests for Acute Skin Irritation , 2002, Alternatives to laboratory animals : ATLA.

[15]  R. Scheuplein,et al.  Effects of ionic surfactants on the permeability of human epidermis: an electrometric study. , 1973, The Journal of investigative dermatology.

[16]  Sac-fry Stages,et al.  OECD GUIDELINE FOR TESTING OF CHEMICALS , 2002 .

[17]  R Roguet,et al.  A prevalidation study on in vitro tests for acute skin irritation. results and evaluation by the Management Team. , 2001, Toxicology in vitro : an international journal published in association with BIBRA.

[18]  Michael Sjöström,et al.  Recommendations for the Application of Biostatistical Methods during the Development and Validation of Alternative Toxicological Methods , 1996 .

[19]  D A Basketter,et al.  Evaluation of a human patch test for the identification and classification of skin irritation potential , 1996, Contact dermatitis.