CONTENTS -- ENVIRONMENTAL HEALTH CRITERIA FOR DERMAL ABSORPTION -- PREAMBLE -- ACRONYMS AND ABBREVIATIONS -- 1. SUMMARY -- 2. INTRODUCTION AND DEFINITIONS -- 2.1 Scope of the document -- 2.2 Definition of dermal absorption -- 2.3 Factors influencing dermal absorption -- 3. SKIN STRUCTURE AND FUNCTION -- 3.1 Functions of the skin -- 3.2 Skin structure -- 3.3 The transport of chemicals through the skin -- 3.4 Variability in skin permeability -- 3.5 Reservoir effects -- 4. SKIN TRANSPORT MECHANISMS AND THEORETICAL CONCEPTS -- 4.1 Transport through the skin -- 4.2 Theoretical aspects of diffusion -- 4.3 Physicochemical factors affecting skin permeation -- 4.4 Concepts of finite and infinite dose -- 5. METABOLISM IN THE SKIN -- 5.1 The drug-metabolizing systems of the skin -- 5.2 Methodology for evaluating skin metabolism in in vitro systems -- 5.3 Effects of skin metabolism -- 5.4 Importance of metabolism for percutaneous absorption -- 6. IN VITRO TESTS FOR DERMAL ABSORPTION -- 6.1 Test guidelines -- 6.2 Principles of the standard in vitro tests using skin samples -- 6.3 Other in vitro methods -- 6.4 Examination of skin reservoir characteristics -- 6.5 Experimental factors affecting dermal absorption in vitro -- 7. IN VIVO TESTS FOR DERMAL ABSORPTION -- 7.1 Laboratory animal studies -- 7.2 Studies with human volunteers -- 7.3 Other methods -- 7.4 Factors affecting dermal absorption in vivo -- 8. COMPARATIVE STUDIES -- 8.1 Comparison between in vitro and in vivo skin absorption results -- 8.2 Inter-and intralaboratory variation in in vitro percutaneous absorption methodology -- 9. DATA COLLECTIONS -- 9.1 Data sets from homologous or closely related molecules -- 9.2 Flynn data set -- 9.3 Expanded permeability coefficient data sets -- 9.4 EDETOX database -- 9.5 Maximum flux databases -- 10. ESTIMATION/PREDICTION OF DERMAL PENETRATION.

10.1 QSAR analysis -- 10.2 Mathematicak modelling -- 10.3 Mathematical pharmacokinetic models of percutaneous penetration -- 11. USE OF DERMAL PENETRATION STUDIES IN RISK ASSESSMENT -- 11.1 Decision-making process for setting dermal absorption values -- 11.2 Use of relative absorption values versus flux (and their derived permeability coefficients) -- 11.3 Other topics related to risk assessment -- 12. CONTROVERSIAL TOPICS IN THE ASSESSMENT OF DERMAL ABSORPTION -- 12.1 QSARs/QSPeRs -- 12.2 Reduction of intralaboratory/interlaboratory variation -- 12.3 Consequences of reservoir effect for risk assessment -- 12.4 Relevance for percutaneous measurements to data required by risk assessors: finite and infinite exposures -- 12.5 Single-versus multiple-exposure regimes -- 12.6 Barrier integrity test for skin barries function of human skin in skin penetration tests -- 12.7 Dermal absorption in susceptible populations -- 12.8 Skin notation -- 12.9 Dermal absoprtion of nanoparticles -- 13. CONCLUSIONS AND RECOMMENDATIONS -- REFERENCES -- APPENDIX 1: GUIDELINES AND PROTOCOLS -- APPENDIX 2: PAST AND PRESENT INITIATIVES ON EXCHANGE OF INFORMATION AND HARMONIZATION OF METHODOLOGY ON DERMAL ABSORPTION -- RESUME -- RESUMEN.