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I. Soc. Cosmet. Chem., 27, 607-623 (December 1976) Physical Techniques For Assessing Skin Moisturization ALFRED J. QUATTRONE, Ph.D.* and KARL LADEN, Ph.D.? Presented, May 30, 1975, SCC Seminar, St. Louis, MO. Synopsis: An overview is presented of some PHYSICAL TECHNIQUES currently avail- able for use in SKIN MOISTURIZATION studies. Water soaking of unmodified versus ether-extracted stratmn comeurn, for example, causes a marked alteration in the BIO- MECHANICAL properties of these tissues (i.e., swelling capacity, elastic modulus, relaxa- tion function, and work index). Differences in moisture binding properties as measured by GRAVIMETRIC and SCANNING CALORIMETRIC analyses of the tissue at various rel- ative humidities are related. The correlation of changes in these traits with changes in the pliability and strength of corncure tissue and its capacity to retain moisture is discussed. Criteria for judging dry versus hydrated skin IN VIVO are also reviewed through the utilization of TRANSPIROMETRY, PHOTOGRAPHY, and SCANNING ELECTRON MICROSCOPY (SEM). Analysis via these techniques of the effect of humectants and oc- clusive oils on water retention within skin is presented. INTRODUCTION A wide variety of in vitro and in vivo physical procedures are available for investigating phenomena associated with moisturization of the stratum cor- neum. This presentation will touch on the usefulness of gravimetric, scanning calorimetric and, mechanical techniques in quantRating levels of moisture re- tention and pliability obtained after treating corneum tissue with various ma- terials in vitro. In addition, in vivo evalu, ations by means of transpirometry low magnification photography, and scanning electron microscopy (SEM) of skin replicas before and after treatment of human skin with moisturizing for- mulations will be reviewed in detail. *Past address: Gillette Research Institute, 1413 Research Blvd., Rockville, MD 20850. Present address: Tracor-Jitco, Inc., 1776 E. Jefferson St., Rockville, MD 20852. •Past address: Gillette Research Institute, 1413 Research Blvd., Rockville, MD 20850. Present address: Carter Products Div., Carter-Wallace, Inc., Cranbury, N.J. 08512. 607