356 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS .r" .... /•...?. . •..1•..:..: ? •- '•:..: ' .'.---' '.*' •" -. •..: ...... .'•... ..:, ..? ß ••y.•.. ,. .'.• .• .• .... •½:. .' ..........:, e .. . ,..:.%..?. . -.• .':.. .•..•:...•**f:' • ....... ....t --- .:.. .. . :...-.. ,..' :' '-***.,- .-:x. • : ' ..... ......:.:..•' '":'* '*?' ::..' ,:: • :.:...:%....•:.•, ..,:...,. :... ......... .• '•::-,..:,--' :.:',-' .:• ..:. ...........t?:. .½ *. .. *......:• .::.:.c '• ...... ........ ß .,• ...... ?, :.:...,%?.?.•: •:..:. .:- . /' .•:.:':'::, .:t.-,:***. .... •..':..:.**r. e•:: -• .::•.: ,? ,.f ... " .b: ,•.,' "i•'.r' •*:: • :':• .• ... : .•:..:.. . ß ':*., :. /: ...:• .... ...Q? ' '•.' , ' :.* qC-"' .:½.'-..•: ' .. ,..,:.t,.*.: . ::•** .•.., : .. ?'.T•"... '•:ar. '.$: '.: ':** •i *.'.• " -'"• •.-'• z '..' .... "t ":--'..:..• '.* ::: . :• '..'?*""':".• •. •::" . '* ::'' .'::'..":'"":::-:.::c..s•' • -•:":'•:-::-• f•:•:' .... • **..a,'f•.,af•$- :* :•. •.•: :.- ß .... :..,....':.* }:•.. -. .. .....: •.. "..p•'?..,•....,-_•,$..... ' : . ..??•. :...'.•,.'*' '*:.. '" .': :*½•..'. ,•. **.:•.•..:'*:.:•:::... "*•'• '"••• •:-'*•- :*'•' e.' : • .•. '*. •. ',$:'-•:* ..•.. :.•.:.• •:$.....-..*...:•... ,.-::..: s * ..,..... " ' " • •::, ':• ."*, ' :'•.':': "%X":'.':..' ........ '••••••••4:•...: **:..... . .*'z 45- " •.' -•-"-..• :: :•.** •:: .:: W :.•, ':.:.::• " ....... ß •. '•. ß. :t::,:.. -: ½.... .... ".' ":.•. -".:•'.*•r. •*:• •.:'":'.'"•:.:':'..:•':•::.•..'. ,-. -:*'-.. •-,• % *f?.'--:':*•'•,:w•.. **. ß ::-?:* .,,., .- '%'.L" ':* -..•:':•':*:'.•':"::'".•:/$''-:..'"*'* Figure 4. Scanning electron micrograph of very dry skin. Note cracking in sulci stereomicroscopic observation. About an hour is required for the skin to equilibriate to its original moisture content after washing. Therefore, subjects are instructed to return for evaluation each day, i to 11/2hours after the final washing. Thoroughness of washing can be checked by means of the dryness rating of the untreated hand. For panels of 5, theoretical maximum dryness per panel is 100 (5 panelists with 4 observations per panelist, each having a daily rating of 5). Aggregate dryness ratings of 70 to 80 are routinely obtained on such panels. It has been our experience that frequent reminders to panelists of the im- portance of following the above regimen produce positive responses. Panelists are instructed to avoid the use of hand-care products during the test period and to wash their hands only at scheduled times before observation each day. Following this, they are permitted to follow their usual routine (washing dishes, etc.), except for the use of hand care products, until the resumption of testing the next day.

MOISTUBIZING EFFICACY IN HUMANS 357 To qualify as panelists, volunteers must have a propensity for dry skin at e21der times of the year and develop dry skin (5 rating) on both hands after four days of the above regimen, without the use of test material. Suitable panelists usually develop maximum ratings on both hands by the third test day. IV. Elimination of Bias Volunteers who pass the preliminary washing test are assigned a number. Numbers are drawn at random from the pool of acceptable panelists, until the required number of panels is completed. When panels of five are run, 6 panelists are chosen, and the sixth panelist serves as a supernumerary, and his or her values are used only if one of the first 5 pane]ists is absent at any time during the test period. Determination of panel size will be discussed later. The choice of hand to be treated is randomized and balanced. Panelists are rested for at least 1 week between tests to avoid starting the test with hands that differ widely in dryness. The observers are unaware of what materials are being tested and which hand is treated. Each test day, the panelists report to a coordinator in a separate room who gives them a slip of paper identifying the hand to be examined. This is carried to the ob- server who examines the hand and writes its rating on the slip, which the panelist returns to the coordinator. The sequence of hand examination is also randonfized. The coordinator distributes test material and an instruc- tion-comments form on the first day. Panelists are instructed not to discuss the test with the observer. V. Determination of Numerical Moisturizin• Rating Results Obtained Using &Member Panels Treated and untreated hand values are summed for all members of the panel. The aggregate value of treated hands is subtracted from the total for untreated hands to obtain the "difference" due to treatment. The greater the total difference is, in a positive sense, the greater is the moisturizing efficacy of the test material. Samples that obtain difference ratings above 40 after 4 days, with 5-member panels, are considered to be excellent moisturizers. Dif- ferences of 30-to-40 are rated as good. Distilled water has no effect on this test, as one xvould expect, obtaining difference ratings of approximately 0. Difference ratings of some typical cosmetic ingredients obtained with 5-mem- ber panels are shown in Table II. Of interest is the moisturization advantage of glycerine over propylene gly- col, and sorbit•l. g 11 are humeetants and are xv'dely used in products because of their humeetant properties. Mineral oil and petrolatum perform well, as one might predict, from their known oeelusive nature. Silicone fluid obtained a relatively poor rating this might be anticipated from the relatively low water