14 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Parke-Davis READI-BANDAGE ©, which is an occlusive plastic tape (Blenderin ©) with a Webril © swatch centered on it and (c) the Finn ©, AI-Test ©, Duhring, © and KI © chambers, all of which utilize aluminum shaped into various forms which contain paper or some other absorbent material. The first two systems have been very useful although they have some deficiencies, which include 1) possible interaction between sample and tape, 2) loss of adherence in hot weather due to perspiration, 3) prohibition against showering or bathing while they are worn, and 4) loss of sample while wearing due to inadequate occlusion. The four aluminum systems probably are effective in preventing, or at least minimizing, contact between the sample and the tape. All of these systems are relatively rigid, which renders them less able to conform to the contours of the skin. Also, the relatively small sample volume (0.05 ml for the Finn © chamber and AL-Test © chamber and 0.1 ml for the KI © chamber) has an operational disadvantage in that the absorbent swatch can dry out if any significant time elapses between moistening with the sample and application to the panelists. This is a problem when larger groups of panelists are tested. The patch test system described in this paper was developed to deal with the deficiencies of the older systems. DESCRIPTION OF THE SYSTEM The HTC (Figure ! illustrates one preferred size) is composed of four components: 1) adhesive tape 2) the chamber 3) Webril © 4) release paper Although any adhesive tape may be used, the semiocclusive Durapore © (3M) is preferred for its good adhesion and low irritation potential. Durapore TM Webril © chamber overlay double seal Figure 1. The chamber is made from a polyethylene-vinyl acetate copolymer supplied by United States Industrial Chemical Company. The trade name is ULTRATHENE ©. The grade chosen is identified as U.E. 634-00. This grade has no added plasticizers and has been

PATCH TEST SYTSEM 15 approved by the Food and Drug Administration for use in contact with foods and beverages (alcoholic and non-alcoholic). This grade is quite flexible, and it conforms very well to the contours of the skin. The Webril © is a non-woven, absorbent cotton material supplied by Kleen Test which has a long history of safe use. The release paper is made by the H. P. Smith Paper Company under the designation of 63//BL Polyslik L 275, Code 28385. It serves the purpose of protecting the system until the time it is to be used. EXPERIMENTAL The HTC was evaluated for its occlusive properties in a series of experiments. EXPERIMENT I--TAPE SELECTION AND SHOWERING This experiment was designed not only to evaluate the occlusive property of the HTC but also to find suitable semiocclusive adhesive tapes for the system. The criterion selected was gain in weight of the Webril © and chamber after a 24-hour application time followed by a shower prior to removal of the HTC. Ten panelists participated in this experiment. Each panelist wore duplicate unmoistened systems only the chamber and Webril © were weighed before application and again before and after showering. Half of the panelists used Ultrapore © (M) and SCANPOR © (S) paper tapes, and the other half used DERMILITE © II (L) and Durapore © (D) fabric tapes. The experiment was replicated three times on three consecutive days using the same panelists. The mean weight changes in milligrams and the standard deviation are shown below in Table I. Table I Mean Weight Changes (nag) and Standard Deviations of HTC and Webril © Before and After Showering Tape Type* (N = 30) M S L D Before After Before After Before After Before After (nag) (nag) (nag) (nag) (nag) (nag) (nag) (nag) X 9.7 186 13.2 70 7.9 28 9.0 3.0 SD 8.9 156 8.3 120 7.9 53 8.0 8.0 *M = Ultrapore © S = SCANPOR © L = DERMILITE II © D = Durapore © As shown above, the chamber and Webril © using Durapore © tape gained significantly less weight following a shower than the three other tape systems. EXPERIMENT II--SWIMMING This experiment was designed to determine the effect of swimming on the occlusivity of the HTC system. Again, four adhesive tapes were used, i.e., Ultrapore © (M), SCANPOR © (S), DERMALITE © II (L), and Durapore © (D). Duplicate weighed