136 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS allowed to equilibrate with 0.1 g hair for two hours, and I-•mol bound/g hair was calculated. SUBSTANTIVITY OF Zn-GLY TO SKIN Two pieces of stratum corneum, 50 mg each, were exposed to 2 ml of 50 mM [65Zn] Zn-GLY while two pieces were exposed to 2 ml of 0.01 [65Zn] Zn-GLY. After decant- ing, the stratum corneum pieces were rinsed twice with water, and the rinsings were saved and counted with the solutions and stratum corneum samples. INHIBITORY ACTIVITY OF RESIDUES Activity of the enzymes AS and beta-G can be measured quantitatively using the fluorogenic substrates 4-Me-umbelliferyl sulfate (4-MUS) and 4-Me-umbelliferyl glucu- ronide (4-MUG), respectively, which are hydrolyzed enzymatically to the fluorescent 4-Me-umbelliferol. These materials are analogues of the proposed natural substrates androstenol sulfate and androstenol glucuronide (3). Inhibition of these reactions by Zn-GLY bound to hair was thus measured: A set of 100-mg samples of hair that had been exposed to various levels of Zn-GLY was split in half. One half was placed in reaction mixtures with AS (0.001 mg)/4-MUS (0.1 mg) in 2 ml Tris buffer. The other half was placed in reaction mixtures with beta-G (0. 0001 mg)/4-MUG (0.0025 mg) in 2 ml Tris buffer. Reaction mixtures were irradiated at 334 nm. Fluorescence emission intensity at 444 nm was monitored over a period of one hour as described previously (1). COMPATIBILITY WITH SOAP PRODUCTS Solutions of [65Zn] Zn-GLY were prepared at 0.1 M and 0.5 M Zn in water, and also in solutions of soap and of syndet bar at various concentrations. Samples of chopped hair (0.1 g each) were then exposed to 2 ml of each of these solutions for various time periods, ranging from minutes to hours. AXILLARY DEODORANCY OF Zn-GLY: CLINICAL STUDIES A complete human clinical study was conducted by Hill Top Biolabs, Inc., of Cincin- nati, Ohio (7) to assess its efficacy. The test solution was 4.5% Zn-GLY (1.5% in Zn) this level represents the maximum solubility of Zn-GLY in aqueous solution. The positive control was 5% aluminum chlorhydrate, a level that effects deodorancy by antimicrobial action but does not inhibit perspiration. The negative control was water. Odor assessments were performed by four experienced professional evaluators from Hill Top Research, using a ten-point scoring system. Ninety subjects were recruited, and baseline scores were established after a twenty-four hour conditioning period. Sixty subjects with highest scores (all greater than 4) were retained for the study. Thirty subjects were assigned to Group I, to test Zn-GLY in one axilla, versus water in the other thirty were assigned to Group II, testing aluminum chlorohydrate in the same way.

ODOR INHIBITION 137 During the test the subjects were entered into a regimen of timed, supervised washes with conditioning soap bars, followed by supervised treatments with the test solutions and post-treatment odor evaluation. The evaluations were conducted at 5-hr and 24-hr intervals following treatments 2, 3, and 4, and all aspects were randomized to eliminate any biases. Scores of the four judges were averaged for each person, for each evaluation. The axilla-to-axilla difference for each person was taken as the index of the deodorancy of the test material versus the water control, and these differences were treated statistically by the method of Hollander and Wolfe (8). ANTIMICROBIAL PROPERTIES OF ZINC GLYCINATE MIC values of several zinc complexes were measured for three organisms that occur naturally in the axilla: S. epidermidis, S. aureus, and a lipophilic diphtheroid. During an in-house clinical trial of Zn-GLY deodorancy, and again during the Hill Top Research clinical study, antibacterial potency was determined by the method of Marpies and Kligman (9). 12 10 0 0 Zn GLY at 10 rnM Zn GLY at 1 rnM Zn GLY 0.01 rnM 10 20 3O Time, min. Figure 2. Binding of Zn-GLY to hair, kinetics.