ENCAPSULATED PERFUMES 661 IIIIII ENCAPSULATED OIL i i I 2 3 4 5 6 7 8 9 I0 TIME HOuRs Figure 4. Moisture-induced fragrance release are typical of those obtained in the in vitro tests. Moisture in the in vitro tests was applied by spraying a mist from an atomizer onto the test area. The W's indicate the points at which moisture was applied. Time was allowed to elapse before the first wetting so that some of the IPM in the product could be absorbed by the silicone rubber pads. Sufficient mois- ture was applied to form a visible film of water. These tests were re- peated, in vivo, and similar results were obtained. The subjects were artificially heated at the points, P, to promote per- spiration in an attempt to simulate the results of normal activity at vari- ous times. Tests were then conducted seeking a correlation that might be found between the composition of the aerosol formulation and the degree of release, at any given time, of the encapsulated perfume. The comparison of moisture vapor and fragrance release curves shows the close correlation of the perspiration to the release of volatiles (Fig. 5). Substitutions were made for a portion of the isopropyl myristate in the original formulation. A variety of nonpolar materials was chosen on the basis of their compatibility with the encapsulation. Samples were prepared as shown in Table III. These samples were then subjected to in vitro testing. The results of these tests confirmed the correlation be- tween the aerosol formulation and the susceptability to moisture of highly water-soluble materials, such as the fragrance encapsulations which are dispersed in nonpolar aerosol systems (Fig. 6).

662 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS II II II II II II I I I I I I I I I I I I I I I I m m ß ENCAPSULATED OIL , OIL Illll! RELATIVE WATER VAPOR 2 3 4 5 6 7 B TIME HOURS Figure 5. Perspiration-induced fragrance release Table III Modification of Antiperspirant Bases Concentrate Formulasa 1 2 3 4 Isopropyl myristate a Robaneb Mineral oil c Polylan a Cab-O-Sil* Aluminum chlorhydrate• •)-CAP perfume/ Fill Concentrate Propellants (50: 50) 55.5 27.7 27.7 27.7 ß.. 27.7 ...... ...... 27.7 . .. ......... 27.7 3.6 3.6 3.6 3.6 31.8 31.8 31.8 31.8 9.1 9.1 9.1 9.1 11.0 89.0 a Wickhen Products, Inc., Huguenot, N.Y. b Robeco Chemicals, Inc., New York, N.Y. (hydrogenated squalene). c Witco Chemical Co., New York, N.Y. a American Cholesterol Products, Inc., Edison, N.J. (polyunsaturated liquid esters). e Cabot Corporation, Boston, Mass. (coloidal silicone dioxide). / Registered trademark of Polak's Frutal Works, Inc., Middletown, N.Y. g Formula No. I was the control as used in all of the testing. Formulas No. 2, 3, and 4 are 50% replacements of the IPM with the various nonpolar materials.