ENCAPSULATED PERFUMES 665 strates that the delayed and gradual release of perfume in aerosol prod- ucts can be realized. Antiperspirant products could probably be formu- lated to fulfill specific time-release requirements as well as for subjects lO 9 o 6 4 ¸ o 3 _ IIIIIII ENCAPSLIL01LWATERRbLATIVE ..... VAPOR lO 9 8 7 6 5 ,4 3 2_ 1 2 3 z$ 5 6 7 TIME HOURS Figure 9. Fragrance release with calm snbject " mm mm mm mm mm mm mm mm '' m m m m m m• m m " m m '' m m m m m m llIlII ENCAPSULATED OIL _L •m OIL .... RELATIVE WATER VAPOr 1 2 3 4 5 6 7 8 9 TIME HOURS Figure 10. Fragrance release with nervous subject

666 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS with moderate, heavy, or light perspiration by varying the particular non- polar vehicle used in the formulation. The same delayed and gradual release has been incorporated into other aerosol products, such as feminine deodorant sprays, foot sprays, etc. (3). The same encapsulation system is also capable of incorporating other materials along with perfume oils. Encapsulated perfumes have been prepared with perfume oil to which has been added either hexachloro- phene an oil-soluble, germicidal quaternary or undecylenic acid. In general, oil-soluble, nonpolar materials compatible with the perfume in- gredients may be incorporated in the encapsulations along with the per- fume oil so that they also release over a period of time. A wide variety of fragrance types have been successfully encapsulated. However, adjustments are sometimes necessary in the perfume formula- tion to ensure accurate reproduction of the released perfume oil in the encapsulated form. With these encapsulations it is possible to include perfume types in product formulations which would not otherwise be suitable. Fragrance types, with very volatile character that would not be long lasting enough for inclusion in a product as liquids, can be success- fully employed using encapsulated perfumes. The encapsulated perfumes in aerosol formulations have been tested for extended periods of time with positive results. In the aerosol anti- perspirant formulations used in most of our testing, we ran elevated- temperature-stability tests at 130øF for 14 months. These tests showed that both the release characteristics and fragrance character of the encap- sulated perfume oil were maintained even though the small amount of surface oil on the encapsulations had broken down. It is concluded that a stable and functional encapsulated perfume for use in aerosol products can be produced. The technology developed also provides for other new product possibilities and helps solve problems that previously had no solution. A novel analytical method has also been de- veloped to measure the rate of perfume release as well as moisture release in the axillary region. (Received February 10, 1971) REFERENCES (1) Flinn, James E., and Nack, Herman, What is happening in microencapsulation? Chem. Eng. (New Yorh), 74 (25), 171-8 (1967). (2) Report by the Graduate Students at the Harvard Business School, Microencapsulation, Management Reports, 196•, p. 72. (3) Bakan, Joseph A., Paper on microencapsulation presented to the Eastern Regional IPT Section of the Academy of Pharmaceutical Science, Philadelphia, Pa., October 4, 1968.