EVALUATION OF ANTIBACTERIAL SOAP BARS 353 double-blind study. Individual subjects were sampled for the levels of bacteria on their hands (second basin counts) after two and four weeks of assigned product usage. Over 160 subjects in each group com- pleted the study. Results are presented in Table VI. A statistically significant (P 0.05) reduction in the bacterial flora of subjects using the antibacterial bar soaps when compared to the control group was evident at both the second and fourth week sampling. More- over, the analysis of variance showed that the observed difference in skin degerming effectiveness between the two antibacterial bar soaps was significant at P 0.05. The ability to demonstrate statistically significant differences be- tween two effective antibacterial soaps under normal usage conditions is evidence of the resolving power of which properly designed and exe- cuted testing techniques are capable. CONCLUSIONS Results of in vitro testing may be of value in screening for potential antibacterial ingredients. They are not reliable, however, for predict- ing actual skin degerming effectiveness of products. In the case of minimum inhibitory concentration tests, the results are too dependent upon the particular bacterial species or strains selected for the test to be meaningful in determining the relative effectiveness of various anti- bacterial bar soaps. At the present time, the only reliable way to determine efficacy of antibacterial bar soaps is the measurement of a change in the number of cutaneous bacteria resulting from exposure of the skin of human subjects to the products. Procedures are available for conducting such studies. These are feasible not only for use under controlled conditions in the laboratory, but also for ad lib. consumer use studies in the field. (Received December 2, 1965) REFERENCES (1) Pillsbury, D. M., Livingood, C. S., and Nichols, Anna C., Arch. Dermatol. Syphilol., 45, 61 (1942). (2) Price, P. B., J. Infect. Diseases, 6/I, 301 (1938). (3) Cade, A. R., Soap Sanit. Chemicals, 73, 35 (1950). (4) Quinn, H., Voss, J. G., and Whitehouse, H. S., Appl. Microbiol., 2,202 (1954). (5) Travers, J. J., Rohloff, A. C., Ambye, E. L., and Vinson, L. J., J. Soc. Cosmetic Chemists, 10,410 (1959).

J. Soc. Cosmetic Chemists, 17, 355-360(1966) Cyclic Salicylanilides Antibacterial Agents as WINTHROP E. LANGE, Ph.D.,* and JON C. ANDERSON, M.S. Presented May 4, 1965, New I/ork City Synopsis--A number of halogen, trifluoromethyl, and sulfur-containing salicylanilides along with cyclic derivatives of these same compounds were prepared for evaluation as antibacterial agents. The effects of structure modification on activity were shown by a densitometric minimum inhibitory concentration technique. The trifluoromethyl-sub- stituted salicylanilides and their cyclic derivatives were found to be the most potent anti- bacterial agents. INTRODUCTION Antimicrobial agents have been used for many years in cosmetic and pharmaceutical products to protect and preserve them from de- terioration due to growth of bacteria, fungi, or yeasts. Today many of the same agents are incorporated into soaps, shampoos, deodorants, toilet preparations, and the like as medicinal agents. Recently a considerable amount of interest has centered about the halogen and trifluoromethyl substituted salicylanilides (1). Investigation has also been carried on with the cyclic derivatives of various salicylanilides, namely the benzoxazinediones and benzothiazinediones which, de- pending upon substitution, have increased the activity of the parent molecule (2). Thus, it has been proposed that a series of salicylanilides and cyclic derivatives of salicylanilide be prepared and subjected to antibacterial testing. * Massachusetts College of Pharmacy, Boston, Mass. 02115. 355