314 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS In the cosmetic and allied fields, there is presently no important litera- ture pertaining to the use of antibiotics. This is not surprising because many of the antibiotics such as penicillin, streptomycin, and certain broad spectrum antibiotics, etc., have rather high incidences of sensitivity and development of drug resistance. However, not all antibiotics have high incidences of sensitivity and drug resistance. Whether there are implications for the use of the several anti- biotics in this category, in the cosmetic and allied fields, and the extent to which these implications exist, would seem to depend on the quantity and quality of researches carried out in this direction. Bacitracin, neomycin and tyrothricin are virtually nontoxic and have documented records of extremely low incidences of sensitivity and resistance development when employed topically and orally. In the pharmaceutical field, these drugs are permissible for use in products sold over-the-counter in drug stores. Neomycin and tyrothricin in products must adhere to the provisions of the Food, Drug and Cosmetic Act, and a "new drug applica- tion" must be submitted to the Food and Drug Administration before marketing is permitted. Bacitracin is a "certifiable" antibiotic, and prod- ucts containing this drug require certification with the Division of Anti- biotics, Food and Drug Administration but for use as a pharmaceutical product the plain ointment of bacitracin has now been de-certified, al- though such ointment is still subject to Food and Drug Administration approval. Where it is desirable to study this interesting trio of antibiotics, and to limit the study to their topical possibilities in other than medical and phar- maceutical fields, it is first desirable to review such data as the properties, stabilities, compatibilities and applications which make these agents useful and important. Such fundamental material, which would naturally make the study more valuable, is available elsewhere in the literature (12, 18-23, 26-28, 54-59, 68). Any possible implications for topical usage of these antibiotics in the cosmetic and allied fields would be determined primarily t•om established findings in the dermatological field. Consequently, it would be of value to review herein, very briefly, documented data from clinical sources. BACITRACIN Uses: Bacitracin has a wide antibiotic spectrum effective against Gram- positive organisms (1, 2). Its antibacterial spectrum is quite similar to penicillin (3-5). Numerous investigators have been in agreement on the efficacy of baci- tracin in the treatment of various local skin conditions (4-9), etc. In the treatment of superficial pyodermas, response to bacitracin is very rapid, often within forty-eight hours and the drug has been called the most effi- cient topical application against pyodermas (7, 10).

TOPICAL USES OF SEVERAL ANTIBIOTICS 315 Drug Resistance and Sensitivity: In the dermatological field it has been noted, by and large, that resistance of susceptible bacteria appears to be inconsequential with bacitracin (3, 11). In the use of bacitracin, many dermatologists had been impressed from the early days of usage by the low incidence of allergic reactions, as contrasted with other agents, whether antibiotics or chemicals. This good impression dealing with low incidence of sensitivity has been maintained with continued experiences, during the past several years, and right up to the present time (1, 4, 6, 8, 10, 12-15). To select an example, one group of investigators studied bacitracin for sensitivity in 288 individuals, patch testing with bacitracin ointments (1000 units per gram) for forty-eight hours. All of those tested were nega- tive for sensitivity, except one. However, this exceptional individual was also allergic to the petrolatum in the ointment and also reacted violently to liquid petrolatum, olive oil, wool fat, soybean oil bases, lard, carbowax, greaseless ointment bases, sulfonamides and quinolines (10). Another study noted that not a single instance of allergy or irritation occurred in 400 individuals, and concluded that either the incidence of total hypersensitivity of the drug is extremely low, or else the time required for local allergy to develop, if it develops, is an unusually long time (16). Still other investigators have stated that bacitracin is the least allergenic of local agents currently used, and place the sensitization rate at less than 0.5 per cent (15). Another worker pointed out that it is noteworthy that lack of irritation is an important attribute of bacitracin, since it is manda- tory to avoid agents which have any tendency to irritate the skin (17). NEOMYCIN Uses: Neomycin is a broad spectrum antibiotic. It has been shown to have a wide range of activity, in vitro and in vivo, against Gram-negative and Gram-positive organisms (5, 18, 22, 29-33). While Gram-negative bacilli, especially, exhibit a wide range of susceptibility toward neomycin, the drug is said to have no effect against fhngi (18). Neomycin is said to be bactericidal in a concentration equal to or only slightly higher than that in which it is bacteriostatic (34, 35). In some of the early published work on neomycin used topically, 200 cases were first reported (36), followed by a report totaling 675 cases, with the conclusion that neomycin was more effective for certain skin conditions than other topical agents (37). Also, later dermatoloõical studies with neomycin confirmed its valuable effects in 264 individuals with various types of cutaneous conditions. Many other published reports have further confirmed the highly satis- factory topical effects of neomycin, especially when applied either as an ointment or in aqueous solution (1, 5, 17, 35, 36, 38, 39, 40, 41, 42, 43, 44).