US3431207A - Water-insoluble bacteriostats in soap and detergent solutions - Google Patents

Description

United States Patent 3 431,207 WATER-INSOLUBLE BACTERIOSTATS IN SOAP AND DETERGENT SOLUTIONS Kenneth L. Russell, Nutley, N.J., assignor to Malmstrom fhemical Corp., Linden, N.J., a corporation of New ersey N0 Drawing. Filed June 28, 1965, Ser. No. 467,693 U.S. Cl. 252-106 3 Claims Int. Cl. Clld 3/48 This invention relates to aqueous compositions suitable for use as shampoos, skin cleansers, and for like purposes, and is particularly concerned with the production of compositions of this character having normally waterinsoluble bacteriostatic agents incorporated therein.

In recent years, a number of efiorts have been made to impart antibacterial and antifungal properties to shampoos and other skin cleansing products. As a result of those eiforts, numerous varieties of antibacterial liquid cleansers, soaps and detergent bars, as well as of anti-dandruli shampoos have appeared on the market.

These known products derive their claimed antibacterial properties from the incorporation therein of antibacterial agents which are poorly or only slightly Watersoluble. Some of the slightly water-soluble antibacterial agents employed in these products may be quite readily solubilized in significant concentrations in fatty acid soap or anionic synthetic detergent solutions, usually with the aid of heat. Illustrative of these latter antibacterial agents is 2,2-methylenebis [3,4,6-trichlorophenol] commonly referred to as hexachlorop'hene, a commercial variety of which is sold under the trademark G-ll. Also illustrative of the aforesaid agents is bis(2-hydroxy-5- chloro-phenyhsulfide, a commercial variety of which, known by the designation S-7.

Other antibacterial agents employed in the above-mentioned products are, however, not adequately solubilizable in soap or anionic synthetic detergent solutions as aforesaid, but require the use of added chemicals and rather careful techniques in order to solubilize them in significant amounts, even in soap or other anionic detergent solutions.

Illustrative of such practically water-insoluble antibacterial agents are: (a) 3,4,4'-trichloroca-rbanilide, commonly referred to as TCC; and (b) a mixture of 5,4- dibromosalicylanilide and 3,5,4-tribromosalyicylanilide, a commercial variety of which is sold under the trademark Diaphene.

By reason of their being practically water-insoluble and of the consequent difliculties of solubilizing significant amounts thereof in soap or other anionic detergent solutions, the use of these antibacterial agents has been essentially confined to the opaque types of liquid cleansers, shampoos and the like, since they may remain suspended in their insoluble state in such products without affecting the opaque appearance of the products.

The principal object of the present invention is to provide aqueous compositions suitable for use as shampoos, skin cleansers and the like, having incorporated therein effective amounts of a bacteriostat of the type which is normally practically insoluble in water and solu ble only with difficulty in soap or other anionic detergents, but which is rendered soluble in aqueous solutions of soap and synthetic detergents, whether of the anionic or amphoteric variety, constituting the base of the shampoo, skin cleanser or like aqueous composition.

Another object of the invention is to provide aqueous compositions as aforesaid, wherein the agent employed for solubilizing such bacteriostat is one which exerts substantially no effect upon the antibacterial activity of the bacteriostat.

Still another object of the invention is to provide aqueous compositions as aforesaid, and containing lanolin oil, in addition to effective amounts of such bacteriostat.

A further object of the invention is to provide aqueous compositions as aforesaid, containing effective amounts of such bacteriostats and a suitable quantity of lanolin oil, and wherein the agent employed for solubilizing the bacteriostat serves also to render the lanolin oil soluble in the aqueous solution of the detergent, thereby making possible the production of clear and transparent liquid shampoos and the like, containing such bacteriostats as well as lanolin.

The foregoing and other objects of invention and the advantages thereof will be more specifically apparent from the detailed description which follows herebelow.

Stated generally, the objects of the invention may be achieved by preparing an aqueous shampoo, skin cleanser, or like composition, utilizing soaps or known synthetic detergents as the base, and incorporating therein a bacteriostat of the aforesaid water-insoluble type, solubilized in the aqueous base by means of a non-ionic organic material comprising particularly a polyethoxylated compound selected from the group consisting of polyethoxylated lanolin alcohol, polyethoxylated fatty acid salts of sorbitan, as for example, sorbitan mono-oleate, and polyethoxylated phenols, as for example, nonyl phenol. M More specifically, the bacteriostat employed in the practice of the invention may be a polyhalocarbanilide, as exemplified by the TCC referred to above, or polyhalosalicylanilides or suitable mixtures of the latter as exemplified by the Diaphene product also referred to above.

The polyethoxylated compounds employed as solubilizer for the bacteriostat in the practice of the invention have been found to serve the purposes hereof when present in amounts of from about 2% to about 5%, preferably 4%, by weight of the composition, the higher amounts being particularly advantageous when the composition contains lanolin oil in addition to the bacteriostat, in which event the solubilizer serves, dually, to solubilize the lanolin oil in the aqueous soap or detergent solution constituting the base of the composition.

In the following table, there are shown the formulations of four typical soap or detergent base solutions which may be treated in accordance with the invention for the product-ion of shampoos or skin cleansers having antibacterial properties.

TABLE I.-COMPOSITION OF DETERGENT SOLUTIONS Amount in Grams A B C D Concentrated Liquid Soap (36%).. Diethanolamicle of coconut fatty ac Deiouized water The aqueous solutions of the detergents shown in Table I may be made up as stock solutions, for use in the preparation of compositions containing the practically water-insoluble bacteriostats.

Thus, for example, 90 gram portions of these solutions may be utilized to prepare 100 grams of the bacteriostatcontaining product.

The maximum percentage of the bacteriostat which may be solubilized in the aqueous detergent solution may conveniently be determined by trial and observation, as in the following manner: one gram of the bacteriostat, weighed on an analytical balance to the nearest milligram, is added to 4.0 grams of the polyethoxylated nonionic material, weighed to the nearest one-tenth gram in a 30 milliliter beaker. The mixture is heated at 75 to 80 C., until the bacteriostat is dissolved. If occasionally a slightly higher temperature is required to hasten solution of the bacteriostat, the solution is then permitted to return to a temperature of 7580 C. 90 grams of the detergent solution is weighed into a 150 milliliter beaker and 5.0 grams of deionized water is added, both these being weighed to the nearest one-tenth gram. This detergent solution is heated to 75-80 C., whereupon the solution of the bacteriostat in the non-ionic material is added at that temperature to the detergent solu-ion with stirring. The 30 milliliter beaker in which the bacteriostat was dissolved in the non-ionic material is washed with the detergent solution to assure that all of the non-ionic material having the bacteriostat in solution therein is contained in the product. The latter is allowed to stand until it cools to around room temperature, and is then again weighed and sufiicient water added to replace any water that may have been lost by evaporation, so that the total weight of the product is 100.0 grams. The product is then bottled for observation during varying periods of aging thereof.

In the case of the two typical water-insoluble bacteriostats mentioned above, viz, TCC and Diaphene, tests were conducted to determine the amounts thereof, respectively, that could be solubilized by each of the three polyethoxylated non-ionic compounds mentioned above, viz, polyethoxylated lanolin alcohol, a polyethoxylated sorbitan monooleate (Tween) 80) and polyethoxylated nonyl phenol (Igepal CO-630) in each of the four above-mentioned detergent solutions. In each instance, the amount of the polyethoxylated compound employed was 4% by weight of the total composition. In Table II herebelow, are set forth the data with respect to the maximum percentage of the respective bacteriostats which were solubilized in this manner. These maximum percentage figures set forth in Table II represent the percentages of the bacteriostats solubilized in the various aqueous detergent systems therein shown, to the extent that the solutions remained clear during a period of aging for at least one month. It will be understood, nevertheless, that when using the non-ionic solubilizing agents in amounts less than the above-stated 4% by weight of the composition, the resultant product may be clear when first prepared, but that precipitation of the bacteriostat may occur after a period of aging at room temperature, the aging period varying from overnight to as long as perhaps one month after preparation of the composition.

In accordance with the invention, it has further been found that detergent solutions containing the normally water-insoluble bacteriostats solubilized as stated above and as set forth in Table II may also be made to contain liquid lanolin oil as an ingredient thereof. To that end, the lanolin oil may be incorporated in the mixture of the polyethoxylated nonionic material and bacteriostat, and then combining that mixture with the aqueous solution of the detergent, in the manner above described, without otherwise altering the procedure for producing the desired composition. Thus, referring to the abovedescribed procedure, one gram of lanolin oil, replacing one gram of water may be thus utilized, to provide a composition containing about 1.0% to about 3% by weight of the lanolin oil. With this percentage of lanolin oil, it appeared that by the procedure described above, only the polyethoxylated lanolin alcohol served effectively to solubilize both the bacteriostat and the lanolin oil, and then only in the detergent solutions made with the single synthetic detergents (i.e., detergents A and B, supra) and not in the case of the soap solution or the solution of mixed synthetic detergents (i.e., detergents C and D, supra). In the case of detergent solutions A and B, however, it was found that with the polyethoxylated lanolin alcohol, namely, polyoxyethylene lanolin alcohol condensed with 16 mols of ethylene oxide, the presence of the lanolin oil surprisingly brought about an increase in the amount of bacteriostat which could be solubilized. Thus, compared to the 1.0% of Diaphene and 0.2% of TCC solubilized in detergent A by the Nimcolan S in the absence of lanolin oil, the respective amounts thereof solubilized in the presence thereof by the Nimcolan S in detergent A were 1.2% and 0.3%. Similarly, whereas the Nimcolan S served to solubilize 0.6% of Diaphene and 0.1% of TCC in detergent B in the absence of lanolin oil, it served to solubilize 0.7% and 0.3% of the Diaphene and the TCC, respectively, in the presence of 1.0% of lanolin oil. Here again, the percentages stated for the amount of the respective bacteriostats solubilized by the Nimcolan S in the present of the 1.0% of the lanolin oil represents concentrations which remained stable during an aging period of at least one month at room temperature.

Although no extensive tests have been made with respect to the bacteriological properties of the above-described compositions, such tests were made on those of the products above set forth wherein triethanolamine lauryl sulfate constituted the detergent (detergent A, supra). Accordingly, Table III sets forth the compositions of a number of samples subjected to bacteriological testing as hereinafter set forth. In Table III, samples designated Nos. 1 to 8, inclusive, represent compositions embodying the invention. As indicated above, bacteriostats such as hexachlorophene, although only slightly soluble in water, may be solubilized in anionic synthetic detergent solutions. Samples designated 9 and 10 in Table III are compositions containing 1% of hexachlorophene in the presence and in the absence, respectively, of a nonionic polyethoxylated solubilizer (namely, Nimcolan S), sample 9 having been prepared under conditions the same as those used for the insoluble bacteriostats of samples 1 to 8, inclusive, and sample 10 having been made by TABLE II.-MAXIMUM PERCENTAGE OF BACTERIOSTAT SOLUBILIZED TEA Lauryl TEA Dodecyl Mixed K. Coco Soap Sulfate Benzene Detergent C Detergent D Nonionic Detergent A Detergent B Diaphene TC 0 Diaphene TCC Diaphene TC 0 Diaphene TOO Nimcolan S 1 1. 0 0. 2 0. 0 0. 1 0. 4 0. 1 0.7 0.2 Tween 0.9 0.2 1.0 0.5 1. 7 0. 4 0. 8 0.2 Igepal 00-630 0. 9 0. 3 0. 7 0. 2 0. 9 0. 3 0. 8 0. 2

l Trademark for a polyoxyethylene ether of lanolin alcohol with 16 mols Eth O.

heating the hexachlorophene with the other ingredients at 75-80 C. Table III is as follows:

TABLE III.PERCENTAGE COMPOSITIONS OF SAMPLES FOR BACTERIOLO GY TESTING Sample No. 1 2 3 4 5 7 8 9 10 11 12 13 14 15 16 TEA Lauryl Sulfate 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 Schercomide S00 Extra-.. 3 3 3 8 3 3 3 3 3 3 3 3 3 3 3 Nimcolan S 4 4 4 4 Tween 80 4 4 Igepal 00-630. 4

Diaphene 1. 2

Lantrol l 1. 0 1. 0

HexachlorophenepH of Samples l Trademark for a liquid lanolin oil.

Although soap and detergent solutions have been known to possess antibacterial properties, and have been utilized as carriers for more powerful antibacterial agents, it is also known that under many conditions the soaps or detergents in fact reduce the bactericidal action of the antibacterials (M. E. L. McBain and E. Huchison, Solubilization 199-203, Academic Press, New York, N.Y., 1955).

There is also extensive literature dealing with the interference of polyethoxylated nonionic surfactants with cosmetic preservatives, particularly phenolics.

Accordingly, in organizing the procedure for the bacteriological tests hereinafter referred to, they were conducted so as to determine whether or not the polyethoxylated nonionic solubilizers for the normally insoluble bacteriostats employed in accordance with the invention would have an additional effect upon the activity of the bacteriostats. As already indicated above, in the absence of these nonionic polyethoxylated compounds as solubilizers for the bacteriostats, the latter can exist in the aqueous solutions of the detergents only in suspended form, or at best only slightly solubilized therein. With the foregoing in view, the compositions of samples 12 to 16, inclusive, were prepared in order to compare as accurately as possible their antibacterial activities with those of the compositions represented by samples 1 to 8, inclusive, containing the normally water-insoluble bacteriostats solu bilized in the aqueous detergent solutions in accordance with the invention. In the preparation of the compositions of samples 12 to 16, inclusive, the bacteriostat was heated with the other ingredients for a few minutes at 75-80 C. and the mixture then allowed to cool. After adjusting for lost water, the sample was then treated with a mortar and pestle to grind the suspended bacteriostat to a smaller particle size in order to decrease its settling rate.

The composition represented by sample 11 of Table III, and containing only the triethanolamine lauryl sulfate and the diethanolamide of coconut fatty acids (Schercomide SCO Extra) was prepared by heating the ingredients together, again bringing the temperature to 75-80 C. This sample 11 served, accordingly, as the control sample in the bacteriological tests.

The bacteriological tests and the data obtained as a result thereof were conducted by the laboratories of two separate suppliers of bacteriostats, and by one commercial testing laboratory.

The tests to determine bacteriostatic activity were conducted by a two-fold agar dilution technique. Stock solutions of each formulation were made in sterile distilled water to give a 20% solution (v./v.). Two-fold serial dilutions with sterile distilled water were then prepared in x 150 mm. culture tubes such that the final volume of each tube in the dilution series was 1.0 ml. 24 ml. of 48 degree molten, sterile dextrose tryptone extract agar were then added to each tube in the dilution series, and the mixture immediately poured into sterile petri plates (1.00 mm.). Hardened agar plates were surface-streaked with 0.01 ml. of a 1-100 water dilution of Escherichia coli and Staphylococcus aureus. Twenty-four hour C., Asso- 1.0 (7Dgilonized Water (1.5 in all samples) nocula. Samples were all tested simultaneously on the same day. As a result of the foregoing tests, it was observed that none of the samples inhibited growth E. coli at a product dilution of 1:125. In the case of S. aureus, however, the dilutions at which growth thereof is completely inhibited at the end of 48 hours incubation at 35 C., are shown in the following table.

TABLE IV.INHIBITING DILUTION, AGAR PLATES, S. AUREUS P.p.m.

Sample No. Bacterlostat Solubilizer Inhibitory Bacte- Dilutlon riostat 1 1.0% Diaphene.... NS 18,000 1.25 2 0.9% Diaphene.-.- Tw. 1-8, 000 1.11 do. I 1. 11 0. 25 0. 25 0. 18 l. 50 0.37 1. 25 1. 25

12 1.0% Diaphene d0 1-8,000 1 25 13. 0.9% Diaphene d0 18,000 1. 11 14 1.2% Diaphene.. l. 50 15- 0.3% T00" .37 ML 0.3% TCC .25

1 NS=Nin1colan S, Tw=Tween 80, Ig=Igepal 00-630, NS(+L)= Nimcolan S and 1.0% Lantrol.

The undiluted samples, supra, were also tested to determine their phenol coeflicients. These tests were made according to the phenol coefficient procedure given in Methods of Analysis of the Association of Official Agricultural Chemists, 9th edition, pp. 63-65. The test organism used was Staphylococcus aureus ATCC No. 6538. The subculture medium was Letheen broth.

After an incubation period of 24 hours, all culture tubes from samples containing TCC and those containing hexachlorophene showed growth. There was little or no growth, however, after such incubation, in the tubes containing Diaphene. One ml. of sterile horse serum was added to all the tubes prepared from the samples containing Diaphene. After incubating for an additional 24 hours, all tubes showed growth of the test organisms.

The phenol resistance of the test innoculum was determined in accordance with the above-mentioned procedure, a 1:60 dilution killing in ten minutes but not in five, and a 1:70 dilution killing in fifteen but not in ten. According to this test, none of the 16 samples tested killed an innoculum of S. aureus in a fifteen-minute exposure at 20 C.

Tests to determine the bacteriostatic and bactericidial activity of the compositions in nutrient broths were made by preparing dilutions of the test samples in distilled water. Initial dilutions of 1:100 were made with all of the samples. Subsequent dilutions were made, where required, so as to contain ten times the highest concentration of the active material to be tested. Three serial two-fold dilutions were made of the solutions. The active material concentrations of these 10X solutions were 20.0, 10.0, 5.0 and 2.5 ppm. for tests of samples 1, 2, 3, 7, 12, 13 and 14, which contained Diaphene. In the case of samples 4, 5, 6, 8, 15 and 16, which contained TCC, the solutions contained 15.0, 7.5, 3.75 and 1.8 ppm. Samples 9 and 10, which contained hexachlorophene, were prepared at concentrations of 10.0, 5.0, 2.50 and 1.25 p.p.m. hexachlorophene. Sample 11 (the detergent control) was diluted so as to provide detergent concentrations in the broth tubes equivalent to that present in the test of the samples containing the bacteriostats. Thus, the concentrations of the dilutions in the case of sample 11 were 750 ppm. to 23.4 ppm. by two-fold increments, sample 11 being considered 100% active in calculating these dilutions.

In preparing the dilutions of samples 12 to 16, inclusive, which contained the bacteriostats but without the solubilizer of the present invention, and hence having the bacteriostats only in suspended form in the aqueous mediurn, or at best only slightly solubilized in the detergent solutions, care was taken to insure that the bacteriostatic material under test was thoroughly dispersed in the aqueous medium by shaking the test material before withdrawal of each aliquot.

The broth culture medium utilized in these tests was prepared according to the formula specified for germicide testing in Methods of Analysis of the Association of Official Agricultural Chemists, 9th edition, paragraph 5.001 (a) (l). The specified Armour peptone was replaced by Bacto-Peptemin, a USP peptone. The broth was tubed in 8.9 ml. amounts, capped with aluminum caps, and sterilized by autoclaving at 121 C. for 20 minutes. One-ml. amounts of each sample dilution were added to each of four tubes of broth. Three of these were each innoculated with 0.1 ml. of a 24-hour nutrient broth culture of 3O Staphylococcus aureus ATCC No. 6538. The fourth tube was not inoculated and served as a sample sterility control as well as a sample turbidity control.

Two sets of four culture controls were prepared. For

these, one ml. of water was added to each tube in each set. The uninoculated tube from one set of these culture control tubes was utilized as a reference tube for standardizing a Coleman Junior spectrotometer. The instrument was standardized at 80% transmittance at a wave length of 580 millimicrons. The transmittance of each of each of the tubes containing the various test dilutions was determined immediately after the addition of the inoculum. The tubes prepared from samples 12 to 16, inclusive, were shaken continually from the time of the addition of the test dilution until removal from the incubator. The tubes were removed individually from the shaker, in order to determine transmittance. All of the tubes were incubated for 24 hours at 37 C. and transmittances were then re-determined. One set of the culture control tubes was shaken during incubation, and the other set was not shaken.

In order to determine more precisely the minimal amounts of growth in the culture tubes and to detect any decrease in the innoculum during the 24-hour exposure of the inoculum to the test materials in broth, plate counts were made of all tubes showing little or no change in turbidity during incubation. After making the final transmittance readings, the three incubated tubes in each set were cooled and appropriate aliquots were plated with trypticase soya agar (BBL). The plates were incubated for 24 hours at 37 C. and the developed colonies were counted. The population of the original inoculum was determined by plate count at the time of inoculation of the culture tubes. Plate counts were also made of the culture control tubes and the detergent control tubes (sample 11).

The results of the bacteriological tests above described are summarized in the following Tables V and VI.

P.p.m. of Active Amount of Growth None Slight Moderate Unlnhibited Solubilizer 1 Sample:

1 0.5 Diaphene NS X 0.25 Diapheue NS 2 0.5 Diaphene Tw X 0.25 Diaphene Tw X 3 1.0 D e Ig X 0.5 Dlaphene Ig-.. X 0.25 Diaphene Ig X 4 1.5 TOG NS X 0.75 TCC. N X 0375 T NS X 0.18 TOO" NS 5 1 5 TOO Tw 0.75 TCC- 0.375 'ICC- 0.18 TCC-- 6 0.18 'ICC Tr! X 7 0.5 Diaphene NS(+L) X 0.25 Diaphene NS(+L) 8 0.375 'ICC NS(+L X 0.18 TOO--- NS(+L) 9 0.5 G-11 NS X 0.25 G-ll NS 0.125 G-11 NS 10 1.0 G-ll Nnna X 0.5 G-ll (in X 0 G" an X 0 G-11 do X 11 (Control) 750 Product Basis 375 Product: Basis X 187.5 Product Basis" X 93.8 Product Basis"--. X 47 Product Basis X 28.5 Product Basis X 12 2.0 Dlanhann Nnnn X 10 Dianhano fin X 0.5 Din'nhane do X 13 2.0 Dirmhane Nona X 1,0 Dirmhann do X 0,5 Dinphmm do X TABLE VCon'tin'ued' Amount of Growth P.p.m. of Active Solubilizer 1 None Slight Moderate Uninhiblted 14 2.0 Diaphene Nmm X 1,0 Dianhann do x 15 1.50 TCC- None X 0.375 TOO do X 16 20.0 TCC N X l NS=Nimcolau S, Tw=Tween 80, Ig=Igepal -630, NS(+L)=Ni.meo1an S and 1.0% Lantrol.

TABLE VI.PERCENT DECREASE IN POPULATION, NUTRIENT BROTH, S. AUREUS, 24 HOURS P.p.m. of Diaphene Solubillzer 1 P.p.m. of TCC P.p.m. of Hexaehlorophene 9 (NS 10 None .8%

NS=Nimoolan Tw=Tween 80, Ig=Igepa1 00-630, NS(+L)= s Nimeolan s and 1.0%

lncrease.

In evaluating the tests referred to above, on the 'basis of the tubridinetric changes only, net transmittance changes up to 10% 0f the change in the culture control are considered to indicate complete inhibition of growth. Changes in net transmittance over 50% of that of the culture control tubes are considered to indicate too little inhibitory activity to have any practical significance. These net transmittance changes are arrived at by determining the average decrease in transmittance of the three innoculated tubes of each set and correcting this figure by subtracting any decrease in transmittance of the sample control or by adding any increase in transmittance of the sample control. Degrees of inhibition of growth as indicated by the changes in transmittances are shown in Table V, above. Decreases in the initial population present in the culture tubes containing various concentrations of the test materials as determined by plate counts are shown in Table VI, above.

Lantrol.

In addition to the foregoing tests, calf skin substantivity tests were also conducted. For the purposes of the last-named test, fresh calf skin was obtained from the flang area before any curing procedure such as salting or pickling had been undertaken. The skin was prepared for the test by shaving off the epidermis, and defleshing the flesh side, The shaving operation involved the use of no soap or other shaving assistants. In performing this test, the original samples were diluted before testing to provide a concentration of 0.1% bacteriostat in each. The control sample, i.e., sample 11, was diluted 1: 10. The shaved skin samples were placed on glass plates and the diluted composition to be tested was applied to the epidermis side, massaging it into the skin lightly for a period of ten seconds. After this massaging, the sample was allowed to remain on the skin for a period of one minute, after which it was removed first by wiping and then by rinsing in cold, clear Water. The rinsing was performed by allowing clear, cool water to pass over the skin pieces after treatment with the samples, in a running water bath for thirty seconds. In Table VII herebelow, showing the results of the calf skin substantivity tests, the figures for two and four rinses have reference to removal of the test pieces, allowing them to drip for one minute, and then reimmersing them.

Test pieces 12 mm. in diameter were removed from the skins by use of a cork borer of the appropriate size. Test pieces were taken after 1, 2 and 4 rinsings as described above. Three pieces from each rinsing period were placed on nutrient agar plates seeded with Staphylococcus aureus from a 24-hour old culture, with the epidermis side in contact with the agar. After incubation for 24 hours at 37 C., the results were read as zones of inhibition in millimeters, Other test pieces, taken after two and four rinsings, were held in a room temperature-% relative humidity chamber for periods of 24 hours and 72 hours before placing them on the seeded agar plates for determination of the zone of inhibition. All tests were performed in triplicate and all readings are based on the average of these three readings to the nearest 0.5 mm. The results are shown in the following table.

TABLE VII.-CALF SKIN SUBSTANTIVITY, ZONES OF INHIBITION (1mm), S. AUREUS No Aging 24 hours, R.'I., 72 hours, R.T., Bacteriostat slpzlub i- 85% R.H. 85% R.H.

1 n'nse 2 rinses 3 rinses 2 rinses 4 rinses 2 rinses 4 rinses Sam 1e No.

I Dlaphene--. NS 10. 5 8. 5 8. 0 8. 0 8. 0 8. 0 8. 0 d T 8.0 8.0 8.0 8.0 8.0 8.0 8.0 10. 0 8. 5 8. 0 8. 0 8. 0 8. 0 8. 0 7.0 4.0 3.0 0.0 0.0 0.0 0.0 8. 0 4. 0 3. 0 0. 0 0. 0 0. 0 0. 0 10. 0 4. 0 3. 0 0. 0 0. 0 0. 0 0. 0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 7.5 4.5 3.0 0.0 0.0 0.0 0.0 6.5 5.0 8.0 0.0 0.0 0.0 0.0 6.5 5.0 8.0 0.0 0.0 0.0 0.0 2.0 0.0 0.0 0.0 0.0 0.0 0.0 12 Diaphene .-d0 5. 5 5. 0 5. 0 5. 0 5. 0 5. 0 5. 0 13 do o 6.0 5.5 5.5 5.0 5.0 5.0 5.0 7.0 5.5 5.5 5.5 5.0 5.0 5.0 5.5 4.0 2.5 0.0 0.0 0.0 0.0 6.0 4.0 3.0 0.0 0.0 0.0 0.0

I All samples diluted to 0.1% concentration of bacteriostat before testing. Sample 11 diluted 1:10.

for meaning of abbreviations.

1 See Tables IV, V and VI From the foregoing description, it will be apparent to those skilled in the art that While the invention hereof has been illustrated in embodiments wherein the waterinsoluble bacteriostats are illustrated by TCC and Diaphene, the objects and advantages of the invention may be obtained with the use of other such bacteriostats, such as 2-hydroxy-5-chlorobenzoic acid 3',4-dichloranilide, marketed under the trademark Anobial.

As is evident from the description, and particularly the data set forth in Table II, a useful percentage of each of the bacteriostats may be solubilized in each of the four typical detergent solutions by the use of any one of the three polyethoxylated compounds herein set forth, as illustrative of nonionic polyethoxylated compounds suitable for the purposes hereof. As demonstrated by the data hereinabove set forth, each of the three specific nonionic compounds has been found capable of effecting the solubilization of a greater amount of the Diaphene than of TCC in each of the detergent solutions. It is apparent, therefore, that the efficiency of a given nonionic polyethoxylated compound for solubilizing a given bacteriostat varies somewhat, depending upon the detergent system utilized as the base of the composition in which the bacteriostat is to be dissolved.

Furthermore, as already pointed out, simultaneous solubilization of lanolin oil in an amount of 1.0 by weight thereof, based on the weight of the total composition, may be achieved when using certain of the detergent solutions, if the solubilizing agent employed is a polyoxyethylene ether of lanolin alcohol condensed with 16 mols of ethylene oxide, without causing any interference by the lanolin oil with the solubilization of the bacteriostats, the presence of the lanolin oil indeed serving to increase the amount of the bacteriostat which can be solubilized by the aforementioned polyoxyethylene ether of lanolin alcohol.

Insofar as concerns the bacteriological activity of the compositions hereof, if appears that while the bactericidal action is not sufficient to be measured by a short time killing test, such as the phenol coefficient test, the bactericidal action is nevertheless readily apparent at fairly low active ingredient concentrations in a longer term test, as shown by the data in Table VI. Bacteriostatic action against Staphylococcus aureus, by both of the test trations of TCC than of Diaphene or of hexachlorophene,

and none of these three bacteriostats shows bacteriostatic action against E. call at sample dilutions of 1:125.

Moreover, as is shown by the data hereinabove set forth, the presence of the nonionic polyethoxylated compounds used as solubilizers for the bacteriostat in accordance with the present invention does not appear to reduce the antibacterial action of the active ingredients.

What is claimed is:

1. A shampoo composition consisting essentially of an aqueous solution of a water-soluble synthetic organic detergent, said detergent constituting from about 10% to about 30% by weight of the composition, lanolin oil in an amount of from about 1% to about 3% of the composition, a water-insoluble bacteriostat constituting from about 0.3% to about 1.5% by weight of the composition and being selected from the group consisting of 3,4,4 trichlorocarbanalide, a mixture of 5,4 dibromosalicylanilide with 3,5,4 tribromosalicylanilide, 2- hydroxy-S-chlorobenzoic acid, and 3',4 dichloranilide, and a solubilizer for said bacteriostat, said solubilizer consisting of approximately 2% to 5% by weight of a nonionic polyethoxylated compound selected from the group consisting of polyethoxylated lanolin alcohol, polyethoxylated sorbitan mono-oleate and polyethoxylated nonyl phenol, said amount of said polyethoxylated compound serving also to render said lanolin oil soluble in said aqueous solution of the detergent.

2. A shampoo composition as defined in claim 1, wherein said solubilizer consists of a polyoxyethylene ether of lanolin alcohol condensed with 16 mols of ethylene oxide.

3. A shampoo composition as defined in claim 1, wherein said amount of said lanolin oil does not impair the antibacterial activity of said bacteriostat.

References Cited UNITED STATES PATENTS 2,904,468 9/1959 Davis et al. 252-106 3,118,842 1/1964 Besser 252106 3,152,039 10/1964 Mattson 252107 3,156,656 10/1964 Libby 252-106 3,224,976 12/1965 Farrar et al. 252107 FOREIGN PATENTS 887,247 1/1962 Great Britain.

LE methods referred to above 1s apparent at lower concen- ON D ROSDOL Exammer' W. SCHULZ, Assistant Examiner.

US. Cl. X.R. 252351, 356, 107

Claims (1)

1. A SHAMPOO COMPOSITION CONSISTING ESSENTIALLY OF AN AQUEOUS SOLUTION OF A WATER-SOLUBLE SYNTHETIC ORGANIC DETERGENT SAID DETERGENT CONSTITUTING FROM ABOUT 10% TO ABOUT 30% BY WEIGHT OF THE COMPOSITION , LANOLIN OIL IN AN AMOUNT OF FROM ABOUT 1% TO ABOUT 3% OF THE COMPOSITION, A WATER-INSOLUBLE BACTERIOSTAT CONSTITUTING FROM ABOUT 0.3% TO ABOUT 1.5% BY WEIGHT OF THE COMPOSITION AND BEING SELECTED FROM THE GROUP CONSISTING OF 3,4,4'' TRICHLOROCARBANALIDE, A MIXTURE OF 5,4'' DIBROMOSALICYLANILIDE WITH 3,5,4'' TRIBROMOSALICYLANILIDE, 2HYDROXY-5-CHLOROBENZOIC ACID, AND 3'',4 DICHLORANILIDE, AND A SOLUBILIZER FOR SAID BACTERIOSTAT, SAID SOLUBILIZER CONSISTING OF APPROXIMATELY 2% TO 5% BY WEIGHT OF A NONIONIC POLYETHOXYLATED COMPOUND SELECTED FROM THE GROUP CONSISTING OF POLYETHOXYLATED LANOLIN ALCOHOL, POLYETHOXYLATED SORBITAN MONO-OLEATE AND POLYETHOXYLATED NONYL PHENOL, SAID AMOUNT OF SAID POLYETHOXYLATED COMPOUND SERVING ALSO TO RENDER SAID ALNOLIN OIL SOLUBLE IN SAID AQUEOUS SOLUTION OF THE DETERGENT.