US3177115A

US3177115A - Antiseptic compositions

Info

Publication number: US3177115A
Application number: US184672A
Authority: US
Inventors: Robert E Casely; Darwin R Noel
Original assignee: Armour and Co
Current assignee: Armour and Co
Priority date: 1962-04-03
Filing date: 1962-04-03
Publication date: 1965-04-06
Anticipated expiration: 1982-04-06

Description

United States Patent 3,177,115 ANTISEPTIC CDMPOSITIONS Robert E. Casely and Darwin R. Noel, Chicago, Ill., assignors to Armour and Company, Chicago, Ill., a corporation of Delaware No Drawing. Filed Apr. 3, 1962, Ser. No. 184,672 9 Claims. (Cl. 167-30) This invention relates to antiseptic compositions having synergic eifect. In one of its aspects this invention relates to improved germicidal cleansing compositions containing as their essential germicidal ingredients a synergistic combination of either an unalkylated or alkylated polyhalobisphenol and 3,4,4'-trichlorocarbanilide or its position isomer 3,3,4-trichlorocarbanilide.

This application is a continuation-in-part of our copending application Serial No. 741,455, filed June 12, 1958, now abandoned.

The popularity of germicidal cleansing compositions for laundry and toilet use has increased tremendously over the past few years, In fact, it has been estimated that better than'20% of bar soap sales now are of products containing a germicidal agent, and this percentage is steadily increasing. There are a number of germicidal agents currently in use, but the unalkylated halogenated bisphenols appear to be the most widely accepted because of their activity, compatibility and commercial availability. One of the compounds of this class is 2,2- dihydroxy 3,5,6,3,5',6' hexachlorodiphenyl methane, commonly known as hexachlorophene, which is now in widespread commercial use. Another example is 2,2- dihydroxy 3,5,3',5' tetrachlorodi-phenyl sulfide, commonly known as bithionol. The action of halogenated bisphenolssuch as hexachlorophene when incorporated in soap, the proportions required, and other pertinent information, is set out more fully in U.S. Patent No. 2,535,077 to Kunz et a1.

There are certain inherent disadvantages to the use of both unalkylated and alkylated halogenated bisphenols. For example, they are photo-sensitive and tend to cause discoloration in the finished product upon exposure to light. Hence, they cannot be used in a pure white soap. Also, they are somewhat toxic and present a potential hazard todomestic animals which are prone to eat things, even soap. Therefore, it would be desirable to diminish these disadvantages without adversely afiecting their germicidal activity. From a diiferent point of view, it would also be worthwhile if these disadvantages could be maintained at their present level and the germicidal activity of the unalkylated and alkylated halogenated bis phenols increased. We have discovered that these ob- O jects can be accomplished through the production of a synergic effect.

In accordance with the present invention, the germicidal activity of unalkylated and alkylated halogenated bisphenols in antiseptic compositions is enhanced, synergized or potentiated by the incorporation therewith of 3,4,4'-trichlorocarbanilide or its position isomer 3,3,4- Irichlorocarbanilide. The products of the invention, therefore, are antisepticcompositions containing as their essential active ingredients a synergistic combination of either an unalkylated or alkylated' halogenated bisphenol and 3,4,4 trichlorocarbanilide or its position isomer 3,3',4-trichlorocarbanilide.

For the purposes of this invention, any suitable unalkylated or alkylated polyhalobisphenol may be used as one of the ingredients. The unalkylated and alkylated polyhalobisphenols may be represented according to their chemical structure as follows:

3,i77,ll5 Patented Apr. 6, 1965 -CH(CBr etc.; and -S-; and R in the case of alkylated polyhalobisphenols is an alkyl group containing from 1 to 4 carbon atoms.

The preferred compounds are symmetrical in structural configuration. Specific examples of the unalkylated polyhalobisphenols include 2,2'-dihydroxy-3,5,6,3,5,6-hexachlorodiphenyl methane, 2,2'-dihydroxy-3,5,3,5'-tetrachlorodiphenyl methane, 2,2'-dihydroxy-4,5,4,5-tetrachlorodiphenyl methane,

' 2,2'-dihydroxy-3,4,3,4-tetrachlorodiphenyl methane,

2,2-dihydroxy-5,5'-dibromodiphenyl methane, 2,'2'-dihydroxy-3,5,3',5'-tetrachlorodiphenyl sulfide, and 2,2-dihydroxy-5,5'-dichlorodiphenyl sulfide.

Specific examples of the alkylated halogenated bisphenols include I Used in conjunction with the 'unalkylated and alkylated i halogenated bisphenols in the present invention are polyhalooaroanilides, 3,4,4-trichlorocarbanili-de or its position isomer 3,3,4-trichlorocarbanilide in particular, which can be represented by the following structural formula:

CFONHiaa It has been found that when the unalkylated or alkylated halogenated bisphenols and the 3,4,4'-trich-lorocarbanili-de or 3,3',4-trichlorocarbanilide, as illustrated above, are used together in an antiseptic composition a germicidal effect is achieved which is greater than the mere total of the individual effects of the individual ingredients. This has importance in cases where the activity of the 'bisphenol is desired to be increased without employing higher concentrations, and in other cases, it assumes an even greater importance from an economic stand point, since the presence of the trichlorocarbanilide enables a reduction in the total concentration of the germicidal agent while at the same time retaining the desired level of germicidal effect.

What the actual mechanism of the potentia-ting or synergistic effect is, we are unable'to explain. The invention relates to the synergistic cooperation of these two types of compounds when used in minor proportions in antiseptic compositions, especially antiseptic detergent compositions, and the discovery that this synergistic phenomenon occurs even at the high pH conditions existing in soap and detergent formulations provides one of the important phases of the present invention.

Relatively small amounts of the bisphenols and the trichlorocarbanilides are suflicient for the increased germicidal effect in the present invention. Satisfactory results can be obtained when the combined weights of the two agents are from 0.05% to of the total Weight of the composition, The objects of the invention may be achieved when the weight of. the bisphenol is about 0.1% {to 3% and the trichlorocarb-anilide is about 3% to about 0.1% of the soap or detergent weight. The preferred range is a weight concentration of about 0.25% to 175% of the bisphenol and about 1.75% to 0.25% of thetrichlorocarb'anilide, and an excellent product is one containing soap and about 1% of each of the bisphenol and the trichlorocarbanilide. It will be understood that even concentrations below the ranges just set out will provide 7 some degree of germicidal effect and a substantially higher concentration than those referred to will provide satisfactory, results, although there are certain practical considerations suchas the cost of the bisphenols and a cer-- tain impairment in the detergent properties, which limits the desirability of greater amounts of the germicidal come.

position inthe soap. i

As indicated above, the ratio of the preferred range of the'bisphenols to the trichloroca-rbanilide is about 1-7 of the bisphenol to about 7 1 of the trichlorocarbanil-ide, the parts being by weight. In other words, in a soap containing a genmicidal concentration of hexachlorophene or bithionol, the trichlorocarbanilide is preferably used in the proportion of 1-7 parts to 7-1 parts of the hexachlorophone or bithionol,

The term soap refens to the water-soluble ammoniuni, metallic, or organic base salts of various fatty acids, which are'chiefiy lauric, oleic, stearic, and palmitic acids. As used in this description, the term is intended to cover all productsin which soap is a major constituent, for example, bar, flake, powdered, softand liquid soaps; shaving creams, toothpaste, cleansing creams, etc.

The invention also contemplates the use of anionic-typeand non-ionio-type synthetic detergents in place of the soap. The anionic-type synthetics suitable for use in the invention can be described as those detergents havingpronounced cleansing power and including in their molecular structure an alkyl radical containing from 6 to 18 carbon atoms and a sulfonic acid or suifuricacid ester radical.

Either organic base, ammonium, sodium or potassium salts of the anionic-type detergents can be used. The main types of detergents falling within this category are alkylm1 sulfonates, such as sodium or potassium dodecyl benzene sul-fonate, sodium or potassium octadecyl benzone sulfonate, and sodium or potassium octyl naphthaflene sulfonate; the alkyl sulfates, such as sodium or potassium salts of dodecy-l, hexadecyl, and octadecyl sulfates; the sulfonated fatty acid amides, such as sodium or potassium salts .of the oleic acid amide of methyl taurine; and the sulfonated monoglycerides such as the mono-coconut oil.

fatty acid ester of 1,2-hydroxypropane-3 sodium sul-fonate.

The non-ionic-type synthetic detergents suitable for use in the invention may be described as those, detergents which do not ionize in solution but owe their watersolubility to inn-ionized polar groups such as hydroxyl orether linkages. The maintypes of detergents falling within this category are the polyoxyethylene .ethers of the higher fatty alcohols and alkyl phenols; the polyethylene glycols of fatty acids; fatty alkylol amidecondensatiom products; polymers of ethylene and propylene oxides; compounds formed by the addition of propylene oxide to ethylene diamine, followed by the addition of ethylene oxide; fatty acid ethylene oxide condensation products;

condensation products of ethylene oxide and a fatty acid;

ester of a polyhydric alcohol or sugar; and the detergents prepared by heating together. a higher fatty acid with a di-:

ethylene oxide reaction products; propylene oxide-ethy1-. eneoxide reaction products; and combinations of iso-octyl phenol-ethylene oxide with coconutoil fatty acid-ethylene oxide reaction products.

. application Serial No. 263,302, filed December, 26, 1951,

now abandoned.

Specific examples illustrating the invention are set out as follows: V

EXAMPLE I' Antisepticdetergent compositions exemplary of the presentinvention were prepared by intimately mixing the ingredients listed in Table-I below toforma composite containing 2% by weight active ingredient,

Table 1 Composition Neutral white toilet soap containing about.20% by weight of sodium coco soap and by weight of sodium tallowsoap 3, tetra lorod henyl sulfide 3,4,4-trichloroearbanilide Aliquots of each of the above-described compositions containing 2% by Weight active ingredient. were added to nutrient agar medium so as to give in each instance a concentration of'0.125 part per'million of'factive ingredient in agar. The agar in each case. was then-poured into a Petri'dish, allowed to harden and then streaked with a 24-hour 'oldbroth culture of Mkpyogenes var. aureus diluted 1 10.. The incubation in eachease was at a temperature of 37 C. The degree of growth after a period of 48 hours is, set forthin Table II; as follows:

Table II Composition I A B o D E Period of Incubation 48 48 V 48 48. 48

Amount of Growth. 3+ 3+ 3+ 1+ 1+ Legend:

- :No growth.

1 :Very slight growthi 2 Light to moderate growth. 3+ Normal heavy growth.

EXAMPLE II Soap compositions were preparedto incorporate-2% by weight of germicidal ingredients in each ,sample. Compositions of the samples were:

f Table I Composition B C Neutral toilet soap containing about 30% by weight of sodium coco soap and 80% by weight of sodium tallow soap Aliquots of each "of the above-describedcompositions' containing 2% by weight ofactive ingredients were added to nutrient agar medium-so asto give in each instance a concentration of 0.15 p.p.m;tof active ingredient in the agar. The agar in each'case-was poured into a Petri dish, allowed to harden andthen streakedwith a 24-hour broth culture of M. pyogenes varrziureusdiluted I Composition Growth Legend 3+ :Normal heavy growth. 2 Moderate growth. 1 Light growth. :Extremely light growth. Thus it may be seen that true synergism exists in the test described above.

EXAMPLE III Both individual germicides and combinations of germicides were incorporated in a soap containing 20% sodium coco soap and 80% sodium tallow soap, a nonionic synthetic detergent and an anionic synthetic detergent, at a total concentration of 1% basis soap and 1% detergent solution prepared. Aqueous solutions of the individual germicides were also prepared at a concentration of 100 p.p.m. and further diluted to ppm. The 1% detergent solutions were also diluted with distilled water to 10 ppm. total germicide. Aliquot amounts of these solutions were then added to liquid nutrient agar so as to give the concentrations of the germicide in agar in Table I below. Plates were poured, allowed to harden and streaked with a 24-hour broth culture of M. pyogenes var. aureus FDA strain 209. The plates were incubated 48 hours at 37 C. and the amount of growth in the plates noted. The results are given in Table I as follows:

Table I 6 EXAMPLE IV Antiseptic detergent compositions exemplary of the present invention were prepared by intimately mixing the ingredients listed in Tables I, II and III below to form a composite containing 0.5%, 1.0% and 3.0% respectively by weight active ingredient.

Table I 7 Composition A B O D I E Neutral white toilet soap containtaining about 20% by weight of sodium coco soap and 80% by weight of sodium tallow soap 99. 99.50 99. 50 99. 50 99. 50 2,2-dihydroxy-3,5,6,3,5,6-hexachlorodiphenyl methane. 0. 50 '0. 25 2,2-dihydroxy-3,5,3 ,5-tetraehlorodiphenyl sulfide 0. 50 0. 25 3,4,4-triehlorocarbanilide 0.50 0. 25 0. 25

Table ll Composition D i E Neutral white toilet soap containing about 20% by weight of sodium coco soap and by weight of sodium tallow soap phenyl methane 1 0. 50 2,2-dihydroxy-3,5,3,5-tetrachlorodl-' phenyl sulfide 1 0.50 3,4,4-trichlorocarbanilide 0. 50 0. 50

Amount of growth (M. pyogenes) on agar plates with agar containing aliquots of the germicides incorporated in the following agents:

Water Soap Nonionie Detergent Anionic Synthetic Detergent Total Germicide Basis Agar, ppm- 0. 6 0. 4 0. 2 0.1 0.6 0.4 0.2 0.1 0.6 0. 4 0 2 0.1 0 6 0.4 0.2 0.1

3+ 3+ 1+ 3+ 0 0 3+ 2+ 3+ 0 0 0 3+ 0 0 0 0 0, 0 3+ 3+ 3+ 3+ 0 3+ 3+ 0 2+ 0 0 0 3+ 3+ 3+ 3+ 3+ 1+ 2+ 3+ 1+ 3+ 0 0 0 3+ 3+ 3+ 2+ 3+ 1+ 2+ 3+ 0 3+ 0 0 0 3+ 3+ 3+ 3+ 3+ 2+ 3+ 3+ 3+ 3+ 0 0 0 3+ 3+ 3+ 0 0 0 3+ 2+ 3+ 0 0 3+ 0 0 0 0 2+ 3+ 3+ 3+ 2+ 3+ 3+ 3+ 0 0 0 3+ G S 3+ 3+ 3+ 1+ 2+ 3+ TCC-A+G-11S 0 0 0 2+ 0 0 0 3+ Bithionol 1+ 3+ 3+ 3+ 2+ 1+ 2+ 3+ 0 0 0 0 0 0 3+ 1 3+ 3+ 3+ 3+ 1+ 3+ 3+ TCGA+S1 0 0 2+ 3+ 0 0 2+ Code- 0 -No growth on plates. 1=Light growth.

LEGEND Materials Used:

2=Moderate growth.

G11Hexachlorophene, 2,2dihydroxy hexachlorodiphenyl methane. I

3=Normal heavy growth.

' homogeneous.

. 7 Table Ill Composition A B C D E Neutral white toilet soap containing about 20% by weight of sodium coco soapand 80% by weight of sodium tallow soap 97 97- 97 97 97 2,2-dihydroxy-3,5,6,3,5,6-hexacl1lorodiphenyl methane; 3 1. 50 2,2-dihydroxy-3,5,3 ,5'-tetrachlorodiphenyl sulfide 3 1.50 3,4,4-tr1chlorocarbanilide 1.50 1. 50

g a modified agar streak method. Aliquots of the 1.0%

test soap solutions were added to measured amounts of,

liquid glucose tryptone extract agar, and the resulting mixture was poured'into Petri dishes. agar had hardened, its surface was streaked with a standard loop containing a 24-hour culture of S. azzreus F .D.A.

Aliquots of each of the above-described compositions I containing 0.50%, 1% and 3% respectively by weight active ingredient were added to nutrient agar medium so as to give in each instance a test concentration of 0.125 part per million of active ingredient in agar. The agar in each case was then poured into a Petri dish, allowed to harden and then streaked with a 24-hour old broth culture of M; pyogenes var. aureus diluted 1-10. v The incubation in each case was at a temperature of-37" C. The degree of growthafter a period of 48 hours is set forth in the'following tables, in which Table IA shows the re.- sults for Table I, Table II-A shows the results as to Table II, and Table III-A shows the results as to Table III:

1 :Very slight growth. 2+ :Light to moderate growth. 3 Normal heavy growth.

The foregoing tests indicate that an' excellent product of the active ingredients. All three soaps provided the activity shown in Tables. I-A,- II-A and III- A at the germicidal level indicated.,.; 7 7

EXAMPLE 'V Experiments were carried out to determine the variation of synergistic effect with changes. in the ratio of the i is produced by the composition containing 0.5% of each component active ingredients, All experiments were carriedout in a toilet soap medium. For this purpose the individual germicidal compounds or mixtures of compounds Were incorporated at atotal germicidal level of 1.0% intoa conventional toilet soap base, obtained from thesaponification of a blend of 20%. coconut oil and 80% inedible tallow. This was accomplished by passing a blend of the dry germicidal ingredient and soap chips (moisture content 11%) repeatedly over a three-roll laboratory soap mill untilthe blend appeared physically The blended soap chips were then dis solved in water to give a 1.0% soap solution, whichcorresponds to an 0.01% concentration of germicidal agent.

Since some of the latter are not very water-soluble, these soapsolutions were shaken before each test to insure a uniform SIISPfiIlSlOnzill water.

The bacteriological evaluations were carried out with strain No. 209. ,After an incubation period of 48 hours at 37C. the. plates were examinedvisually', and the amount of growth wasrecorded.

In thismanner a ratio study of thesynergistic pair TCC and hexachlorophene was carried out, the results of which are summarizedin Table I.

by using the same method, and the results of this study are summarized in Table vII. The, growth. was rated and coded in the following manner: 0=no growth; l=slight growth, where only a few sporadic colonies can be seen on the plates; 2=rnoderatejgrowth, where growth occurs along the streaks but one-half or more oi the surface of the plate still showslittle or no growth; 3=heavy growth, where there is luxuriant growthover practically the entire surface of the plate.

Table .I

ANTIBACTERIAL EFFECTIVENESSOF VARIED RATIOS OF HEXACHLOROPHENE AND 3.4'.4-TRICHLOROCAR- BANILIDE (TCC) IN SOAP (MODIFIED AGAR STREAK METHOD Bacterial growth ratings-Total antibacterial agent Ratio,

At 0.04 At 0.02 ppm. ppm.

100% Hexachlorophene, 0% 1000.-.; 2 3 90% Hexachlorophene, TCC 0 2 70% Hexachlorophene, 30% TCC 0 2 50% Hexaohlorophene, 50% TCC 0 1 40% Hexachlorophene, 60%TOC 1 2 30% Hexachlorophene, 70% TCC 1 3 Hexachlorophene, 80% TCC 1 3 10% Hexaehlorophene, 90% TCC 2 3 0% Hexachlorophene, 100% TCC,. 3 3

Code O: No growth.

1 Slight growth.

2 Moderate growth. 3 Heavy growth.

Table II ANTIBACTERIAL EFFECTIVENESSOF VARIED RATIOS OF BI'IHIONOL AND 3.4.4-TRICHLOROCARBANILIDE (TCC IN SOAP (MODIFIED AGAR STRETAK'METHOD) Bacterial growth ratings-Total antibacterial agent Ratio At 0.04 At 0.02 p.p.m. p.p.m.

100% TCC, 0% Bit-hionol 1 3 90% TCC, 10% Bithionolm 0 3 70% T00, BithionoL' V 0 3 60% T00, 40% Bithionol- 0 2 TCC, 50% Bithionbl. '0 1 40% T00, Bithionol- 0 1 30% T00, Bithionol. 0 3 20%"TGC, BithionoL 1 3 10% TCC, Bithionol- 3 3 0% TOG, Bithionol- 3 3 Code:

0:No growth. 1: Slight growth. 2zModerategrowth. V 3=Heavy growth." 1 i As indicated above, synergistic results were obtained when the ratio of the bisphenols' (hexachloro'phene or ,bithionol) 'to trichloroearbanilide was betWeen 90-'-10 parts by weight of the bisphenol to-10-90 parts by weight 01": .the trichlorocarbanilide. 'In other words, the ratio was between 19 parts of bisphenolto between 91 parts of tr-ichlorocarbanilide. The preferred range, as already stated, was between. 17, parts of'the bisplrenol .to .7-1

As' soon as the I The. analogous, study of the pair TC'C and bithiouol was carried out I 9 parts of the trich'lorocarbanilide. In a soap containing a germicidal concentration of hexachloro-phene or bithionol, we prefer to add trichlorocarbanilide in the proportion of between 1-6 parts to between 7-1 parts of the hexachlorophene or bithionol.

The results hereinabove set out with respect to a specific soap (20 coco and 80 tallow soap) are obtained with soaps generally. For example, any fatty acid soap will produce these results, such as sodium laurate, potassium stearate, sodium oleate, potassium myris-tate.

The synergistic action is independent of the soap vehicles .as shown by the activity of the ingredients in nondctergent vehicles and by their activity in anionic detergents other than soap and in non-ionic systems. At the same time, soap is a system in which the synergistic components are highly efiective.

While this invention 'has been described and exemplified in terms of its preferred embodiments, those skilled in the art will appreciate that variations can be made wtihout departing from the spirit and scope of the invention.

We claim:

1. An antiseptic composition containing as its essential active ingredients a synergistic combination of 2,2'-dihydroxy-3,5,6,3',5',6'-hexachlorodiphenyl methane and a polyhalocarbanilide selected from the group consisting of 3,4,4-trichlorocarbanilide and 3,3'4-trichlorocarbanilide, the proportion of said hexachlorodiphenyl methane to said trichlorocarbanilides being about 9 to 1 parts of the hexachlorodiphenyl methane to about 1 to 9 parts by weight of said trichlorocarbanilides, said composition containing from about 0.2% to about 5.0% by weight of said hexachlorodiphenyl methane and said trichlorocarbanilides.

2. An antiseptic composition comprising soap containing as its essential active ingredients from about 0.2% to about 5.0% by weight of a mixture of 2,2'-dihydroxy-3,5, 6,3',5',6-hexach1orodiphenyl methane and a polyhalocarbanilide selected from the group consisting of 3,4,4-trichlorocarbanilide and 3,3,4-trichlorocarbanilide, the proportion of said hexachlorodiphenyl methane to said trichlorocarbanilides being about 9 to 1 parts of the hexachlorodiphenyl methane to about 1 to 9 parts by weight of said trichlorocarbanilides.

3. The composition of claim 2 wherein said polyhalocarbanilide is 3,4,4-trichlorocarbanilide.

4. An antiseptic composition comprising soap and about 1% by weight based upon the soap of a mixture of about equal parts by Weight of 2,2'-dihydroxy-3,5,6,3',5',6-hexachlorodiphenyl methane and a polyhalocarbanilide selected from the group consisting of 3,4-,4-trichlorocarbanilide and 3,3',4-trichlorocarbanilide.

5. The composition of claim 4 wherein said polyhalocarbanilide is 3,4,4'-trichlorocarbanilide.

6. An antiseptic composition comprising soap and about 1 /2 percent by weight based upon the soap of a mixture of equal parts by weight of 2,2-dihydroxy-3,5,6,3,5',6'- hexachlorodiphenyl methane and a polyhalocarbanilide selected from the group consisting of 3,4,4'-trichlorocarbanilide and 3,3'4-trichlorocarbanilide.

7. The composition of claim 6 wherein said polyhalocarbanilide is 3,4,4'-t-richlorocarbanilide.

8. An antiseptic composition comprising soap contain ing from about /2 to about 3% by weight of a mixture of about equal parts of 2,2'-dihydroxy-3,5,6,3,5,6'-hexachlorodiphenyl methane and 3,4,4-trichlorocar banilide.

9. An antiseptic composition comprising soap and a mixture of 2,2'-dihydroxy-3,5,6,3,5',6-hexach1orodiphenyl methane and 3,4,4'-trichlorocarbanilide in which the ratio of the said trichlorocarbanilide to 2,2'-dihydroxy-3, 5,6,3',5,6'-hexachlorodiphenyl methane is about 9 to 1 parts by Weight of said triehlorocarbanilide to about 1 to 9 parts by Weight of said 2,2-dihydroxy-3,5,6,3',5',6-hexachlorodiphenyl methane, said trichlorocarbanilide and said 2,2 dihydroxy 3,5,6,3,5,6 hexachlorodiphenyl methane being present in said soap at a total level of about 1% by Weight of said soap.

References Qited by the Examiner UNITED STATES PATENTS 2,353,735 7/44 Kunz l6731 2,544,826 3/51 Craige l67-31 2,606,210 8/52 Moyle 16731 2,818,390 12/57 Beaver 167--31 JULIAN S. LEVITT, Primary Examiner. LEWIS GOTTS Examiner.

Claims

1. AN ANTISEPTIC COMPOSITION CONTAINING AS ITS ESSENTIALLY ACTIVE INGREDIENTS A SYNERGISTIC COMBINATION OF 2,2''-DIHYDROXY-3,5,6,3'',5'',6''-HEXACHLORODIPHENYL METHANE AND A POLYHALOCARBANILIDE SELECTED FROM THE GROUP CONSISTING OF 3,4,4''-TRICHLOROCARBANILIDE AND 3,3''4-TRICHLOROCARBANILIDE, THE PROPORTION OF SAID HEXACHLORODIPHENYL METHANE TO SAID TRICHLOROCARBANILIDES BEING ABOUT 9 TO 1 PARTS OF THE HEXACHLORODIPHENYL METHANE TO ABOUT 1 TO 9 PARTS BY WEIGHT OF SAID TRICHLOROCARBANILIDES, SAID COMPOSITION CONTAINING FROM ABOUT 0.2% TO ABOUT 5.0% BY WEIGHT OF SAID HEXACHLORODIPHENYL METHANE AND SAID TRICHLOROCARBAILIDES.