Natural insect repellant

Abstract

A topical insect repellent with extended duration of protection was obtained from mixtures of molecules based on two or more volatile repellent organic molecular species occurring naturally on the human skin surface. The novel repellent comprises mixtures of lower, intermediate, and higher volatility organic molecules. Active ingredients for formulations are obtained from homologous series of carboxylic acids, alcohols, ketones, and lactones which span a similar range of volatility and which occur naturally on the skin surface. Volatile silicone fluid imparts mildness and water repellency to the repellent formulations. The new natural repellent exhibits the longevity and repellency that is comparable to N,N-diethyl-m-toluamide (DEET), a synthetic compound employed in almost all commercial formulations, but the inventive natural repellent is more acceptable than DEET, which has an unpleasant odor and imparts a greasy feel to the skin. The inventive insect repellent, formulated in a volatile silicone fluid, was shown to repel and incapcitate stable flies. This finding demonstrated that repellency was not limited to mosquitoes, but extends to other biting flies or insects, thus demonstrating the utility of the novel insect repellent for protecting pets and livestock as well as humans.

1 .- 65 . (canceled)  
   
   
       66 . An insect repellant composition comprising: 
 a) a dermatologically acceptable carrier, and    b) active ingredients comprising 
 a mixture of fatty acids, each of the fatty acids having a straight carbon chain 6 to 12 carbon atoms long, wherein the mixture of fatty acids includes 
 (i) a first fatty acid molecule having 6 to 8 carbon atoms, and a carboxylic acid group, and  
 (ii) a second fatty acid molecule having 8 to 12 carbon atoms, and a carboxylic acid group,  
 wherein the second fatty acid molecule is different from the first fatty acid molecule and  
 
   wherein the first fatty acid molecule and the second fatty acid molecule are in the insect repellent composition in an amount effective to repel more insects away from a test subject that has been treated with the insect repellant composition than a control subject without the insect repellant composition after about 3 hours or more, and    wherein the first fatty acid molecule is octanoic acid, and wherein the second fatty acid molecule is nonanoic acid.    
   
   
       67 . The composition of  claim 66  wherein the active ingredients comprise about 10 to 90% by weight of the first fatty acid molecule and about 10 to 90% by weight of the second fatty acid molecule, wherein the weight percentages of the first and the second fatty acid molecules are based on the total weight of the active ingredients.  
   
   
       68 . The composition of  claim 66  wherein the insects are stable flies.  
   
   
       69 . The composition of  claim 66  wherein the dermatologically acceptable carrier comprises silicone.  
   
   
       70 . The composition of  claim 66  wherein the composition is in the form of a topical dose, wherein the topical dose includes about 0.3 mg/cm 2  or more of the active ingredients.  
   
   
       71 . The composition of  claim 66  wherein the first fatty acid molecule and the second fatty acid molecule are in approximately equal proportions in the insect repellant composition.  
   
   
       72 . The composition of  claim 66  wherein the insects are mosquitoes.  
   
   
       73 . The composition of  claim 66  wherein the test subject is livestock.  
   
   
       74 . The composition of  claim 66  wherein the active ingredients further comprise a third fatty acid molecule having 9 to 12 carbon atoms, and a carboxylic acid group, and 
 wherein the first fatty acid molecule, the second fatty acid molecule and the third fatty acid molecule are all different.    
   
   
       75 . An insect repellant composition comprising: 
 a) a dermatologically acceptable carrier, and    b) active ingredients comprising 
 a mixture of fatty acids, each of the fatty acids having a straight carbon chain 6 to 12 carbon atoms long, wherein the mixture of fatty acids includes 
 (i) a first fatty acid molecule having 6 to 8 carbon atoms, and a carboxylic acid group, and  
 (ii) a second fatty acid molecule having 8 to 12 carbon atoms, and a carboxylic acid group,  
 wherein the second fatty acid molecule is different from the first fatty acid molecule and  
 
   wherein the first fatty acid molecule and the second fatty acid molecule are in the insect repellent composition in an amount effective to repel more insects away from a test subject that has been treated with the insect repellant composition than a control subject without the insect repellant composition after about 3 hours or more, and wherein    the first fatty acid molecule is octanoic acid,    the second fatty acid molecule is nonanoic acid, and wherein the composition further comprises a third fatty acid molecule which is decanoic acid.    
   
   
       76 . An insect repellant composition comprising: 
 a) a dermatologically acceptable carrier, and    b) active ingredients comprising 
 a mixture of fatty acids, each of the fatty acids having a straight carbon chain 6 to 12 carbon atoms long, wherein the mixture of fatty acids includes 
 (i) a first fatty acid molecule having 6 to 8 carbon atoms, and a carboxylic acid group, and  
 (ii) a second fatty acid molecule having 8 to 12 carbon atoms, and a carboxylic acid group,  
 wherein the second fatty acid molecule is different from the first fatty acid molecule and  
 
   wherein the first fatty acid molecule and the second fatty acid molecule are in the insect repellent composition in an-amount effective to repel more insects away from a test subject that has been treated with the insect repellant composition than a control subject without the insect repellant composition after about 3 hours or more,    wherein the second fatty acid molecule has 8 to 9 carbon atoms and wherein the active ingredients further comprise (iii) a third fatty acid molecule having 9 to 12 carbon atoms, and a carboxylic acid group, and    wherein the first fatty acid molecule, the second fatty acid molecule and the third fatty acid molecule are all different, and wherein the dermatologically acceptable carrier comprises silicone.    
   
   
       77 . An insect repellant composition comprising: 
 a) a dermatologically acceptable carrier, and    b) active ingredients comprising 
 a mixture of fatty acids, each of the fatty acids having a straight carbon chain 6 to 12 carbon atoms long, wherein the mixture of fatty acids includes 
 (i) a first fatty acid molecule having 6 to 8 carbon atoms, and a carboxylic acid group, and  
 (ii) a second fatty acid molecule having 8 to 12 carbon atoms, and a carboxylic acid group,  
 wherein the second fatty acid molecule is different from the first fatty acid molecule and  
 
   wherein the first fatty acid molecule and the second fatty acid molecule are in the insect repellent composition in an amount effective to repel more insects away from a test subject that has been treated with the insect repellant composition than a control subject without the insect repellant composition after about 3 hours or more, and    wherein the second fatty acid molecule has 8 to 9 carbon atoms and wherein the active ingredients further comprise (iii) a third fatty acid molecule having 9 to 12 carbon atoms, and a carboxylic acid group, and    wherein the first fatty acid molecule, the second fatty acid molecule and the third fatty acid molecule are all different, wherein the active ingredients consist of the first fatty acid molecule, the second fatty acid molecule, and the third fatty acid molecule.    
   
   
       78 . An insect repellant composition comprising: 
 a) a dermatologically acceptable carrier, and    b) active ingredients comprising 
 a mixture of fatty acids, each of the fatty acids having a straight carbon chain 6 to 12 carbon atoms long, wherein the mixture of fatty acids includes 
 (i) a first fatty acid molecule having 6 to 8 carbon atoms, and a carboxylic acid group, and  
 (ii) a second fatty acid molecule having 8 to 12 carbon atoms, and a carboxylic acid group,  
 wherein the second fatty acid molecule is different from the first fatty acid molecule and  
 
   wherein the first fatty acid molecule and the second fatty acid molecule are in the insect repellent composition in an amount effective to repel more insects away from a test subject that has been treated with the insect repellant composition than a control subject without the insect repellant composition after about 3 hours or more; and    wherein the second fatty acid molecule has 8 to 9 carbon atoms and wherein the active ingredients further comprise (iii) a third fatty acid molecule having 9 to 12 carbon atoms, and a carboxylic acid group, and    wherein the first fatty acid molecule, the second fatty acid molecule and the third fatty acid molecule are all different.    
   
   
       79 . The composition of  claim 78  wherein the active ingredients comprise about 10 to 90% by weight of the first fatty acid molecule, about 10 to 90% by weight of the second fatty acid molecule, and about 10 to 90% by weight of the third fatty acid molecule, wherein the weight percentages of the first, second, and the third fatty acid molecules are based on the total weight of the active ingredients.  
   
   
       80 . The composition of  claim 78  wherein the insects are flies.  
   
   
       81 . The composition of  claim 78  wherein the insects are mosquitoes.  
   
   
       82 . An insect repellant composition comprising: 
 a) a dermatologically acceptable carrier, and    b) active ingredients comprising 
 (i) octanoic acid,  
 (ii) nonanoic acid, and  
 (iii) decanoic acid,  
   wherein the octanoic acid, nonanoic acid, and decanoic acid are in the insect repellant composition in an amount effective to repel more flies or mosquitoes away from a test subject that has been treated with the insect repellant composition than a control subject without the insect repellant composition after about 3 hours or more.    
   
   
       83 . The composition of  claim 82  wherein the carrier comprises silicone.  
   
   
       84 . An insect repellent composition comprising: 
 a) a dermatologically acceptable carrier; and    b) active ingredients comprising 
 a mixture of fatty acids, each of the fatty acids having a straight carbon chain 6 to 12 carbon atoms long, wherein the mixture of fatty acids includes 
 (i) a first fatty acid molecule having 6 to 8 carbon atoms, and a carboxylic acid group, and  
 (ii) a second fatty acid molecule having 8 to 12 carbon atoms, and a carboxylic acid group,  
 wherein the second fatty acid molecule is different from the first fatty acid molecule and  
 
   wherein the first fatty acid molecule and the second fatty acid molecule are in the insect repellent composition in an amount effective to repel more insects away from a test subject with the insect repellent composition than a control subject without the insect repellant composition after about 3 hours or more.    
   
   
       85 . The composition of  claim 84  wherein the insect repellent composition has a concentration of the active ingredients of about 0.3 mg/cm 2  or more.