Natural insect repellent

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.

Description

I. BACKGROUND OF THE INVENTION[0001] This application claims the benefit of prior U.S. application Ser. No. 60 / 051,320, filed Jun. 30, 1997 and is incorporated herein by reference.[0002] 1. Field of the Invention[0003] This invention relates generally to insect and arthropod repellents and more specifically to mosquito, fly, tick and mite repellents using biologically based components.[0004] 2. Description of Related Art[0005] At the present time, N,N,-diethyl-m-toluamide (DEET) is the active ingredient of most commercial topical insect repellents (see Table 1, below), and the current US Army insect repellent (EDTIAR) contains DEET as its active ingredient. The major commercial brands, Off!.RTM., "Deep Woods Off!.RTM., and Cutter.RTM., are all DEET based products and comprise 85% of insect repellent sales (Consumer Reports Buying Guide, 1994 Special Year-End Issue). Consumer Reports tests indicated that products with the highest concentration of DEET lasted the longest against mosqu...

AI Technical Summary

Benefits of technology

The formulation provides effective and long-lasting protection against mosquitoes, maintaining a consistent evaporation rate above the minimum effective evaporation rate, comparable to DEET in duration, while being safe and pleasant to use, without damaging plastics or causing skin irritation.

Problems solved by technology

Consumer Reports tests indicated that products with the highest concentration of DEET lasted the longest against mosquitoes, but cautioned that excessive use of DEET could pose some risk, especially for children.

Other disadvantages associated with DEET include: It is a synthetic chemical having a limited spectrum of activity and a noticeably unpleasant odor; DEET is a powerful plasticizer and will dissolve or mar many plastics and painted surfaces; DEET plasticizes the inert ingredients typically used in topical formulations in order to lengthen the time of effectiveness.

This leads to DEET formulations with low user acceptability.

However, the bath oil was reported as less effective and less persistent than DEET (Rutledge et al., 1982, Repellent activity of a proprietary bath oil (Skin-So-Soft), Mosquito News:42:557-559).

Efforts to develop a natural insect repellent have motivated studies of oils of citronella, turpentine, pennyroyal, cedarwood, eucalyptus and wintergreen, but these are relatively ineffective (Handbook of Nonprescription Drugs, 1993, 10th Ed., American Pharmaceutical Assn., Washington, D.C.).

Because the term "first runnings" is not a term of art and is not understood by the average knowledgeable person working in the field, it is impossible to know exactly what substance Bencsits tested.

Many experts also do not understand this term and were not able to discover its meaning even with research.

Furthermore, the limited number of tests and controls, and lack of attention to fatty acids as potential skin irritants appear to limit Bencsits' invention to non-animal surfaces.

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