Acute Toxicity Studies of Safer and More Effective Analogues of N,N-Diethyl-2-Phenylacetamide
ABSTRACT The present work was designed to evaluate the toxicity of various synthesized aromatic amides that are analogs of N,N-diethyl-2-phenylacetamide, a well known insect repellent. The toxicity profile of these compounds was compared with N,N-diethyl-2-phenylacetamide as well as other registered insect repellents namely N,N-diethyl-3-methyl benzamide and N,N-diethylbenzamide. The primary skin irritation index values of the compounds, dermal toxicity of the chemicals and acute oral toxicity data to assess the safety of the synthesized aromatic amides are reported in this paper. Results of hematological and biochemical studies of these analogues are reported and discussed.
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ABSTRACT: The toxicological and repellent activity of four ethanol and petroleum ether extracts derived from different parts of the indigenous water plant, Phragmites australis was studied against the 2 nd instar larvae and adult of Culex pipiens. Petroleum ether extracts showed higher larvicidal and repellent activity than ethanol extracts for the different plant parts tested. According to the value of the lethal concentration causing 50% mortality (LC 50), ethanol extracts of leaves were the most effective (LC 50 98.72) followed by stems (LC 50 619.52). On the other hand, the LC 50 values of the tested petroleum ether extracts of different plant parts varied from 16.13 (stems) to 60.06 (leaves). The plant extracts tested showed variable effects on pupation and adult emergence. Also, different morphogenic abnormalities were observed in immature and adult stages. All concentrations of plant extracts used in the present study exhibited a repellent activity against adults with an effect depending on plant part, solvent used in extraction and dose of the extract. The most effective plant extract exhibiting 100% repellency or biting deterrence was the petroleum ether extract of leaves at a dose of 6.6 mg/cm 2 . Results of this study may contribute to design an alternative way to control mosquitoes currently based on applications of synthetic insecticides. These extracts could be developed commercially as an effective personal protection measure against mosquito bites and to control diseases caused by mosquito–borne pathogens.
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ABSTRACT: Comparative inhalation toxicity studies of aerosols of insect repellents N,N-diethylbenzamide (DEB), N,N-diethylphenylacetamide (DEPA), and N,N-diethyl-3-methylbenzamide (DEET) were carried out in mice. The respiratory pattern was monitored using a computer program that recognizes the modifications of the breathing pattern. Exposure to the aerosols caused a dose-dependent decrease in normal breath, with an increase in airway obstruction. All the three insect "sensilla irritants" showed no significant mammalian sensory irritation. The acute LC(50) value for a 4-h exposure of DEB, DEPA, and DEET aerosols in male mice was found to be >2.5 g/m(3), 1714 mg/m(3), and 1369 mg/m(3), respectively. Irreversible depression in respiratory frequency was observed after exposure to DEB aerosol at a concentration of 277 mg/m(3) and above, which did not revert back to normal level even after aerosol exposure was stopped. At a concentration of 156 mg/m(3) of DEB, no respiratory depression was observed. DEPA and DEET caused no depression in respiratory frequency up to a concentration 1292 and 950 mg/m(3), respectively. Hence the two insect repellents DEET and DEPA do not cause any harmful effect to the respiratory parameters in acute exposure, showing that they are more suitable chemicals to be used as insect repellents as compared to DEB.Inhalation Toxicology 04/2010; 22(6):469-78. DOI:10.3109/08958370903456652 · 2.26 Impact Factor
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ABSTRACT: The worldwide threat of arthropod-transmitted diseases, with their associated morbidity and mortality, underscores the need for effective insect repellents. Multiple chemical, botanical, and "alternative" repellent products are marketed to consumers. We sought to determine which products available in the United States provide reliable and prolonged complete protection from mosquito bites. We conducted studies involving 15 volunteers to test the relative efficacy of seven botanical insect repellents; four products containing N,N-diethyl-m-toluamide, now called N,N-diethyl-3-methylbenzamide (DEET); a repellent containing IR3535 (ethyl butylacetylaminopropionate); three repellent-impregnated wristbands; and a moisturizer that is commonly claimed to have repellent effects. These products were tested in a controlled laboratory environment in which the species of the mosquitoes, their age, their degree of hunger, the humidity, the temperature, and the light-dark cycle were all kept constant. DEET-based products provided complete protection for the longest duration. Higher concentrations of DEET provided longer-lasting protection. A formulation containing 23.8 percent DEET had a mean complete-protection time of 301.5 minutes. A soybean-oil-based repellent protected against mosquito bites for an average of 94.6 minutes. The IR3535-based repellent protected for an average of 22.9 minutes. All other botanical repellents we tested provided protection for a mean duration of less than 20 minutes. Repellent-impregnated wristbands offered no protection. Currently available non-DEET repellents do not provide protection for durations similar to those of DEET-based repellents and cannot be relied on to provide prolonged protection in environments where mosquito-borne diseases are a substantial threat.New England Journal of Medicine 08/2002; 347(1):13-8. DOI:10.1056/NEJMoa011699 · 55.87 Impact Factor