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At least 19 recordsLinked to original sources

Olfactory stimulation of Africanized honey bee (Hymenoptera: Apidae) attacks by insect repellents.

Three common insect repellents (N,N-diethyl-m-toluamide [DEET], Pyranha, and Repel X) were tested to determine whether they affected Africanized honey bee attack behavior. Eight Africanized honey bee (Apis mellifera L.) colonies were exposed in an alternating series to the test repellents or blank controls delivered in a stream of air directed toward the colony entrances. The response generated by the repellents and the controls was measured as the number of attacking honey bees recorded with an electronic temper tester. Neither a citronella-based repellent (Pyranha) nor DEET had any effect on colony behavior; however, Repel X consistently caused a greater attack response after exposure.

Africa↗

The effect of sunscreen on the efficacy of insect repellent: a clinical trial.

Sunscreen loses efficacy when used with the insect repellent N,N -diethyl-3-methylbenzamide (diethyltoluamide; deet). A previous study demonstrated a 33.3% decrease in sun protection factor when insect repellent and sunscreen were applied sequentially to the skin. The purpose of this study was to determine whether the efficacy of insect repellent is affected by two different formulations of sunscreen. The combination of sunscreen and insect repellent was tested in 8 groups: a control group (no sunscreen or insect repellent), sunscreen alone (two groups [gel and cream]), insect repellent alone, insect repellent applied before sunscreen (two groups), and insect repellent applied after sunscreen (two groups). The results of this study showed that insect repellent has the same efficacy even when sunscreen is applied with it. This indicates that in the formulations tested, sunscreen does not reduce the efficacy of insect repellent.

Drug Combinations↗

Perception and use of insect repellent among soldiers in the Singapore Armed Forces.

The Singapore Armed Forces currently uses the 75% DEET formulation insect repellent. To study the perception, use, and acceptability of this insect repellent, a survey was carried out on servicemen who had participated in field exercises. Although over 80% of the servicemen knew the proper use of the insect repellent and brought along the army-issued repellent in the field, less than half used this repellent frequently while on exercise. Eighty-three percent felt that the army repellent was only effective sometimes and that it lasted for 4 hours or less. Skin irritation was a common side effect when using the repellent. About 70.4% had used commercial insect repellents and perceived them to be more long lasting and with fewer side effects. The results from our study indicate that the army-issued insect repellent currently used is not totally acceptable to our servicemen. Thus, there is a pressing need to develop or acquire a better insect repellent that is more or just as effective, has fewer side effects in terms of smell and skin irritation, and with an improved mode of delivery, such as aerosol or pump spray.

Adolescent↗

Evaluation of commercial insect repellents on human skin against Aedes aegypti (Diptera: Culicidae).

An olfactometer was used to evaluate the efficacy of selected commercial insect repellent products against Aedes aegypti (L.). A comparison of 12 commercial repellent products was made on human skin. The products tested included 2 natural oil insect repellent formulations (Buzz Away and Green Ban) containing plant extracts, 2 proprietary products (Skin-So-Soft lotion and bath oil), and 8 commercial deet preparations in various concentrations and forms of spray, aerosol, stick, cream, and lotion. Behavioral responses and time to probe were determined in triplicate using 10 female mosquito challenges per replicate for each product. Generally, products with higher concentrations of deet were found to have longer repellence times. OFF spray and Muskol lotion offered the longest repellence times. However, there was no significant difference in time for mosquitoes to probe among the formulations. Skin-So-Soft lotion and bath oil were not as effective as deet in repelling Ae. aegypti. Natural oil insect repellent formulations offered essentially no repellency against Ae. aegypti. This is a simple and reproducible method to evaluate the efficacy of insect repellents and is recommended for preliminary screening of new insect repellents or formulations.

Aedes↗

Reduced transdermal absorption of N,N-diethyl-m-toluamide from a new topical insect repellent formulation.

Extensive absorption of the topical insect repellent N, N-diethyl-m-toluamide (DEET) causes systemic and local toxicities. This report describes the preparation and characterization of a new insect repellent formulation (FA), a PEG-polyacrylic acid polymer system, for its DEET release, in vitro skin permeation, and in vivo transdermal absorption properties; and for its relative repellency against Aedes aegypti mosquitoes. DEET release and skin permeation were studied in Franz diffusion cells. DEET transdermal absorption and relative repellency of FA were assessed in beagle dogs. A commercial DEET lotion (FB) and technical DEET (FC) were used as references. FA exhibited 19.5% and 61.7% decrease in DEET steady-state skin flux compared with FB and FC, respectively. At 15 mg DEET/kg, the absolute DEET transdermal bioavailability and Cmax were 13.4% and 154.3 ng/ml, respectively, for FA; and were 17.5% and 196.5 ng/ml, respectively, for FB. DEET half-lives (t1/2) for FA (2.52 hr) and FB (2.73 hr) were similar, while MRT for FA (4.99 hr) was significantly greater (p < 0.05) than that for FB (4.38 hr). FA showed lower mosquito biting rates at 1, 2, 3, 4, 5, and 6 hr postdose at 0.5 mg DEET/cm2. FA exhibited reduced in vitro skin permeation and in vivo transdermal absorption of DEET as well as superior repellency compared with FB. The PEG-polyacrylic acid polymer system is of value in the formulation of DEET lotions.

Administration, Topical↗

Application of insect repellents by travelers to malaria endemic areas.

The use of insect repellents applied to the skin is always encouraged in those visiting malaria endemic areas. There are a number of factors contributing to the efficacy of insect repellents in the field and an important factor contributing to their longevity relates to the applied dose. This study investigated the dose of insect repellent that travelers might normally apply to the skin. Subjects were asked to apply a product they had purchased to the arms and neck, and the dose applied (mg/cm(2)) was calculated. The study was conducted using three different populations; 74 travelers to malaria endemic areas visiting pharmacies to purchase repellents before they left the UK, 23 travelers on safari in India, and 24 on safari in Kenya. There was a significant difference in the mean applied arm dose of product (mg/cm(2)) [p < 0.001, analysis of variance (ANOVA)]; UK 1.15 (SD 0.29), India 0.96 (SD 0.23), and Kenya 1.34 (SD 0.54). Higher concentrations were achieved on the neck area. Few of the participants in the field trial used long-sleeved shirts at night. Even using 50% wt/vol repellent products, 32% in the Kenya and 25% in the India, study achieved a dose of active ingredient less than 0.5 mg/cm(2). These pilot studies would indicate that travelers tend to apply below the optimal concentration of active ingredient of repellent as might be suggested by mathematical models.

Administration, Cutaneous↗

Picaridin: a new insect repellent.

Picaridin is a new insect repellent that is comparable in effect and less irritating than diethyl toluamide (deet). Its activity and effects are reviewed in this article.

Administration, Cutaneous↗

In vitro evaluation of concurrent use of commercially available insect repellent and sunscreen preparations.

BACKGROUND: Insect repellents and sunscreens are over-the-counter products extensively used by the general public. Concurrent application of these products has become widespread in many regions across North America, because of concerns about West Nile virus and skin cancers. OBJECTIVES: We investigated whether formulation type, application amount, and sequence would affect the percutaneous absorption profiles of the active repellent and sunscreen ingredients. METHODS: In vitro percutaneous permeation of the repellent N,N-diethyl-m-toluamide (DEET) and the sunscreen oxybenzone from concurrent application of five commercially available products (A, repellent spray; B, repellent lotion; C, sunscreen lotion; D and E, combined repellent/sunscreen lotions) was measured and compared using Franz-style diffusion cells with piglet skin at 37 degrees C. RESULTS: Penetration of DEET in A and B increased by 1640% and 282%, respectively, when C was applied concurrently. Penetration of DEET in D and E was 53% and 79% higher than that in B. Permeation of DEET from A + C (2:1) and A + C (1: 2) increased by 530% and 278%, respectively. Permeation of oxybenzone was 189% and 280% higher in A + C and B + C than in C. Permeation of oxybenzone in D and E was also 221% and 296% higher than that in C. Permeation of oxybenzone was 196% greater when A was applied on top of C than when C was applied on top of A, while oxybenzone in A + C (1:2) permeated 171% more than that in A + C (2:1). CONCLUSIONS: Concurrent application of commercially available repellent and sunscreen products resulted in significant synergistic percutaneous permeation of the repellent DEET and the sunscreen oxybenzone in vitro. The percutaneous penetration profiles were dependent upon the type of formulation, application sequence and application proportion.

Administration, Topical↗

Analysis and fate of insect repellents.

During summer months the insect repellent N,N-diethyl-m-toluamide (DEET) could always be detected in influents and effluents of wastewater treatment plants (WWTP) and anthropogenically influenced surface waters. In Germany the concentrations have decreased constantly since 1999, when DEET was substituted by Bayrepel. DEET can be degraded in WWTP, but only after an adaptation period and values in the influent above the threshold value. Since the year 2000 Bayrepel could also be detected during the summer months in the influents of WWTP, whereas in the effluents Bayrepel was not present.

Animals↗

Soldier acceptability of a camouflage face paint combined with DEET insect repellent.

Under operational conditions, current doctrine requires separate application of the standard military insect repellent and camouflage face paint. Working with an industrial partner, Amon Re, Inc., we developed a combined camouflage face paint and insect repellent that offers excellent protection from arthropod disease vectors. We undertook a study to determine whether the new product was acceptable to soldiers under field conditions. A new formulation of camouflage face paint containing the insect repellent N,N-diethyl-3-methyl-benzamide (DEET) was tested for user acceptability during a joint-service, multinational, military field training exercise (Operation Cobra Gold 1999) in Thailand. Soldiers testing the camouflage face paint were members of one of three companies (A, B, and C) of 1st Battalion, 21st Infantry Regiment, 25th Infantry Division. Soldiers in A company (N = 98) received standard military camouflage face paint and the U.S. military's Extended Duration Topical Insect and Arthropod Repellent containing 33% DEET, soldiers in B company (N = 75) received a new formulation of camouflage face paint without DEET, and soldiers in C company (N = 88) received the new formulation of camouflage face paint containing 30% DEET. Every soldier who volunteered to participate completed the study and submitted responses to the questionnaire. The different treatments were evaluated while soldiers spent 4 days conducting simulated combat exercises in a hot, tropical environment in central Thailand. Soldiers were provided the test materials, given a briefing on the study, and completed an initial questionnaire on May 19, 1999. Soldiers completed a final questionnaire after they returned from the training exercise on May 24, 1999. Results of the study indicated that soldiers found the new formulation of 30% DEET camouflage face paint easier to apply (88% of respondents) and remove (77%) than the current standard issue camouflage face paint. Soldiers liked the new 30% DEET camouflage face paint formulation better (61%) and were more likely to recommend it (67%) than the old camouflage face paint formulation. Although the addition of DEET to the camouflage face paint occasionally caused minor irritation after application for a short period (less than 15 minutes), the new camouflage face paint formulation with 30% DEET was evaluated most often (72%) as either good or excellent. The new 30% DEET camouflage face paint formulation offers significant operational advantages: protection from disease-transmitting arthropods, elimination of the need to carry separate insect repellent and camouflage face paint, and reduction in the time required to apply repellent and camouflage face paint separately.

Adolescent↗

Field efficacy of four insect repellent products against vector mosquitoes in a tropical environment.

Four insect repellent products (RPs) (RP 1, Experimental Repellent Lotion [Bayrepel 12%]; RP 2, Experimental Repellent Cream [Bayrepel 5%]; RP 3, Off! Insect Repellent II Aerosol [deet 15%]; and RP 4, Off! Skintastic II Cream [deet 7.5%]) were evaluated simultaneously for their efficacy against vector and nuisance mosquitoes. The aim of this study was to compare the relative efficacy of RPs based on a new repellent compound, Bayrepel (1-piperidinecarboxylic acid, 2-(2-hydroxyethyl)-1-methylpropylester), with deet (N,N-diethyl-m-toluamide)-based RPs. An 8-h field efficacy of above repellents was evaluated against the day-biting mosquito (Aedes albopictus) and night-biting mosquitoes (Culex quinquefasciatus and Anopheles spp.). Evaluation was carried out by exposing humans with repellent-treated bare limbs to mosquitoes landing and to mosquitoes landing and biting. Repellent product 1 or 2 was applied on the left arm and leg, whereas RP 3 or 4 was applied on the right arm and leg, respectively. Application of these 4 RPs significantly reduced (P < 0.05) the landing and the landing and biting of day-biting and night-biting mosquitoes. All 4 RPs were found to be equally effective (P < 0.05) against Ae. albopictus and Cx. quinquefasciatus. However, for protection against Anopheles spp., RPs 1 and 3 exhibited significantly (P < 0.05) better repellency effect than RPs 2 and 4.

Aedes↗

Percutaneous absorption of carbon 14 labeled insect repellents in hairless dogs.

The percutaneous penetration of three insect repellents was determined in hairless dogs. Each compound was administered intravenously and topically to three dogs. Urine, feces and blood samples were assayed for radioactivity by scintillation counting. The percent penetration for N,N-diethyl-m-toluamide (m-deet, the most widely used insect repellent), its isomer N,N-diethyl-p-toluamide and 2-ethyl-1,3-hexanediol were 7.9%, 7.6%, and 10.3% respectively. The results for m-deet penetration in the hairless dog are comparable to those in man.

Administration, Topical↗

Analysis and mass spectrometric characterization of the insect repellent Bayrepel and its main metabolite Bayrepel-acid.

Insect repellents such as N,N-diethyl-m-toluamide (DEET) which are used as protection against mosquitoes or ticks were detected in all wastewater and anthropogenically influenced surface waters analyzed. In Germany, the concentrations of DEET have constantly decreased since 1999, when DEET was substituted by Bayrepel (1-piperidinecarboxylic acid, 2-(2-hydroxyethyl), 1-methylpropyl ester; KBR 3023) in commercial insect repellent formulations. A sensitive quantitative method was developed in order to study the occurrence and fate of Bayrepel in the aquatic environment. It was thus determined that Bayrepel undergoes rapid primary aerobic biodegradation, yielding a more stable metabolite, Bayrepel-acid (1-piperidinecarboxylic acid, 1-methylpropyl ester, 2-acetic acid). In order to study the biodegradation and investigate the fate of this metabolite, Bayrepel-acid was synthesized and characterized. Various chromatographic and mass spectrometric techniques, such as gas chromatography-mass spectrometry (MS) after derivatization, liquid chromatography (LC)-electrospray ionization (ESI) MS and LC-ESI time-of-flight MS were applied.

Chromatography, High Pressure Liquid↗

Molecular similarity analysis between insect juvenile hormone and N, N-diethyl-m-toluamide (DEET) analogs may aid design of novel insect repellents.

Molecular similarity analysis of stereoelectronic properties between natural insect juvenile hormone (JH), -a synthetic insect juvenile hormone mimic (JH-mimic, undecen-2-yl carbamate), and N, N-diethyl-m-toluamide (DEET) and its analogs reveals similarities that may aid the design of more efficacious insect repellents and give a better insight into the mechanism of repellent action. The study involves quantum chemical calculations using the AM1 semi-empirical computational method enabling a conformational search for the lowest and most abundant energy conformers of JH, JH-mimic, and 15 DEET compounds, followed by complete geometry optimization of the conformers. Similarity analyses of stereoelectronic properties such as structural parameters, atomic charges, dipole moments, molecular electrostatic potentials, and highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies were performed on JH, JH-mimic and the DEET compounds. The similarity of stereoelectronic attributes of the amide/ester moiety, the negative electrostatic potential regions beyond the van der Waals surface, and the large distribution of hydrophobic regions in the compounds appear to be the three important factors leading to a similar interaction with the JH receptor. The similarity of electrostatic profiles beyond the van der Waals surface is likely to play a crucial role in molecular recognition interaction with the JH receptor from a distance. This also suggests electrostatic bioisosterism of the amide group of the DEET compounds and JH-mimic and, thus, a model for molecular recognition at the JH receptor. The insect repellent property of the DEET analogs may thus be attributed to a conflict of complementarity for the JH receptor binding sites.

Algorithms↗