Compendium of the most significant studies with reference to properties, intake, effects.

Mapossa AB, Sitoe A, Focke WW, Izadi H, du Toit EL, Androsch R, Sungkapreecha C, van der Merwe EM. Mosquito repellent thermal stability, permeability and air volatility. Pest Manag Sci. 2020 Mar;76(3):1112-1120. doi: 10.1002/ps.5623. 

Abstract. The effectiveness of mosquito repellents, whether applied topically on the skin or released from a wearable device, is determined by the evaporation rate. This is because a repellent has to be present in the form of a vapour in the vicinity of the exposed skin that needs protection. Therefore, gravimetric techniques were used to investigate the direct evaporation of selected liquid repellents, their permeation through polymer films, and their release from a microporous polyethylene matrix....

Tavares M, da Silva MRM, de Oliveira de Siqueira LB, Rodrigues RAS, Bodjolle-d'Almeida L, Dos Santos EP, Ricci-Júnior E. Trends in insect repellent formulations: A review. Int J Pharm. 2018 Mar 25;539(1-2):190-209. doi: 10.1016/j.ijpharm.2018.01.046

Abstract. The use of natural and synthetic repellents, marketed in different pharmaceutical forms, is growing in the world due to the emerging vector-borne viral diseases as Dengue, Zika, Chikungunya, Yellow Fever and Malaria. The choice of the ideal formulation will depend on a series of factors to be analyzed: type of repellent active (natural or synthetic), pharmaceutical forms (spray, lotion, cream, gel), action time duration (short or long), environment of exposure and the user (adult, pregnant women, children, newborn)....

Pinto IC, Cerqueira-Coutinho CS, Santos EP, Carmo FA, Ricci-Junior E. Development and characterization of repellent formulations based on nanostructured hydrogels. Drug Dev Ind Pharm. 2017 Jan;43(1):67-73. doi: 10.1080/03639045.2016.1220564. 

Abstract. ... Ethyl butylacetylaminopropionate (EB) is a synthetic mosquito repellent, which could be used in products for adults and children due to its low-allergenic potential. The aim of this study was to develop and characterize EB and Poloxamer 407 nanoemulsions regarding their droplets mean size, pH, rheological properties, cytotoxicity and in vitro permeation profile. ...

N'Guessan R, Rowland M, Moumouni TL, Kesse NB, Carnevale P. Evaluation of synthetic repellents on mosquito nets in experimental huts against insecticide-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes. Trans R Soc Trop Med Hyg. 2006 Dec;100(12):1091-7. doi: 10.1016/j.trstmh.2006.04.005.

Abstract. Owing to the development of pyrethroid resistance in Anopheles gambiae, there is a need to develop chemical alternatives for use on mosquito nets. Synthetic insect repellents are widely used for personal protection as skin or clothing applications. The efficacy of repellent-treated nets (RTN) was evaluated in experimental huts in Côte d'Ivoire against pyrethroid-resistant populations of An. gambiae and Culex quinquefasciatus. The repellents tested were DEET (N,N-diethyl-3-methylbenzamide) at 7.9 g/m2 and two formulations of ethyl butylacetylaminopropionate (IR3535) at 7.6 g/m2 and 7.3 g/m2. Over 45 nights there was a 74-82% reduction in the number of An. gambiae entering the huts containing RTNs but no significant reduction in entry of C. quinquefasciatus. There was a 63-64% reduction in the proportion of An. gambiae blood feeding but no reduction in the proportion of C. quinquefasciatus blood feeding in huts with RTNs. An unexpected result was the 69-76% mortality of An. gambiae and 51-61% mortality of C. quinquefasciatus in huts containing RTNs. Treated filter paper bioassays in WHO test kits confirmed that confined contact with DEET induces mortality. The DEET-based product provided better and longer protection; tunnel test bioassays confirmed that residual activity lasted for up to 6 weeks. Application of repellents to nets warrants further investigation and development.

Izadi H, Focke WW, Asaadi E, Maharaj R, Pretorius J, Loots MT. A promising azeotrope-like mosquito repellent blend. Sci Rep. 2017 Aug 31;7(1):10273. doi: 10.1038/s41598-017-10548-y. 

Abstract. Topical repellents play a key role in reducing the outdoor transmission of mosquito-borne diseases by reducing human-vector contact. Excellent repellents are available, but there is always room for improvement. This article reports on a particularly effective binary repellent blend of ethyl butylacetylaminopropionate and nonanoic acid. A composition containing 25 mol% of the acid exhibits negative pseudo-azeotrope behaviour at 50 °C, meaning that the liquid vapour pressure is lower than that of the parent compounds and evaporation occurs without a change in the liquid composition. In tests performed using the South African Medical Research Council's cup-on-arm procedure, this mixture provided better protection for a longer time than the "gold standard of mosquito repellents", namely N,N-diethyl-m-toluamide, commonly known as DEET.

Frances SP, MacKenzie DO, Rowcliffe KL, Corcoran SK. Comparative field evaluation of repellent formulations containing deet and IR3535 against mosquitoes in Queensland, Australia. J Am Mosq Control Assoc. 2009 Dec;25(4):511-3. doi: 10.2987/Moco-09-5938.1. 

Abstract. Field trials comparing repellent formulations containing IR3535 (ethyl butylacetylaminopropionate) and deet (N,N-diethyl-3-methylbenzamide) against mosquitoes in Queensland, Australia, were conducted. Two repellents were compared: Avon Bug Guard, containing 7.5% IR3535; and Australian Defense Force (ADF) deet, containing 35% deet in a gel. Two tests were conducted, one in February-March 2006, and the second in February 2007. In the 1st test, the predominant mosquito species collected were Mansonia uniformis (58.9% of collection) and Culex annulirostris (33.4%), and in the 2nd test, the predominant species was Aedes vigilax (85.7% of collection). In the 1st test, Avon Bug Guard provided >95% protection against all mosquitoes for only 1 h, and ADF deet provided the same level of protection for 5 h. In the 2nd field test, Avon Bug Guard provided only 85% protection against all mosquitoes 1 h after repellent application, while ADF deet provided 5 h of protection. The study showed that ADF deet provided significantly better protection against mosquitoes than Avon Bug Guard (IR3535).

Fradin MS, Day JF. Comparative efficacy of insect repellents against mosquito bites. N Engl J Med. 2002 Jul 4;347(1):13-8. doi: 10.1056/NEJMoa011699.

Abstract. 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....Conclusions: 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.