A Milestone In Botanical Mosquito Repellents: Novel PMD-Based Formulation Protects More Than Twice As Long As High-Concentration Deet and Other Leading Products

The use of skin-applied repellents is the primary method recommended by the Centers for Disease Control and Prevention for personal protection against biting mosquitoes. Historically, the majority of long-efficacy mosquito repellents have been N,N diethyl-3-methylbenzamide (deet)–based. Recently, a variety of new botanical formulations have been marketed, but their protection times generally continue to fall well short of high-concentration deet products. We present a laboratory arm-in-cage study of a Neo-Innova® repellent that has a prolonged action “NEO-PART®” (Prolonged Action Release Technology) formulation with 40% Citriodiol®. This formulation provides the botanical molecule para-menthane 3,8-diol (PMD) at 25% w/v of the total formulation. Against Aedes aegypti, Neo-Innova's mean complete protection time (CPT; 14.2 h) was approximately 2 to 3 times longer than that of 5 leading high-performance repellents marketed in the USA, including 25% deet and a 20% PMD ethanolic formulation. When testing Neo-Innova, 5 of the 6 subjects had no landings after 15 h. The 6th had single landings at 10 and 11 h (individual CPT of 10 h), but received no additional landings in further exposures made at 13 and 15 h. Neo-Innova repellency against Culex quinquefasciatus was similarly prolonged. The tremendous increment in repellency duration observed for the Neo-Innova product, when compared with both current standard and botanical repellent options, represents a milestone in repellent development and supports “once-a-day” applications as a practical strategy for personal protection against mosquitoes.