title: Nanoformulation of poly(ethylene glycol) polymerized organic insect repellent by PIT emulsification method and its application for Japanese encephalitis vector control.
abstract: The utilization of increased dosage of insect repellents to overcome mosquito resistance has raised environmental concerns globally. In accord to this, we have formulated an efficacious, water-dispersive, nanometric formulation of a poor water-soluble insect repellent, diethylphenylacetamide (DEPA) by poly(ethylene glycol) (PEG) polymerization followed by PIT emulsification method. The critical micelle concentration of PEG in the spontaneously emulsified conventional DEPA droplets was determined, based on the droplets physical stability. Subjecting them to PIT emulsification yielded monodispersed polymeric nanomicelles of DEPA (Nano DEPA) with hydrodynamic mean diameter of 153.74 nm. The high-resolution scanning and transmission electron microscopic studies revealed the characteristic core-shell structure of micelle. The comparative efficacy of Bulk DEPA and Nano DEPA was evaluated by larvicidal and WHO cone bioassay against the Japanese encephalitis vector Culex tritaeniorhynchus. The median lethal concentrations (48 h) for 3rd instars C. tritaeniorhynchus larvae were found to be 0.416 mg/L for Bulk DEPA and 0.052 mg/L for Nano DEPA, respectively. The median knockdown concentrations (60 min) for the two to three-day-old, sucrose-fed, female adult mosquitoes were 5.372% (v/v) and 3.471% (v/v) for Bulk and Nano DEPA, respectively. Further investigation by histopathological and biochemical studies propound that Nano DEPA exerted better bioefficacy as comparative to its bulk form even at minimal exposure concentrations. Hence, Nano DEPA will serve as an effective alternate in controlling the vector expansion with reduced dosage.
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, India.
authors.forename: A P B
authors.initials: APB
authors.lastname: Balaji
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, India.
authors.forename: Prabhakar
authors.initials: P
authors.lastname: Mishra
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, India.
authors.forename: R S
authors.initials: RS
authors.lastname: Suresh Kumar
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, India.
authors.forename: Amitava
authors.initials: A
authors.lastname: Mukherjee
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, India. Electronic address: nchandrasekaran@vit.ac.in.
authors.forename: Natarajan
authors.initials: N
authors.lastname: Chandrasekaran
mesh_terms: D000083:Acetanilides / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D003465:Culex / Q000187:drug effects* / Q000502:physiology; D004655:Emulsions; D004672:Encephalitis, Japanese / Q000517:prevention & control; D005260:Female; D007300:Insect Control / Q000379:methods; D007302:Insect Repellents / Q000737:chemistry / Q000494:pharmacology*; D007303:Insect Vectors / Q000187:drug effects* / Q000502:physiology; D007814:Larva / Q000187:drug effects / Q000502:physiology; D008823:Micelles; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D044367:Phase Transition; D011092:Polyethylene Glycols / Q000737:chemistry*; D013696:Temperature
chemical_list: D000083:Acetanilides; D004655:Emulsions; D007302:Insect Repellents; D008823:Micelles; D011092:Polyethylene Glycols; C044250:N,N-diethylphenylacetamide
keywords: CMC; Nanopesticides; PIT emulsification; Poly(ethylene glycol); Polymeric micelles; Steric stability