title: Repellent effect of microencapsulated essential oil in lotion formulation against mosquito bites.
abstract: OBJECTIVE
  Many essential oils have been reported as natural sources of insect repellents; however, due to high volatility, they present low repellent effect. Formulation technique by using microencapsulation enables to control the volatility of essential oil and thereby extends the duration of repellency. In this study, the effectiveness of microencapsulated essential oils of Alpinia galanga, Citrus grandis and C. aurantifolia in the lotion formulations were evaluated against mosquito bites.
  
  
  METHODS
  Essential oils and N,N-Diethyl-3-methylbenzamide (DEET) were encapsulated by using interfacial pre- cipitation techniques before incorporation into lotion base to form microencapsulated (ME) formulation. The pure essential oil and DEET were also prepared into lotion base to produce non-encapsulated (NE) formulation. All the prepared formulations were assessed for their repellent activity against Culex quinquefasciatus under laboratory condition. Field evaluations also were conducted in three different study sites in Peninsular Malaysia. In addi- tion, Citriodiol® (Mosiquard®) and citronella-based repellents (KAPS®, MozAway® and BioZ Natural®) were also included for comparison.
  
  
  RESULTS
  In laboratory conditions, the ME formulations of the essential oils showed no significant difference with regard to the duration of repellent effect compared to the microencapsulated DEET used at the highest con- centration (20%). It exhibited >98% repellent effect for duration of 4 h (p = 0.06). In the field conditions, these formulations demonstrated comparable repellent effect (100% for a duration of 3 h) to Citriodiol® based repellent (Mosiguard®) (p = 0.07). In both test conditions, the ME formulations of the essential oils presented longer duration of 100% repellent effect (between 1 and 2 h) compared to NE formulations.
  
  
  CONCLUSIONS
  The findings of the study demonstrate that the application of the microencapsulation technique during the preparation of the formulations significantly increases the duration of the repellent effect of the essential oils, suggesting that the ME formulation of essential oils have potential to be commercialized as an alternative plant-based repellent in the market against the mosquitoes.
authors.affiliation: Department of Parasitology, Faculty of Medicine, University Malaya, Kuala Lumpur; Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, University Putra Malaysia, Serdang, Selangor, Malaysia.
authors.forename: Norashiqin
authors.initials: N
authors.lastname: Misni
authors.affiliation: Department of Parasitology, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia.
authors.forename: Zurainee Mohamed
authors.initials: ZM
authors.lastname: Nor
authors.affiliation: Medical Entomology Unit, Institute of Medical Research, Kuala Lumpur, Malaysia.
authors.forename: Rohani
authors.initials: R
authors.lastname: Ahmad
mesh_terms: D032429:Alpinia / Q000737:chemistry; D000818:Animals; D002214:Capsules / Q000008:administration & dosage*; D002957:Citrus / Q000737:chemistry; D003465:Culex / Q000187:drug effects*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007299:Insect Bites and Stings / Q000517:prevention & control*; D007302:Insect Repellents / Q000008:administration & dosage* / Q000302:isolation & purification / Q000494:pharmacology; D008296:Malaysia; D009822:Oils, Volatile / Q000008:administration & dosage* / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D002214:Capsules; D007302:Insect Repellents; D009822:Oils, Volatile