Formulation of an effective mosquito-repellent topical product from lemongrass oil

Ointment and cream formulations of lemongrass oil in different classes of base and the oil in liquid paraffin solution have been evaluated for mosquito repellency in a topical application. Mosquito repellency was tested by determining the bite-deterrence of product samples applied on an experimental bird's skin against a 2-day starved culture of Aedes aegypti L. mosquitoes. The 1% v/v solution and 15% v/w cream and ointment preparations of the oil exhibited greater than or equal to50% repellency lasting 2-3 h, which may be attributed to citral, a major oil constituent. This activity was comparable to that of a commercial mosquito repellent. Base properties of the lemongrass oil formulations influenced their effectiveness. The oil demonstrated efficacy from the different bases in the order of hydrophilic base > emulsion base > oleaginous base.