A new two-phase dimeticone pediculicide shows high efficacy in a comparative bioassay
1 Department of Community Health, School of Medicine, Federal University of Ceará, Rua Prof. Costa Mendes 1608, 5. andar, Fortaleza CE 60430-140, Brazil
2 Anton Breinl Centre for Tropical Medicine and Public Health; School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Townsville, Australia
3 Department of Hygiene and Microbiology, Charité Medical School, Campus Benjamin Franklin, Berlin, Germany
4 Department of Dermatology, University of Düsseldorf, Düsseldorf, Germany
BMC Dermatology 2009, 9:12 doi:10.1186/1471-5945-9-12Published: 14 December 2009
Dimeticones kill head lice by physical means. Here we assessed in a comparative bioassay the ex vivo efficacy of "NYDA® sensitiv", a new two-phase dimeticone-based pediculicide similar to a product established on the market, but without fragrances.
We compared efficacy of the new product to a positive dimeticone control group, a sample of four other insecticidal and natural head lice products marketed in Germany, and an untreated control. In a bioassay, lice were exposed ex vivo to products and examined for activity for up to 24 hours, following a standard protocol.
After 6 and 24 hours, 13.7 and 88.5% of untreated control lice did not show major vital signs. In contrast, no lice showed major vital signs 5 minutes after treatment with the new product or the control dimeticone group (NYDA®). This effect persisted at all observation points (100% efficacy). Efficacy of 0.5% permethrin (Infectopedicul®) ranged between 76 and 96% in evaluations between 5 min and 6 hours. All lice treated with a coconut-based compound (mosquito® Läuseshampoo) did not show major vital signs after 5 min, but mortality was only 58% after one hour. Pyrethrum extract (Goldgeist® forte) showed an efficacy of 22 - 52% between 5 min and 3 hours after treatment; after 6 hours, 76% of lice were judged dead. An oxyphthirine®-based compound (Liberalice DUO LP-PRO®) killed 22 - 54% of lice in the first 6 hours.
The two-phase dimeticone compound NYDA® sensitiv is highly efficacious. The removal of fragrances as compared to an established dimeticone product did not affect in vitro efficacy.