Analysis of N,N-diethyl-m-toluamide in porcine skin perfusates using solid-phase extraction disks and reversed-phase high-performance liquid chromatography.
N,N-Diethyl-m-toluamide (DEET) is frequently used as an insect repellent by military and civilian populations. Because dermal exposure has resulted in several cases of DEET toxicosis, there is a need to rapidly and reliably determine DEET concentrations in biological matrices. An improved method for the analysis of DEET was developed for determining transdermal diffusion of low levels of DEET following application to an in vitro porcine skin flow-through diffusion cell system. The technical improvement involved the use of disk solid-phase extraction (SPE) instead of packed-bed SPE. The disk SPE method required small volumes of preconditioning, wash, and elution solvent (0.5-1 ml) to extract DEET from perfusate samples containing bovine serum albumin (BSA). The limit of quantitation (LOQ) was estimated as 0.08 micro g/ml DEET and recoveries from BSA media samples spiked with DEET ranged from 90.1 to 117% with relative standard deviation (RSD) ranging from 2.0 to 13.1%. This method was used to analyze perfusate samples from skin (n=4) topically exposed to DEET-ethanol formulations. The data from these analyses determined that DEET permeability in porcine skin was 2.55 x 10(-5)+/-0.54 x 10(-5) cm/h.
Baynes
Ronald E
RE
North Carolina State University-College of Veterinary Medicine, Center for Chemical Toxicology Research and Pharmacokinetics, 4700 Hillsborough St, Raleigh, NC 27606, USA. ronald_baynes@ncsu.edu
Yeatts
James L
JL
Riviere
Jim E
JE
D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003671:DEET / Q000032:analysis*; D007302:Insect Repellents / Q000032:analysis*; D010539:Permeability; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012867:Skin / Q000737:chemistry*; D013552:Swine
D007302:Insect Repellents; D003671:DEET