Determination of methylphenidate in Calliphorid larvae by liquid-liquid extraction and liquid chromatography mass spectrometry--forensic entomotoxicology using an in vivo rat brain model.
The aim of this study was to examine the potential forensic utilisation of blowfly larvae (Diptera: Calliphoridae) as an alternative toxicological specimen for the detection of the psychotropic model drug methylphenidate (MPH). MPH was extracted from biological matrices (rat brain, serum and Calliphorid larvae) by liquid-liquid extraction with recovery of >80%, and quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The LC-MS/MS assay was validated for entomotoxicological use and initially applied to male Sprague-Dawley rats (n=6) that were dosed with MPH (20mg/kg) ante-mortem. MPH could be detected in Calliphorid larvae (n=15) reared on the rat brains at 3.2±1.6 ng/g. Secondly, MPH-spiked porcine brain tissue (450 mg/kg) was used to investigate drug concentration in larvae over a period of 72 h. After larvae had feed for 60 h, MPH was detected at 19.8±1.4 μg/g in the feeding larvae and at 3.5±0.1 μg/g in the MPH-spiked porcine brain tissue. It could be advantageous to use Calliphorid larvae as an alternative toxicological specimen to detect alkaline labile drugs, such as MPH.
School of Pharmacy, Otago University, 18 Frederick Street, Dunedin 9016, New Zealand.
Sarah K
SK
Bushby
Nicky
N
Thomas
Petra A
PA
Priemel
Carolyn V
CV
Coulter
Thomas
T
Rades
Jules A
JA
Kieser
D000818:Animals; D001921:Brain / Q000469:parasitology*; D002138:Calibration; D002853:Chromatography, Liquid / Q000592:standards; D004175:Diptera / Q000196:embryology / Q000378:metabolism*; D004355:Drug Stability; D004772:Entomology / Q000592:standards; D053593:Forensic Toxicology / Q000379:methods* / Q000592:standards; D007814:Larva / Q000378:metabolism; D057230:Limit of Detection; D016014:Linear Models; D059625:Liquid-Liquid Extraction / Q000592:standards; D008297:Male; D008774:Methylphenidate / Q000378:metabolism*; D011180:Postmortem Changes; D011619:Psychotropic Drugs / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D053719:Tandem Mass Spectrometry / Q000592:standards; D013997:Time Factors
D011619:Psychotropic Drugs; D008774:Methylphenidate