Serge Schneider

Analysis of illicit cocaine and heroin samples seized in Luxembourg from 2005–2010

This article discusses drug purity, frequency of appearance and concentration ranges of adulterants of 471 illicit cocaine and 962 illicit heroin samples seized in Luxembourg from January 2005 to December 2010. For cocaine samples the mean concentration was lowest in 2009 (43.2%) and highest in 2005 (54.7%) but no clear trend could be observed during the last 6 years. 14 different adulterants have been detected in cocaine samples, from which phenacetin has been the most abundant in terms of frequency of appearance and concentration until 2009. In 2010 the veterinary antihelminthic drug levamisole has become the most abundant adulterant detected in cocaine samples, its concentrations however remained low (1.5-4.1%). The mean heroin concentration was 26.6% in 2005, a decline has been observed in 2006 and the concentrations have been relatively stable since then (15.8-17.4%). Paracetamol and caffeine were by far the most abundant adulterants detected in heroin samples.

Time resolved analysis of risperidone and 9-hydroxy-risperidone in hair using LC/MS-MS

Risperidone (RSP) is a second generation anti-psychotic drug used for the treatment of schizophrenia and anxiety disorders. In the last decades, clinical applications of hair analysis have received an increasing attention, because of its wide surveillance window. In this work, we describe a simple and fast method for detection and quantification of RSP and its major metabolite, 9-OH-risperidone (9-OH-RSP), in human hair. The validated method (cv of interday precision, intraday precision and accuracy<15%, r(2) of the calibration curves>0.98, limit of detection (LOD) was 0.90 pg/mg hair (RSP) and 1.52 pg/mg hair (9-OH-RSP), the lower limit of quantification (LLOQ) were 1.8 and 4.56 pg/mg, respectively, extraction yield were 86.9% for RSP and 86.7% for 9-OH-RSP) was successfully applied to quantify both substances in the hair of psychiatric patients treated with RSP. After washing, pulverisation, incubation in an ultrasound bath and liquid/liquid extraction of the hair samples, quantification was performed using LC/MS-MS in selected reaction monitoring mode with methaqualone as internal standard. Concentrations for RSP and its major metabolite ranged from 36 to 4765 pg/mg and from 14 to 57 pg/mg, respectively in the different hair segments. These preliminary results indicate a better relationship between the administered dose and hair concentration for 9-OH-RSP than for the parent drug. Furthermore, the RSP/9-OH-RSP ratio varied from 1 to 83.

Rapid extraction, identification and quantification of oral hypoglycaemic drugs in serum and hair using LC-MS/MS

A sensitive and accurate LC-MS/MS method for the identification and quantification of 5 oral anti-diabetics (glipizide, glibenclamide, gliclazide, gliquidone and metformin) in serum and hair was developed using glibornuride as the internal standard. We have developed a rapid and robust extraction procedure by using acetonitrile for serum protein precipitation and methanol for the extraction of anti-diabetics from hair. Anti-diabetics (ADs) were separated by UPLC over a C18 column and detection was performed on a Waters Xevo TQ MS mass spectrometer in positive ionization mode using electrospray ionization. Each AD was identified by three specific ion transitions in multiple reaction monitoring (MRM) mode. The method was validated according to international guidelines. For all compounds the variation coefficient (CV) was <20%, and accuracies ranged from 85 to 115% in serum and hair. The limits of detection (LODs) were <1.5 ng/mL for all ADs in serum and <3.59 pg/mg in hair. Recoveries varied from 56.41% (gliclazide) to 67.58% (glipizide) in serum and from 68% (gliclazide) to 91.2% (metformin) in hair. The method was successfully applied to quantify ADs in serum of 33 patients and in hair of 15 patients.

Pregabalin Determination in Hair by Ultra-High-Performance Liquid Chromatography–Tandem Mass Spectrometry

Pregabalin is an antiepileptic and analgesic drug, commercialized under the name of Lyrica, and generally used to treat neuropathic pain. The determination of pregabalin was performed by using spiked hair samples extracted in methanol and analyzed by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry. The validation of a quantification method of pregabalin in hair has been successfully achieved (precision, accuracy, matrix effects and extraction yield). The limit of detection was 0.76 pg/mg and the lower limit of quantification was 2.5 pg/mg. A real case of pregabalin in hair has been analyzed using this method. The result showed a concentration of 540 pg/mg.

Evaluation of saliva as an alternative matrix for monitoring plasma Zidovudine, Lamivudine and nevirapine concentrations in Rwanda

Saliva may provide interesting advantages as matrix for compliance measurements, pharmacokinetic studies and therapeutic drug monitoring in resource limited countries. We investigated the feasibility of using saliva for compliance monitoring of zidovudine (ZDV), lamivudine (3TC) and nevirapine (NVP) in 29 HIV-1 infected patients from Rwanda. ZDV, 3TC and NVP drug levels were quantified by an LC/MS-MS method in plasma and stimulated saliva samples and compared using Bland-Altman analysis. Seven patients demonstrated undetectable saliva ZDV levels while five out of these seven also showed no 3TC salivary concentrations. For the other samples, we observed a good agreement between salivary and plasma concentrations of each antiretroviral drug. A significant relation between the difference in saliva and plasma ZDV concentrations and the average ZDV concentration in the two matrices was deduced as follow: y = -380.15 + 1.79 x. The log saliva and plasma concentration difference of both 3TC and NVP was consistent across the range of average log concentration. Overall, we showed large agreement limits suggesting a wide inter patient variability that may result to non-reliable plasma level predictions from saliva drug measurements. Therefore, our results indicate that saliva may serve as a valuable tool only for NVP compliance testing because of its high salivary concentration.

Impact of UGT1A1 polymorphisms on Raltegravir and its glucuronide plasma concentrations in a cohort of HIV-1 infected patients.

The aim of this study was to evaluate the effect of UGT1A1 polymorphisms on Raltegravir (RAL) and its metabolite RAL-glucuronide trough plasma concentrations ([RAL]plasma and [RAL-glu]plasma) and on the metabolic ratio (MR): [RAL-glu]plasma/[RAL]plasma. UGT1A1 genotyping was performed on 96 patients. 44% (n = 42) were homozygous UGT1A1*1/*1 while 50% (n = 48) and 6% (n = 6) were UGT1A1*28 and UGT1A1*36 carriers, respectively. The median concentration and interquartile range (IQR) of [RAL]plasma were 88.5 ng/ml (41.0–236), 168 ng/ml (85.8–318) and 92.5 ng/ml (36.4–316) for UGT1A1*1/*1, UGT1A1*28 and UGT1A1*36 carriers, respectively. Only the difference between UGT1A1*1/*1 and *28 carriers was statistically significant (p = 0.022). The median MR (IQR) were 5.8 (3–10), 2.9 (1.6–5.3) and 3.2 (1.7–5.9) for UGT1A1*1/*1, UGT1A1*28 and UGT1A1*36 carriers, respectively. Only the difference between UGT1A1*1/*1 and *28 carriers was statistically significant (p = 0.004) with an allele-dependent effect: UGT1A1*28 homozygous having lower MR than heterozygous carriers who show lower MR compared to *1/*1. Except for the sensation of fatigue, this PK effect did not correlate with clinical adverse events or biological abnormalities. In Conclusion, we demonstrate that UGT1A1*28 polymorphism has a significant impact on RAL metabolism: UGT1A1*28 carriers being characterized by higher [RAL]plasma and lower MR.

Determination of cannabinoids in hair of CBD rich extracts consumers using gas chromatography with tandem mass spectrometry (GC/MS–MS)

Medical cannabis is becoming increasingly popular for many different ailments and improvement of general well-being. Particularly CBD-rich extracts are easily available via online pharmacies, health stores or directly from producers. However, almost all of the extracts contain small amounts of THC. Thus, in case of continuous or heavy use of CBD rich cannabis, THC concentrations in hair may rise above accepted legal limits. In our study, we investigated THC, CBN and CBD in hair samples from regular CBD rich cannabis users. The goals were to determine levels of the cannabinoids in hair and to evaluate a possible correlation between regular CBD intake and CBD levels in hair. All participants consumed cannabis extracts from the same producer. It contained CBD at different concentrations and small amounts of THC with a CBD/THC concentration ratio of 30. The self-declared CBD dosage ranged from 4 to 128mg CBD/day, corresponding to a daily THC intake of 0.1 to 4.3mg. After extraction and derivatization, hair samples were analysed using a validated GC/MS-MS method. CBD concentrations ranged from 10 to 325pg/mg of hair, but no significant correlation was observed between CBD concentrations and the daily dose. THC was detected in one sample only at a concentration below our cut-off, whereas CBN was not detected. In this study, we showed that even after repeated consumption of CBD-rich cannabis extracts in medium to high doses, consumers are generally tested negative for THC in hair.

Frontline Testing for Drugs of Abuse

Many non-instrument based immunoassays have been developed and commercialized due their ease of use and rapid results. At least 15 different tests are available, such as the Frontline rapid screen for drugs of abuse. Since the early 1990s Boehringer Mannheim (now Roche Diagnostics) has developed and commercialized these single parameter test strips for qualitative and semiquantitative analysis of cannabinoids, cocaine, opiates, benzodiazepines and amphetamines in urine specimens. The test for methadone is currently under development (1999). The test principle and an evaluation of the different Frontline tests will be presented in this chapter.