Articles

Although human oral fluid has become more routine for quantitative drug detection in pain management, detecting a large scope of medications and substances is costly and technically challenging for laboratories. This paper presents a quantitative assay for 64 pain medications, illicit substances, and drug metabolites in human oral fluid. The novelty of this assay is that it was developed on an older model AB SCIEX 4000 instrument and renders obscure the need for more technical and expensive laboratory equipment. This method includes addition of internal standard and a 2-step liquid-liquid extraction and dry-down step to concentrate and clean the samples. The samples were suspended in 50% MeOH in water and separation and detection was accomplished using triple quadrupole mass spectrometry (LC-MS/MS). Separation was achieved using reverse-phase liquid chromatography with detection by LC-MS/MS. A second injection was done in negative mode to determine THC-COOH concentration as an indicator of THC. An aliquot of the (already) extracted samples was analyzed for D- and L- isomers of amphetamine and methamphetamine using a chiral column. The standard curve spanned from 5 to 2000 ng/mL for most of the analytes (1 to 2000 ng/mL for fentanyl and THC-COOH) and up to 1000 ng/mL for 13 analytes. Pregabalin and gabapentin ranged from 25 to 2000 ng/mL. The result is a low-cost method for the sensitive detection of a wide-ranging oral fluid menu for pain management. This assay has a high sensitivity, and good precision and accuracy for all analytes with an older model mass spectrometer.

Methamphetamine and its metabolite amphetamine are frequently abused drugs. Whether obtained legally or from clandestine laboratories it is of relevance to determine the chiral makeup of these drugs for investigative purpose. Although urine and oral fluid matrices are commonly offered, less available to independent laboratories are techniques to verify dextro (D-) or levo (L-) (meth)amphetamine from human K2EDTA plasma. This paper outlines the development and validation of a method that includes the addition of internal standard and a two-step liquid-liquid extraction to remove the analytes from human K2EDTA plasma by triple quadrupole mass spectrometry (LC-MS/MS). The assay was validated according to the United States Food and Drug Administration and College of American Pathologists guidelines, including assessment of the following parameters in plasma validation samples: linear range, limit of detection, lower limit of quantitation, matrix effects, inter- and intra-day assay precision and accuracy, carry over, linearity of dilution, matrix effects and stability. The outcome is a validated and reliable method for the determination of D- and L- isomer concentration of meth(amphetamine) human plasma samples that can be easily adopted by independent clinical laboratories.