Hydrophilic stationary phases: a practical approach for the co-analysis of compounds with varying polarity in biological matrices.

The aim was to simultaneously extract, separate and detect not only the opioid methadone and its primary metabolites (2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine and 2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline), but also creatinine from urine, plasma and fingerprints. Creatinine is highly polar and analysis by RP chromatography using conventional stationary phases such as silica-bonded C8 and C18 is unsuitable. Hydrophilic stationary phases are increasingly being applied for the analysis of highly polar analytes, this chemistry being investigated as a suitable alternative. A hydrophilic interaction liquid chromatography phase column successfully retained creatinine and permitted the co-analysis of methadone and its metabolites by LC-MS/MS. Prior to analysis, an extraction protocol for urine and plasma was required but for fingerprint deposits this was not necessary. Alteration of sample pH, necessary to extract methadone, and its metabolites led to difficulties associated with the extraction of creatinine. This problem was addressed by first performing an SPE incorporating a hydrophilic interaction phase to extract creatinine, and the eluent then combined with the opioid extract from a mixed-mode cation exchange phase. The assay for creatinine, methadone and its primary phase I metabolites met validation criteria. LC-MS/MS analysis of creatinine and drug compounds together offers considerable advantages over traditional approaches that necessitate the quantification of creatinine using spectrophotometric approaches.

The detection and quantification of lorazepam and its 3-O-glucuronide in fingerprint deposits by LC-MS/MS.

The use of fingerprints as an alternative biological matrix to test for the presence of drugs and/or their metabolites is a novel area of research in analytical toxicology. This investigation describes quantitative analysis for the benzodiazepine lorazepam and its 3-O-glucuronide conjugate in fingerprints following the oral administration of a single 2 mg dose of lorazepam to five volunteers. Creatinine was also measured to investigate whether the amount of drug relative to that of creatinine would help to account for the variable amount of secretory material deposited. Fingerprints were deposited on glass cover slips and extracted by dissolving them in a solution of dichloromethane/methanol, containing tetradeuterated lorazepam as an internal standard. The samples were evaporated, reconstituted with mobile phase and analysed by LC-MS/MS. Chromatography was achieved using an RP (C18) column for the analysis of lorazapem and its glucuronide, and a hydrophilic interaction column (HILIC) for the analysis of creatinine. Lorazepam and its glucuronide were only detected where ten prints had been combined, up to 12 h following drug administration. In every case, the amount of lorazepam glucuronide exceeded that of lorazepam, the peak amounts being 210 and 11 pg, respectively. Adjusting for creatinine smoothed the elimination profile. To our knowledge, this represents the first time a drug glucuronide has been detected in deposited fingerprints.