Study on the determination and chiral inversion of R-salbutamol in human plasma and urine by liquid chromatography-tandem mass spectrometry

Chirality Supramolecular Systems: Helical Assemblies, Structure Designs, and Functions

Chirality, as one of the most striking characteristics, exists at various scales in nature. Originating from the interactions of host and guest molecules, supramolecular chirality possesses huge potential in the design of functional materials. Here, an overview of the recent progress in structure designs and functions of chiral supramolecular materials is present. First, three design routes of the chiral supramolecular structure are summarized. Compared with the template-induced and chemical synthesis strategies that depend on accurate molecular identification, the twisted-assembly technique creates chiral materials through the ordered stacking of the nanowire or films. Next, chirality inversion and amplification are reviewed to explain the chirality transfer from the molecular level to the macroscopic scale, where the available external stimuli on the chirality inversion are also given. Lastly, owing to the optical activity and the characteristics of the layer-by-layer stacking structure, the supramolecular chirality materials display various excellent performances, including smart response, shape-memorization, superior mechanical performance, and applications in biomedical fields. To sum up, this work provides a systematic review of the helical assemblies, structure design, and applications of supramolecular chirality systems.

Development of an HPLC-MS/MS Method for Chiral Separation and Quantitation of (R)- and (S)-Salbutamol and Their Sulfoconjugated Metabolites in Urine to Investigate Stereoselective Sulfonation

The aim of this study was to develop and optimize a chiral HPLC-MS/MS method for quantitative analysis of (R)-/(S)-salbutamol and (R)-/(S)-salbutamol-4'-O-sulfate in human urine to allow for bioanalytical quantitation of the targeted analytes and investigations of stereoselectivity in the sulfonation pathway of human phase Ⅱ metabolism. For analytical method development, a systematic screening of columns and mobile phases to develop a separation via enantiomerically selective high performance liquid chromatography was performed. Electrospray ionization settings were optimized via multiple-step screening and a full factorial design-of-experiment. Both approaches were performed matrix-assisted and the predicted values were compared. The full factorial design was superior in terms of prediction power and knowledge generation. Performing a longitudinal excretion study in one healthy volunteer allowed for the calculation of excretion rates for all four targeted analytes. For this proof-of-concept, either racemic salbutamol or enantiopure levosalbutamol was administered perorally or via inhalation, respectively. A strong preference for sulfonation of (R)-salbutamol for inhalation and peroral application was found in in vivo experiments. In previous studies phenol sulfotransferase 1A3 was described to be mainly responsible for salbutamol sulfonation in humans. Thus, in vitro and in silico investigations of the stereoselectivity of sulfotransferase 1A3 complemented the study and confirmed these findings.

Measurement Uncertainty and Validation for Quantitation of Salbutamol in Human Urine by Gas Chromatography-Tandem Mass Spectrometry

A simple, rapid, sensitive and specific gas chromatography-tandem mass spectrometry (GC-MS/MS) method was developed for quantitation of salbutamol in human urine using salbutamol-d3 as the internal standard. The processing of urines samples includes deconjugation with enzymatic hydrolysis, solid phase extraction procedure utilizing XAD2 column and liquid-liquid extraction accompanied by the derivatization by means of MSTFA/IODO-TMS/DTE mixture. The GC column was a HP Ultra-1 (17 m × 0.22 mm × 0.11 μm) used to separate the peak of interest. The data for GC-MS/MS were acquired and processed utilizing GC Labs Solution and Insight GCMS Software. The detection of spectra was performed on TQ 8050. This method included a chromatographic run of 13.67 min and the linearity was found over the concentration range of 250-2000 ng/mL with a regression coefficient (r2) of 0.99. The coefficient of variation for intra and interday assay precision was between 1.85 and 2.85% and the accuracy was between 95.50 and 107.04% for low quality control (QC), medium QC and high QC. The recovery was adequate to reliable detect the analyte at or below the level recommended by the World Anti-Doping Agency i.e., threshold 1000 ng/mL. The limit of detection and limit of quantification were found to be 10 and 100 ng/mL, respectively. The expanded measurement uncertainty (Uexp%) was found to be 8.28%.

Simultaneous determination of fourteen β2-agonist enantiomers in food animal muscles by liquid chromatography coupled with tandem mass spectrometry

Illegal drug residues in animal derived foods are closely related to human's life and health. Studies on illegal drug residues and the metabolism, such as β2-agonists in animals have attracted more and more attention. In most cases, β2-agonists are suppliedand used astheracemate. The metabolic process and distribution of the two enantiomers in animal tissues are different. Therefore, it is very necessary to develop a simple and fast method for chiral resolution of these drugs in animal tissues. In this paper, a reliable resolution and determination method was presented using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for fourteen enantiomers of seven β2-agonist racemates, clenbuterol (CLE), salbutamol (SAL), cimaterol (CIM), terbutaline (TER), clorprenaline (CLO), tulobuterol (TUL), penbuterol (PEN) in pork, beef, and lamb muscle samples. The samples were added the internal standard solution (IS) and extracted in the alkaline medium with acetonitrile. The further sample purification was accomplished through MCX solid phase extraction cartridge. Chromatographic chiral separation was carried out on a VancoShell chiral column (100 mm × 4.6 mm, 2.7 μm) with an isocratic mobile phase consisting of methanol and 10 mmol mL-1 ammonium formate aqueous solution (85:15, v/v). Under the optimized conditions, the resolution (R) of CIM was 2.0, CLE and PEN were 1.5, the others were all greater than 1.0. Enantiomeric determination was performed in the positive electrospray ionization mode using multiple reaction monitoring (MRM). The correlation coefficient (r) in the range of 0.2-25.0 μg L-1 was above 0.993. The average recoveries at the three spiking levels ranged from 95.3% to 117.7% with the relative standard deviation (RSD) lower than 15%. The limit of detection (LOD) and the limit of quantification (LOQ) of β2-agonist enantiomers was 0.2 μg kg-1 and 0.5 μg kg-1 respectively. The method was successfully applied in the analysis and evaluation of β2-agonist enantiomers in positive food animal muscle samples, CLE, SAL, TEB and CIM enantiomers were detected. The concentrations of the corresponding enantiomers were in the range of 1.06-17.3 μg kg-1, the lowest enantiomer fraction (EF) value was 0.42, and the highest value was 0.69. The work is expected to provide a method for chiral separation and enantiomeric determination of the further study of pharmacology, toxicity and residue elimination of β2-agonist enantiomers.

Spatial Distribution of (R)-salbutamol in Rat Brain Following Nasal and Intravenous Administration Using DESI-MS

Recent studies have shown that β2-Adrenoreceptor is a regulator of the a-synuclein gene driving risk of Parkinson’s disease. The β2-AR agonist (R)-salbutamol, eutomer of rac-salbutamol, may hold therapeutic potential for Parkinson’s disease (PD) following nasal administration. In this study, we use desorption electrospray ionization mass spectrometry (DESI-MS) to analyze spatial distribution of (R)-salbutamol in rat brain following nasal and intravenous administration. Here, we report that (R)-salbutamol efficiently deliver to the brain and had more drug dosage exposure in rat’s brain through nasal route administration than that of intravenous route administration. In conclusion, administering (R)-salbutamol through nasal route of administration may hold advantages in improving spatial distribution and increased exposure of drug in brain.

Identification of the major metabolites of (R)-salbutamol in human urine, plasma and feces using ultra high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

(R)-Salbutamol is a selective β2-adrenoreceptor agonist, which produces a short-acting bronchodilator effect and is widely used for the treatment of respiratory diseases in humans. Drug metabolism and identification of the metabolites play an essential role in the evaluation of the overall efficacy and safety of the drugs in clinical practices. There are few reports on the identification of major metabolites of (R)-salbutamol in humans, and the number of identified metabolites is very limited. In this research, a method of ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was developed for the discovery and identification of (R)-salbutamol and its major metabolites in human biological samples. Totally, twelve metabolites of (R)-salbutamol were found and identified and all the metabolites could be found in urine, one metabolite in plasma and two metabolites in feces. Among all the metabolites, eight metabolites have never been reported before. The results indicated that (R)-salbutamol was mainly metabolized through isomerization, oxidation, reduction, glucuronidation, and sulfation pathways in vivo. The possible metabolic pathways of (R)-salbutamol were subsequently presented in this study, which contribute to a better understanding of the metabolism of (R)-salbutamol in humans.

Source discrimination of drug residues in wastewater: The case of salbutamol

Analytical methods used for pharmaceuticals and drugs of abuse in sewage play a fundamental role in wastewater-based epidemiology (WBE) studies. Here quantitative analysis of drug metabolites in raw wastewaters is used to determine consumption from general population. Its great advantage in public health studies is that it gives objective, real-time data about community use of chemicals, highlighting the relationship between environmental and human health. Within a WBE study on salbutamol use in a large population, we developed a procedure to distinguish human metabolic excretion from external source of contamination, possibly industrial, in wastewaters. Salbutamol is mainly excreted as the sulphate metabolite, which is rapidly hydrolyzed to the parent compound in the environment, so this is currently not detected. When a molecule is either excreted un-metabolized or its metabolites are unstable in the environment, studies can be completed by monitoring the parent compound. In this case it is mandatory to assess whether the drug in wastewater is present because of population use or because of a specific source of contamination, such as industrial manufacturing waste. Because commercial salbutamol mainly occurs as a racemic mixture and is stereoselective in the human metabolism, the enantiomeric relative fraction (EFrel) in wastewater samples should reflect excretion, being unbalanced towards one of two enantiomers, if the drug is of metabolic origin. The procedure described involves chiral analysis of the salbutamol enantiomers by liquid chromatography-tandem mass spectrometry (LC-MS-MS) and calculation of EFrel, to detect samples where external contamination occurs. Samples were collected daily between October and December 2013 from the Milano Nosedo wastewater treatment plant. Carbamazepine and atenolol were measured in the sewage collector, as "control" drugs. Salbutamol EFrel was highly consistent in all samples during this three-month period, but a limited number of samples had unexpectedly high concentrations where the EFrel was close to that observed of the un-metabolized, commercially available drug, supporting the idea of an external source of contamination, besides human metabolic excretion. Results showed that, when present, non-metabolic daily loads could be evaluated indicating an average of 4.12g/day of salbutamol extra load due to non-metabolic sources. The stereoselectivity in metabolism and enantiomeric ratio analysis appears to be a useful approach in WBE studies to identify different sources of drugs in the environment, when no metabolic products are present at useful analytical levels.

Annual banned-substance review: analytical approaches in human sports drug testing

The aim of improving anti-doping efforts is predicated on several different pillars, including, amongst others, optimized analytical methods. These commonly result from exploiting most recent developments in analytical instrumentation as well as research data on elite athletes' physiology in general, and pharmacology, metabolism, elimination, and downstream effects of prohibited substances and methods of doping, in particular. The need for frequent and adequate adaptations of sports drug testing procedures has been incessant, largely due to the uninterrupted emergence of new chemical entities but also due to the apparent use of established or even obsolete drugs for reasons other than therapeutic means, such as assumed beneficial effects on endurance, strength, and regeneration capacities. Continuing the series of annual banned-substance reviews, literature concerning human sports drug testing published between October 2014 and September 2015 is summarized and reviewed in reference to the content of the 2015 Prohibited List as issued by the World Anti-Doping Agency (WADA), with particular emphasis on analytical approaches and their contribution to enhanced doping controls.