A fast and simple method for the simultaneous analysis of midazolam, 1-hydroxymidazolam, 4-hydroxymidazolam and 1-hydroxymidazolam glucuronide in human serum, plasma and urine

Metabolic Stability and Metabolite Identification of CYP450 Probe Substrates in Ferret Hepatocytes

BACKGROUND

Ferrets exhibit similar lung physiology to humans and display similar clinical signs following influenza infection, making them a valuable model for studying high susceptibility and infection patterns. However, the metabolic fate of several common human CYP450 probe substrates in ferrets is still unknown and has not been studied.

OBJECTIVE

The purpose of this study was to investigate the metabolism of nine human CYP450 probe substrates in ferret hepatocytes and explore their metabolic rate differences between ferrets and other species.

METHOD

Nine substrates were individually incubated in ferret hepatocytes for up to 120 min. At each time point, 30 μL mixtures were extracted for stability analysis using LC-MS/MS methods. After a 120-minute incubation period, 400 μL of the mixtures were extracted for metabolite identification using UHPLC-QExactive Plus.

RESULTS

The metabolic clearance was determined as follows: testosterone > phenacetin > bupropion > omeprazole > midazolam > dextromethorphan > chlorzoxazone > taxol > diclofenac. Seven metabolites were identified from phenacetin. Deethylation was found to be the major pathway, and the major metabolite was matched with acetaminophen as probed with the CYP1A2 enzyme. Six metabolites were identified from diclofenac. Glucuronidation was the primary pathway, and a metabolite was found to match 4-OH-diclofenac as probed with the CYP2C9 enzyme. Twenty-two metabolites were identified from omeprazole. The major metabolic pathways included mono-oxygenation and sulfoxide to thioether conversion. No metabolite was found to match with 5-OH-omeprazole as probed with the CYP2C19 enzyme. Twenty-two metabolites were identified from dextromethorphan. Demethylation was found to be the major metabolic pathway, and one demethylation metabolite was matched with dextrorphan as probed with the CYP2D6 enzyme. Fourteen metabolites were identified from midazolam. Mono-oxygenation was found to be the primary metabolic pathway, and one of the mono-oxygenation metabolites was matched with 1-OH-midazolam as probed with the CYP3A4 enzyme. Eight metabolites were identified from testosterone. Mono-oxygenation and glucuronidation were identified as the major metabolic pathways. One mono-oxygenation was matched with 6-.-testosterone as probed with the CYP3A4 enzyme. Six metabolites were identified from taxol. Hydrolysis and mono-oxygenation were the top two metabolic pathways. No metabolite was matched with 6-.-OH-taxol as probed with the CYP2C8 enzyme. Ten metabolites were identified from bupropion. Mono-oxygenation and hydrogenation were identified as the top two metabolic pathways. No mono-oxygenation metabolite was matched with hydroxy-bupropion as probed with the CYP2B6 enzyme. Nine metabolites were identified from chlorzoxazone. Monooxygenation and sulfation were the top two metabolic pathways. One mono-oxygenation metabolite was matched with 6-OH-chlorzoxazone as probed with the CYP2E1 enzyme.

CONCLUSION

Nine human CYP probe substrates were clearly metabolized in ferret hepatocytes, demonstrating substrate-dependent metabolic rates in ferret hepatocytes and species-dependent metabolic rates in mouse, rat, dog, monkey, and human hepatocytes. Except for 6-a-5-OH-omeprazole, 6-.-OH-taxol, and hydroxy-bupropion, specific metabolites of other six probe substrates in ferret hepatocytes were detected and identified as probed with six human CYP enzymes, respectively.

Physiologically Based Pharmacokinetic Modeling to Predict the Impact of Liver Cirrhosis on Glucuronidation via UGT1A4 and UGT2B7/2B4-A Case Study with Midazolam

Hepatic impairment, due to liver cirrhosis, decreases the activity of cytochrome P450 enzymes (CYPs). The use of physiologically based pharmacokinetic (PBPK) modeling to predict this effect for CYP substrates has been well-established, but the effect of cirrhosis on uridine-glucuronosyltransferase (UGT) activities is less studied and few PBPK models have been reported. UGT enzymes are involved in primary N-glucuronidation of midazolam and glucuronidation of 1'-OH-midazolam following CYP3A hydroxylation. In this study, Simcyp was used to establish PBPK models for midazolam, its primary metabolites midazolam-N-glucuronide (UGT1A4) and 1'-OH midazolam (CYP3A4/3A5), and the secondary metabolite 1'-OH-midazolam-O-glucuronide (UGT2B7/2B4), allowing to simulate the impact of liver cirrhosis on the primary and secondary glucuronidation of midazolam. The model was verified in noncirrhotic subjects before extrapolation to cirrhotic patients of Child-Pugh (CP) classes A, B, and C. Our model successfully predicted the exposures of midazolam and its metabolites in noncirrhotic and cirrhotic patients, with 86% of observed plasma concentrations within 5th-95th percentiles of predictions and observed geometrical mean of area under the plasma concentration curve between 0 hours to infinity and maximal plasma concentration within 0.7- to 1.43-fold of predictions. The simulated metabolic ratio defined as the ratio of the glucuronide metabolite AUC over the parent compound AUC (AUCglucuronide/AUCparent, metabolic ratio [MR]), was calculated for midazolam-N-glucuronide to midazolam (indicative of UGT1A4 activity) and decreased by 40% (CP A), 48% (CP B), and 75% (CP C). For 1'-OH-midazolam-O-glucuronide to 1'-OH-midazolam, the MR (indicative of UGT2B7/2B4 activity) dropped by 35% (CP A), 51% (CP B), and 64% (CP C). These predicted MRs were corroborated by the observed data. This work thus increases confidence in Simcyp predictions of the effect of liver cirrhosis on the pharmacokinetics of UGT1A4 and UGT2B7/UGT2B4 substrates. SIGNIFICANCE STATEMENT: This article presents a physiologically based pharmacokinetic model for midazolam and its metabolites and verifies the accurate simulation of pharmacokinetic profiles when using the Simcyp hepatic impairment population models. Exposure changes of midazolam-N-glucuronide and 1'-OH-midazolam-O-glucuronide reflect the impact of decreases in UGT1A4 and UGT2B7/2B4 glucuronidation activity in cirrhotic patients. The approach used in this study may be extended to verify the modeling of other uridine glucuronosyltransferase enzymes affected by liver cirrhosis.

A review of analytical parameters in 'rapid' liquid chromatographic methods for bioanalysis: Can we do better?

Rapid bioanalysis is beneficial to many applications. However, how 'rapid' a method is, or could be, is often an unanswered question. In this statistical review, the authors have assessed multiple pre-analytical (i.e. sample preparation), and analytical method parameters specifically for liquid chromatography to assist researchers in developing and validating 'rapid' bioanalytical methods. We restricted the search to urine and plasma matrices only. Data were extracted from over 2,000 recent studies and evaluated to assess how these parameters affected the 'on-instrument' analysis time. In addition to methods using ultra-violet (UV) detection, there were a large number of mass spectrometric (MS) methods, allowing additional review of the differences between high- and low-resolution MS on analysis time. We observed that most (N = 922, 70 %) methods used 5 or 10 cm columns, and that whilst uptake of ultra-high performance (U)HPLC columns was good, the use of sub-5 cm columns and/or flow rates in excess of 1 mL/min was incredibly rare (N = 25, 3 %). The detector of choice for quantitative (U)HPLC-MS remains the triple quadrupole, although a number of groups report the use of high-resolution MS for such methods.

Quantification of sedative-hypnotics in human urine and plasma via polystyrene-based solid phase extraction-LC-MS/MS analysis

Owing to the adverse effects of the overuse of common sedative-hypnotics on human health, the development of an efficient analytical method for the detection of drugs in clinical emergencies and forensic science is significant. Although conventional analytical methods, such as immunoassay, liquid chromatography (LC), gas chromatography, and mass spectrometry (MS) are reliable, they exhibit drawbacks such low-throughput screening and high costs. Thus, in this study, we developed a novel high-throughput method consisting of a polystyrene-based solid phase extraction (SPE) and an LC with tandem MS analysis for the detection of drugs in biological samples and investigated its precision and reliability via the detection of twelve sedative-hypnotics in human urine and plasma samples. Good linear relationship (r ≥ 0.99) were achieved within the concentration range of 0.1-20 ng/mL for the 12 analytes in urine samples. Whereas, in the plasma samples, the correlation coefficient was greater than 0.99 in the concentration range 1-100 ng/mL for lorazepam and clonazepam and in the range 0.5-100 ng/mL for the remaining analytes. The intra- and inter-day precision, autosampler and freeze-thaw stabilities, and lower limit of quantitation (LLOQ) for all twelve analytes in the urine and plasma samples were favorable. Furthermore, sedative-hypnotics were detected in clinical samples obtained from the Hebei General Hospital using this method. These results indicated that the analytical method proposed in this study can be effectively applied in toxicology screening and drug abuse monitoring.The method developed in this study could be applied in clinical and forensic toxicology laboratories for sedative-hypnotic drug screening, providing support for drug abuse monitoring and clinical diagnosis.

Time-course relationship between cerebrospinal fluid and serum concentrations of midazolam and albumin in patients with cardiac arrest undergoing targeted temperature management

AIM

To understand the serum and cerebrospinal fluid (CSF) distribution of midazolam is important for proper timing of neurological prognostication of targeted temperature management(TTM) patients. Midazolam binds extensively to albumin in serum although non protein bound form exist in CSF. We investigated the time-course of CSF, serum concentrations of midazolam and albumin in patients with cardiac arrest who underwent TTM.

METHODS

This prospective, single-center, observational study was conducted between May 2020 and April 2022. Midazolam and albumin concentrations in CSF and serum were quantified 0, 24, 48, and 72 h after the return of spontaneous circulation for comparison between the good (Cerebral Performance Category (CPC) 1 and 2) and poor (CPC 3, 4, and 5) neurologic outcome groups. The CSF/serum (C/S) ratios of midazolam and albumin concentrations were determined, along with their correlation coefficients.

RESULTS

Of the 19 enrolled patients, 13 experienced poor outcomes. At 0 h, serum midazolam concentrations were the lowest, whereas serum albumin levels were the highest; in the CSF, the concentrations of both peaked at 24 h. There were no significant inter-group differences in midazolam concentrations in CSF or serum. The C/S ratios of midazolam and albumin significantly differed between the groups. Moderate to strong positive correlations were observed between the midazolam and albumin C/S ratios.

CONCLUSION

In CSF, midazolam and albumin concentrations peaked 24 h post-cardiac arrest. Midazolam and albumin C/S ratios were significantly higher in the poor outcome group and positively correlated with each other, suggesting blood-brain barrier disruption 24 h post-cardiac arrest.

Two DFSA cases involving midazolam clarified by the micro-segmental hair analyses

PURPOSE

In this study, an analytical procedure to identify trace amounts of drug in hair based on micro-segmental hair analysis was presented. The method also can be used to estimate the time of drug ingestion at daily precision by cutting a single hair into sub-millimeter segments which correspond to daily hair growth.

METHODS

A method was established for efficient extraction of midazolam, one of the most frequently detected compound in drug-facilitated sexual assault (DFSA) cases, from each 0.4-mm hair segment and validated by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Moreover, two DFSA cases were used to compare the micro-segmental hair analysis with the 1- cm segmental analysis method.

RESULTS

The validation showed a lower limit of quantification of 0.5 pg/mm for midazolam, with intraday and interday accuracies (bias) from  - 5.2 to 0.9%. The micro-segmental hair analysis method was applied to proximal 1-cm hair segment including hair bulbs in two DFSA cases. The micro-segmental hair analysis results in case 1 showed midazolam in the S15-S17 (5.6-6.8 mm from hair bulb) in a concentration range from 0.5 to 0.9 pg/mm, and the concentrations of midazolam in all hair micro-segments (0-1 cm from the scalp) in case 2 were from 0.5 to 2.0 pg/mm.

CONCLUSIONS

Comparison with the conventional method revealed that micro-segmental hair analysis may enhance the utility of hair drug testing and strengthen probative force in DFSA cases.

Extending the viability of human precision-cut intestinal slice model for drug metabolism studies

Human Precision-cut intestinal slices (hPCIS) are used to study intestinal physiology, pathophysiology, drug efficacy, toxicology, kinetics, and metabolism. However, the use of this ex vivo model is restricted to approximately a 24 h timeframe because of declining viability of the hPCIS during traditional culture. We hypothesized that we could extend the hPCIS viability by using organoid medium. Therefore, we cultured hPCIS for up to 72 h in organoid media [expansion medium (Emed) and differentiation medium (Dmed)]. After incubation, we assessed culture-induced changes on viability markers, specific cell type markers and we assessed the metabolic activity of enterocytes by measuring midazolam metabolite formation. We show that the adenosine triphosphate (ATP)/protein ratio of Emed-cultured hPCIS and morphology of both Emed- and Dmed-cultured hPCIS was improved compared to WME-cultured hPCIS. Emed-cultured hPCIS showed an increased expression of proliferation and stem cell markers, whereas Dmed-cultured hPCIS showed an increased expression of proliferation and enterocyte markers, along with increased midazolam metabolism. Using the Emed, the viability of hPCIS could be extended for up to 72 h, and proliferating stem cells remained preserved. Using Dmed, hPCS also remained viable for up to 72 h, and specifically rescued the metabolizing enterocytes during culture. In conclusion, by using two different organoid culture media, we could extend the hPCIS viability for up to 72 h of incubation and specifically steer stem cells or enterocytes towards their original function, metabolism, and proliferation, potentially allowing pharmacokinetic and toxicology studies beyond the 24 h timeframe.