Simultaneous determination of barbiturates, phenytoin and topiramate in hair by LC-MS/MS and application to real samples

High-Throughput Quantitative LC-MS/MS Analysis of Barbiturates in Human Urine

We hereby present a fast, high-throughput, and clinical LC-MS/MS assay for the simultaneous analysis of barbiturates in human urine. It is deployed as a quantitative assay for phenobarbital, butalbital, pentobarbital/amobarbital, and secobarbital, as well as for confirmations following positive immunoassay drug screens in patient urine. Briefly, urine specimens are processed via dilute and shoot, i.e., by mixing the sample with 20 times volume of internal standard reagent and injecting 50 μL of that mixture into the analytical instrument. Chromatographic separation is performed using a reversed-phase C18 column in a mobile-phase system doped with <1 mM ammonium fluoride. Mass spectrometric detection occurs via negative-mode electrospray ionization multiple reaction monitoring in the TSQ Quantiva triple-quadrupole instrument. All the analytes in the mixture are detected and quantified simultaneously with respect to internal calibration in the range 20-2500 ng/mL. However, the assay cannot distinguish pentobarbital from amobarbital, which are isobaric analytes. Nonetheless, the assay is sensitive, robust, and amenable to harmonization with other assays that employ barbiturate cutoffs in the range of 20-150 ng/mL.

Comprehensive evaluation of drug cases in Seoul and its metropolitan areas - 2022

In order to prepare a response strategy for future drug analyses, the number and results of drug cases handled by the Seoul Institute of National Forensic Service were comprehensively evaluated, with a focus on Seoul and its metropolitan areas. In 2022, the Seoul Institute received approximately 12,150 requests for drug testing related to drug abuse and possession, and the urine samples were tested for approximately 16,000 drug species. The most frequently requested test was for cannabis (Δ-9-THC and Δ-8-THC), followed by methamphetamine, MDMA, ketamine, and synthetic cannabinoids. ADB-5'Br-BUTINACA and propyl butylone were newly emerging substances in 2022. These results were consistent with the main drug detection findings of the confiscated materials. During this period, 24 cases of drug-related deaths were reported, of which 6 were suspected to be the result of acute overdose poisoning caused by methamphetamine, MDMA, fentanyl, and heroin. In addition to the controlled substances regulated by the Narcotics Control Act, new psychoactive substances are being found to be circulating, and various measures are required to address this issue. This study is expected to improve future drug analyses methods and assist in establishing drug policies, and responding to future investigations.

Rapid quantification of phenobarbital and barbital in human whole blood by liquid-liquid extraction combined with DART-orbitrap-HRMS

PURPOSE

This study aims to develop and validate a rapid, simple, and efficient bioanalytical method for the simultaneous quantification of phenobarbital and barbital in human whole blood using liquid-liquid extraction combined with direct analysis in real time (DART) and high-resolution mass spectrometry (HRMS).

METHOD

Phenobarbital-d5 and aprobarbital were selected as internal standards (ISs) of phenobarbital and barbital, respectively. A mixed solvent of o-xylene and ethyl acetate at a ratio of 1:6 was used to extract analytes of interest and ISs from 100 μL of human whole blood samples. Phenobarbital and barbital were detected by DART-HRMS. The proposed method has been validated in accordance with United States Food and Drug Administration Guidelines for Bioanalytical Method Validation in terms of selectivity, linearity, accuracy, precision, matrix effect, recovery, stability, and dilution integrity.

RESULTS

The lower limits of quantification (LLOQs) of phenobarbital and barbital were both 10 ng/mL. The linearities were in the range of 10-1000 ng/mL (R² ≥ 0.99). The mean recovery values of phenobarbital and barbital were 99.7% and 88.1%, respectively. The interday and intraday precision values were less than 10.4%, and the interday and intraday accuracy values ranged from 87.6 to 106.7%. Furthermore, the validated method was applied to four cases of phenobarbital poisoning at the Shanghai Institute of Forensic Science.

CONCLUSION

The developed and fully validated method enabled the simultaneous quantification of phenobarbital and barbital in human whole blood and was successfully applied to authentic cases.

A Greener Stability-Indicating High-Performance Thin-Layer Chromatography Approach for the Estimation of Topiramate

Despite various reported analytical methods for topiramate (TPM) analysis, greener analytical approaches are scarce in literature. As a consequence, the objective of the current research is to design a normal-phase stability-indicating high-performance thin-layer chromatography (SI-HPTLC) methodology for TPM analysis in marketed tablet dosage forms that is rapid, sensitive, and greener. TPM was derivatized densitometrically and analyzed at 423 nm in visible mode with anisaldehyde-sulfuric acid as the derivatizing agent. The greener SI-HPTLC technique was linear in the 30–1200 ng band⁻¹ range. In addition, the suggested SI-HPTLC methodology for TPM analysis was simple, rapid, cheaper, precise, robust, sensitive, and environmentally friendly. The greener SI-HPTLC method was able to detect TPM along with its degradation products under acid, base, and oxidative degradation conditions. However, no TPM degradation was recorded under thermal and photolytic stress conditions. TPM contents in commercial tablet dosage forms were recorded as 99.14%. Using 12 different principles of green analytical chemistry, the overall analytical GREEnness (AGREE) score for the greener SI-HPTLC method was calculated to be 0.76, confirming the proposed normal-phase SI-HPTLC method’s good greener nature. Overall, these results demonstrated that the suggested SI-HPTLC technique for TPM measurement in pharmaceutical products was reliable and selective.