A high-throughput LC-MS/MS method for simultaneous determination of isoniazid, ethambutol and pyrazinamide in human plasma

RATIONALE

Tuberculosis (TB) remains a challenging global infectious disease, mainly affecting the lungs. First-line anti-TB drugs play a crucial role in slowing down the rapid spread of TB. In addition, the patient might benefit from therapeutic drug monitoring since it has become an accepted clinical tool for optimizing TB treatment.

METHODS

A simple and sensitive liquid chromatography/tandem mass spectrometry method was developed to monitor the plasma level of isoniazid, ethambutol and pyrazinamide in plasma samples. A one-step extraction procedure using an Ostro™ plate was applied, and extracts were analyzed by gradient elution followed by detection on a mass spectrometer by multiple reaction monitoring mode.

RESULTS

The analytes were separated within 4.2 min and over the concentration range of 0.2-10 μg/ml for isoniazid and ethambutol and 1-65 μg/ml for pyrazinamide. The method was successfully validated according to the European Medicine Agency guideline for the selectivity, linearity and lower limit of detection, precision and accuracy, matrix effect, extraction recovery, carryover, dilution integrity and stability, and applied for quantification of analytes in clinical samples from TB patients.

CONCLUSIONS

The presented method allows sensitive and reproducible determination of selected anti-TB drugs with advantages such as low sample volume requirement, short run time of analysis, one-step sample preparation procedure with capabilities for phospholipids removal, and a low quantification limit as well as a high degree of selectivity.

When we are worried, what are we thinking? Anxiety, lack of control, and conspiracy beliefs amidst the COVID-19 pandemic

Societal crises and stressful events are associated with an upsurge of conspiracy beliefs that may help people to tackle feelings of lack of control. In our study (N = 783), we examined whether people with higher feelings of anxiety and lack of control early in the COVID-19 pandemic endorse more conspiracy theories. Our results show that a higher perception of risk of COVID-19 and lower trust in institutions' response to the pandemic were related to feelings of anxiety and lack of control. Feeling the lack of control, but not anxiety, independently predicted COVID-19 conspiracy theory endorsement. Importantly, COVID-19 conspiracy beliefs were strongly correlated with generic conspiracy and pseudoscientific beliefs, which were likewise associated with the feeling of lack of control and lower trust in institutions. The results highlight that considering people's emotional responses to the COVID-19 pandemic is crucial for our understanding of the spread of conspiracy and pseudoscientific beliefs.