Simultaneous analysis of 11 medications for drug resistant TB in small hair samples to quantify adherence and exposure using a validated LC-MS/MS panel

Push forward LC-MS-based therapeutic drug monitoring and pharmacometabolomics for anti-tuberculosis precision dosing and comprehensive clinical management

The spread of tuberculosis (TB), especially multidrug-resistant TB and extensively drug-resistant TB, has strongly motivated the research and development of new anti-TB drugs. New strategies to facilitate drug combinations, including pharmacokinetics-guided dose optimization and toxicology studies of first- and second-line anti-TB drugs have also been introduced and recommended. Liquid chromatography-mass spectrometry (LC-MS) has arguably become the gold standard in the analysis of both endo- and exo-genous compounds. This technique has been applied successfully not only for therapeutic drug monitoring (TDM) but also for pharmacometabolomics analysis. TDM improves the effectiveness of treatment, reduces adverse drug reactions, and the likelihood of drug resistance development in TB patients by determining dosage regimens that produce concentrations within the therapeutic target window. Based on TDM, the dose would be optimized individually to achieve favorable outcomes. Pharmacometabolomics is essential in generating and validating hypotheses regarding the metabolism of anti-TB drugs, aiding in the discovery of potential biomarkers for TB diagnostics, treatment monitoring, and outcome evaluation. This article highlighted the current progresses in TDM of anti-TB drugs based on LC-MS bioassay in the last two decades. Besides, we discussed the advantages and disadvantages of this technique in practical use. The pressing need for non-invasive sampling approaches and stability studies of anti-TB drugs was highlighted. Lastly, we provided perspectives on the prospects of combining LC-MS-based TDM and pharmacometabolomics with other advanced strategies (pharmacometrics, drug and vaccine developments, machine learning/artificial intelligence, among others) to encapsulate in an all-inclusive approach to improve treatment outcomes of TB patients.

Measurement Tools and Utility of Hair Analysis for Screening Adherence to Antihypertensive Medication

Poor adherence to the prescribed antihypertensive therapy is an understated public health problem and is one of the main causes of the high prevalence of uncontrolled hypertension in sub-Saharan Africa. Medication adherence is vital for the effectiveness of antihypertensive treatment and is key to ameliorating the clinical outcomes in hypertensive patients. However, it has often been ignored because the current methods used to assess medication adherence are not reliable, limiting their utilization in clinical practice. Therefore, the identification of the most accurate and clinically feasible method for measuring medication adherence is critical for tailoring effective strategies to improve medication adherence and consequently achieve blood pressure goals. This review not only explores various available methods for estimating medication adherence but also proposes therapeutic drug monitoring in hair for the measurement of medication adherence to the antihypertensive medication period.

Alternative Methods for Therapeutic Drug Monitoring and Dose Adjustment of Tuberculosis Treatment in Clinical Settings: A Systematic Review

BACKGROUND AND OBJECTIVE

Quantifying exposure to drugs for personalized dose adjustment is of critical importance in patients with tuberculosis who may be at risk of treatment failure or toxicity due to individual variability in pharmacokinetics. Traditionally, serum or plasma samples have been used for drug monitoring, which only poses collection and logistical challenges in high-tuberculosis burden/low-resourced areas. Less invasive and lower cost tests using alternative biomatrices other than serum or plasma may improve the feasibility of therapeutic drug monitoring.

METHODS

A systematic review was conducted to include studies reporting anti-tuberculosis drug concentration measurements in dried blood spots, urine, saliva, and hair. Reports were screened to include study design, population, analytical methods, relevant pharmacokinetic parameters, and risk of bias.

RESULTS

A total of 75 reports encompassing all four biomatrices were included. Dried blood spots reduced the sample volume requirement and cut shipping costs whereas simpler laboratory methods to test the presence of drug in urine can allow point-of-care testing in high-burden settings. Minimal pre-processing requirements with saliva samples may further increase acceptability for laboratory staff. Multi-analyte panels have been tested in hair with the capacity to test a wide range of drugs and some of their metabolites.

CONCLUSIONS

Reported data were mostly from small-scale studies and alternative biomatrices need to be qualified in large and diverse populations for the demonstration of feasibility in operational settings. High-quality interventional studies will improve the uptake of alternative biomatrices in guidelines and accelerate implementation in programmatic tuberculosis treatment.

Chromatographic Methods for the Determination of Rifampicin, Isoniazid, Pyrazinamide, Ethambutol, and Main Metabolites in Biological Samples: A Review

Bioanalytical methods are used to quantify drugs and their metabolites in biological samples in order to determine bioequivalence, perform pharmacokinetic and bioavailability studies, and complete therapeutic drug monitoring. The objective of this review paper is to describe bioanalytical methods based on Liquid Chromatography that are used to quantify antitubercular drugs and their metabolites in different biological samples, utilizing scientific literature from 1992 to 2021.

Diagnostic accuracy of a liquid chromatography-tandem mass spectrometry assay in small hair samples for rifampin-resistant tuberculosis drug concentrations in a routine care setting

Background

Treatment monitoring of drug-resistant tuberculosis (DR-TB) in resource-limited settings is challenging. We developed a multi-analyte assay for eleven anti-TB drugs in small hair samples as an objective metric of drug exposure.

Methods

Small hair samples were collected from participants at various timepoints during directly observed RR-TB treatment at an inpatient tertiary referral facility in South Africa (DR-TB cohort). We assessed qualitative determination (i.e., detection above limit of detection) of bedaquiline, linezolid, clofazimine, pretomanid, levofloxacin, moxifloxacin, pyrazinamide, isoniazid, ethambutol, ethionamide, and prothionamide in an LC-MS/MS index panel assay against a reference standard of inpatient treatment records. Because treatment regimens prior to hospitalization were not available, we also analyzed specificity (for all drugs except isoniazid) using an external cohort of HIV-positive patients treated for latent TB infection with daily isoniazid (HIV/LTBI cohort) in Uganda.

Results

Among the 57 DR-TB patients (58% with pre-XDR/XDR-TB; 70% HIV-positive) contributing analyzable hair samples, the sensitivity of the investigational assay was 94% or higher for all drugs except ethionamide (58.5, 95% confidence interval [CI], 40.7–99.9). Assay specificity was low across all tested analytes within the DR-TB cohort; conversely, assay specificity was 100% for all drugs in the HIV/LTBI cohort.

Conclusions

Hair drug concentrations reflect long-term exposure, and multiple successive regimens commonly employed in DR-TB treatment may result in apparent false-positive qualitative and falsely elevated quantitative hair drug levels when prior treatment histories within the hair growth window are not known.

Development and validation of a liquid chromatography-tandem mass spectrometry method for quantifying delamanid and its metabolite in small hair samples

New all-oral regimens for rifampin-resistant tuberculosis (RR-TB) are being scaled up globally. Measurement of drug concentrations in hair assesses long-term drug exposure. Delamanid (DLM) is likely to be a key component of future RR-TB treatment regimens, but a method to describe its quantification in hair via liquid chromatography-tandem mass spectrometry (LC-MS/MS) has not previously been described. We developed and validated a simple, fast, sensitive, and accurate LC-MS/MS method for quantifying DLM and its metabolite DM-6705 in small hair samples. We pulverized and extracted two milligrams of hair in methanol at 37 °C for two hours, and diluted 1:1 with water. A gradient elution method eluted DLM, DM-6705, and the internal standard OPC 14714 within 3 min, bringing overall analysis time to 5.5 min. The method has limits of detection (LOD) of 0.0003 ng/mg for DLM and 0.003 ng/mg for DM-6705. The established linear dynamic ranges are 0.003-2.1 ng/mg and 0.03-21 ng/mg for DLM and DM-6705, respectively. Eleven of 12 participant hair samples had concentrations within DLM's linear dynamic range, while all 12 samples had concentrations within the quantifiable range for DM-6705. The ranges of concentrations observed in these clinical samples for DLM and DM-6705 were 0.004-0.264 ng/mg hair and 0.412-12.041 ng/mg hair respectively. We demonstrate that while DLM was detected in hair at very low levels, its primary metabolite DM-6705 had levels approximately 100 times higher. Measuring DM-6705 in hair may accurately reflect long-term adherence to DLM-containing regimens for drug-resistant TB.

Validation of a universal and highly sensitive two-dimensional liquid chromatography-tandem mass spectrometry methodology for the quantification of pyrazinamide, ethambutol, protionamide, and clofazimine in different biological matrices

A novel and potent anti-tuberculosis drug combination pyrazinamide (PZA), ethambutol (EMB), protionamide (PTO), and clofazimine (CFZ) that rapidly kills Mycobacterium tuberculosis (Mtb) in the lungs has been identified using the artificial-intelligence-enabled parabolic response surface approach. A universal and highly sensitive two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS) method for the simultaneous determination of PZA, EMB, PTO, and CFZ in various biological samples in different states (liquid samples: plasma, bile, and urine; solid samples: tissue and feces) using simple pretreatment was established and validated. For the first dimension of this column-switching arrangement, the automated purification and enrichment of the drugs were achieved on a Polar-RP column. The subsequent analytical separation was performed on an Agilent Zorbax SB-Aq column, and the total loop time was 7.5 min. The positive-ionization mode with multiple reaction monitoring was used for detection. The sensitivity was good with no carry-over detected, and the lower limit of quantification ranged from 100 to 500 pg/mL. This quantification method was fully validated and proved to be robust in accordance with US Food and Drug Administration guidelines. High recoveries (85.3-111.4%) and accuracies (92.1-109.3%), together with high precision values (0.5-13.8%), were verified in all matrices. All standard curves showed favorable linearities with r2 > 0.995. This validated method was applied to study plasma pharmacokinetics, tissue distribution, and excretion in Sprague-Dawley rats after oral administration of the drug combination.