Development and validation of a simple LC-MS/MS method for simultaneous determination of moxifloxacin, levofloxacin, prothionamide, pyrazinamide and ethambutol in human plasma

Preanalytical Stability of 13 Antibiotics in Biological Samples: A Crucial Factor for Therapeutic Drug Monitoring

The stability of antibiotic preanalytical samples is a critical factor in therapeutic drug monitoring (TDM), a practice of undoubted importance for the proper therapeutic use of antibiotics, especially in complex management patients, such as pediatrics. This review aims to analyze the data in the literature regarding the preanalytical stability of some of the antibiotics for which TDM is most frequently requested. The literature regarding the preanalytical stability of amikacin, ampicillin, cefepime, ceftazidime, ciprofloxacin, daptomycin, gentamicin, levofloxacin, linezolid, meropenem, piperacillin, teicoplanin, and vancomycin in plasma, serum, whole blood, and dried blood/plasma spot samples was analyzed. Various storage temperatures (room temperature, 4 °C, -20 °C, and -80 °C) and various storage times (from 1 h up to 12 months) as well as subjecting to multiple freeze-thaw cycles were considered. The collected data showed that the non-beta-lactam antibiotics analyzed were generally stable under the normal storage conditions used in analytical laboratories. Beta-lactam antibiotics have more pronounced instability, particularly meropenem, piperacillin, cefepime, and ceftazidime. For this class of antibiotics, we suggest that storage at room temperature should be limited to a maximum of 4 h, storage at 2-8 °C should be limited to a maximum of 24 h, and storage at -20 °C should be limited to a maximum of 7 days; while, for longer storage, freezing at -80 °C is suggested.

Second-line antituberculosis drug exposure thresholds predictive of adverse events in multidrug-resistant tuberculosis treatment

OBJECTIVES

This study aimed to investigate the association between drug exposure and adverse events (AEs) during the standardized multidrug-resistant tuberculosis (MDR-TB) treatment, as well as to identify predictive drug exposure thresholds.

METHODS

We conducted a prospective, observational multicenter study among participants receiving standardized MDR-TB treatment between 2016 and 2019 in China. AEs were monitored throughout the treatment and their relationships to drug exposure (e.g., the area under the drug concentration-time curve from 0 to 24 h, AUC0-24 h) were analyzed. The thresholds of pharmacokinetic predictors of observed AEs were identified by boosted classification and regression tree (CART) and further evaluated by external validation.

RESULTS

Of 197 study participants, 124 (62.9%) had at least one AE, and 15 (7.6%) experienced serious AEs. The association between drug exposure and AEs was observed including bedaquiline, its metabolite M2, moxifloxacin and QTcF prolongation (QTcF >450 ms), linezolid and mitochondrial toxicity, cycloserine and psychiatric AEs. The CART-derived thresholds of AUC0-24 h predictive of the respective AEs were 3.2 mg·h/l (bedaquiline M2); 49.3 mg·h/l (moxifloxacin); 119.3 mg·h/l (linezolid); 718.7 mg·h/l (cycloserine).

CONCLUSIONS

This study demonstrated the drug exposure thresholds predictive of AEs for key drugs against MDR-TB treatment. Using the derived thresholds will provide the knowledge base for further randomized clinical trials of dose adjustment to minimize the risk of AEs.

Drug Exposure and Susceptibility of Pyrazinamide Correlate with Treatment Response in Pyrazinamide-Susceptible Patients with Multidrug-Resistant Tuberculosis

Exploring the influence of pyrazinamide exposure and susceptibility on treatment response is crucial for optimizing the management of multidrug-resistant tuberculosis (MDR-TB). This study aimed to investigate the association between pyrazinamide exposure, susceptibility, and response to MDR-TB treatment, as well as find clinical thresholds for pyrazinamide. A prospective multi-center cohort study of participants with MDR-TB using pyrazinamide was conducted in three TB-designated hospitals in China. Univariate and multivariate analyses were applied to investigate the associations. Classification and Regression Tree (CART) analysis was used to identify clinical thresholds, which were further evaluated by multivariate analysis and receiver operating characteristic (ROC) curves. The study included 143 patients with MDR-TB. The exposure/susceptibility ratio of pyrazinamide was associated with two-month culture conversion (adjusted risk ratio (aRR), 1.1; 95% confidence interval (CI), 1.07-1.20), six-month culture conversion (aRR, 1.1; 95% CI, 1.06-1.16), treatment success (aRR, 1.07; 95% CI, 1.03-1.10), as well as culture conversion time (adjusted hazard ratio (aHR) 1.18; 95% CI,1.14-1.23). The threshold for optimal improvement in sputum culture results at the sixth month of treatment was determined to be a pyrazinamide AUC0-24h/MIC ratio of 7.8. In conclusion, the exposure/susceptibility ratio of pyrazinamide is associated with the treatment response of MDR-TB, which may change in different Group A drug-based regimens.

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.

Development and validation of synchronous spectrofluorimetric method for the simultaneous determination of duvelisib and moxifloxacin: greenness metric assessment and application to a pharmacokinetic study in rats

Duvelisib (DUV) is a potent anticancer drug whereas Moxifloxacin (MOX) is an antimicrobial drug with anti-proliferative potency against cancerous cells, which is empirically administered in cancer treatment. DUV and MOX combination is commonly prescribed to combat infections in patients while they are under chemotherapy treatment. This study describes, for the first time, the development of a simple and green synchronous spectrofluorimetric (SSF) method for the simultaneous estimation of DUV and MOX in plasma. DUV and MOX were quantified at 273 and 362 nm, respectively without interference between each other at Δλof 120 nm. The experimental variables influencing fluorescence intensities were thoroughly investigated and the optimum conditions were established. At pH 3.5, the optimum synchronous fluorescence intensity (SFI) was achieved in water solvent by using sodium acetate buffer solution. Calibration curves for DUV and MOX, correlating the SFI with the corresponding drug concentration, were linear in the range of 50-1000 ng mL-1for both drugs, with good correlation coefficients. The method was extremely sensitive, with limits of detection of 24 and 22 ng mL-1, and limits of quantitation of 40 and 45 ngmL-1for DUV and MOX, respectively. The SSF method was validated according to the Food and Drug Administration (FDA) guidelines for validation of analytical procedures, and the validation parameters were acceptable. The proposed SSF method was applied to the pharmacokinetic and bioavailability studies in rats' plasma after single concurrent oral administration of both drugs. The results of the study revealed that caution should be taken with DUV dose when concurrently administered with MOX. The greenness of SSF method was assessed by three different metric tools namely Analytical Eco-scale, Green Analytical Procedure Index, and Analytical Greenness Calculator. The results confirmed that SSF method is an eco-friendly and green analytical approach. In conclusion, the proposed SSF method is a valuable tool for pharmacokinetic/bioavailability studies and therapeutic drug monitoring of simultaneously administered DUV and MOX.

Standardization and validation of a novel UPLC-MS/MS method to quantify first line anti-tuberculosis drugs in plasma and dried blood spots

Tuberculosis (TB) is a high-burden infectious disease with high prevalence and mortality rates. The first-line anti-TB drugs include isoniazid (INH), rifampicin (RMP), pyrazinamide (PZA), and ethambutol (EMB). At present, the standard method of blood sampling for therapeutic drug monitoring (TDM) analysis is venipuncture. Dried blood spots (DBS) are a minimally invasive method for collecting small quantities of whole blood from fingertips. The aim of the current study was to develop an ultrahigh-performance liquid chromatography technique coupled to tandem mass spectrometry (UPLC-MS/MS) for simultaneous quantification of the first-line anti-TB drugs in human plasma and DBS as a sampling alternative. The separation and detection conditions were optimized to quantify INH, RMP, PZA, and EMB in both matrices in an ACQUITY UPLC H Class system coupled to a XEVO TQD detector. Chromatographic separation was performed through an Acquity HSS T3 column (2.1 × 100 mm, 1.8 μm) with 0.1% formic acid in water and acetonitrile as the mobile phase. The total run time was 7 min for both methods, with retention time in plasma of 0.85, 1.22, 3.16, and 4.04 min and 0.74, 0.87, 0.97, and 4.16 min for EMB, INH, PZA, and RMP in DBS, respectively. The bioanalytical methods developed were proved selective, linear, precise, and accurate (inter- and intra-assay); the matrix effect was demonstrated to be within the established limits. Short- and long-term stability, freeze-thaw cycles for plasma, and short-term stability for DBS were established. A total of 15 patients with 46 ± 17 (mean ± SD) years old were included, and anti-TB drug concentrations were quantified on plasma and DBS as proof of concept. Based on RMP and INH plasma concentrations (Cp), and Bayesian estimation of individual pharmacokinetic parameters, a dose adjustment was necessary for 93% of patients. The slopes of the correlation lines between plasma and DBS concentrations of RMP, EMB, INH, and PZA were 0.5321, 0.8125, 0.5680, and 0.6791, respectively. Finally, significant correlations (p < 0.05) were observed between DBS and plasma concentrations for RMP (r2 = 0.6961), EMB (r2 = 0.4369), INH (r2 = 0.8675) and PZA (r2 = 0.7363). A simple, fast, and reliable UPLC-MS/MS method was developed to quantify first-line anti-TB drugs in plasma and DBS, which provides an easy sampling and storage to be applied as a new strategy for TDM in patients with TB.

Moxifloxacin: Physical-chemical and Microbiological Analytical Methods in the Context of Green Analytical Chemistry

Moxifloxacin (MOX) is a fourth-generation fluoroquinolone used in the form of tablets, infusion solutions and ophthalmic solutions. It does not have a physical-chemical or microbiological analytical method described in an official compendium. However, the literature shows some analysis methods for pharmaceuticals and biological matrices. In this context, the objective is to show the analytical methods present in the literature for the investigation of MOX by physical-chemical and microbiological techniques, as well as discussing them according to the requirements of current pharmaceutical analyses and green analytical chemistry. Among the physical-chemical methods present in the literature for MOX evaluation, 33% are HPLC, 21% are UV-Vis and 17% are capillary electrophoresis. On the other hand, among the microbiological methods, all of them are based on diffusion in agar. There is still scope in the literature to incorporate new and improved analytical methods for MOX evaluation, which adopt the concepts of green and sustainable analytical chemistry, either by using less (or not using) toxic organic solvents, reducing waste generation or even reducing the analysis time according to the intended objectives.

When and How to Use MIC in Clinical Practice?

Bacterial resistance to antibiotics continues to be a global public health problem. The choice of the most effective antibiotic and the use of an adapted dose in the initial phase of the infection are essential to limit the emergence of resistance. This will depend on (i) the isolated bacteria and its resistance profile, (ii) the pharmacodynamic (PD) profile of the antibiotic used and its level of toxicity, (iii) the site of infection, and (iv) the pharmacokinetic (PK) profile of the patient. In order to take account of both parameters to optimize the administered treatment, a minimal inhibitory concentration (MIC) determination associated with therapeutic drug monitoring (TDM) and their combined interpretation are required. The objective of this narrative review is thus to suggest microbiological, pharmacological, and/or clinical situations for which this approach could be useful. Regarding the microbiological aspect, such as the detection of antibiotic resistance and its level, the preservation of broad-spectrum β-lactams is particularly discussed. PK-PD profiles are relevant for difficult-to-reach infections and specific populations such as intensive care patients, cystic fibrosis patients, obese, or elderly patients. Finally, MIC and TDM are tools available to clinicians, who should not hesitate to use them to manage their patients.

Use of Antibiotics in Preterm Newborns

Due to complex maturational and physiological changes that characterize neonates and affect their response to pharmacological treatments, neonatal pharmacology is different from children and adults and deserves particular attention. Although preterms are usually considered part of the neonatal population, they have physiological and pharmacological hallmarks different from full-terms and, therefore, need specific considerations. Antibiotics are widely used among preterms. In fact, during their stay in neonatal intensive care units (NICUs), invasive procedures, including central catheters for parental nutrition and ventilators for respiratory support, are often sources of microbes and require antimicrobial treatments. Unfortunately, the majority of drugs administered to neonates are off-label due to the lack of clinical studies conducted on this special population. In fact, physiological and ethical concerns represent a huge limit in performing pharmacokinetic (PK) studies on these subjects, since they limit the number and volume of blood sampling. Therapeutic drug monitoring (TDM) is a useful tool that allows dose adjustments aiming to fit plasma concentrations within the therapeutic range and to reach specific drug target attainment. In this review of the last ten years’ literature, we performed Pubmed research aiming to summarize the PK aspects for the most used antibiotics in preterms.

Drug exposure and susceptibility of second-line drugs correlate with treatment response in patients with multidrug-resistant tuberculosis: a multi-centre prospective cohort study in China

Background

Understanding the impact of drug exposure and susceptibility on treatment response of multidrug-resistant tuberculosis (MDR-TB) will help to optimise treatment. This study aimed to investigate the association between drug exposure, susceptibility and response to MDR-TB treatment.

Methods

Drug exposure and susceptibility for second-line drugs were measured for patients with MDR-TB. Multivariate analysis was applied to investigate the impact of drug exposure and susceptibility on sputum culture conversion and treatment outcome. Probability of target attainment was evaluated. Random Forest and CART (Classification and Regression Tree) analysis was used to identify key predictors and their clinical targets among patients on World Health Organization-recommended regimens.

Results

Drug exposure and corresponding susceptibility were available for 197 patients with MDR-TB. The probability of target attainment was highly variable, ranging from 0% for ethambutol to 97% for linezolid, while patients with fluoroquinolones above targets had a higher probability of 2-month culture conversion (56.3% versus 28.6%; adjusted OR 2.91, 95% CI 1.42–5.94) and favourable outcome (88.8% versus 68.8%; adjusted OR 2.89, 95% CI 1.16–7.17). Higher exposure values of fluoroquinolones, linezolid and pyrazinamide were associated with earlier sputum culture conversion. CART analysis selected moxifloxacin area under the drug concentration–time curve/minimum inhibitory concentration (AUC_0–24h/MIC) of 231 and linezolid AUC_0–24h/MIC of 287 as best predictors for 6-month culture conversion in patients receiving identical Group A-based regimens. These associations were confirmed in multivariate analysis.

Conclusions

Our findings indicate that target attainment of TB drugs is associated with response to treatment. The CART-derived thresholds may serve as targets for early dose adjustment in a future randomised controlled study to improve MDR-TB treatment outcome.

Drug exposure and susceptibility were proved to be associated with treatment responses during multidrug-resistant tuberculosis treatment, and identified thresholds may serve as targets for dose adjustment in future clinical studies to improve treatment efficacyhttps://bit.ly/3pZQbFU

Eco-friendly fluorimetric approaches for the simultaneous estimation of the co-administered ternary mixture: etoposide, moxifloxacin and nalbuphine

Antineoplastic drugs, etoposide (ETO), are widely used in leukaemia. A patient with leukaemia has a relative infection with pneumonia treated by fluoroquinolones as moxifloxacin HCL (MOX). Because opioid analgesic as nalbuphine HCL (NAL) does not have a ceiling dose, it is used to manage the distasteful sensory in leukaemia. Consequently, green methods for synchronous spectrofluorimetric quantification of a ternary mixture of ETO, MOX and NAL were developed. The first approach relies simply on the estimation of MOX at 371 nm by conventional synchronous fluorimetric technique (Δλ of 60 nm). The second approach depends on applying the first derivative synchronous fluorimetric technique (Δλ of 60 nm) for simultaneous estimation of ETO and NAL at 257 and 273 nm, respectively. A good linear correlation was obtained in the ranges of 0.04-0.40, 0.10-1.00 and 0.50-5.00 µg ml-1 for MOX, ETO and NAL, respectively. Moreover, the proposed approaches were successfully applied for the estimation of the studied drugs in the pharmaceutical dosage forms. Additionally, the synchronous assessment of ETO, MOX and NAL in the spiked human urine was successfully attained by the facile protein precipitation technique. The mean % recoveries in spiked human urine were 99.49, 98.07 and 98.48 for MOX, ETO and NAL, respectively.