Simultaneous determination of five systemic azoles in plasma by high-performance liquid chromatography with ultraviolet detection

Biomonitoring of azole fungicides in free-living blackbird plasma using on-line solid-phase extraction coupled to liquid chromatography-tandem mass spectrometry (SPE HPLC-MS/MS)

In this study, a rapid and sensitive method using on-line solid-phase extraction (SPE) coupled to liquid chromatography - tandem mass spectrometry (SPE HPLC-MS/MS) was developed to analyse 15 azole fungicides currently used in vineyards in blackbird plasma samples. The monitored fungicides included 13 triazoles (cyproconazole, difenoconazole, epoxiconazole, fenbuconazole, flusilazole, flutriafol, metconazole, penconazole, propiconazole, tebuconazole, tetraconazole, triadimefon, triadimenol) and 2 imidazoles (imazalil and prochloraz). After a rapid preparation step by protein precipitation with acetonitrile on 25 µL of plasma samples, final extracts diluted with Milli-Q water were analyzed by on-line SPE-LC-MS/MS in positive electrospray mode (ESI+) using the dynamic multi-reaction monitoring mode (dMRM). Following optimization, method validation was achieved through studies of linearity, sensitivity, accuracy, precision, and sample extract conservation. The limits of quantification (LOQs) obtained for a low volume of plasma (25 µL) ranged from 0.01 to 0.43 ng g-1 plasma, except for triadimenol (1.37 ng g-1). Finally, the validated method was successfully applied to 34 Eurasian blackbird plasma samples, with blackbirds from different habitats (city, forest, vineyards) submitted to contrasted azole pressures. Five of them were detected, tebuconazole and tetraconazole being the predominant ones. As expected, azoles concentrations were more elevated in blackbirds sampled in vineyards where most of these fungicides are used.

Therapeutic drug monitoring of azole antifungal agents

Deep-seated mycoses are generally opportunistic infections that are difficult to diagnose and treat. They are expected to increase with the spread of advanced medical care and aging populations, thus highlighting the need for safe, effective, and rapid drug-based treatments. Depending on a patient's age, sex, underlying diseases, and immune system status, therapeutic drug monitoring (TDM) may be important for assessing variable pharmacokinetic parameters, as well as preventing drug-drug interactions, adverse events, and breakthrough infections caused by fungal resistance. Azole antifungal agents play an important role in the prevention and treatment of deep-seated fungal infections, with each azoles having its own unique pharmacokinetic properties and specific adverse events. Therefore, it is necessary to use national and international guidelines to build evidence for the expansion of TDM indications. This review focuses on the clinical utility and future perspectives of TDM using azole antifungal agents, in the context of recent evidence in the literature.

The Application of the Design of Experiments and Artificial Neural Networks in the Development of a Fast and Straightforward HPLC-UV Method for Fluconazole Determination in Hemato-Oncologic Pediatric Patients and Its Adaptation to Therapeutic Drug Monitoring

Objectives: This study aimed to develop an optimized and wide concentration range HPLC-UV method for fluconazole (FLU) determination and its adaptation for pharmacokinetics (PK) studies in the pediatric population. Methods: The following parameters of chromatographic separation were optimized: retention time, tailing factor, peak height, and the sample preconditioning parameter, such as recovery. The optimization process involved the use of a central composite design (CCD) and Box-Behnken design (BBD) in the design of experiments (DoE) approach and a multilayer perceptron (MLP) for artificial neural network (ANN) application. Statistical and PK analyses were performed using Statistica and PKanalix. Results: The acetonitrile (ACN) concentration revealed the most significant factor influencing the retention time, tailing factor, and peak height of FLU and the internal standard. For recovery, the extracting agent's volume was the most significant factor. In most cases, the analysis conducted with the DoE and ANN indicated the same factors in a similar order regarding their impact on the analyzed variables. The optimization process allowed for achieving a wide range of determined concentrations (0.5-100 mg/L) and ~100% recovery. The developed method enabled PK analysis of 12 samples from three pediatric patients, proving its clinical usability. The estimated median clearance (CL) and volume of distribution (Vd) were 1.01 L/h and 18.64 L, respectively. Conclusions: DoE and ANNs are promising and useful tools in the optimization of sample preconditioning as well as the HPLC separation procedure. The investigated fluconazole determination method meets the European Medicines Agency (EMA) validation objectives and might be used in pediatric and adult PK studies.

Development of an HPLC-UV method for quantification of posaconazole in low-volume plasma samples: design of experiments and machine learning models

Posaconazole (PCZ) is a triazole antifungal agent with a broad-spectrum activity. Our research aims to present a novel approach by combining a 2-level fractional factorial design and machine learning to optimize both chromatography and extraction experiments, allowing for the development of a rapid method with a low limit of quantification (LOQ) in low-volume plasma samples. The PCZ retention time at the optimized condition (organic phase 58%, methanol 6%, mobile pH = 7, column temperature: 39 °C, and flow rate of 1.2 mL/min) was found to be 8.2 ± 0.2 min, and the recovery of the PCZ at the optimized extraction condition (500 µL extraction solvent, NaCl 10% w/v, plasma pH = 11, extraction time = 10 min, and centrifuge time = 1 min) was calculated above 98%. The results of machine learning models were in line with the results of experimental design. Method validation was performed according to ICH guideline. The method was linear in the range of 50-2000 ng/mL and LOQ was found to be 50 ng/mL. Additionally, the validated method was applied to analyze PCZ nanomicelles and conduct pharmacokinetic studies on rats. Half-life (t1/2), mean residence time (MRT), and the area under the drug concentration-time curve (AUC) were found to be 7.1 ± 0.6 h, 10.5 ± 0.9 h, and 1725.7 ± 44.1 ng × h/mL, respectively.

Triazole Antifungal Quantification for Therapeutic Drug Monitoring in Serum by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS): Posaconazole, Voriconazole, Itraconazole, and Hydroxyitraconazole

Antifungal therapy with triazole drugs including posaconazole, voriconazole, itraconazole, and its active metabolite hydroxyitraconazole is routinely accompanied by therapeutic drug monitoring to ensure optimal dosing. The method presented here simultaneously quantitates these compounds in serum by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Specimen preparation includes protein precipitation with a methanol and acetonitrile mixture, centrifugation, and filtration. Analyte separation is achieved by reverse-phase chromatography using a dC18 column and a linear gradient of methanol in water. Analytes are detected by multiple reaction monitoring mass spectrometry and quantitated by comparison to a standard curve.

Advancing posaconazole quantification analysis with a new reverse-phase HPLC method in its bulk and marketed dosage form

Introduction: Posaconazole is a widely used antifungal drug, and its accurate quantification is essential for quality control and assessment of its pharmaceutical products. This study aimed to develop and validate a reverse-phase high-performance liquid chromatography (HPLC) analytical method for quantifying Posaconazole in bulk and dosage form. Methods: The HPLC method was developed and validated based on International Conference on Harmonisation (ICH) guidelines. The developed method was then applied to quantify Posaconazole in a marketed tablet formulation. The method's specificity, linearity, precision, accuracy, robustness, and stability were evaluated. Results: The developed HPLC method showed good linearity over a 2-20 μg/mL concentration range. The percentage recovery of Posaconazole from the bulk and marketed formulations was found to be 99.01% and 99.05%, respectively. The intra-day and inter-day precisions were less than 1%, and the method was stable under different conditions. The HPLC method was successfully applied to quantify Posaconazole in the marketed formulation. Conclusion: The developed and validated HPLC method is reliable and efficient for analyzing Posaconazole in bulk and dosage forms. The method's accuracy, precision, specificity, linearity, robustness, and stability demonstrate its effectiveness. The method can be used for the quality control and assessment of Posaconazole-containing pharmaceutical products.

A New Electrochemical Sensor for the Detection of Ketoconazole Using Carbon Paste Electrode Modified with Sheaf-like Ce-BTC MOF Nanostructure and Ionic Liquid

An ultrasensitive and selective voltammetric sensor with an ultratrace-level detection limit is introduced for ketoconazole (KTC) determination in real samples using a modified carbon paste electrode with a sheaf-like Ce-BTC MOF nanostructure and ionic liquid. The as-synthesized nanostructure was characterized by several techniques, including energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). The electrocatalytic performance of the developed electrode was observed by cyclic voltammetry (CV), differential pulse voltammetry (DPV), linear sweep voltammetry (LSV), and chronoamperometry. The limit of detection (LOD) of the developed sensor for KTC is 0.04 μM, and the response was found to be in the dynamic concentration range of 0.1-110.0 μM in a phosphate buffer solution. The proposed electrode exhibits acceptable electrocatalytic activity for KTC oxidation with a high sensitivity of 0.1342 μA·μM^-1. The ability of the fabricated sensor to monitor KTC in real aqueous samples is demonstrated using standard addition data.

Progress of triazole antifungal agent posaconazole in individualized therapy

WHAT IS KNOWN AND OBJECTIVE

Posaconazole is the second-generation triazole antifungal agent with widespread clinical application. Posaconazole exposure is influenced by various factors such as drug interactions, disease state and diet, resulting in a high interindividual variability in many patients and failure to ensure therapeutic efficacy. Therefore, it is necessary to conduct individualized therapy on posaconazole to ensure the efficacy and safety of treatment.

METHODS

Articles were identified through PubMed using the keywords such as "posaconazole," "therapeutic drug monitoring" and "Population pharmacokinetics" from 1 January 2001 to 30 April 2022.

RESULTS AND DISCUSSION

In this paper, we review the individualized treatment studies of posaconazole from the three aspects of therapeutic drug monitoring, population pharmacokinetic study and Monte Carlo simulation to provide reference for in-depth individualized posaconazole dosing studies.

WHAT IS NEW AND CONCLUSION

This review suggests that therapeutic drug monitoring should be performed in patients taking posaconazole to adjust the dosage and assess the efficacy and cost-effectiveness of posaconazole under different clinical conditions and different dosing regimens through Monte Carlo simulations. In the future, a more detailed delineation and comprehensive examination of posaconazole PPK for specific populations requires further study.

A dual action small molecule enhances azoles and overcomes resistance through co-targeting Pdr5 and Vma1

Fungal infection threatens human health worldwide due to the limited arsenal of antifungals and the rapid emergence of resistance. Epidermal growth factor receptor (EGFR) is demonstrated to mediate epithelial cell endocytosis of the leading human fungal pathogen, Candida albicans. However, whether EGFR inhibitors act on fungal cells remains unknown. Here, we discovered that the specific EGFR inhibitor osimertinib mesylate (OSI) potentiates azole efficacy against diverse fungal pathogens and overcomes azole resistance. Mechanistic investigation revealed a conserved activity of OSI by promoting intracellular fluconazole accumulation via inhibiting Pdr5 and disrupting V-ATPase function via targeting Vma1 at serine 274, eventually leading to inactivation of the global regulator TOR. Evaluation of the in vivo efficacy and toxicity of OSI demonstrated its potential clinical application in impeding fluconazole resistance. Thus, the identification of OSI as a dual action antifungal with co-targeting activity proposes a potentially effective therapeutic strategy to treat life-threatening fungal infection and overcome antifungal resistance.

Air assisted in situ deep eutectic solvent decomposition followed by the solidification of floating organic droplets-liquid-liquid microextraction method for extraction of azole antifungal drugs in biological samples prior to high-performance liquid chromatography

A free dispersive method, air-assisted in situ deep eutectic solvent decomposition followed by the solidification of floating organic droplets liquid-liquid microextraction was indicated in this study. This technique was utilized to simultaneously ascertain some azole antifungal drugs prior to high-performance liquid chromatography. In this research, a quasi-hydrophobic deep eutectic solvent was formed from tetrabutylammonium bromide and 1-dodecanol as an organic solvent at a 1:2 molar ratio. The synthesized deep decomposition in the sample solution caused in situ dispersion of extraction solvent and analytes. Air-assisted enhanced a dispersion condition in the sample solution. 1-dodecanol as a green option was replaced with typical extraction solvents providing the advantages of a suitable freezing point near room temperature and low density. The effect of important analytical parameters on the extraction recovery of analytes was assessed. Under these optimal conditions, the limits of detection and limits of quantitation determined were in the range of 0.5-2.8 μg L^-1 and 1.5-9 μg L^-1 , for water, urine and plasma samples, respectively. The Intra-day and inter-day relative standard deviations (RSD% n = 5) were calculated to be 2.9-4.6 % and 4.2-8.9 %, respectively. The results represented the effectiveness of the developed method for the extraction and determination of analytes in biological samples. This article is protected by copyright. All rights reserved.

A versatile high-performance LC-MS/MS assay for the quantification of voriconazole and its N-oxide metabolite in small sample volumes of multiple human matrices for biomedical applications

Voriconazole (VRC) pharmacokinetics, in particular its complex metabolism, is still not fully understood which challenges its optimal therapeutic use. To increase knowledge on the pharmacokinetics of this antifungal drug, it is essential to broaden the perspective and expand in vitro and clinical in vivo investigations in particular to aspects such as unbound plasma, target-site and metabolite concentrations. Innovative sampling approaches such as microdialysis, a minimally-invasive technique for the analysis of compound concentrations in target-site human tissue fluids, are associated with bioanalytical challenges, i.e. small sample volumes and low concentrations. Thus, a bioanalytical LC-MS/MS assay for the simultaneous quantification of VRC and its main N-oxide (NO) metabolite in human plasma, ultrafiltrate and microdialysate was developed and validated according to the European Medicines Agency guideline. Quantification was rapid, simple and feasible for clinically relevant concentrations from 5 to 5000 ng/mL in plasma and ultrafiltrate as well as from 4 to 4000 ng/mL in microdialysate. Due to the high sensitivity of the assay, only 20 µL of plasma or ultrafiltrate and 5 µL of microdialysate were required. For VRC and NO in all matrices, between-run accuracy was high with a maximum mean deviation of 7.0% from the nominal value and between-run precision was demonstrated by ≤ 11.8% coefficient of variation. Both compounds proved stable under various conditions. The assay suitability was demonstrated by the application to a clinical study quantifying simultaneously VRC and NO concentrations in plasma, ultrafiltrate and microdialysate. Additionally, the assay was successfully adapted for pharmacokinetic analyses in human tissue-derived in vitro experiments. Overall, by reducing the required sample volume, the bioanalytical method allows for an increased number of plasma samples in vulnerable populations, e.g. infants, and enables the generation of concentration-time profiles with a higher temporal resolution in microdialysis studies. Consequently, the developed assay is apt to elucidate the complex pharmacokinetics of VRC in clinical settings as prerequisite for therapy optimisation.

Evaluation of artemisinin derivative artemether as a fluconazole potentiator through inhibition of Pdr5

Antifungal development has gained increasing attention due to its limited armamentarium and drug resistance. Drug repurposing holds great potential in antifungal discovery. In this study, we explored the antifungal activity of artemisinin and its derivatives, dihydroartemisinin, artesunate and artemether. We identified that artemisinins can inhibit the growth of Candida albicans, and can enhance the activity of three commonly used antifungals, amphotericin B, micafungin and fluconazole (FLC), on Candida albicans growth and filamentation. Artemisinins possess stronger antifungal effect with FLC than with other antifungals. Among artemisinins, artemether exhibits the most potent antifungal activity with FLC and can recover the susceptibility of FLC-resistant clinical isolates to FLC treatment. The combinatorial antifungal activity of artemether and FLC is broad-spectrum, as it can inhibit the growth of Candida auris, Candida tropicalis, Candida parapsilosis, Saccharomyces cerevisiae and Cryptococcus neoformans. Mechanistic investigation revealed that artemether might enhance azole efficacy through disrupting the function of Pdr5, leading to intracellular accumulation of FLC. This study identified artemether as a novel FLC potentiator, providing potential therapeutic insights against fungal infection and antifungal resistance.

Application of the Westgard Multi-rule Theory to Internal Quality Control Evaluation of Voriconazole for Therapeutic Drug Monitoring

Background:

There is no worldwide recognized reference internal quality control method for Therapeutic Drug Monitoring (TDM) of voriconazole (VCZ) by Liquid Chromatography (LC). In this study, we aimed to develop an internal quality control method for TDM of VCZ, evaluate it by the Westgard multi-rule theory, and guarantee the analytical quality of the assays.

Methods:

The plasma concentration of VCZ was detected by two-dimensional liquid chromatography with ultraviolet detection (2D-LC-UV) method. The internal quality control results accompanying with TDM of VCZ in our laboratory from July 2019 to January 2020 were collected and retrospectively studied. The Levey-Jennings quality chart and Z-score quality chart were drawn and Westgard multirules of 12s/13s/22s/R4s/41s/10x were applied to assess the suitable quality control method for TDM of VCZ.

Results:

The 2D-LC-UV method was well suited to monitor the plasma concentration of VCZ and increase the real-time capability of TDM for VCZ. Combined with Westgard multi-rules, the quality control charts of Levery-Jennings and Z-score both can timely discover and judge the systematic errors and random errors for the internal quality control results. 86 batches of quality control products were assessed and 7 times warnings and 6 times out of control were detected.

Conclusion:

The Westgard multi-rules, with high efficacy in determining detection errors, has important application value in the internal quality control for TDM of VCZ. The developed quality control method can improve the accuracy and reliability for VCZ measurement by the 2D-LC-UV method and further promote the clinical rational use of the drug.

A sensitive method for analyzing fluconazole in extremely small volumes of neonatal serum

BACKGROUND

The need for a large volume of serum sample significantly reduces the feasibility of neonatal pharmacokinetic studies in daily practice, which must often rely on scavenged or opportunistic sampling. This problem is most apparent in preterm newborns, where ethical and practical considerations prohibit the collection of large sample volumes. Most of the fluconazole analysis assays published thus far required a minimum serum sample of 50 to 100 μL for a single assay. The purpose of the present study was to develop and validate a sensitive method requiring a smaller sample volume (10 μL) to satisfy clinically relevant research requirements.

METHODS

Following simple protein precipitation and centrifugation, the filtrated supernatant was injected into a liquid chromatography system and separated with a C18 reverse-phase column. Fluconazole and the internal standard (IS, fluconazole-d4) were detected and quantified using tandem mass spectrometry. The method was validated with reference to the Food and Drug Administration's Guidance for Industry. Accuracy and precision were evaluated at six quality control concentration levels (ranging from 0.01 to 100 μg/mL).

RESULTS

Investigated calibration curves were linear in the 0.01-100 μg/mL range. Intra- and inter-day accuracy (- 7.7 to 7.4%) and precision (0.3 to 6.0%) were below 15%. The calculated limit of detection and the lower limit of quantification (LLOQ) was 0.0019 μg/mL and 0.0031 μg/mL, respectively. Fluconazole in the prepared samples was stable for at least 4 months at - 20 °C and - 80 °C. This method was applied to analyze 234 serum samples from ten neonates who received fosfluconazole, a water-soluble phosphate prodrug of fluconazole which converts to fluconazole in the body, as part of a pharmacokinetic study using daily scavenged laboratory samples. The median (range) concentration up to 72 h after fosfluconazole administration was 2.9 (0.02 to 26.8 μg/mL) μg/mL, which was within the range of the calibration curve.

CONCLUSION

Fluconazole was able to be detected in an extremely small volume (10 μL) of serum from neonates receiving fosfluconazole. The method presented here can be used to quantify fluconazole concentrations for pharmacokinetic studies of the neonatal population by using scavenged samples.

Preparation of magnetic metal organic framework and development of solid phase extraction method for simultaneous determination of fluconazole and voriconazole in rat plasma samples by HPLC

Fluconazole and voriconazole are the two broad-spectrum triazole antifungals. The present work described the fabrication method for the synthesis of the amino-modified magnetic metal-organic framework. This material was applied as a pre-sample treatment sorbent for the selective extraction of fluconazole and voriconazole in rat plasma samples. The material was fabricated by the chemical bonding approach method and was characterized by different parameters. The factors which affect the extraction efficiency of the sorbent material were also optimized in this study. Due to the optimization of solid-phase extraction conditions, the nonspecific interaction was reduced and the extraction recoveries of target drugs were increased in plasma samples. The extraction method was combined with the HPLC-UV method for the analysis. Excellent linearity (0.1-25 µg/mL), detections (0.02, 0.03 µg/mL) and quantification limits (0.04, 0.05 µg/mL) were resulted for fluconazole and voriconazole respectively. The maximum recoveries from spiked plasma samples of fluconazole and voriconazole were 86.8% and 78.6% and relative standard deviation were 0.9-2.8% and 2.2-3.6% respectively. Moreover, this sorbent material was used multiple times which was an improvement over single-use commercial sorbent materials. This validated method has practical potential for the simultaneous determination of these drugs in therapeutic drug monitoring studies as well as for routine pharmacokinetic evaluations.

Therapeutic Drug Monitoring of Antifungal Drugs: Another Tool to Improve Patient Outcome?

Introduction

This study aimed to examine the relationship among adequate dose, serum concentration and clinical outcome in a non-selected group of hospitalized patients receiving antifungals.

Methods

Prospective cross-sectional study performed between March 2015 and June 2015. Dosage of antifungals was considered adequate according to the IDSA guidelines, whereas trough serum concentrations (determined with HPLC) were considered adequate as follows: fluconazole > 11 µg/ml, echinocandins > 1 µg/ml, voriconazole 1–5.5 µg/ml and posaconazole > 0.7 µg/ml.

Results

During the study period, 84 patients (65.4% male, 59.6 years) received antifungals for prophylaxis (40.4%), targeted (31.0%) and empirical therapy (28.6%). The most frequent drug was micafungin (28/84; 33.3%) followed by fluconazole (23/84; 27.4%), voriconazole (15/84; 17.9%), anidulafungin (8/84; 9.5%), posaconazole (7/84; 8.3%) and caspofungin (3/84; 3.6%). Considerable interindividual variability was observed for all antifungals with a large proportion of the patients (64.3%) not attaining adequate trough serum concentrations, despite receiving an adequate antifungal dose. Attaining the on-target serum antifungal level was significantly associated with a favorable clinical outcome (OR = 0.02; 95% CI 0.01–0.64; p = 0.03), whereas the administration of an adequate antifungal dosage was not.

Conclusions

With the standard antifungal dosage, a considerable proportion of patients have low drug concentrations, which are associated with poor clinical outcome.

Pharmacokinetics and Pharmacodynamics of Anti-infective Agents during Continuous Veno-venous Hemofiltration in Critically Ill Patients: Lessons Learned from an Ancillary Study of the IVOIRE Trial

BACKGROUND

Hemofiltration rate, changes in blood and ultrafiltration flow, and discrepancies between the prescribed and administered doses strongly influence pharmacokinetics (PK) and pharmacodynamics (PD) of antimicrobial agents during continuous veno-venous hemofiltration (CVVH) in critically ill patients.

METHODS

Ancillary data were from the prospective multicenter IVOIRE (hIgh VOlume in Intensive caRE) study. High volume (HV, 70 mL/kg/h) was at random compared with standard volume (SV, 35 mL/kg/h) CVVH in septic shock patients with acute kidney injury (AKI). PK/PD parameters for all antimicrobial agents used in each patient were studied during five days.

RESULTS

Antimicrobial treatment met efficacy targets for both percentage of time above the minimal inhibitory concentration and inhibitory quotient. A significant correlation was observed between the ultrafiltration flow and total systemic clearance (Spearman test: P < 0.005) and between CVVH clearance and drug elimination half-life (Spearman test: P < 0.005). All agents were easily filtered. Mean sieving coefficient ranged from 38.7% to 96.7%. Mean elimination half-life of all agents was significantly shorter during HV-CVVH (from 1.29 to 28.54 h) than during SV-CVVH (from 1.51 to 33.85 h) (P < 0.05).

CONCLUSIONS

This study confirms that CVVH influences the PK/PD behavior of most antimicrobial agents. Antimicrobial elimination was directly correlated with convection rate. Current antimicrobial dose recommendations will expose patients to underdosing and increase the risk for treatment failure and development of resistance. Dose recommendations are proposed for some major antibiotic and antifungal treatments in patients receiving at least 25 mL/kg/h CVVH.

Interlaboratory Analysis of Isavuconazole Plasma Concentration Assays Among European Laboratories

BACKGROUND

Under certain circumstances, clinicians treating patients with isavuconazole for invasive aspergillosis or mucormycosis may use therapeutic drug monitoring. However, the accuracy and reproducibility of the various assays used by different laboratories for the quantification of isavuconazole plasma concentrations have yet to be determined.

METHODS

Human plasma samples spiked with known concentrations of isavuconazole were provided to 27 European laboratories that took part in a "round-robin" test (an interlaboratory test performed independently at least 2 times; 2 rounds performed in the current study). Assay methods included liquid chromatography-tandem mass spectrometry (LC-MS/MS), LC with ultraviolet detection (LC-UV), LC with fluorescence detection (LC-FL), and bioassay. The accuracy and reproducibility compared with the known concentrations for each sample in each round were compared overall, between assays, and between laboratories.

RESULTS

Twenty-seven laboratories participated in the study (LC-MS/MS, n = 15; LC-UV; n = 9; LC-FL, n = 1; bioassay, n = 2). In round 1, for nominal concentrations of 1000, 1700, 2500, and 4000 ng/mL, the mean (SD) determined concentrations were 1007 (183), 1710 (323), 2528 (540), and 3898 (842) ng/mL, respectively. In round 2, for nominal concentrations of 1200, 1800, 2400, and 4000 ng/mL, the mean (SD) determined concentrations were 1411 (303), 2111 (409), 2789 (511), and 4723 (798) ng/mL, respectively. Over both rounds, determined concentrations were consistently within 15% of the nominal concentrations for 10 laboratories (LC-MS/MS, n = 4; LC-UV, n = 5; bioassay, n = 1) and consistently exceeded the upper 15% margin for 7 laboratories (LC-MS/MS and LC-UV, n = 3 each; LC-FL, n = 1).

CONCLUSIONS

Alignment of methodologies among laboratories may be warranted to improve the accuracy and reproducibility of therapeutic drug measurements.

Qualitative and quantitative assessment of related substances in the Compound Ketoconazole and Clobetasol Propionate Cream by HPLC-TOF-MS and HPLC

Related substances in pharmaceutical formulations are associated with their safety, efficacy and stability. However, there is no overall study already published on the assessment of related substances in the Compound Ketoconazole and Clobetasol Propionate Cream. In this work, a reliable HPLC-TOF-MS qualitative method was developed for the analysis of related substances in this preparation with a quick and easy extraction procedure. Besides the active pharmaceutical ingredients, two compounds named ketoconazole impurity B′ optical isomer and ketoconazole impurity E were identified. Furthermore, a new HPLC method for qualitative and quantitative assessment on related substances and degradation products, which were found in the stability test, was established and validated. The single standard to determine multi-components method was applied in the quantitative analysis, which was an effective way for reducing cost and improving accuracy. This study can provide a creative idea for routine analysis of quality control of the Compound Ketoconazole and Clobetasol Propionate Cream.

Application of HPTLC, spectrofluorimetry and differential pulse voltammetry for determination of the antifungal drug posaconazole in suspension dosage form

This work presents the development, validation and application of three simple and direct analytical methods for determination of posaconazole (PSZ) in its pure form and in suspension dosage form. Method I is based on high performance thin layer chromatography (HPTLC) where effective separation of PSZ and the internal standard (itraconazole) was achieved using Merck HPTLC plates (20×10cm aluminium plates with 250μm layer thickness precoated with silicagel 60 F₂₅₄) and a mobile phase composed of acetone and chloroform (1:2, by volume), followed by densitometric measurement of the drugs' spots at 262nm. Method II involves measurement of the native fluorescence of PSZ in 0.1M H₂SO₄ at excitation and emission wavelengths of 260 and 365nm, respectively. Method III depends on the voltammetric analysis of PSZ. A well-defined cathodic wave was obtained for PSZ in Britton-Robinson buffer pH 6.5 using the differential-pulse mode at the hanging mercury drop electrode (HMDE). The developed methods were validated according to the International Conference on Harmonization (ICH) guidelines regarding linearity, ranges, accuracy, precision, robustness and limits of detection and quantification. The proposed methods showed good linearity over the concentration ranges 5-50, 0.05-0.3, 0.005-0.05μg/mL PSZ for methods I, II, and III respectively. Intra and inter-day precision were verified by the RSD% values which were less than 2%. The proposed methods were successfully applied for the quantification of PSZ in suspension dosage form with no observable interferences. Assay methods were favorably compared with those obtained by previously reported HPLC method.

Simultaneous Quantification of Benznidazole and Posaconazole by HPLC-DAD Using QbD Approach

Objective

To develop an analytical method to simultaneous quantification of benznidazole (BNZ) and posaconazole (POS) by high-performance liquid chromatography with diode-array detection (HPLC-DAD) using design of experiments.

Methods

Percentages of organic phase, buffer pH and flow rates of mobile phase were selected as independent variables by full factorial design (33), totaling 27 experiments. Significant factors were evaluated using factorial analysis of variance with 95% confidence level. Method optimization was performed using desirability profiles, considering BNZ/POS chromatographic resolution and peak areas. Further, the method was evaluated regarding its suitability and properly validated according to the international compendiums using the parameters: specificity, linearity, accuracy, precision, limit of detection and limit of quantification.

Results

The optimized method was achieved using Discovery® C8 column (250 mm × 4.6 mm; 5 μm particle size), methanol/acetate buffer (pH 3.5)(71:29) and detection at 260 nm. Retention times were 3.6 and 7.6 min for BNZ and POS, respectively, with good suitability of system and it was specific and linear (r2 >0.99) for both drugs, proving the efficiency of the method even in the presence of degradation products of POS.

Conclusion

This new method is a great alternative to perform reliable, faster and cheaper analysis since the simultaneous quantification of the association BZN/POS is not reported yet in the literature.

Validation of a Reversed-Phase Ultra-High-Performance Liquid Chromatographic Method With Photodiode Array Detection for the Determination of Voriconazole in Human Serum and Its Application to Therapeutic Drug Monitoring

BACKGROUND

Voriconazole is a broad-spectrum triazole antifungal agent. It is widely used in the treatment of invasive fungal infections in immunocompromised patients. Because the pharmacokinetics of voriconazole demonstrates considerable variability, monitoring its serum levels plays an important role in optimizing therapies against many clinically relevant fungal pathogens. The aim of this study was to validate a simple and rapid U-HPLC-PDA method with minimal sample preparation for routine therapeutic drug monitoring (TDM) of voriconazole.

METHODS

After protein precipitation with the internal standard solution (posaconazole 5.0 mg/L in acetonitrile), chromatographic separation was performed in 4 minutes using water and acetonitrile as mobile phases and an Acquity UPLC BEH HSS C18 column (2.1 × 100 mm, 1.7 µm). The temperature was set at 45°C and the flow rate was 0.4 mL/min. Photodiode array detection at 256 nm was used as detection system. The method was validated according international guidelines for linearity, accuracy, precision, selectivity, lower limit of quantitation, carry over, and stability under different conditions.

RESULTS

All performance parameters were within acceptance criteria, demonstrating that the validated method is fit for purpose. After assay validation, 115 serum samples collected from 41 patients were analyzed to report the experience of the laboratory in TDM of voriconazole. Results showed a large variability in voriconazole trough levels, suggesting that this drug should be frequently measured in patients under treatment to enhance therapies efficacy and improve safety.

CONCLUSIONS

In this study, a reproducible U-HPLC-PDA assay with a short analysis time, requiring only a small amount of serum, good accuracy and reproducibility was validated, which is suitable for routine TDM of voriconazole in serum.

A new cause of false positive voriconazole levels: Watch your collection tubes!

We communicate the interference of a compound of the blood collection tube with the accuracy of a validated high-pressure liquid chromatography method with ultraviolet detection for quantifying voriconazole levels, which led to false positive results. This could have serious consequences for patient management. Our advice is to implement external assessment programs.

Breakthrough invasive aspergillosis and diagnostic accuracy of serum galactomannan enzyme immune assay during acute myeloid leukemia induction chemotherapy with posaconazole prophylaxis

Posaconazole prophylaxis has demonstrated efficacy in the prevention of invasive aspergillosis during prolonged neutropenia following acute myeloid leukemia induction chemotherapy. Antifungal treatment decreases serum galactomannan enzyme immunoassay diagnostic accuracy that could delay the diagnosis and treatment.

We retrospectively studied patients with acute myeloid leukemia who underwent intensive chemotherapy and antifungal prophylaxis by posaconazole oral suspension. Clinical, radiological, microbiological features and treatment response of patients with invasive aspergillosis that occurred despite posaconazole prophylaxis were analyzed. Diagnostic accuracy of serum galactomannan assay according to posaconazole plasma concentrations has been performed.

A total of 288 patients with acute myeloid leukemia, treated by induction chemotherapy, who received posaconazole prophylaxis for more than five days were included in the present study. The incidence of invasive aspergillosis was 8% with 12 (4.2%), 8 (2.8%) and 3 (1%), possible, probable and proven invasive aspergillosis, respectively. Posaconazole plasma concentration was available for 258 patients. Median duration of posaconazole treatment was 17 days, and median posaconazole plasma concentration was 0.5 mg/L. None of patients with invasive aspergillosis and posaconazole concentration ≥ 0.5 mg/L had a serum galactomannan positive test. Sensitivity of serum galactomannan assay to detect probable and proven invasive aspergillosis was 81.8%. Decreasing the cut-off value for serum galactomannan optical density index from 0.5 to 0.3 increased sensitivity to 90.9%.

In a homogenous cohort of acute myeloid leukemia patients during induction chemotherapy, increasing the posaconazole concentration decreases the sensitivity of serum galactomannan assay.

Analysis of imidazoles and triazoles in biological samples after MicroExtraction by packed sorbent

This paper reports the MEPS-HPLC-DAD method for the simultaneous determination of 12 azole drugs (bifonazole, butoconazole, clotrimazole, econazole, itraconazole, ketoconazole, miconazole, posaconazole, ravuconazole, terconazole, tioconazole and voriconazole) administered to treat different systemic and topical fungal infections, in biological samples. Azole drugs separation was performed in 36 min. The analytical method was validated in the ranges as follows: 0.02–5 μg mL⁻¹ for ravuconazole; 0.2–5 μg mL⁻¹ for terconazole; 0.05–5 μg mL⁻¹ for the other compounds. Human plasma and urine were used as biological samples during the analysis, while benzyl-4-hydroxybenzoate was used as an internal standard. The precision (RSD%) and trueness (Bias%) values fulfill with International Guidelines requirements. To the best of our knowledge, this is the first HPLC-DAD procedure coupled to MEPS, which provides the simultaneous analysis of 12 azole drugs, available in the market, in human plasma and urine. Moreover, the method was successfully applied for the quantitative determination of two model drugs (itraconazole and miconazole) after oral administration in real samples.

Advances in Clinical Mass Spectrometry

Although mass spectrometry has been used clinically for decades, the advent of immunoassay technology moved the clinical laboratory to more labor saving automated platforms requiring little if any sample preparation. It became clear, however, that immunoassays lacked sufficient sensitivity and specificity necessary for measurement of certain analytes or for measurement of analytes in specific patient populations. This limitation prompted clinical laboratories to revisit mass spectrometry which could additionally be used to develop assays for which there was no commercial source. In this chapter, the clinical applications of mass spectrometry in therapeutic drug monitoring, toxicology, and steroid hormone analysis will be reviewed. Technologic advances and new clinical applications will also be discussed.

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Posaconazole, systemic antifungal marketed in France since 2006, is indicated as second line in curative treatment of invasive fungal infections (IFI) (aspergillosis. . . ) and prophylaxis of IFI in patients receiving chemotherapy or hematopoietic stem cell transplantation. The analysis of the literature indicates a concentration-efficacy relationship, but to date, no study has been able to show a concentration-toxicity correlation due to its favourable safety profile and the difficulty to obtain high concentrations. In curative, maintenance of trough plasma concentrations between 0.5 and 1.5 mg/L seems to be associate with an efficacy. In prophylaxis, a threshold of 0.5 mg/L corresponds to a minimal exposure. However this target is not yet well defined. Saturation of absorption above the 800 mg oral dose limits the adjustment of concentrations. As such, the Therapeutic Drug Monitoring of posaconazole can be recommended.

A highly sensitive LC-MS/MS method for determination of ketoconazole in human plasma: Application to a clinical study of the exposure to ketoconazole in patients after topical administration

A simple, rapid and highly sensitive LC-MS/MS method was developed and validated for the determination of ketoconazole in human plasma. Sample preparation was accomplished through a single step liquid-liquid extraction by ethyl acetate. The chromatography separation was carried out on a Hedera CN (150mm×2.1mm, 5μm) column with isocratic elution using acetonitrile and 10mM ammonium acetate containing 0.1% formic acid (45:55, v/v) as the mobile phase. The flow rate was 0.5mL/min. Detection was performed in the positive ion electrospray ionization mode using multiple reaction monitoring of the transitions of 531.2→489.3 and 286.1→217.1 for ketoconazole and letrozole (the internal standard), respectively. The method exhibited good linearity over the concentration range of 0.01-12ng/mL for ketoconazole. The intra- and inter-batch precision and accuracy of ketoconazole were all within the acceptable criteria. The method was successfully applied to a clinical study of the exposure to ketoconazole in Chinese seborrheic dermatitis patients after topical administration of two ketoconazole formulations of foam and lotion, respectively. The study results showed that there was little systemic absorption of ketoconazole in patients for the two formulations, and the ketoconazole foam and lotion are safe therapeutic drugs for seborrheic dermatitis patients.

Therapeutic drug monitoring of voriconazole helps to decrease the percentage of patients with off-target trough serum levels

We monitored trough voriconazole serum concentrations from 107 patients (n = 258 samples) at 6 hospitals in Madrid. Most of the patients were male (67%) and had the following underlying conditions: hematological cancer (42%), solid organ transplantation (15%), chronic obstructive pulmonary disease (14%), human immunodeficiency virus infection (8.4%), solid cancer (5.6%), and other (29%). The indication for voriconazole administration was aspergillosis treatment (74.6%) and prophylaxis (14%). The main reasons for voriconazole trough drug monitoring were initiation of treatment/prophylaxis (33%), patient monitoring (47%), and suspected toxicity (3.5%). Levels (μg/ml) were subtherapeutic (<1; 18.2%), on-target (1-5.5; 71.3%), and high (>5.5; 10.5%). The samples percentage with on-target levels was significantly lower for the first sample than for subsequent samples (62.6% vs. 77.5%). "Subsequent samples," "admission in nonpediatric wards," "voriconazole used for treatment of invasive aspergillosis," and "use of proton pump inhibitors" were predictors of voriconazole therapeutic levels (≥1 μg/ml).

Development of an itraconazole encapsulated polymeric nanoparticle platform for effective antifungal therapy

Schematic illustration of the construction andin vivotrafficking of ITZ-NPs.

Quantification of the Triazole Antifungal Compounds Voriconazole and Posaconazole in Human Serum or Plasma Using Liquid Chromatography Electrospray Tandem Mass Spectrometry (HPLC-ESI-MS/MS)

Voriconazole and posaconazole are triazole antifungal compounds used in the treatment of fungal infections. Therapeutic drug monitoring of both compounds is recommended in order to guide drug dosing to achieve optimal blood concentrations. In this chapter we describe an HPLC-ESI-MS/MS method for the quantification of both compounds in human plasma or serum following a simple specimen preparation procedure. Specimen preparation consists of protein precipitation using methanol and acetonitrile followed by a cleanup step that involves filtration through a cellulose acetate membrane. The specimen is then injected into an HPLC-ESI-MS/MS equipped with a C18 column and separated over an acetonitrile gradient. Quantification of the drugs in the specimen is achieved by comparing the response of the unknown specimen to that of the calibrators in the standard curve using multiple reaction monitoring.

High Performance Liquid Chromatographic Assay for the Simultaneous Determination of Posaconazole and Vincristine in Rat Plasma

Purpose. Developing a validated HPLC-DAD method for simultaneous determination of posaconazole (PSZ) and vincristine (VCR) in rat plasma. Methods. PSZ, VCR, and itraconazole (ITZ) were extracted from 200 μL plasma using diethyl ether in the presence of 0.1 M sodium hydroxide solution. The organic layer was evaporated in vacuo and dried residue was reconstituted and injected through HC-C18 (4.6 × 250 mm, 5 μm) column. In the mobile phase, acetonitrile and 0.015 M potassium dihydrogen orthophosphate (30 : 70 to 80 : 20, linear gradient over 7 minutes) pumped at 1.5 mL/min. VCR and PSZ were measured at 220 and 262 nm, respectively. Two Sprague Dawley rats were orally dosed PSZ followed by iv dosing of VCR and serial blood sampling was performed. Results. VCR, PSZ, and ITZ were successfully separated within 11 min. Calibration curves were linear over the range of 50–5000 ng/mL for both drugs. The CV% and % error of the mean were ≤18% and limit of quantitation was 50 ng/mL for both drugs. Rat plasma concentrations of PSZ and VCR were simultaneously measured up to 72 h and their calculated pharmacokinetics parameters were comparable to the literature. Conclusion. The assay was validated as per ICH guidelines and is appropriate for pharmacokinetics drug-drug interaction studies.

Antifungal wound penetration of amphotericin and voriconazole in combat-related injuries: case report

Background

Survivors of combat trauma can have long and challenging recoveries, which may be complicated by infection. Invasive fungal infections are a rare but serious complication with limited treatment options. Currently, aggressive surgical debridement is the standard of care, with antifungal agents used adjunctively with uncertain efficacy. Anecdotal evidence suggests that antifungal agents may be ineffective in the absence of surgical debridement, and studies have yet to correlate antifungal concentrations in plasma and wounds.

Case presentation

Here we report the systemic pharmacokinetics and wound effluent antifungal concentrations of five wounds from two male patients, aged 28 and 30 years old who sustained combat-related blast injuries in southern Afghanistan, with proven or possible invasive fungal infection. Our data demonstrate that while voriconazole sufficiently penetrated the wound resulting in detectable effluent levels, free amphotericin B (unbound to plasma) was not present in wound effluent despite sufficient concentrations in circulating plasma. In addition, considerable between-patient and within-patient variability was observed in antifungal pharmacokinetic parameters.

Conclusion

These data highlight the need for further studies evaluating wound penetration of commonly used antifungals and the role for therapeutic drug monitoring in providing optimal care for critically ill and injured war fighters.