Plasma Voriconazole Estimation by HPLC

Development, optimization and validation of an analytical method for the determination of voriconazole in plasma by high-performance liquid chromatography-ultraviolet detection: Application for comprehensive study

OBJECTIVES

Voriconazole is a widely used antifungal agent in clinical settings. However, its use has been associated with neurological side effects in some patients. For this reason, it is crucial to monitor its plasma levels to ensure that they are within the therapeutic range. Thus, in this study, we aimed to develop a simple, fast, and efficient method for the determination of voriconazole in plasma using reversed-phase HPLC-UV. We also aimed to validate the method for its application to routine analysis of immunocompromised patients.

MATERIAL AND METHODS

Plasma samples from immunocompromised patients were subjected to deproteinization with acetonitrile followed by centrifugation. Chromatographic separation was carried out on a C18 column with UV detection at 254nm in isocratic mode. The concentrations were calculated by comparing peak areas to those of the internal standard, ketoconazole. The method was validated using the accuracy profile, which uses a calibration curve established for the therapeutic range of 1 to 5.5μg/mL.

RESULTS

The developed method was proved to be rapid by giving a short analysis time for voriconazole at around 5.5min. Additionally, no interference with the biological matrix was detected. The obtained recoveries were higher than 90%. The accuracy profile showed that the method was accurate and precise for the determination of voriconazole in plasma.

CONCLUSION

The developed method was proved to be simple, efficient, that requires minimal sample preparation. Thus, it can be routinely applied for the therapeutic monitoring of voriconazole.

Population Pharmacokinetics of Voriconazole and Dose Optimization in Elderly Chinese Patients

Voriconazole is commonly recommended as a first-line therapy for invasive aspergillosis infections. Elderly patients are susceptible to infectious diseases owing to their decreased physical function and immune system. Our study aims to establish a population pharmacokinetics model for elderly patients receiving intravenous voriconazole, and to optimize dosing protocols through a simulated approach. An accurate fit to the concentration-time profile of voriconazole was achieved by employing a 1-compartment model featuring first-order elimination. The typical clearance rate of voriconazole was found to be 3.22 L/h, with a typical volume of distribution of 194 L. The covariate analysis revealed that albumin (ALB), gamma-glutamyl transpeptidase, and direct bilirubin had significant impacts on voriconazole clearance. Additionally, body weight was found to be associated with the volume of distribution. Individualized dosing regimens were recommended for different ALB levels based on population pharmacokinetics model prediction. The proposed dosing regimens could provide a rationale for dosage individualization, improve the clinical outcomes, and minimize drug-related toxicities.

Comparison of ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and enzyme-multiplied immunoassay technique (EMIT) for quantification of voriconazole plasma concentration from Chinese patients

Introduction

Voriconazole (VRZ) is the recommended standard treatment for life-threatening invasive aspergillosis. The plasma concentration of VRZ should be determined to optimise treatment results and reduce side effects. This study aimed to compare the correlation and concordance of ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and enzyme-multiplied immunoassay technique (EMIT) to determine VRZ plasma concentration in clinical practice.

Methods

An isotopically labelled internal standard UPLC-MS/MS method was established, validated, and subsequently applied to determine VRZ concentration. The UPLC-MS/MS method was also compared with a commercial EMIT method regarding results correlation and concordance.

Results

The calibration curve of UPLC-MS/MS was linear from 0.1 to 10 mg/L, the inter- and intra-day relative standard deviations (RSDs), and the stability of quality control samples were less than 15 %, satisfying the Bioanalytical Method Validation Guidelines. A total of 122 plasma samples were collected and analyzed using both methods. UPLC-MS/MS and EMIT showed a high correlation (r = 0.9534), and Bland-Altman analysis indicated a mean absolute bias of 1.035 mg/L and an average bias of 27.56 % between UPLC-MS/MS and EMIT. The paired Wilcoxon test and Bland-Altman analysis revealed poor consistency between the two methods. Furthermore, we compared the effects of different methods in clinical applications. Two threshold values for treatment efficacy (1.0 mg/L) and safety (5.5 mg/L) were established, and considerable discordance was observed between the original EMIT and UPLC-MS/MS results at both thresholds (p < 0.05). Nevertheless, the adjusted EMIT results were not inconsistent with the UPLC-MS/MS results regarding the efficacy (p = 0.125) and safety (p = 1.0) thresholds.

Conclusions

The isotopically labelled internal standard UPLC-MS/MS method is established and well applied in the clinical setting. A strong correlation but discordance was found between UPLC-MS/MS and EMIT, indicating that switching from UPLC-MS/MS to EMIT was unsuitable. However, the adjusted EMIT results may serve as a reliable surrogate when UPLC-MS/MS results cannot be obtained when necessary.

Quantitative determination of voriconazole by thionine reduction and its potential application in a pharmaceutical and clinical setting

Voriconazole (VCZ) is a triazolic drug used to treat serious fungal infections and invasive mycosis and has also been more recently used as a generic antifungal treatment. However, VCZ therapies can cause undesirable side effects and doses must be carefully monitored before administration to avoid or reduce severe toxic effects. Analytical techniques used to quantify VCZ are mostly based on HPLC/UV and often associated with multiple technical steps as well as expensive equipment. The present work aimed to develop an accessible and affordable spectrophotometric technique in the visible range (λ = 514 nm) for the simple quantification of VCZ. The technique was based on VCZ-induced reduction of thionine (TH, red) to leucothionine (LTH, colorless) under alkaline conditions. The reaction showed a linear correlation over the range of 1.00 μg mL^-1 to 60.00 μg mL^-1 at room temperature, the limits of detection and quantification being 1.93 μg mL^-1 and 6.45 μg mL^-1, respectively. VCZ degradation products (DPs) according to ¹H and ¹³C-NMR spectrometric determinations not only showed good agreement with the ones previously reported (DP1 and DP2 - T. M. Barbosa, G. A. Morris, M. Nilsson, R. Rittner and C. F. Tormena, RSC Adv., 2017, DOI: 10.1039/c7ra03822d), but also revealed a new degradation product (DP3). Mass spectrometry not only confirmed the presence of LTH as a result of the VCZ DP-induced TH reduction, but also revealed the formation of a novel and stable Schiff base as a reaction product between DP1 and LTH. The latter finding became significant as it stabilizes the reaction for quantification purposes, by hindering LTH ↔TH redox reversibility. This analytical method was then validated according to the ICH Q2 (R1) guidelines, and additionally, it could be demonstrated as applicable for the reliable VCZ quantification in commercially available tablets. Importantly, it also represents a useful tool for detecting toxic threshold concentrations in human plasma from VCZ-treated patients, alerting when these risky limits are exceeded. In this way, this technique independent from sophisticated equipment, highly qualifies as a low-cost, reproducible, trustable, and non-laborious alternative method for VCZ measurements from different matrices.

Nanotechnology-Based Approaches for Voriconazole Delivery Applied to Invasive Fungal Infections

Invasive fungal infections increase mortality and morbidity rates worldwide. The treatment of these infections is still limited due to the low bioavailability and toxicity, requiring therapeutic monitoring, especially in the most severe cases. Voriconazole is an azole widely used to treat invasive aspergillosis, other hyaline molds, many dematiaceous molds, Candida spp., including those resistant to fluconazole, and for infections caused by endemic mycoses, in addition to those that occur in the central nervous system. However, despite its broad activity, using voriconazole has limitations related to its non-linear pharmacokinetics, leading to supratherapeutic doses and increased toxicity according to individual polymorphisms during its metabolism. In this sense, nanotechnology-based drug delivery systems have successfully improved the physicochemical and biological aspects of different classes of drugs, including antifungals. In this review, we highlighted recent work that has applied nanotechnology to deliver voriconazole. These systems allowed increased permeation and deposition of voriconazole in target tissues from a controlled and sustained release in different routes of administration such as ocular, pulmonary, oral, topical, and parenteral. Thus, nanotechnology application aiming to delivery voriconazole becomes a more effective and safer therapeutic alternative in the treatment of fungal infections.

Comparison of LC-MS3 and LC-MRM Method for Quantifying Voriconazole and Its Application in Therapeutic Drug Monitoring of Human Plasma

The TDM of voriconazole which exhibits wide inter-individual variability is indispensable for treatment in clinic. In this study, a method that high-performance liquid chromatography tandem mass spectrometry cubed (HPLC-MS3) is first built and validated to quantify voriconazole in human plasma. The system is composed of Shimadzu Exion LCTM UPLC coupled with a Qtrap 5500 mass spectrometer. The separation of voriconazole is performed on a Poroshell 120 SB-C18 column at a flow rate of 0.8 mL/min remaining 7 min for each sample. The calibration curves are linear in the concentration range of 0.25–20 μg/mL. Intra-day and inter-day accuracies and precisions are within 8.0% at three concentrations, and the recoveries and matrix effect are all within accepted limits. In terms of stability, there is no significant degradation of voriconazole under various conditions. The HPLC-MS3 and HPLC-MRM (multiple reaction monitoring) methods are compared in 42 patients with Passing–Bablok regression and Bland–Altman plots, and the results show no significant difference between the two methods. However, HPLC-MS3 has a higher S/N (signal-to-noise ratio) and response than the MRM. Finally, the HPLC-MS3 assay is successfully applied to monitor the TDM (therapeutic drug monitoring) of voriconazole in human plasma, and this verifies that the dosing guidelines for voriconazole have been well implemented in the clinic and patients have received excellent treatment.

Simultaneous determination of linezolid and voriconazole serum concentrations using liquid chromatography-tandem mass spectrometry

Linezolid and voriconazole are two antimicrobials used for severe infections in critically ill patients. Pharmacokinetics and pharmacodynamics are altered in critically ill patients. Therefore, standard dosing of anti-infective agents may not reach the optimal therapeutic targets. A rapid and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of linezolid and voriconazole in human serum only 3 min after one-step protein precipitation pretreatment to monitor their concentrations. Multiple-reaction monitoring (MRM) mode was used for detection. The calibration curves were linear over the range of 0.5-100 μg/mL for both linezolid and voriconazole, with regression coefficients above 0.9900 for all analytes. The intra- and interday coefficients of variation were below 15% at all concentration levels (LLOQ/LQC/MQC/HQC). This method was successfully applied to routine therapeutic drug monitoring (TDM) for critically ill patients and other patients in need.

A New Application of MALDI Biotyper for a Potential Use in Therapeutic Drug Monitoring of Voriconazole

We present a proof-of-concept study on the use of MALDI Biotyper to detect and monitor the levels of voriconazole in human serum. A simple extraction-concentration method and a MALDI Biotyper protocol were developed, and a parent ion of voriconazole (1 H⁺) could be detected and quantified with good reproducibility. Our results point to a new application of MALDI Biotyper for therapeutic drug monitoring.

Determination of Voriconazole Plasma Concentration by HPLC Technique and Evaluating Its Association with Clinical Outcome and Adverse Effects in Patients with Invasive Aspergillosis

Purpose

Invasive aspergillosis is a prevalent fungal disease, especially in Asian countries with a high mortality rate. Voriconazole (VRZ) is the first choice for invasive aspergillosis treatment. Plasma concentration of this drug is unpredictable and varies among individuals. This variability is influenced by many factors leading to clinical implication. Therapeutic drug monitoring (TDM) may have a crucial role in the patients' treatment process. The HPLC method provides sufficient specificity and sensitivity for plasma VRZ concentration determination for TDM purposes of this drug.

Methods

Patients who initiated oral or intravenous VRZ for invasive aspergillosis were enrolled in this study. Demographic characteristics and clinical data, outcome, and adverse effects were documented. For each patient, the plasma sample was collected under steady-state condition and analyzed using a validated HPLC method.

Results

A total of 22 measurements were performed. Fifty percent of patients were out of the therapeutic range. From them, 27.27% and 22.73% were in subtherapeutic and supratherapeutic ranges (<1 μg/mL and >5.5 μg/mL), respectively. There was a significant correlation between VRZ plasma concentration and treatment outcomes (P=0.022). Treatment failure was five times higher than treatment success in those in the subtherapeutic range. Adverse effects were observed more frequently in patients with supratherapeutic concentrations compared to those with non-supratherapeutic levels. Furthermore, the mortality rate in patients experiencing treatment failure was 2.17 times higher than those with treatment success.

Conclusions

TDM of VRZ plays an important role in better evaluation of efficacy and toxicity during treatment. Therefore, determination of the drug level may be of clinical significance.

Correlation between enzyme multiplied immunoassay technique and high-performance liquid chromatography in the quantification of voriconazole in a paediatric population

The enzyme multiplied immunoassay technique (EMIT) is a new method for determining the plasma concentration of voriconazole (VRZ). This study aimed to investigate the correlation between EMIT and high-performance liquid chromatography/ultraviolet rays (HPLC/UV) in determining the plasma VRZ trough concentration in children, in China. A total of 419 blood samples were collected, and plasma VRZ concentrations were detected by the EMIT and HPLC methods. The results of 304 samples were analysed after excluding samples that were undetectable or beyond the quantification limit. A test result value of 0 was defined as undetectable, while concentrations outside the detection range (0.2 - 20.0 μg/ml for HPLC and 0.5 - 16.0 µg/ml for EMIT) were defined as beyond the quantification limit. Results from both methods were compared using the Passing Bablok regression, Bland-Altman plot analysis, and paired Wilcoxon test. The plasma VRZ concentrations determined by EMIT and HPLC showed a strong linear correlation through the linear regression equation Y_EMIT = 1.310 × HPLC +0.149 (R² = 0.9082). The Bland-Altman plot analysis showed poor level consistency as measured by the two methods. The paired Wilcoxon-test showed a significant difference between the two methods (p < .0001). Compared to EMIT, HPLC accurately detected plasma VRZ concentration, making it suitable for VRZ therapeutic drug monitoring. The numerical values of the EMIT-measured levels were higher than those of HPLC, which may be related to VRZ metabolites interference and co-administrated drugs.

Polymer microparticles with a cavity designed for transarterial chemo-embolization with crystalline drug formulations

Transarterial chemo-embolization with drug-eluting embolic beads (DEB-TACE) is still evolving. Recent developments include the introduction of radiopaque (X-ray imageable) drug-eluting particles. Here, we report on conceptually different radiopaque polymeric drug-eluting embolic particles, which are (i), cross-linked poly(methacrylates); (ii), radiopaque; (iii), microporous. Furthermore, the particles are not perfectly spherical: they have a large indentation in the sense that they are either a spherical/cup-shaped or ellipsoid/mouth-shaped. The micropores and the large indentation can confer useful features upon the particles, since they can be filled with a crystalline lipophilic chemotherapeutic drug. It is important, in this respect that (i), many potent chemotherapeutics are lipophilic and crystalline; (ii), available drug-eluting beads (DEBs) have the limitation that they can only be used in combination with water-soluble chemotherapeutic agents. Cup- and mouth-shaped particles were obtained in a Cu(0) catalyzed free-radical polymerization reaction. The microparticles could be charged with crystalline drug, in such a manner that the crystals reside in both the micropores and the large cavity, and in quantities that would be required for effective local chemotherapy. The antifungal drug voriconazole, lipophilic, and crystalline, was used to demonstrate this. We believe that the ability of the microporous/cavitated DEBs to carry lipophilic chemotherapeutic drugs is especially important. DEB-TACE is likely to become a cornerstone method of interventional oncology in the years ahead, and the new embolic particles described herein hold the promise of becoming scope widening for the technique.

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.

Determination of voriconazole and co-administered drugs in plasma of pediatric cancer patients using UPLC-MS/MS: A key step towards personalized therapeutics

Untreated invasive aspergillosis results in high mortality rate in pediatric cancer patients. Voriconazole (VORI), the first line of treatment, requires strict dose monitoring because of its narrow therapeutic index and individual variation in plasma concentration levels. Commonly co-administered drugs; either Esomeprazole (ESO) or Ondansetron (OND) have reported drug-drug interaction with VORI that should adversely alter therapeutic outcomes of the latter. Although VORI, ESO and OND are co-administered to pediatric cancer patients, the combined effect of ESO and OND on the plasma concentration levels of VORI has not been fully explored. In this study, an accurate, reliable and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was developed and validated for simultaneous determination of VORI, ESO, and OND in ultra-low sample volumes (25 μL) of plasma of pediatric cancer patients. Based on the physicochemical properties of the studied drugs and internal standard, liquid-liquid extraction was successfully adopted with methyl t-butyl ether. Consistent and reproducible recovery of the three drugs and the internal standard were calculated using plasma and matrix matched samples (RE% > 72.97%, RSD < 8.29%). Chromatographic separation was carried out using UPLC with C18 column and a mobile phase of acetonitrile:water:methanol (70:25:5 V/V/V) at 0.3 mL/min. Mass spectrometric determination at positive electrospray ionization in the MRM mode was employed. The analysis was achieved within 4 min over a linear concentration range of 1.00-200.00 ng/mL for the three drugs. The assay validity was assessed as per the Food and Drug Administration guidelines for bioanalytical method validation, and satisfactory results were obtained. The accuracy and precision were within the acceptable limits for the three drugs in both quality control and incurred plasma samples. Matrix effect and process efficiency were investigated in neat solvent, post-extraction matrix, and plasma. Correlation of the plasma concentration levels of the three drugs revealed differences from the reported drug-drug interactions. This confirmed the need for simultaneous determination of VORI and co-administered drugs in order to achieve optimal therapeutic outcomes. To achieve this, analysis results of this study, genetic polymorphisms in CYP2C19 and clinical data will be used to establish one model incorporating all possible factors that might lead to variation in therapeutic outcomes.