A rapid and simple UPLC method for serum vancomycin determination in pediatric patients undergoing continuous infusion or intermittent infusion of vancomycin

A rapid and simple HPLC-MS/MS method for the therapeutic drug monitoring of six special-grade antimicrobials in pediatric patients

Meropenem, linezolid, fluconazole, voriconazole, posaconazole, and vancomycin are six important antimicrobials used for severe infections in critically ill patients listed in special-grade antimicrobials in China. The six antimicrobials' highly variable pharmacodynamics and pharmacokinetics in critically ill pediatric patients present significant challenges to clinicians in ensuring optimal therapeutic targets. Therefore, therapeutic drug monitoring of these antimicrobials in human plasma is necessary to obtain their plasma concentration. A rapid, simple, and sample-saving high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed, which could simultaneously determine all six antimicrobials. It required only 10 μL of plasma and a one-step protein precipitation process. Chromatographic separation was achieved on a reversed-phase column (C18, 30 × 2.1 mm, 2.6 μm) via gradient elution using water and acetonitrile containing 0.1 % formic acid as mobile phase. The injection volume was 2 μL, and the total run time was only 2.5 min. Detection was done using a Triple Quad™ 4500MD tandem mass spectrometer coupled with an electrospray ionization (ESI) source in positive mode. The calibration curves ranged from 0.5 to 64 μg/mL for meropenem and fluconazole, 0.2-25.6 μg/mL for linezolid and voriconazole, 0.1-12.8 μg/mL for posaconazole and 1-128 μg/mL for vancomycin, with the coefficients of correlation all greater than 0.996. Furthermore, the method was validated rigorously according to the European Medicines Agency (EMA) guidelines, demonstrating excellent accuracy (from 93.0 % to 110.6 %) and precision (from 2.0 % to 12.8 %). Moreover, its applicability to various matrices (including serum, hemolytic plasma, and hyperlipidemic plasma) was evaluated. Thus, this method was successfully applied to routine therapeutic drug monitoring for critically ill pediatric patients and other patients in need.

Surface molecularly imprinted solid-phase extraction for the determination of vancomycin in plasma samples using HPLC-MS/MS

Vancomycin is a glycopeptide antibiotic used to treat infections caused by Gram-positive bacteria. Due to the narrow therapeutic index of vancomycin, it is necessary to develop a sensitive and reliable analytical method to monitor the drug concentration in plasma. A novel method based on surface molecularly imprinted solid-phase extraction combined with liquid chromatography-tandem mass spectrometry for the determination of vancomycin in plasma sample was developed. The plasma sample was cleaned up through the solid-phase extraction process before the analysis. The calibration standard of vancomycin in plasma ranged between 1 and 100 ng/mL, and the correlation coefficient (r) was 0.9993. The average recoveries were from 94.3 to 104.0%, and the precision was less than 10.5%. The limit of detection and limit of quantification were 0.5 ng/mL and 1 ng/mL, respectively. The method validated was successfully used for the detection of vancomycin in mice after oral administration.

CuS nanoparticles-enhanced luminol-O2 chemiluminescence reaction used for determination of paracetamol and vancomycin

A new chemiluminescence (CL) method was proposed to measure two widely used drugs, including paracetamol (PCM) and vancomycin (VAN). The CL reaction used was the CuS nanoparticles (CuS NPs)-luminol-O₂ system. In this system, CuS NPs played the role of catalyst and increased the CL intensity. CuS NPs were easily synthesized by quick-precipitation. CuS NPs were characterized by spectroscopic techniques, and the mean size of NPs was estimated to be about 9 nm. In the developed CL methods, PCM and VAN decreased the CL intensity. In the proposed method, the linear concentration ranges were 4.0 × 10^-5-4.0 × 10^-4 mol L^-1 of PCM and 2.0 × 10^-5-6.0 × 10^-4 mol L^-1 of VAN. The limit of detections were 2.9 × 10^-5 mol L^-1 and 8.9 × 10^-6 mol L^-1 for PCM and VAN, respectively. The relative standard deviations (RSD) of the CL method were 2.99 and 4.31 (n = 6) for the determination of 3.0 × 10^-4 mol L^-1 PCM and VAN, respectively. It was also shown that the CL methods can measure PCM and VAN concentrations in various real samples.

A UPLC-MS/MS method for simultaneous determination of nine antiepileptic drugs in human plasma and its application in TDM

With the purpose of carrying out therapeutic drug monitoring (TDM) of nine antiepileptic drugs simultaneously in the clinic, a UPLC-MS/MS assay method was developed and validated. Separation of antiepileptic drugs and internal standard (naproxen and diazepam) was performed on an Agilent Eclipse XDB-C₁₈ column (50.0 × 2.1 mm, 1.7 μm) using water and acetonitrile as mobile phase for gradient elution. Polarity switch ionization mode (positive-negative-positive) was performed in a total run time of 3.0 min. The method validation was conducted based on bioanalytical method validation guidance, including specificity, calibration curve, precision, accuracy, recovery, matrix effect, stability and dilution integrity, and all of the results satisfied the requirements. Consequently, the proposed method was applied to the TDM of nine antiepileptic drugs and was proved to be sensitive, reliable and specific to determine antiepileptic drugs in human plasma simultaneously. Meanwhile, the TDM results showed that the plasma drug concentration of many patients was not within the effective therapeutic range, especially those taking topiramate, oxcarbazepine and levetiracetam, which was of great guiding significance to rational drug use and timely adjustment of the treatment plan. Therefore, individualized therapy based on advanced analytical methods and TDM theory is of great practical significance.

A systematic review on chromatography-based method validation for quantification of vancomycin in biological matrices

A fully validated bioanalytical methods are prerequisite for pharmacokinetic and bioequivalence studies as well as for therapeutic drug monitoring. Due to high pharmacokinetic variability and narrow therapeutic index, vancomycin requires reliable quantification methods for therapeutic drug monitoring. To identify published chromatographic based bioanalytical methods for vancomycin in current systematic review, PubMed and ScienceDirect databases were searched. The selected records were evaluated against the method validation criteria derived from international guidelines for critical assessment. The major deficiencies were identified in method validation parameters specifically for accuracy, precision and number of calibration and validation standards, which compromised the reliability of the validated bioanalytical methods. The systematic review enacts to adapt the recommended international guidelines for suggested validation parameters to make bioanalysis reliable.

A network composed of gold nanoparticles and a poly(vinyl alcohol) hydrogel for colorimetric determination of ceftriaxone

A hydrogel network was prepared from poly(vinyl alcohol) (PVA) and borax, and then was modified with gold nanoparticles (AuNPs) that were obtained by in-situ nucleation and growth. This modified network is shown to be a viable optical nanoprobe for the drug ceftriaxone (CTRX) in biological samples. The properties and morphology of the modified network were investigated using energy dispersive X-ray analysis, transmission electron microscopy, zeta-sizing and viscosimetry. The UV-vis spectrum was recorded to verify the nanosynthesis of the red AuNPs, and the maximum absorption is found at 517 nm. This AuNP-poly(vinyl alcohol)-borax hydrogel nanoprobe (AuNP/PBH) is introduced as an optical nanoprobe for ceftriaxone in biological samples. The AuNPs have a better ability to attach the sulfur functional groups than amino functional groups. Hence, the probable mechanism is based on the attachment of sulfur functional groups of CRTX structure with AuNPs located in the PBH. As a result of this interaction, the surface plasmon resonance of AuNPs is altered in the presence of CTRX and the absorption of the nanoprobe is decreased at 517 nm. The effects of pH value, borax and PVA concentration were investigated. Under optimum conditions, the calibration graph is linear in the 1-90 μg mL^-1 CTRX concentration range, and the limit of detection is 0.33 μg mL^-1. The relative standard deviation for ten replicate measurements of at levels of 20 and 70 μg mL^-1 of CTRX was 4.0% and 2.2%, respectively. The nanoprobe was successfully applied to the determination of CTRX in (spiked) serum and urine samples. The performance of the nanoprobe was compared with HPLC method and the results were satisfactory. Graphical abstract Schematic representation of a new nanoprobe based on in situ formation of AuNPs into poly(vinyl alcohol) (PVA)-borax (PBH) hydrogel fabricated for ceftriaxone detection. The hydrogel acts as the reducing agent for production and embedding of AuNPs in the network.