Determination of levofloxacin, ciprofloxacin, moxifloxacin and gemifloxacin in urine and plasma by HPLC-FLD-DAD using pentafluorophenyl core-shell column: Application to drug monitoring

Luminescent and time-resolved determination of gemifloxacin mesylate in pharmaceutical formulations and spiked blood plasma samples using a lanthanide complex as a probe

A novel luminescence-based analytical methodology was established employing a europium(III) complex with 3-allyl-2-hydroxybenzohydrazide (HAZ) as the coordinating ligand for the quantification of gemifloxacin mesylate (GMF) in pharmaceutical preparations and human plasma samples spiked with the compound. The stoichiometry of the europium complex with HAZ was determined via the Job plot and exhibited a metal-to-ligand ratio of 1 : 2. The analytical procedure relies on a rapid and significant enhancement of luminescence by the Eu(AZ)2 complex when it interacts with gemifloxacin mesylate, which allowed for the rapid detection of 96 samples within approximately 2 minutes. The thermodynamic parameters of the complexation of GMF with Eu(AZ)2 were evaluated and showed that the complexation of GMF was spontaneous with a negative ΔG. The binding constant K was 4.27 × 105 L mol-1 and DFT calculations supported GMF binding and the formation of Eu(AZ)2-GMF without further ligand exchange. The calibration graph for the luminescence quantitation of GMF was linear over a wide concentration range of 0.11-16 μg mL-1 (2.26 × 10-7 to 3.30 × 10-5 mol L-1), with a limit of quantification (LOQ) of 110 ng mL-1 (230 nmol L-1) and a detection limit (LOD) of 40 ng mL-1 (82 nmol L-1). The proposed method showed good accuracy with an average recovery of 99% with relative standard deviations of less than 5% in spiking experiments, even in complex pharmaceutical dosage forms such as tablets and in human blood plasma. Herein, the ability of the suppression of the luminescence background by using the long lag times of the lanthanide probe in a time-resolved detection scheme provided reliable and precise results, which suggests its potential for use in further real or patient samples.

Ocular bioanalysis of moxifloxacin and ketorolac tromethamine in rabbit lacrimal matrix using liquid chromatography-tandem mass spectrometry

Aim: The fixed-dose combination of moxifloxacin (MOXI) and ketorolac tromethamine (KTR) is widely used for the treatment of bacterial keratitis. Thus, a new LC-MS/MS method was developed to determine MOXI and KTR in lacrimal fluid. Methods: Bioanalysis was performed using a Shimadzu 8050 LC-MS/MS in electrospray ionization-positive mode and the method was validated per US FDA guidelines. Isocratic separation was performed with a Waters Symmetry C18 column using methanol and 0.1% formic acid containing deionized water (85:15, v/v). Results & conclusion: An easy, quick and selective method was established and applied to assess the ocular pharmacokinetic profile of a commercially available formulation containing MOXI and KTR. Based on the pharmacokinetic data, this work describes pharmacokinetics-based dosage regimen calculations and their clinical significance.

Development, Validation, and Clinical Application of an Ultra-High-Performance Liquid Chromatography Coupled With Tandem Mass Spectrometry Method for the Determination of 10 Antituberculosis Drugs in Human Serum

INTRODUCTION

Linezolid, moxifloxacin, rifapentine, rifabutin, cycloserine, clofazimine, bedaquiline, levofloxacin, prothionamide, and ethionamide are commonly used second-line antituberculosis (anti-TB) drugs. To support therapeutic drug monitoring in regular clinical practice, the authors sought to develop a method based on ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) that would allow for the simultaneous quantification of multiple second-line anti-TB drugs in human serum.

METHODS

Analytes were extracted from human serum by protein precipitation. UHPLC-MS/MS was performed using a gradient at a flow rate of 0.3 mL/min, and each sample was taken for 7.5 minutes. The mass spectrometry scanning mode used was electrospray ionization with multiple reaction monitoring in the positive mode.

RESULTS

Validation showed that endogenous substances in the sample did not interfere with the assay, and the relationship between X and Y was highly linear, with a coefficient of determination (R2) >0.9954 for each curve. The accuracy (85.0%-114.7%) and precision (intraday: 0.27%-9.32%; interday: 0.20%-7.66%) were less than 15.0%, and the internal standard-normalized matrix effects were consistent (coefficient of variation ≤4.40%). The analytes were stable in the final extract and human serum under various storage conditions (recovery: 87.0%-115.0%). The clinical applicability of the method was demonstrated by quantitative determination of analytes in serum samples obtained from patients with TB. Reproducibility of the drug concentrations measured in clinical samples was confirmed by incurred sample reanalysis.

CONCLUSIONS

A simple and reliable analytical method was developed and validated for the simultaneous determination of 10 anti-TB drugs in human serum using UHPLC-MS/MS. Quantitation of anti-TB drugs in clinical samples confirmed that the assay is suitable for therapeutic drug monitoring in regular clinical practice.

A QbD-led simple and sensitive RP-UHPLC method for simultaneous determination of moxifloxacin, voriconazole, and pirfenidone: An application to pharmaceutical analysis

A novel, quick and precise RP-UHPLC analytical method for the simultaneous determination of moxifloxacin (MFX), voriconazole (VCZ) and pirfenidone (PIR) was developed and validated according to the International Conference on Harmonization guidelines using a QbD-driven response surface Box-Behnken design. The developed method was validated considering the selectivity, sensitivity, linearity, accuracy-precision, robustness, stability, limit of detection and limit of quantification, respectively. Resolution between MFX, VCZ and PIR was achieved using a gradient elution protocol against a Waters Symmetry Shield C18 column (150 × 4.6 mm2 , 5 μm) using an Agilent 1290, Infinity II series LC system. The method was applied to quantitatively estimate proprietary and in-house prepared pharmaceutical topical ophthalmic formulations containing MFX, VCZ and PIR at wavelength (λmax ) of 296, 260 and 316 nm. The method is sensitive enough to detect up to 0.1 ppm of analytes in the formulation. The method was further exploited to study and identify the possible degradation products of the analytes. The proposed chromatographic method is simple, economical, reliable and reproducible. In conclusion, the developed method could be applicable for routine quality control analysis of single or combined MFX, VCZ and PIR-containing units or bulk dosage forms in pharmaceutical industries and research organizations working on drug discovery and development.

Lab-in-syringe automated protein precipitation and salting-out homogenous liquid-liquid extraction coupled online to UHPLC-MS/MS for the determination of beta-blockers in serum

A sample preparation method involving tandem implementation of protein precipitation and salting-out homogenous liquid-liquid extraction was developed for the determination of beta-blockers in serum. The entire procedure was automated using a computer-controlled syringe pump following the Lab-In-Syringe approach. It is based on the denaturation of serum proteins with acetonitrile followed by salt-induced phase separation upon which the proteins accumulate as a compact layer at the interphase of the solutions. The extract is then separated and diluted in-syringe before being submitted to online coupled UHPLC-MS/MS. A 1 mL glass syringe containing a small stir bar for solution mixing at up to 3000 rpm, was used to deal with sample volumes as small as 100 μL. A sample throughput of 7 h^-1 was achieved by performing the chromatographic run and sample preparation procedure in parallel. Linear working ranges were obtained for all analytes between 5 and 100 ng mL^-1, with LOD values ranging from 0.4 to 1.5 ng mL^-1. Accuracy values in the range of 88.2-106% and high precision of <11% RSD suggest applicability for routine analysis that can be further improved using deuterated standards.

Simple, fast and reliable CE method for simultaneous determination of ciprofloxacin and ofloxacin in human urine

A simple, fast, and accurate capillary zone electrophoresis method has been developed for the determination of ciprofloxacin and ofloxacin. This method uses liquid–liquid extraction. Therefore, it is characterized by a very simple procedure of sample preparation but at the same time satisfactory precision and accuracy. The extraction process of the same urine sample was repeated three times. The extraction protocol was performed each time for 15 min with 1 mL of dichloromethane and chloroform mixture in a 3:1 volume ratio. A 0.1 mol/L phosphate-borate buffer (pH 8.40) was selected as the background electrolyte. UV detection was performed at 288 nm. The separation was carried out at a voltage of 16 kV, at a temperature of 25 °C. Experimentally evaluated LOQ values for ciprofloxacin and ofloxacin were 0.2 nmol/mL urine and 0.05 nmol/mL urine, respectively. For both analytes the calibration curves exhibited linearity over the entire tested concentration range of 1–6 nmol/mL urine. The precision of the method did not exceed 15%, and the recovery was in the range of 85–115%. The developed and validated procedure was applied to analyze human urine for the content of ciprofloxacin and ofloxacin.

Lab-In-Syringe automation of deep eutectic solvent-based direct immersion single drop microextraction coupled online to high-performance liquid chromatography for the determination of fluoroquinolones

Lab-In-Syringe direct immersion single drop microextraction is proposed as an automated sample pretreatment methodology and coupled online to HPLC with fluorescence detection for the determination of fluoroquinolones in environmental waters. For the first time, a drop of a natural deep eutectic solvent (NADES), synthesized from hexanoic acid and thymol, has been used as an extractant in automated single-drop microextraction. The extraction procedure was carried out within the 5 mL void of an automatic syringe pump. A 9-position head valve served the aspiration of all required solutions, air, waste disposal, and hyphenation with the HPLC instrument. Sample mixing during extraction was done by a magnetic stirring bar placed inside the syringe. Only 60 μL of NADES were required omitting toxic classical solvents and improving the greenness of the proposed methodology. By direct injection, linear working ranges between 0.1 and 5 μg L^-1 were achieved for all fluoroquinolones. The limit of quantification values and enrichment factors ranged from 20 ng L^-1 to 30 ng L^-1 and 35 to 45, respectively. Accuracies obtained from the analysis of spiked surface water and wastewater treatment plant effluent analysis at two concentration levels (0.5 and 4 μg L^-1) ranged from 84.6% to 119.7%, with RSD values typically <3%.

Simultaneous Determination of Ciprofloxacin and Ofloxacin in Animal Tissues with the Use of Capillary Electrophoresis with Transient Pseudo-Isotachophoresis

We have developed a precise and accurate method for the determination of ciprofloxacin and ofloxacin in meat tissues. Our method utilizes capillary electrophoresis with a transient pseudo-isotachophoresis mechanism and liquid–liquid extraction during sample preparation. For our experiment, a meat tissue sample was homogenized in pH 7.00 phosphate buffer at a ratio of 1:10 (tissue mass: buffer volume; g/mL). The extraction of each sample was carried out twice for 15 min with 600 µL of a mixture of dichloromethane and acetonitrile at a 2:1 volume ratio. We then conducted the electrophoretic separation at a voltage of 16 kV and a temperature of 25 °C using a background electrolyte of 0.1 mol/L phosphate–borate (pH 8.40). We used the UV detection at 288 nm. The experimentally determined LOQs for ciprofloxacin and ofloxacin were 0.27 ppm (0.8 nmol/g tissue) and 0.11 ppm (0.3 nmol/g tissue), respectively. The calibration curves exhibited linearity over the tested concentration range of 2 to 10 nmol/g tissue for both analytes. The relative standard deviation of the determination did not exceed 15%, and the recovery was in the range of 85–115%. We used the method to analyze various meat tissues for their ciprofloxacin and ofloxacin contents.

A comprehensive review of pharmacokinetic and pharmacodynamic in animals: exploration of interaction with antibiotics of Shuang-Huang-Lian preparations

As a traditional Chinese medicine, Shuang-Huang-Lian (SHL) has been widely used for treating infectious diseases of the respiratory tract such as encephalitis, pneumonia and asthma. During the past few decades, considerable research has focused on the pharmacological action, pharmacokinetic interaction with antibiotics and clinical applications of SHL. A huge and more recent body of pharmacokinetic study supports the combination of SHL and antibiotics has different effects such as antagonism and synergism. SHL has been one of the best-selling traditional Chinese medicine (TCM) products. However, there is no system review of SHL preparations, ranging from protection against respiratory tract infections to interaction with antibiotics. Since their important significance in clinical therapy, the pharmacodynamic, pharmacokinetic, and interactions with antibiotics of SHL were reviewed and discussed. In addition, this review attempts to explore the possible potential mechanism of SHL preparations in prevention and treatment of COVID-19. We are concerned about what is known of the effects of SHL against virus, bacterium, and its interactions with antibiotics, providing a new strategy for expanding the clinical research and medication of SHL preparations.

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.