Determination of vancomycin and meropenem in serum and synovial fluid of patients with prosthetic joint infections using UPLC-MS/MS.

Numerous studies have suggested that intra-articular administration of antibiotics following primary revision surgery may be one of the methods for treating prosthetic joint infection (PJI). Vancomycin and meropenem are the two most commonly used antibiotics for local application. Determining the concentrations of vancomycin and meropenem in the serum and synovial fluid of patients with PJI plays a significant role in further optimizing local medication schemes and effectively eradicating biofilm infections. This study aimed to establish a rapid, sensitive, and accurate ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determining the concentrations of vancomycin and meropenem in human serum and synovial fluid. Serum samples were processed using acetonitrile precipitation of proteins and dichloromethane extraction, while synovial fluid samples were diluted before analysis. Chromatographic separation was achieved in 6 min on a Waters Acquity UPLC BEH C18 column, with the mobile phase consisting of 0.1% formic acid in water (solvent A) and acetonitrile (solvent B). Quantification was carried out using a Waters XEVO TQD triple quadrupole mass spectrometer with an electrospray ionization (ESI) source in positive ion mode. The multiple reaction monitoring (MRM) mode was employed to detect the following quantifier ion transitions: 717.95-99.97 (norvancomycin), 725.90-100.04 (vancomycin), 384.16-67.99 (meropenem). The method validation conformed to the guidelines of the FDA and the Chinese Pharmacopoeia. The method demonstrated good linearity within the range of 0.5-50 µg/ml for serum and 0.5-100 µg/ml for synovial fluid. Selectivity, intra-day and inter-day precision and accuracy, extraction recovery, matrix effect, and stability validation results all met the required standards. This method has been successfully applied in the pharmacokinetic/pharmacodynamic (PK/PD) studies of patients with PJI.

Development of an HPLC Method for the Determination of Meropenem/Vaborbactam in Biological and Aqueous Matrixes.

A HPLC method was developed and validated to analyze meropenem and vaborbactam simultaneously in murine plasma and saline matrixes. A 60-µL volume of extracted sample was injected onto a 5-µm BDS Phenyl-Hypersil C18 reversed-phase column and analyzed with a UV detector set at 298 nm for the first 4.9 min and switched to 240 nm. The mobile phase contained a mixture of methanol and 25-mM sodium phosphate buffer set at a flow rate of 1.0 mL/min for the 16 min run time. Cefuroxime was used as the internal standard. The standard curves were linear over a range of 0.25-50 µg/mL. The precision and accuracy for 0.25 µg/mL (LLQ) in plasma for both compounds were <4.8% and >98.9%, respectively. Interday and intraday precision and accuracy for all QC plasma samples for both compounds were <6.2% and >95.7%, respectively. This methodology details a reproducible assay for both compounds using a single extraction with good accuracy and precision.

A High-Performance Liquid Chromatographic Method for the Determination of Meropenem in Serum.

In this study, a new, sensitive and selective high-performance liquid chromatographic method was developed for the determination of meropenem (MEM) in human serum. In the developed method, C18 column (3.9 × 150 mm, 5 µm) was selected as stationary phase at 30°C, and methanol: acetic acid solution mixture was used as mobile phase with gradient program. Chromatographic separation was carried out at a flow rate of 1 mL/min, and detection was performed at 300 nm with diode array detector. Doripenem was selected as an internal standard, and the analytes were extracted from serum using protein precipitation method with ortho-phosphoric acid: methanol. Detection wavelength was selected as 300 nm. The developed method was validated according to International Council for Harmonisation (ICH) guidelines. The calibration curve was linear over a concentration range of 4-240 µg/mL with correlation coefficient of 0.9985. The limit of detection and limit of quantification values were found as 0.057 and 0.192 µg/mL, respectively. The validated method was successfully applied for the determination of MEM in human serum samples collected from patient volunteers at different time intervals, and therapeutic drug monitoring of MEM has been investigated.

Plasma and Renal Cortex Meropenem Concentrations in Patients Undergoing Percutaneous Renal Biopsy.

BACKGROUND: Urinary tract infection (UTI) is the most common bacterial infection in the world. Some cases can have serious complication as death by septic shock. With the increasing spread of multidrug-resistant bacteria, the therapeutic possibilities against the complicated UTI are exhausted, forcing the use of broad-spectrum antibiotics such as meropenem. OBJECTIVES: To evaluate the penetrating ability of meropenem to renal tissue using an enzymatic biosensor in samples of renal cortex and its correlation with plasma levels. METHOD: We conducted a descriptive study in humans with indication of kidney biopsy. Meropenem was administered 1 hour before performing the biopsy, and the concentrations of meropenem in a series of samples of plasma and renal biopsy were determined. RESULTS: Renal biopsy and plasma samples of 14 patients, 64% women with body mass index of 26.3 kg/m2 (SD ± 2.9) and estimated glomerular filtration rate of 57.5 mL/min/1.73 m2 (SD ± 44.1), were examined. Renal biopsy was done at 68.9 minutes (SD ± 20.3), and the second plasma sample was obtained at 82.1 minutes (SD ± 21.2) and the third at 149.6 minutes (SD ± 31.5). The mean kidney meropenem concentration was 3.1 µg/mL (SD ± 1.9). For each patient, a decay curve of plasma meropenem concentration was constructed. The proportion of meropenem concentrations in renal tissue and plasma at biopsy moment was 14% (SD ± 10) with an interquartile range of 5.5-20.3%. With normal renal function, meropenem can achieve a bactericidal effect towards bacteria with MIC-90 < 0.76 µg/mL in the renal parenchyma. CONCLUSIONS: Meropenem is effective to treat the most frequent uropathogens with the bactericidal effect. Nevertheless, for resistant bacteria, it is necessary to adjust the dose to achieve adequate parenchymal concentration.

Plasma and synovial fluid pharmacokinetics of a single intravenous dose of meropenem in adult horses.

The objective of this study was to determine the pharmacokinetics of meropenem in horses after intravenous (IV) administration. A single IV dose of meropenem was administered to six adult horses at 10 mg/kg. Plasma and synovial fluid samples were collected for 6 hr following administration. Meropenem concentrations were determined by bioassay. Plasma and synovial fluid data were analyzed by compartmental and noncompartmental pharmacokinetic methods. Mean ± SD values for elimination half-life, volume of distribution at steady-state, and clearance after IV administration for plasma samples were 0.78 ± 0.176 hr, 136.1 ± 19.69 ml/kg, and 165.2 ± 29.72 ml hr-1  kg-1 , respectively. Meropenem in synovial fluid had a slower elimination than plasma with a terminal half-life of 2.4 ± 1.16 hr. Plasma protein binding was estimated at 11%. Based on a 3-compartment open pharmacokinetic model of simultaneously fit plasma and synovial fluid, dosage simulations were performed. An intermittent dosage of meropenem at 5 mg/kg IV every 8 hr or a constant rate IV infusion at 0.5 mg/kg per hour should maintain adequate time above the MIC target of 1 µg/ml. Carbapenems are antibiotics of last resort in humans and should only be used in horses when no other antimicrobial would likely be effective.

UPLC/MS/MS assay for the simultaneous determination of seven antibiotics in human serum-Application to pediatric studies.

A rapid and highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) assay was developed for quantification of 7 antibiotics in low sample volumes (50 µL): amoxicillin, azithromycin, cefotaxime, ciprofloxacin, meropenem, metronidazole and piperacillin, for both routine monitoring and pharmacokinetic studies. After protein precipitation by acetonitrile, the antibiotics were separated on an Acquity UPLC HSS T3 column (run time, 4 min). The mobile phase consisted of a mixture of (A) ammonium acetate (pH 2.4; 5 mM) and (B) acetonitrile acidified with 0.1% formic acid, delivered at 500 µl/min in a gradient elution mode. Total time run was 2.75 min. Ions were detected in the turbo-ion-spray-positive and multiple-reaction-monitoring modes. The assay was accurate and reproductible for the quantification of the seven antibiotics in serum samples over large concentration ranges.

Meropenem and ciprofloxacin in complicated gastric surgery for cancer patients: A simple SPE-UHPLC-PDA method for their determination in human plasma.

A simple and rapid ultra-high-performance liquid chromatographic (UHPLC) for the simultaneous determination of meropenem and ciprofloxacin in human plasma was developed and validated. All of the analytes were separated in <5 min. A solid-phase extraction method was applied from sample preparation. Analytical separation was performed on a Poroshell SB C18 column (50 × 2.1 mm, 2.7 µm particle size) with photodiode array (PDA) detection. Meropenem and ciprofloxacin were determined at wavelengths of 300 and 277 nm, respectively. The mobile phase was a mixture of acetonitrile-10 mm ammonium acetate-methanol in gradient elution. The method has been validated for both drugs in gastric surgery for cancer patients. The method showed good linearity with correlation coefficients, r2  = 0.994 for the two drugs, as well as high precision (RSD < 10.5% in each case); accuracy ranged from -5.8 to +6.0%. The limit of quantitation of the two drugs was established at 0.02 and 0.01 µg/mL, respectively. Meropenem, ciprofloxacin and the internal standard were extracted from human plasma with a mean recovery ranging from 92.5 to 98.6%. The method was applied to quantify the drugs dosage in complicated gastric surgery patients.

The exploration of population pharmacokinetic model for meropenem in augmented renal clearance and investigation of optimum setting of dose.

In recent years, augmented renal clearance (ARC), in which renal function is excessively enhanced, has been reported, and its influence on ß-lactam antibiotics has been investigated. In this study, we aimed to determine the optimum population pharmacokinetic model of meropenem in patients with sepsis with ARC, and evaluated dosing regimens based on renal function. Seventeen subjects (6 with ARC and 11 without) were enrolled in this study. Predicted meropenem concentrations were evaluated for bias and precision using the Bland-Altman method. To examine the dosing regimen, Monte Carlo simulation was performed to calculate the cumulative fraction of response (CFR). In patients with ARC, the bias (average of the predicted value and measured value residuals) of models constructed by Crandon et al. (2011), Roberts et al. (2009), and Jaruratanasirikul et al. (2015) were 5.96 µg/mL, 10.91 µg/mL, and 4.41 µg/mL, respectively. Following 2 g meropenem every 8 h (180 min infusion), CFR ≥ 90%, a criterion of success for empirical therapy, was achieved, even with creatinine clearance of 130-250 mL/min. For patients with sepsis and ARC, the model of Jaruratanasirikul et al. showed the highest degree of accuracy and precision and confirmed the efficacy of the meropenem dosing regimen in this patient population.