Determination of cefuroxime in human serum or plasma by liquid chromatography with electrospray tandem mass spectrometry

Determination of cefuroxime in breast milk by LC-MS/MS using SALLME technique

The World Health Organization recommends that infants be exclusively breastfed for the first 6 months. Antibiotics are among the most commonly prescribed drugs for pregnant and lactating women. The vast majority of drugs pass into breast milk, which may create a risk for the infant. In cases where drug exposure may pose a risk, breastfeeding should be discontinued. Therefore, the mother's drug use should be decided by considering the most accurate and recent data. Cefuroxime is a second-generation cephalosporin antibiotic with a broad spectrum of activity against Gram-negative and -positive microorganisms. In this study, we aimed to develop the LC-MS/MS method using salt-assisted liquid-liquid micro-extraction (SALLME) for the determination of cefuroxime in breast milk. The method was validated according to the European Medicines Agency (EMA) guidelines. Cefuroxime and the internal standard cefixime were extracted from plasma by a SALLME technique. The results obtained from the entire validation study are at an acceptable level according to the EMA criteria. The calibration curve of cefuroxime was between 25 and 1000 ng/ml, with correlation coefficients of >0.99. The lower limit of quantitation was 25 ng/ml for cefuroxime. Furthermore, the developed method was applied for the determination of cefuroxime in real patient breast milk.

Quantification of total and unbound cefuroxime in plasma by ultra-performance liquid chromatography tandem mass spectrometry in a cohort of critically ill patients with hypoalbuminemia and renal failure

Background

Pharmacokinetic studies of cefuroxime by ultra‐performance liquid chromatography tandem mass spectrometry (UPLC‐MS/MS) have been limited to measurements of total concentrations. Here, we developed a robust method for quantifying total and unbound cefuroxime concentrations using UPLC‐MS/MS and ultrafiltration in critically ill patients with hypoalbuminemia and renal failure.

Methods

Method validation included accuracy, linearity, precision, repeatability, recovery, and limit of quantification (LOQ). Feasibility of the method was performed on samples obtained from randomly selected intensive care unit (ICU) patients. Total and unbound cefuroxime concentrations were quantified using UPLC‐MS/MS. Sampling times were categorized as trough (180‐1 min prior to administration), peak (10‐30 min after administration), mid (30‐360 min after administration), and continuous (sampling during administration). Pharmacokinetic/pharmacodynamic (PK/PD) targets were unbound cefuroxime concentrations above 4 times the minimum inhibitory concentration (32 mg/L).

Results

Intra‐assay and inter‐assay precision was <3%. Recovery was 99.7%‐100.3%, and LOQ was 0.1 mg/L. We included 11 patients (median age 72 years (range 54‐77). Median albumin serum concentrations and eGFR were 19 g/L (range 11‐40 g/L) and 48 mL/min/1.73 m² (range 7‐115 mL/min/1.73 m²), respectively. Median trough and mid concentrations of total cefuroxime were 22.27 mg/L (range 5.42‐54.03 mg/L) and 71.49 mg/L (range 53.87‐73.86 mg/L), and median unbound fraction was 75.42% (range 27.36%‐99.75%). Median unbound cefuroxime concentrations were 11.94 mg/L (range 3.85‐32.39 mg/L) (trough) and 55.62 mg/L (range 10.03‐62.62 mg/L) (mid).

Conclusion

The method is precise and accurate according to ISO 15189 and within the clinical range of cefuroxime (0.5‐100 mg/L). The method was applied in ICU patients and is suitable for TDM on unbound cefuroxime concentrations.

Simple and Robust Analysis of Cefuroxime in Human Plasma by LC-MS/MS: Application to a Bioequivalence Study

A simple, robust LC-MS/MS assay for quantifying cefuroxime in human plasma was developed. Cefuroxime and tazobactam, as internal standard (IS), were extracted from human plasma by methanol to precipitate protein. Separation was achieved on a Zorbax SB-Aq (4.6 × 250 mm, 5  μ m) column under isocratic conditions. The calibration curve was linear in the concentration range of 0.0525-21.0  μ g/mL (r = 0.9998). The accuracy was higher than 90.92%, while the intra- and interday precision were less than 6.26%. The extraction procedure provides recovery ranged from 89.44% to 92.32%, for both analyte and IS. Finally, the method was successfully applied to a bioequivalence study of a single 500 mg dose of cefuroxime axetil in 22 healthy Chinese male subjects under fasting condition. Bioequivalence was determined by calculating 90% Cls for the ratios of C max, AUC0-t , and AUC0-∞ values for the test and reference products, using logarithmic transformed data. The 90% Cls for the ratios of C max (91.4%~104.2%), AUC0-t (97.4%~110.9%), and AUC0-∞ (97.6%~111.1%) values were within the predetermined range. It was concluded that the two formulations (test for capsule, reference for tablet) analyzed were bioequivalent in terms of rate and extent of absorption and the method met the principle of quick and easy clinical analysis.

[Determination of cefuroxime in liver-injured rat plasma by ultra fast liquid chromatography-tandem mass spectrometry via acidified protein precipitation]

In order to investigate the pharmacokinetic profiles of cefuroxime lysine, a new second generation cephalosporins, in liver-injured rat model, an ultra fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method for the determination of cefuroxime in liver-injured rat plasma was developed and validated. The plasma sample was pretreated by protein precipitation with acidified acetonitrile. The analytes were separated on a Shim-pack XR-ODS column (75 mm x 3.0 mm, 2.2 microm) with acetonitrile-0. 1% formic acid aqueous solution (40:60, v/v) as the mobile phase at a flow rate of 400 microL/min. The mass spectrometer was operated in multiple reaction monitoring (MRM) mode with a negative electrospray ionization (ESI) interface. The precursor to product ion transitions of m/z 423.2 --> 206.8 and m/z 454.1 --> 238.4 were selected to determine cefuroxime and cefotaxime (internal standard, IS), respectively. The linearities ranged from 0.01 to 1 mg/L and 1 to 400 mg/L (r > 0.99), and the limit of quantification of cefuroxime was 0.01 mg/L. The relative standard deviations (RSDs) of intra- and inter-day precisions were both less than 11.5%, and the accuracy (relative error) was between -7.1% and 2.2%. The mean extraction recovery was more than 83.5%. The total run time was 3.0 min per sample. The method is simple and fast for the preliminary pharmacokinetic study of cefuroxime lysine in liver-injured rats.

Monitoring bacterial resistance to chloramphenicol and other antibiotics by liquid chromatography electrospray ionization tandem mass spectrometry using selected reaction monitoring

Antibiotic resistance is a growing problem worldwide. For this reason, clinical laboratories often determine the susceptibility of the bacterial isolate to a number of different antibiotics in order to establish the most effective antibiotic for treatment. Unfortunately, current susceptibility assays are time consuming. Antibiotic resistance often involves the chemical modification of an antibiotic to an inactive form by an enzyme expressed by the bacterium. Selected reaction monitoring (SRM) has the ability to quickly monitor and identify these chemical changes in an unprecedented time scale. In this work, we used SRM as a technique to determine the susceptibility of several different antibiotics to the chemically modifying enzymes β-lactamase and chloramphenicol acetyltransferase, enzymes used by bacteria to confer resistance to major classes of commonly used antibiotics. We also used this technique to directly monitor the effects of resistant bacteria grown in a broth containing a specific antibiotic. Because SRM is highly selective and can also identify chemical changes in a multitude of antibiotics in a single assay, SRM has the ability to detect organisms that are resistant to multiple antibiotics in a single assay. For these reasons, the use of SRM greatly reduces the time it takes to determine the susceptibility or resistance of an organism to a multitude of antibiotics by eliminating the time-consuming process found in other currently used methods.

Comparative pharmacokinetics of cefuroxime lysine after single intravenous, intraperitoneal, and intramuscular administration to rats

AIM

To compare the pharmacokinetic parameters of cefuroxime lysine, a new second-generation of cephalosporin antibiotics, after intravenous (IV), intraperitoneal (IP), or intramuscular (IM) administration.

METHODS

Twelve male and 12 virgin female Sprague-Dawley rats, weighing from 200 to 250 g, were divided into three groups (n=4 for each gender in each group). The rats were administered a single dose (67.5 mg/kg) of cefuroxime lysine via IV bolus or IP or IM injection. Blood samples were collected and analyzed with a validated UFLC-MS/MS method. The concentration-time data were then calculated by compartmental and non-compartmental pharmacokinetic methods using DAS software.

RESULTS

After IV, IP or IM administration, the plasma cefuroxime lysine disposition was best described by a tri-compartmental, bi-compartmental or mono-compartmental open model, respectively, with first-order elimination. The plasma concentration profiles were similar through the 3 administration routes. The distribution process was rapid after IV administration [t(1/2(d)), 0.10 ± 0.11 h vs 1.36 ± 0.65 and 1.25 ± 1.01 h]. The AUMC(0-∞) is markedly larger, and mean residence time (MRT) is greatly longer after IP administration than that in IV, or IM routes (AUMC(0-∞): 55.33 ± 20.34 vs 16.84 ± 4.85 and 36.17 ± 13.24 mg·h(2)/L; MRT: 0.93 ± 0.10 h vs 0.37 ± 0.07 h and 0.65 ± 0.05 h). The C(max) after IM injection was significantly higher than that in IP injection (73.51 ± 12.46 vs 49.09 ± 7.06 mg/L). The AUC(0-∞) in male rats were significantly higher than that in female rats after IM administration (66.38 ± 16.5 vs 44.23 ± 6.37 mg·h/L). There was no significantly sex-related difference in other pharmacokinetic parameters of cefuroxime lysine between male and female rats.

CONCLUSION

Cefuroxime lysine shows quick absorption after IV injection, a long retension after IP injection, and a high C(max) after IM injection. After IM administration the AUC(0-∞) in male rats was significantly larger than that in female rats.

Advances in antibiotic measurement

Antibiotics are most commonly prescribed drugs in clinical practice. Therapeutic drug monitoring of these medications is typically associated with a select group of antibiotics such as aminoglycosides and vancomycin. Outside this group, other antibiotics such as chloramphenicol and antituberculosis agents may also require monitoring. Due to their wide therapeutic index, other classes of antibiotics such as penicillins, cephalosporin, sulfonamides, quinolones, and macrolides do not generally require routine therapeutic drug monitoring. Determination of serum or plasma concentration of these drugs, however, may be beneficial in those patients with compromised renal function. As can be expected, immunoassays for routine monitoring of aminoglycosides and vancomycin have been developed and are widely commercially available. Tests for other antibiotics, due to their infrequent use and low clinical application, are generally limited to in-house developed methods.

Characterization of biomarkers in polycystic ovary syndrome (PCOS) using multiple distinct proteomic platforms

A variety of prefractionation methods (including a novel reversed-phase solid-phase-extraction (RP-SPE) combined with SDS-PAGE and proteomic based approaches (e.g., 2-dimensional gel electrophoresis (2DE) and MALDI-TOF mass spectrometry combined with Artificial Neural Network (ANN) bioinformatic tools) were used to investigate the protein/peptide signatures in patients with Polycystic Ovary Syndrome (PCOS). Four potential PCOS biomarkers were identified (complement C4alpha3c and C4gamma and haptoglobin alpha and beta chains).

A population pharmacokinetic model for cefuroxime using cystatin C as a marker of renal function

AIMS

Since cefuroxime mainly is excreted by renal filtration, dosing is currently based on serum creatinine (Scr) or creatinine clearance (CLcr). However, it has been suggested that cystatin C (CysC) is superior to Scr as a marker of renal function. The aim of this prospective study was to develop a population model that describes the pharmacokinetics of cefuroxime and to investigate the usefulness of CysC as a covariate of the model parameters.

METHODS

Ninety-seven patients were studied (CLcr range 6.5-115 ml min(-1)). Blood samples (n = 407) for the determination of cefuroxime were withdrawn according to a sparse data sampling schedule and analysed by liquid chromatography mass spectrometry. The population analysis was performed in NONMEM.

RESULTS

A two-compartment model described the data well. The biomarkers Scr, CLcr and CysC were evaluated as covariates on clearance (CL). The model that included CysC generated the best fit. In the final population model CL was a function of CysC and body weight, whereas V(1) was only a function of body weight. Final parameter estimates (relative standard errors) were 6.00 (3.2%) l h(-1), 11.4 (5.3%) l and 5.11 (11%) l for CL, V(1) and V(2), respectively.

CONCLUSIONS

Based on the results of the present study, and because CysC is practical to use in the clinic, it is suggested that individual dosing of cefuroxime may be based on CysC rather than on Scr or CLcr. Furthermore, our final population model may be useful as a tool when designing new dosing schedules for cefuroxime.