An adapted LC-MS/MS method for the determination of free plasma concentration of cefoperazone in children: Age-dependent protein binding

Simultaneous determination of four antibiotics in human plasma by high-performance LC-MS/MS: application to therapeutic drug monitoring

Background: Aimed to simultaneously measure linezolid, voriconazole, cefoperazone and fluconazole in human plasma suitable for therapeutic drug monitoring applications, a robust, rapid and easy-to-use HPLC-MS/MS approach was developed and validated. Materials & methods: Protein precipitation was used to prepare analytes from 100 μl plasma. HPLC was employed for analyte separation, and quantification was conducted via multiple reaction monitoring in positive ion mode. The methodology was fully validated. Results & conclusion: All four antibiotics were found to be stable under the tested conditions, and accuracy values ranged from 90.96 to 113.25% and CV values were <14.0%. This HPLC-MS/MS method can be used for routine clinical therapeutic drug monitoring of linezolid, voriconazole, cefoperazone and fluconazole simultaneously.

Developmental Pharmacokinetics of Antibiotics Used in Neonatal ICU: Focus on Preterm Infants

Neonatal Infections are among the most common reasons for admission to the intensive care unit. Neonatal sepsis (NS) significantly contributes to mortality rates. Empiric antibiotic therapy of NS recommended by current international guidelines includes benzylpenicillin, ampicillin/amoxicillin, and aminoglycosides (gentamicin). The rise of antibacterial resistance precipitates the growth of the use of antibiotics of the Watch (second, third, and fourth generations of cephalosporines, carbapenems, macrolides, glycopeptides, rifamycins, fluoroquinolones) and Reserve groups (fifth generation of cephalosporines, oxazolidinones, lipoglycopeptides, fosfomycin), which are associated with a less clinical experience and higher risks of toxic reactions. A proper dosing regimen is essential for effective and safe antibiotic therapy, but its choice in neonates is complicated with high variability in the maturation of organ systems affecting drug absorption, distribution, metabolism, and excretion. Changes in antibiotic pharmacokinetic parameters result in altered efficacy and safety. Population pharmacokinetics can help to prognosis outcomes of antibiotic therapy, but it should be considered that the neonatal population is heterogeneous, and this heterogeneity is mainly determined by gestational and postnatal age. Preterm neonates are common in clinical practice, and due to the different physiology compared to the full terms, constitute a specific neonatal subpopulation. The objective of this review is to summarize the evidence about the developmental changes (specific for preterm and full-term infants, separately) of pharmacokinetic parameters of antibiotics used in neonatal intensive care units.

Current knowledge, challenges and innovations in developmental pharmacology: A combined conect4children Expert Group and European Society for Developmental, Perinatal and Paediatric Pharmacology White Paper

Developmental pharmacology describes the impact of maturation on drug disposition (pharmacokinetics, PK) and drug effects (pharmacodynamics, PD) throughout the paediatric age range. This paper, written by a multidisciplinary group of experts, summarizes current knowledge, and provides suggestions to pharmaceutical companies, regulatory agencies and academicians on how to incorporate the latest knowledge regarding developmental pharmacology and innovative techniques into neonatal and paediatric drug development. Biological aspects of drug absorption, distribution, metabolism and excretion throughout development are summarized. Although this area made enormous progress during the last two decades, remaining knowledge gaps were identified. Minimal risk and burden designs allow for optimally informative but minimally invasive PK sampling, while concomitant profiling of drug metabolites may provide additional insight in the unique PK behaviour in children. Furthermore, developmental PD needs to be considered during drug development, which is illustrated by disease- and/or target organ-specific examples. Identifying and testing PD targets and effects in special populations, and application of age- and/or population-specific assessment tools are discussed. Drug development plans also need to incorporate innovative techniques such as preclinical models to study therapeutic strategies, and shift from sequential enrolment of subgroups, to more rational designs. To stimulate appropriate research plans, illustrations of specific PK/PD-related as well as drug safety-related challenges during drug development are provided. The suggestions made in this joint paper of the Innovative Medicines Initiative conect4children Expert group on Developmental Pharmacology and the European Society for Developmental, Perinatal and Paediatric Pharmacology, should facilitate all those involved in drug development.

Quantification of sixteen cephalosporins in the aquatic environment by liquid chromatography-tandem mass spectrometry

Antimicrobial agents are essential to protect human and animal health. During the COVID-19 pandemic, antimicrobials such as cephalosporins were widely used as prophylactics and to prevent bacterial co-infection. Undoubtedly, the prevalence of antibiotics in the aquatic environment will ultimately affect the degree of resistance against these bacteria in animals and the environmental systems. In order to monitor sixteen cephalosporins in the aquatic environment, we developed a new LC-MS/MS method that functioned simultaneously under positive and negative ESI switching modes. The chromatographic separation has been implemented using a pentafluorophenyl propyl column kept at 40°C. The limits of detection and quantitation for the studied cephalosporins ranged from (8 × 10^-4 ) to (7.11 × 10^-2 ) ng/mL and from (2.61 × 10^-3 ) to (2.37 × 10^-1 ) ng/mL, respectively. The percent extraction efficiency (apparent recovery) and relative standard deviations for the analyzed cephalosporins ranged from 61.69 to 167.67% and 2.45 to 13.48%, respectively. The overall findings showed that the effluent from the wastewater treatment plants that receive wastewater from pharmaceutical factories had a higher detected amount of cephalosporins than that of domestic sewage. Moreover, seven cephalosporins, including cefuroxime, ceftazidime, cefradine, cefprozil, cefixime, cefalexin, and cefadroxil (0.68-105.45 ng/L) were determined in the aquatic environment. This article is protected by copyright. All rights reserved.

An Overview of the Protein Binding of Cephalosporins in Human Body Fluids: A Systematic Review

Introduction: Protein binding can diminish the pharmacological effect of beta-lactam antibiotics. Only the free fraction has an antibacterial effect. The aim of this systematic literature review was to give an overview of the current knowledge of protein binding of cephalosporins in human body fluids as well as to describe patient characteristics influencing the level of protein binding.

Method: A systematic literature search was performed in Embase, Medline ALL, Web of Science Core Collection and the Cochrane Central Register of Controlled Trials with the following search terms: “protein binding,” “beta-lactam antibiotic,” and “body fluid.” Only studies were included where protein binding was measured in humans in vivo.

Results: The majority of studies reporting protein binding were performed in serum or plasma. Other fluids included pericardial fluid, blister fluid, bronchial secretion, pleural exudate, wound exudate, cerebrospinal fluid, dialysate, and peritoneal fluid. Protein binding differs between diverse cephalosporins and between different patient categories. For cefazolin, ceftriaxone, cefpiramide, and cefonicid a non-linear pattern in protein binding in serum or plasma was described. Several patient characteristics were associated with low serum albumin concentrations and were found to have lower protein binding compared to healthy volunteers. This was for critically ill patients, dialysis patients, and patients undergoing cardiopulmonary bypass during surgery. While mean/median percentages of protein binding are lower in these patient groups, individual values may vary considerably. Age is not likely to influence protein binding by itself, however limited data suggest that lower protein binding in newborns. Obesity was not correlated with altered protein binding.

Discussion/Conclusion: Conclusions on protein binding in other body fluids than blood cannot be drawn due to the scarcity of data. In serum and plasma, there is a large variability in protein binding per cephalosporin and between different categories of patients. Several characteristics were identified which lead to a lower protein binding. The finding that some of the cephalosporins display a non-linear pattern of protein binding makes it even more difficult to predict the unbound concentrations in individual patients. Taken all these factors, it is recommended to measure unbound concentrations to optimize antibiotic exposure in individual patients.

Systematic Review Registration: PROSPERO, identifier (CRD42021252776).

Prediction of Unbound Ceftriaxone Concentration in Children: Simple Bioanalysis Method and Basic Mathematical Equation

The pharmacological activity of ceftriaxone depends on the unbound concentration. However, direct measurement of unbound concentrations is obstructive, and high individual variability of the unbound fraction of ceftriaxone was shown in children. We aim to evaluate and validate a method to predict unbound ceftriaxone concentrations in pediatric patients. Ninety-five pairs of concentrations (total and unbound) from 92 patients were measured by the bioanalysis method that we developed. The predictive performance of the three equations (empirical in vivo equation, disease-adapted equation, and multiple linear regression equation) was assessed by the mean absolute prediction error (MAPE), the mean prediction error (MPE), the proportions of the prediction error within ±30% (P ₃₀) and ±50% (P ₅₀), and linear regression of predicted versus actual unbound levels (R ²). The average total and unbound ceftriaxone concentrations were 126.18 ± 81.46 μg/ml and 18.82 ± 21.75 μg/ml, and the unbound fraction varied greatly from 4.75% to 39.97%. The MPE, MAPE, P ₃₀, P ₅₀, and R ² of the empirical in vivo equation, disease equation, and multiple linear equation were 0.17 versus 0.00 versus 0.06, 0.24 versus 0.15 versus 0.27, 63.2% versus 89.5% versus 74.7%, 96.8% versus 97.9% versus 86.3%, and 0.8730 versus 0.9342 versus 0.9315, respectively. The disease-adapted equation showed the best predictive performance. We have developed and validated a bioanalysis method with one-step extraction pretreatment for the determination of total ceftriaxone concentrations, and a prediction equation of the unbound concentration is recommended. The proposed method can facilitate clinical practice and research on unbound ceftriaxone in children. (This study has been registered at ClinicalTrials.gov under identifier NCT03113344.).