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Liu Y, Mack JO, Shojaee M, Shaver A, George A, Clarke W, Patel N, Arroyo-Currás N. Analytical Validation of Aptamer-Based Serum Vancomycin Monitoring Relative to Automated Immunoassays. ACS Sens 2024; 9:228-235. [PMID: 38110361 PMCID: PMC10826698 DOI: 10.1021/acssensors.3c01868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/27/2023] [Accepted: 12/05/2023] [Indexed: 12/20/2023]
Abstract
The practice of monitoring therapeutic drug concentrations in patient biofluids can significantly improve clinical outcomes while simultaneously minimizing adverse side effects. A model example of this practice is vancomycin dosing in intensive care units. If dosed correctly, vancomycin can effectively treat methicillin-resistant streptococcus aureus (MRSA) infections. However, it can also induce nephrotoxicity or fail to kill the bacteria if dosed too high or too low, respectively. Although undeniably important to achieve effectiveness, therapeutic drug monitoring remains inconvenient in practice due primarily to the lengthy process of sample collection, transport to a centralized facility, and analysis using costly instrumentation. Adding to this workflow is the possibility of backlogs at centralized clinical laboratories, which is not uncommon and may result in additional delays between biofluid sampling and concentration measurement, which can negatively affect clinical outcomes. Here, we explore the possibility of using point-of-care electrochemical aptamer-based (E-AB) sensors to minimize the time delay between biofluid sampling and drug measurement. Specifically, we conducted a clinical agreement study comparing the measurement outcomes of E-AB sensors to the benchmark automated competitive immunoassays for vancomycin monitoring in serum. Our results demonstrate that E-ABs are selective for free vancomycin─the active form of the drug, over total vancomycin. In contrast, competitive immunoassays measure total vancomycin, including both protein-bound and free drug. Accounting for these differences in a pilot study consisting of 85 clinical samples, we demonstrate that the E-AB vancomycin measurement achieved a 95% positive correlation rate with the benchmark immunoassays. Therefore, we conclude that E-AB sensors could provide clinically useful stratification of patient samples at trough sampling to guide effective vancomycin dose recommendations.
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Affiliation(s)
- Yu Liu
- ZiO
Health Ltd., The Tower,
St George Wharf, London SW82BW, U.K.
| | - John O. Mack
- Biochemistry,
Cellular and Molecular Biology Program, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Maryam Shojaee
- ZiO
Health Ltd., The Tower,
St George Wharf, London SW82BW, U.K.
| | - Alexander Shaver
- Department
of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Ankitha George
- ZiO
Health Ltd., The Tower,
St George Wharf, London SW82BW, U.K.
| | - William Clarke
- Department
of Pathology, Johns Hopkins University School
of Medicine, Baltimore, Maryland 21205, United States
| | - Neel Patel
- ZiO
Health Ltd., The Tower,
St George Wharf, London SW82BW, U.K.
| | - Netzahualcóyotl Arroyo-Currás
- Biochemistry,
Cellular and Molecular Biology Program, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- Department
of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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Wong S, Reuter SE, Jones GR, Stocker SL. Review and evaluation of vancomycin dosing guidelines for obese individuals. Expert Opin Drug Metab Toxicol 2022; 18:323-335. [PMID: 35815356 DOI: 10.1080/17425255.2022.2098106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Vancomycin dosing decisions are informed by factors such as body weight and renal function. It is important to understand the impact of obesity on vancomycin pharmacokinetics and how this may influence dosing decisions. Vancomycin dosing guidelines use varied descriptors of body weight and renal function. There is uncertainty whether current dosing guidelines result in attainment of therapeutic targets in obese individuals. AREAS COVERED Literature was explored using PubMed, Embase and Google Scholar for articles from January 1980 to July 2021 regarding obesity-driven physiological changes, their influence on vancomycin pharmacokinetics and body size descriptors and renal function calculations in vancomycin dosing. Pharmacokinetic simulations reflective of international vancomycin dosing guidelines were conducted to evaluate the ability of using total, ideal and adjusted body weight, as well as Cockcroft-Gault and CKD-EPI equations to attain an area-under-the-curve to minimum inhibitory concentration ratio (AUC24/MIC) target (400-650) in obese individuals. EXPERT OPINION Vancomycin pharmacokinetics in obese individuals remains debated. Guidelines that determine loading doses using total body weight, and maintenance doses adjusted based on renal function and adjusted body weight, may be most appropriate for obese individuals. Use of ideal body weight leads to subtherapeutic vancomycin exposure and underestimation of renal function.
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Affiliation(s)
- Sherilyn Wong
- UniSA Clinical and Health Sciences, University of South Australia, Adelaide, Australia
| | - Stephanie E Reuter
- UniSA Clinical and Health Sciences, University of South Australia, Adelaide, Australia
| | - Graham Rd Jones
- St Vincent's Clinical School, Faculty of Medicine, The University of New South Wales, Sydney, Australia.,Department of Chemical Pathology and Clinical Pharmacology, SydPath, St Vincent's Hospital, Darlinghurst, Australia
| | - Sophie L Stocker
- St Vincent's Clinical School, Faculty of Medicine, The University of New South Wales, Sydney, Australia.,Sydney School of Pharmacy, The University of Sydney, Sydney, Australia.,Department of Clinical Pharmacology & Toxicology, St Vincent's Hospital Sydney, Darlinghurst, Australia
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Clinical Practice Guidelines for Therapeutic Drug Monitoring of Vancomycin in the Framework of Model-Informed Precision Dosing: A Consensus Review by the Japanese Society of Chemotherapy and the Japanese Society of Therapeutic Drug Monitoring. Pharmaceutics 2022; 14:pharmaceutics14030489. [PMID: 35335866 PMCID: PMC8955715 DOI: 10.3390/pharmaceutics14030489] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 01/08/2023] Open
Abstract
Background: To promote model-informed precision dosing (MIPD) for vancomycin (VCM), we developed statements for therapeutic drug monitoring (TDM). Methods: Ten clinical questions were selected. The committee conducted a systematic review and meta-analysis as well as clinical studies to establish recommendations for area under the concentration-time curve (AUC)-guided dosing. Results: AUC-guided dosing tended to more strongly decrease the risk of acute kidney injury (AKI) than trough-guided dosing, and a lower risk of treatment failure was demonstrated for higher AUC/minimum inhibitory concentration (MIC) ratios (cut-off of 400). Higher AUCs (cut-off of 600 μg·h/mL) significantly increased the risk of AKI. Although Bayesian estimation with two-point measurement was recommended, the trough concentration alone may be used in patients with mild infections in whom VCM was administered with q12h. To increase the concentration on days 1–2, the routine use of a loading dose is required. TDM on day 2 before steady state is reached should be considered to optimize the dose in patients with serious infections and a high risk of AKI. Conclusions: These VCM TDM guidelines provide recommendations based on MIPD to increase treatment response while preventing adverse effects.
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Yan X, Tse AHW, Lee A, Zhang L, Yang M, Zuo Z, Joynt GM. Protein Binding and Population Pharmacokinetics of Dexmedetomidine after Prolonged Infusions in Adult Critically Ill Patients. Clin Ther 2021; 43:1356-1369.e1. [PMID: 34304911 DOI: 10.1016/j.clinthera.2021.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/14/2021] [Accepted: 06/07/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE Dexmedetomidine (DEX) is a highly selective α2-adrenoceptor agonist with high protein binding of 94%. Critical illness may affect protein binding and the pharmacokinetic (PK) parameters of many drugs, including DEX. In critically ill patients receiving prolonged infusions of DEX, there is little information documenting the relationship between key pathophysiologic factors and DEX protein binding or PK parameters. The purpose of this study was to characterize the protein binding and PK profile of prolonged DEX infusion in critically ill patients. METHODS Critically ill, adult intensive care unit patients at a university hospital in Hong Kong were studied. The association between the pathophysiologic changes of critical illness and protein binding was evaluated using a generalized estimating equation. A population pharmacokinetic model to establish the PK profile of DEX was developed, and key pathophysiologic covariate effects of severity of illness, organ dysfunction measures, and altered protein binding on DEX PK parameters in this critically ill population were evaluated. FINDINGS A total of 22 critically ill patients and 1 healthy control were included. Mean protein binding of DEX in the critically ill patients was 90.4% (95% CI, 89.1-91.7), which was 4% lower than that in the healthy control. The PK data were adequately described by a 2-compartment model. The estimated population mean (relative standard error [RSE]) values of systemic clearance (CL), volume of distribution of the central compartment (V2), intercompartmental clearance (Q), and Vd in the peripheral compartment (V3) were 38.6 (11.7) L/h, 32.1 (46.1) L, 114.5 (58.3) L/h and 95.1 (30.6) L, respectively. The corresponding estimated interindividual variability expressed as CV% (RSE) was 52.4 (23.8) for CL, 172.9 (19.3) for V2, 123.7 (33.7) for Q, and 106 (39.9) for V3. No significant explanatory pathophysiologic covariates were identified. IMPLICATIONS Although a marginally significant reduction of protein binding in critically ill patients was demonstrated, the magnitude of the difference was unlikely to be of clinical significance. Higher alanine aminotransferase concentration was associated with decreased protein binding. No significant pathophysiologic covariates were associated with the observed PK parameters. The high interindividual variability of PK parameters supports the current practice of dose titration to ensure the desired clinical effects of DEX infusion in the intensive care unit setting.
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Affiliation(s)
- Xiaoyu Yan
- School of Pharmacy, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Andrew Ho Wai Tse
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
| | - Anna Lee
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China.
| | - Lin Zhang
- School of Pharmacy, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Mengbi Yang
- School of Pharmacy, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Zhong Zuo
- School of Pharmacy, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Gavin Matthew Joynt
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
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Li X, Xu W, Li R, Guo Q, Li X, Sun J, Sun S, Li J. Prediction of Unbound Vancomycin Levels in Intensive Care Unit and Nonintensive Care Unit Patients: Total Bilirubin May Play an Important Role. Infect Drug Resist 2021; 14:2543-2554. [PMID: 34239310 PMCID: PMC8259942 DOI: 10.2147/idr.s311231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/11/2021] [Indexed: 11/23/2022] Open
Abstract
Background The mean unbound vancomycin fraction and whether the unbound vancomycin level could be predicted from the total vancomycin level are still controversial, especially for patients in different groups, such as intensive care unit (ICU) versus non-ICU patients. Other relevant potential patient characteristics that may predict unbound vancomycin levels have yet to be clearly determined. Methods We enrolled a relatively large study population and included widely comprehensive potential covariates to evaluate the unbound vancomycin fractions in a cohort of ICU (n=117 samples) and non-ICU patients (n=73 samples) by using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Results The mean unbound vancomycin fraction was 45.80% ± 18.69% (median, 46.01%; range: 2.13–99.45%) in the samples from the total population. No significant differences in the unbound vancomycin fraction were found between the ICU patients and the non-ICU patients (P=0.359). A significant correlation was established between the unbound and total vancomycin levels. The unbound vancomycin level can be predicted with the following equations: unbound vancomycin level=0.395×total vancomycin level+0.019×total bilirubin level+0.468 (R2=0.771) for the ICU patients and unbound vancomycin level=0.526×total vancomycin level-0.527 (R2=0.749) for the non-ICU patients. Overall, the observed-versus-predicted plots were acceptable. Conclusion A significant correlation between the total and unbound vancomycin levels was found, and measurement of the unbound vancomycin level seems to have no added value over measurement of the total vancomycin level. The study developed parsimonious equations for predicting the unbound vancomycin level and provides a reference for clinicians to predict the unbound vancomycin level in adult populations.
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Affiliation(s)
- Xiao Li
- Department of Clinical Pharmacy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, 266003, People's Republic of China
| | - Wen Xu
- Department of Clinical Pharmacy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, 266003, People's Republic of China
| | - Ran Li
- Department of Infectious Diseases, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, 266003, People's Republic of China
| | - Qie Guo
- Department of Clinical Pharmacy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, 266003, People's Republic of China
| | - Xiangpeng Li
- Department of Clinical Pharmacy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, 266003, People's Republic of China
| | - Jialin Sun
- Department of Clinical Pharmacy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, 266003, People's Republic of China
| | - Shuhong Sun
- Department of Clinical Pharmacy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, 266003, People's Republic of China
| | - Jing Li
- Department of Clinical Pharmacy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, 266003, People's Republic of China
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Kan M, Wu YE, Li X, Dong YN, Du B, Guo ZX, Shi HY, Huang X, Su LQ, Wang WQ, Zheng Y, Zhao W. An adapted LC-MS/MS method for the determination of free plasma concentration of cefoperazone in children: Age-dependent protein binding. J Chromatogr B Analyt Technol Biomed Life Sci 2020; 1144:122081. [DOI: 10.1016/j.jchromb.2020.122081] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 03/22/2020] [Accepted: 03/24/2020] [Indexed: 01/14/2023]
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Tagaya M, Okano S, Murataka T, Handa H, Ichikawa S, Takahashi S. Biocompatibility of a polymer-coated membrane possessing a hydrophilic blood-contacting layer: Adsorption-related assessment. Int J Artif Organs 2019; 43:405-410. [PMID: 31875413 DOI: 10.1177/0391398819895525] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Currently, the foreign surfaces of extracorporeal circulation devices are coated with an acrylate-based copolymer that creates a hydrophilic blood-contacting layer to enhance biocompatibility. Several reports of acrylate-based copolymer with respect to biocompatibility have been published; however, the adsorption of peptide compounds on acrylate-based copolymer-coated membranes still requires clarity. In this study, we aimed to understand the adsorption of several peptide compounds of various molecular weights, including albumin, lysozyme, and vancomycin, on acrylate-based copolymer-coated membranes using in vitro studies. METHODS Six experimental circuits consisting of acrylate-based copolymer-coated tubes and membranes, and six comprising acrylate-based copolymer-coated tubes and non-coated membranes were prepared for comparison. An experimental solution, composed of albumin, lysozyme, vancomycin, and saline, was continuously stirred in a reservoir, recirculated in each experimental circuit, and then filtered. Concentrations of albumin, lysozyme, and vancomycin were measured after 0, 15, 30, 45, 60, 90, and 120 min of recirculation. Similar experiments were performed in all the prepared circuits. RESULTS The ratio of measured values at each time point to those at 0 min was not significantly different between acrylate-based copolymer-coated and non-coated membranes for albumin and lysozyme, but differed significantly for vancomycin; the ratios were higher in acrylate-based copolymer-coated than in non-coated membranes. CONCLUSION This study suggests that albumin is not adsorbed on either acrylate-based copolymer-coated or non-coated membranes, that lysozyme is not adsorbed on either membrane or is adsorbed at a similar rate on both membranes, and that vancomycin is less adsorbed on acrylate-based copolymer-coated membranes. Thus, acrylate-based copolymer coating could inhibit the adsorption of various peptide compounds.
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Affiliation(s)
- Masashi Tagaya
- Department of Medical Engineering, National Hospital Organization Kure Medical Center and Chugoku Cancer Center, Kure, Japan
| | - Shinya Okano
- Department of Medical Engineering, National Hospital Organization Kure Medical Center and Chugoku Cancer Center, Kure, Japan
| | - Takuo Murataka
- Department of Medical Engineering, National Hospital Organization Kure Medical Center and Chugoku Cancer Center, Kure, Japan
| | - Hiroki Handa
- Department of Medical Engineering, National Hospital Organization Kure Medical Center and Chugoku Cancer Center, Kure, Japan
| | - Shunsuke Ichikawa
- Department of Medical Engineering, National Hospital Organization Kure Medical Center and Chugoku Cancer Center, Kure, Japan
| | - Shunsuke Takahashi
- Department of Nephrology, National Hospital Organization Kure Medical Center and Chugoku Cancer Center, Kure, Japan
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Factors impacting unbound vancomycin concentrations in neonates and young infants. Eur J Clin Microbiol Infect Dis 2018; 37:1503-1510. [DOI: 10.1007/s10096-018-3277-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 05/09/2018] [Indexed: 01/19/2023]
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Chou YC, Cheng YS, Hsu YH, Yu YH, Liu SJ. A bio-artificial poly([D,L]-lactide-co-glycolide) drug-eluting nanofibrous periosteum for segmental long bone open fractures with significant periosteal stripping injuries. Int J Nanomedicine 2016; 11:941-53. [PMID: 27022261 PMCID: PMC4792178 DOI: 10.2147/ijn.s99791] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Biodegradable poly([d,l]-lactide-co-glycolide) (PLGA) nanofibrous membrane embedded with two drug-to-polymer weight ratios, namely 1:3 and 1:6, which comprised PLGA 180 mg, lidocaine 20 mg, vancomycin 20 mg, and ceftazidime 20 mg, and PLGA 360 mg, lidocaine 20 mg, vancomycin 20 mg, and ceftazidime 20 mg, respectively, was produced as an artificial periosteum in the treatment of segmental femoral fractures. The nanofibrous membrane’s drug release behavior was assessed in vitro using high-performance liquid chromatography and the disk-diffusion method. A femoral segmental fracture model with intramedullary Kirschner-wire fixation was established for the in vivo rabbit activity study. Twenty-four rabbits were divided into two groups. Twelve rabbits in group A underwent femoral fracture fixation only, and 12 rabbits in group B underwent femoral fracture fixation and were administered the drug-loaded nanofibers. Radiographs obtained at 2, 6, and 12 weeks postoperatively were used to assess the bone unions. The total activity counts in animal behavior cages were also examined to evaluate the clinical performance of the rabbits. After the animals were euthanized, both femoral shafts were harvested and assessed for their torque strengths and toughness. The daily in vitro release curve for lidocaine showed that the nanofibers eluted effective levels of lidocaine for longer than 3 weeks. The bioactivity studies of vancomycin and ceftazidime showed that both antibiotics had effective and sustained bactericidal capacities for over 30 days. The findings from the in vivo animal activity study suggested that the rabbits with the artificial drug-eluting periosteum exhibited statistically increased levels of activity and better clinical performance outcomes compared with the rabbits without the artificial periosteum. In conclusion, this artificial drug-eluting periosteum may eventually be used for the treatment of open fractures.
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Affiliation(s)
- Ying-Chao Chou
- Biomaterials Lab, Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan; Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Yi-Shiun Cheng
- Biomaterials Lab, Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan
| | - Yung-Heng Hsu
- Biomaterials Lab, Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan; Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Yi-Hsun Yu
- Biomaterials Lab, Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan; Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Shih-Jung Liu
- Biomaterials Lab, Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan; Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan
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Measuring unbound versus total vancomycin concentrations in serum and plasma: methodological issues and relevance. Ther Drug Monit 2015; 37:180-7. [PMID: 25072945 DOI: 10.1097/ftd.0000000000000122] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Studies on the unbound fraction (fu) of vancomycin report highly variable results. Great controversy also exists about the correlation between unbound and total vancomycin concentrations. As differences in (pre-)analytic techniques may explain these findings, we investigated the impact of the procedure used to isolate unbound vancomycin in serum/plasma on fu and the correlation between total and unbound concentrations. METHODS Patient samples (n = 39) were analyzed for total and unbound vancomycin concentrations after ultrafiltration (UF, Centrifree at 4°C and 37°C) or equilibrium dialysis (ED, using a Fast Micro-Equilibrium Dialyzer at 37°C) on an Architect i2000SR. To investigate correlations with potential binding proteins, total protein, albumin, alpha-1-acid glycoprotein, and IgA concentrations were also measured. RESULTS The median fu after ED was 72.5% [interquartile range (IQR), 68.7%-75.0%]. Ultrafiltration at 4°C and 37°C resulted in a median fu of 51.6% (IQR, 48.6%-54.8%) and 75.2% (IQR, 69.3%-78.6%), respectively, with no significant difference between unbound vancomycin concentrations after ED and UF at 37°C (P = 0.13). Unbound concentrations obtained through ED and UF correlated linearly (4°C: r = 0.9457; 37°C: r = 0.9478; both P < 0.0001). Linear mixed-model regression showed that total vancomycin as such was the predominant determinant for the unbound concentration, allowing a reliable prediction (mean bias ± SD, 5.0% ± 7.6%). The studied protein concentrations were of no added value in predicting the unbound concentration. CONCLUSIONS Vancomycin fu after UF at 4°C was on average 30.6% lower than that after UF at 37°C, demonstrating the importance of temperature during UF. Ultrafiltration at 37°C resulted in unbound vancomycin concentrations equivalent with ED. As the unbound concentration could be reliably predicted based on total vancomycin concentrations as such, measurement of unbound vancomycin concentrations has little added value over measurements of total vancomycin concentrations.
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Factors impacting unbound vancomycin concentrations in different patient populations. Antimicrob Agents Chemother 2015; 59:7073-9. [PMID: 26349820 DOI: 10.1128/aac.01185-15] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/29/2015] [Indexed: 11/20/2022] Open
Abstract
The unbound drug hypothesis states that only unbound drug concentrations are active and available for clearance, and highly variable results regarding unbound vancomycin fractions have been reported in the literature. We have determined the unbound vancomycin fractions in four different patient groups by a liquid chromatography tandem mass spectrometry (LC-MS/MS) method and identified factors that modulate vancomycin binding. We have further developed and validated a prediction model to estimate unbound vancomycin concentrations. Vancomycin (unbound and total) concentrations were measured in 90 patients in four different hospital wards (hematology [n = 33 samples], intensive care unit [ICU] [n = 51], orthopedics [n = 44], and pediatrics [age range, 6 months to 14 years; n = 18]) by a validated LC-MS/MS method. Multiple linear mixed model analysis was performed to identify patient variables that were predictive of unbound vancomycin fractions and concentrations. The variables included in the model were patient age, ward, number of coadministered drugs with high protein binding, kidney function (estimated glomerular filtration rate [determined by Chronic Kidney Disease Epidemiology Collaboration formula]), alpha-1-acid glycoprotein, albumin, total bilirubin, IgA, IgM, urea, and total vancomycin concentrations. In the pediatric cohort, the median unbound vancomycin fraction was 81.3% (range, 61.9 to 95.9%), which was significantly higher (P < 0.01) than the unbound fraction found in the three adult patient cohorts (hematology, 60.6% [48.7 to 90.6%]; ICU, 61.7% [47.0 to 87.6%]; orthopedics, 56.4% [45.9 to 78.0%]). The strongest significant predictor of the unbound vancomycin concentration was the total drug concentration, completed by albumin in the pediatric cohort and albumin and IgA in the adult cohorts. Validation of our model was performed with data from 13 adult patients. A mean difference of 0.3 mg/liter (95% confidence interval [CI], -1.3 to 0.7 mg/liter; R(2) = 0.99 [95% CI, 0.95 to 0.99]) between measured and calculated unbound vancomycin concentrations demonstrated that the predictive performance of our model was favorable. Unbound vancomycin fractions vary significantly between pediatric and adult patients. We developed a formula to estimate the unbound fraction derived from total vancomycin, albumin, and IgA concentrations in adult patients.
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Housman ST, Bhalodi AA, Shepard A, Nugent J, Nicolau DP. Vancomycin Tissue Pharmacokinetics in Patients with Lower-Limb Infections via In Vivo Microdialysis. J Am Podiatr Med Assoc 2015; 105:381-8. [PMID: 26429605 DOI: 10.7547/14-033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Vancomycin is a common treatment option for skin and skin structure infections caused by methicillin-resistant Staphylococcus aureus (MRSA). Given the increasing prevalence of MRSA, vancomycin is widely used as empirical therapy. In patients with lower-limb infections, antimicrobial penetration is often reduced because of decreased vascular perfusion. In this study, we evaluated the tissue concentrations of vancomycin in hospitalized patients with lower-limb infections. METHODS An in vivo microdialysis catheter was inserted near the margin of the wound and was perfused with lactated Ringer's solution. Tissue and serum samples were obtained after steady state for one dosing interval. Tissue concentrations were corrected for percentage of in vivo recovery using the retrodialysis technique. RESULTS Nine patients were enrolled (mean ± SD: age, 54 ± 19 years; weight, 105.6 ± 31.5 kg). Patients received a mean of 12.8 mg/kg of vancomycin every 12 hours (n = 7), every 8 hours (n = 1), or every 24 hours (n = 1). Mean ± SD steady-state trough vancomycin concentrations in serum and tissue were 11.1 ± 3.3 and 6.0 ± 2.6 μg/mL. The mean ± SD 24-hour free drug areas under the curve for serum and wound were 283.7 ± 89.4 and 232.8 ± 75.7 μg*h/mL, respectively. The mean ± SD tissue penetration ratio was 0.8 ± 0.2. CONCLUSIONS These data suggest that against MRSA with minimum inhibitory concentrations of 1 μg/mL or less, vancomycin achieved blood pharmacodynamic targets required for the likelihood of success. Reduced concentrations may contribute to poor outcomes and the development of resistance. As other literature suggests, alternative agents may be needed when the pathogen of interest has a minimum inhibitory concentration greater than 1 μg/mL.
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Affiliation(s)
- Seth T. Housman
- Center for Anti-infective Research and Development, Hartford Hospital, Hartford, CT
| | - Amira A. Bhalodi
- Center for Anti-infective Research and Development, Hartford Hospital, Hartford, CT
| | - Ashley Shepard
- Hartford Healthcare Medical Group, Hartford Hospital, Hartford, CT
| | - James Nugent
- Hartford Healthcare Medical Group, Hartford Hospital, Hartford, CT
| | - David P. Nicolau
- Department of Medicine, Division of Infectious Diseases, Hartford Hospital, Hartford, CT
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Continuous infusion vs intermittent vancomycin in neurosurgical intensive care unit patients. J Crit Care 2015; 30:1153.e1-6. [PMID: 26239323 DOI: 10.1016/j.jcrc.2015.06.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 05/16/2015] [Accepted: 06/16/2015] [Indexed: 11/23/2022]
Abstract
PURPOSE Target plasma level achievement has remained a challenge in neurosurgical intensive care unit patients receiving intravenous vancomycin. We evaluated continuous infusion (CI) and intermittent vancomycin dosing strategies in these patients. METHODS This retrospective cohort compared CI vancomycin (target random levels, 20-30 mg/L) to intermittent vancomycin (target troughs, 15-20 mg/L) in regards to achievement of target plasma levels, nephrotoxicity, pharmacodynamic target attainment, and cost savings in 130 patients. RESULTS Continuous infusion resulted in greater achievement of goal plasma concentrations at the first steady-state level (40 vs 21.5%, P = .02), more rapid achievement of goal plasma concentrations (2.04 vs 3.76 days, P < .0001), and increased time within therapeutic range (55% vs 34%, P < .0001) but no significant difference in nephrotoxicity (15.4% vs 21.5%, P = .5). Continuous infusion improved pharmacodynamic target attainment (92.3% vs 30.8%, P < .0001) and also reduced levels drawn (3.8 vs 5.7, P = .0007), dose adjustments (1.4 vs 2.4, P = .0006), days of therapy (10.4 vs 14.1, P = .01), and mean total daily dose requirements (33 vs 35.7 mg/kg, P < .0001) per patient. CONCLUSIONS Continuous infusion appears beneficial for improving attainment of target plasma concentrations, pharmacodynamic goals, and financial burden, without increasing risk of acute kidney injury.
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Hamada Y, Kuti JL, Nicolau DP. Vancomycin serum concentrations do not adequately predict tissue exposure in diabetic patients with mild to moderate limb infections. J Antimicrob Chemother 2015; 70:2064-7. [PMID: 25802284 DOI: 10.1093/jac/dkv074] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 02/25/2015] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVES Vancomycin is a common treatment for complicated skin and skin structure infections (cSSSIs) caused by MRSA. This analysis aimed to understand the variability of vancomycin tissue exposure at the site of infection. METHODS Vancomycin serum and interstitial tissue fluid concentration data for nine patients with cSSSI and normal renal function were derived from an in vivo microdialysis study. Using Pmetrics, the non-parametric population modelling package for R, we co-modelled serum and tissue concentration data. A 5000-patient Monte Carlo simulation was conducted for 1 g of vancomycin every 12 h and every 8 h to calculate the penetration distribution (AUCtissue/fAUCserum) and probability of target attainment (PTA) at an fAUC/MIC target of ≥200 in tissue fluid. RESULTS A three-compartment model fitted the data best. The mean (SD) and median penetration ratios into tissue of the simulated population were 1.91 (4.56) and 0.85, respectively, which were consistent with observed values in the original patients. PTAs for 1 g of vancomycin every 12 h and every 8 h in tissue fluid were 39.6% and 56.6% at an MIC of 1 mg/L. Serum trough concentrations (R(2) = 0.06) and serum AUC exposure (R(2) = 0.002) were poor predictors of vancomycin AUC tissue exposure. CONCLUSIONS Standard dosages of vancomycin provide a low likelihood of obtaining target pharmacodynamic exposure in the tissue of a lower limb infection. This low likelihood is due to wide variability in vancomycin penetration in the interstitial tissue fluid, which could not be predicted by serum concentrations.
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Affiliation(s)
- Yukihiro Hamada
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA Aichi Medical University Hospital School of Medicine, Aichi, Japan
| | - Joseph L Kuti
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
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Li X, Wang F, Xu B, Yu X, Yang Y, Zhang L, Li H. Determination of the free and total concentrations of vancomycin by two-dimensional liquid chromatography and its application in elderly patients. J Chromatogr B Analyt Technol Biomed Life Sci 2014; 969:181-9. [PMID: 25178192 DOI: 10.1016/j.jchromb.2014.08.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 07/28/2014] [Accepted: 08/03/2014] [Indexed: 12/25/2022]
Abstract
A robust two-dimensional liquid chromatography (2D-LC) method for determining the free and total concentrations of vancomycin in plasma was developed and validated. The 2D-LC system, which exhibited a strong capacity for inhibiting interference, comprised a unique RP1-IEX-RP2 column system and an "Assistant Flow" configuration. Ultrafiltration technology was employed to separate free vancomycin from the protein-bound fraction in human plasma. The influence of ultrafiltration conditions on the free vancomycin concentration was evaluated. The calibration curve was linear over the 0.195-49.92μg/ml range for the free and total vancomycin concentrations. The within- and between-run precision ranges were 1.5-3.9% and 2.0-4.7% for the total concentration, 1.4-3.3% and 2.4-4.0% for the free concentration, respectively. Ultrafiltration was susceptible to variations in the experimental conditions, including the centrifugation time, the centrifugal force, and the nominal molecular weight limit of the ultrafiltration membrane. A total of 101 serum samples from 84 elderly patients were analyzed by this method. The free vancomycin concentration was 5.88±3.75μg/ml (range: 0.240-16.79μg/ml), the total concentration was 12.36±5.36μg/ml (range: 2.16-27.14μg/ml), and the unbound fraction was 45.6±18.8% (range: 11.1-96.9%). There was a poor correlation between the free and total vancomycin concentrations (R(2)=0.596, p<0.05). This method appears to be sensitive, precise, selective, and suitable for use in protein-binding studies of vancomycin.
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Affiliation(s)
- Xin Li
- Clinical Pharmaceutical Research Institute, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China; The Third Hospital of Changsha, Changsha, Hunan 410015, China
| | - Feng Wang
- Clinical Pharmaceutical Research Institute, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Bin Xu
- The Third Hospital of Changsha, Changsha, Hunan 410015, China
| | - Xiaowei Yu
- The Third Hospital of Changsha, Changsha, Hunan 410015, China
| | - Yang Yang
- School of Pharmaceutical Sciences, Central South University, Changsha, Hunan 410013, China
| | - Li Zhang
- The Third Hospital of Changsha, Changsha, Hunan 410015, China
| | - Huande Li
- Clinical Pharmaceutical Research Institute, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China.
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Pharmacokinetics of arbekacin in bronchial epithelial lining fluid of healthy volunteers. J Infect Chemother 2014; 20:607-11. [PMID: 24973909 DOI: 10.1016/j.jiac.2014.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 04/30/2014] [Accepted: 05/26/2014] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Arbekacin is a unique aminoglycoside antibiotic with anti-methicillin-resistant Staphylococcus aureus activity. The efficacy of aminoglycosides is related to their serum maximum concentration. Local concentration of antibiotics in pulmonary epithelial lining fluid, rather than its serum concentration, can help determine its clinical efficacy more precisely for treatment of respiratory infectious disease. The objective of this study was to sequentially measure arbekacin concentration in epithelial lining fluid after infusion of a single clinically available dose. METHOD After the initial blood sampling, arbekacin was intravenously infused into 6 healthy volunteers over 1 h. Epithelial lining fluid and serum samples were collected by bronchoscopic microsampling 1, 1.5, 2, 2.5, 3, 4, 5, and 6 h after the start of 200 mg arbekacin infusion. RESULTS Each probe sampled 10.1 ± 5.2 μl bronchial epithelial lining fluid. The sample dilution factor was 266.7 ± 157.1. Drug concentration was successfully measured in all but 2 of the epithelial lining fluid samples. The maximum concentration of arbekacin in epithelial lining fluid and serum was 10.4 ± 1.9 μg/ml and 26.0 ± 12.2 μg/ml, respectively. The ratio of the maximum drug concentration in the epithelial lining fluid to that in the serum was 0.47 ± 0.19. CONCLUSIONS The maximum concentration of epithelial lining fluid reached levels that would effectively treat most clinical strains of methicillin-resistant S. aureus.
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Kees MG, Wicha SG, Seefeld A, Kees F, Kloft C. Unbound fraction of vancomycin in intensive care unit patients. J Clin Pharmacol 2013; 54:318-23. [PMID: 24000044 DOI: 10.1002/jcph.175] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Accepted: 08/27/2013] [Indexed: 11/09/2022]
Abstract
Published data on the unbound fraction of vancomycin in patient samples exhibit high variability. In the present study, a robust ultrafiltration method was developed and applied to 102 clinical samples from 22 intensive care unit patients who were treated with continuous infusion of vancomycin. A validated HPLC method was used for determination of total and unbound concentrations. The mean unbound fraction was 67.2% (standard deviation 7.5%, range 47.2-92.1%) and independent of total concentration of vancomycin or of albumin. The unbound fraction was significantly correlated (r = +0.67, P = .0009) with the renally filtered fraction (drug clearance/creatinine clearance), providing functional evidence for the validity of the measurements. Ultrafiltration proved to be susceptible to variations in the experimental conditions such as pH, temperature and centrifugal force. The measured unbound fraction increased from 60% at pH 6 to 100% at pH 9, from 57% at 4°C to 80% at 37°C, and was 76% at 1,000 g compared with 45% at 10,000 g. Lack of standardization may therefore partly explain the variable results reported in the literature.
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Affiliation(s)
- Martin G Kees
- Department of Anesthesiology and Intensive Care, Charité University Hospital Berlin - Campus Benjamin Franklin, Berlin, Germany; Department of Clinical Pharmacy and Biochemistry, Institute of Pharmacy, Freie Universitaet Berlin, Berlin, Germany
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