: Synthetic cannabinoid agonists are chemically diverse with multiple analogs gaining popularity as drugs of abuse. We report on the use of thin layer chromatography, gas chromatography mass ...spectrometry, high‐performance liquid chromatography, and liquid chromatography time of flight mass spectrometry for the identification and quantitation of these pharmacologically active chemicals in street drug dosage forms. Using these approaches, we have identified the synthetic cannabinoids JWH‐018, JWH‐019, JWH‐073, JWH‐081, JWH‐200, JWH‐210, JWH‐250, CP47,497 (C=8) (cannabicyclohexanol), RCS‐4, RCS‐8, AM‐2201, and AM‐694 in various commercially available products. Other noncannabinoid drugs including mitragynine have also been detected. Typical concentrations of drug in the materials are in the range 5–20 mg/g, or 0.5–2% by weight for each compound, although many products contained more than one drug.
WCK 4282 is a combination product of cefepime (FEP) and tazobactam (TAZ) in a 1:1 ratio currently under development for the treatment of multidrug-resistant Gram-negative bacterial infections. We ...investigated the effect of renal impairment on the pharmacokinetics (PK) and safety of WCK 4282 in 48 subjects with various degrees of renal function. Subjects were categorized on the basis of their Cockcroft-Gault equation-estimated creatinine clearance (CL
). We enrolled 6 subjects each into those with mild (CL
, 60 to <90 ml/min), moderate (CL
, 30 to <60 ml/min), or severe (CL
, <30 ml/min) renal impairment and those with end-stage renal disease (ESRD) requiring hemodialysis and 24 healthy control subjects (CL
, ≥90 ml/min). Healthy subjects and subjects with mild and moderate renal impairment received a single 90-min infusion of 4 g of WCK 4282 (2 g FEP and 2 g TAZ). Subjects with severe renal impairment and ESRD received 2 g of WCK 4282 (1 g FEP and 1 g TAZ) over 90 min. The plasma exposure of FEP-TAZ increased as renal function decreased. In subjects with mild, moderate, and severe renal impairment and ESRD, the mean exposure (area under the plasma concentration versus time curve from time zero extrapolated to infinity) of FEP and TAZ increased by 1.3- and 1.2-fold, 2.3- and 2.3-fold, 4.7- and 4.0-fold, and 8.5- and 11.6-fold, respectively. The urinary recovery of FEP and TAZ decreased with increasing renal impairment. There were no adverse events reported during the study. The findings suggest that dose adjustments for WCK 4282 will be required according to the degree of renal impairment. A single infusion of WCK 4282 was found to be safe and well tolerated in subjects with normal and impaired renal function. (This study has been registered at ClinicalTrials.gov under identifier NCT02709382.).
Infections in patients with cirrhosis of the liver can induce decompensation and lead to poor outcome with increased morbidity and mortality. It is unclear which clinical parameters on hospital ...admission best predict the presence of infection and the risk of clinical deterioration when infection is present. Adult patients with decompensated liver cirrhosis admitted consecutively to the Royal London Hospital, UK between July 2017 and December 2019 were evaluated retrospectively. Demographics, laboratory and microbiological data were recorded at admission. Outcome was measured as survival to 30 days and 1 year.233 cirrhotic patients (60.9% male) with a mean of 57.2 years (sd ± 13.7) were included, and 76 patients (32.6%) had evidence of infection at time of admission. The most common infection was respiratory (40.8%), then ascitic fluid (21.1%) and urinary tract (15.8%). 7.9% of patients had a positive blood culture. Compared to those without infection, patients with infection had significantly higher C-reactive protein (CRP) (48.3 vs. 22.8, p-value <0.001), white blood cell count (10.0 vs. 8.0, p-value = 0.016), MELD-Na score (19.7 vs. 17.6, p-value = 0.042) and lower serum albumin (30.8 vs. 33.6, p-value = 0.005). Both 30-day mortality (18.4% vs. 8.3%, p-value = 0.023) and 1 year mortality (35.5% vs. 22.3%, p-value = 0.032) were significantly higher in patients with infection. In a multivariate logistic regression both increasing age and CRP were associated with 30-day mortality in those with evidence of infection. The area under the receiver operator curve (AUROC) for 30-day mortality using a logistic regression model incorporating CRP and age was 0.78 and CRP level > 50.5 demonstrated specificity of 72% and sensitivity of 69%.Abstract P42 Table 1Characteristics of cirrhotic cohort – stratified by infection status Variable No Infection Infection p-value Age (years) 57.4 56.6 0.65 ALD (%) 52.2 53.9 Viral (%) 16.6 19.7 NASH (%) 13.4 11.8 WBC (x109/L) 8.0 10.0 <0.01* Platelet (x109/L) 144.4 153.0 0.57 Sodium (mmol/L) 135.9 134.4 0.10 Creatinine (µmol/L) 95.9 99.7 0.72 Bilirubin (µmol/L) 71.7 96.1 0.19 Albumin (g/L) 33.6 30.8 <0.01* INR 1.5 1.5 0.35 CRP (mg/L) 22.8 48.3 <0.001* MELD-Na 17.6 19.7 0.04* Proton pump inhibitor use on admission 51.5 48.7 0.61 30-day mortality (%) 8.3 18.4 0.02* 1-year mortality (%) 22.3 35.5 0.03* ALD = alcoholic liver disease, NASH = Non-alcoholic steatohepatitis, WBC = white blood cell, INR = international normalised ratio, CRP = C -reactive protein, MELD-Na = Model for End-stage Liver Disease – SodiumBacterial infection was present in almost one third of the patients with decompensated cirrhosis and led to significantly worse short- and long-term outcomes. Older infected patients with higher CRP are at particularly raised risk of short-term mortality and this cohort should be identified and treated early in admission to improve outcomes.
Abstract
Objectives
Dalbavancin is a lipoglycopeptide with a long half-life, making it a promising treatment for infections requiring prolonged therapy, such as complicated Staphylococcus aureus ...bacteraemia. Free drug concentration is a critical consideration with prolonged treatment, since free concentration–time profiles may best correlate with therapeutic effect. In support of future clinical trials, we aimed to develop a reliable and reproducible assay for measuring free dalbavancin concentrations.
Methods
The ultracentrifugation technique was used to determine free dalbavancin concentrations in plasma at two concentrations (50 and 200 mg/L) in duplicate. Centrifuge tubes and pipette tips were treated for 24 h before use with Tween 80 to assess adsorption. Dalbavancin concentrations were analysed from the plasma samples (total) and middle layer samples (free) by LC/MS/MS with isotopically labelled internal standard. Warfarin served as a positive control with known high protein binding.
Results
Measurement of free dalbavancin was sensitive to adsorption onto plastic. Treatment of tubes and pipette tips with ≥2% Tween 80 effectively prevented drug loss during protein binding experiments. By the ultracentrifugation method, dalbavancin’s protein binding was estimated to be approximately 99%.
Conclusions
Dalbavancin has very high protein binding. Given dalbavancin’s high protein binding, accurate measurement of free dalbavancin concentrations should be a key consideration in future exposure–response studies, especially clinical trials. Future investigations should confirm if the active fraction is best predicted by the free or total fraction.
The objective of this communication was to determine the intravenous compatibility of ceftazidime/avibactam and aztreonam using simulated and actual Y-site administration.
Ceftazidime–avibactam was ...reconstituted and diluted to concentrations of 8, 25, and 50 mg/mL in 0.9% sodium chloride. Aztreonam was reconstituted and diluted to concentrations of 10 and 20 mg/mL. Each combination of concentrations was tested for compatibility using visual, Tyndall beam, microscopy, turbidity, and pH assessments. Microscopy results were compared to those from sodium chloride 0.9% in water, pH was compared to that at time 0, and turbidity of combinations was compared to that of individual agents. Actual Y-site mixing was conducted over 2-h infusions with samples collected at 0, 1, and 2 h. Test results were evaluated at 0, 1, 2, 4, 8, and 12 h after mixing. All experiments were completed in triplicate.
Across simulated and actual Y-site experiments, no evidence of incompatibility between combinations of ceftazidime–avibactam + aztreonam was observed. Visual and microscopic tests revealed no particulate matter, color changes, or turbidity. Tyndall beam tests were negative with all combinations. No evidence of incompatibility was observed in turbidity testing. The pH values were consistent across each of the 6 combinations, from immediately after mixing until 12 h after mixing. When the addition of agents was reversed in simulated Y-site experiments, no differences in compatibility were observed. No differences in compatibility between actual and simulated Y-site administration were observed, and there was minimal variability across all replicate experiments.
Ceftazidime–avibactam, at concentrations of 8, 25, and 50 mg/mL, appeared compatible with aztreonam at concentrations of 10 and 20 mg/mL.
WCK 5222 is a novel β-lactam-β-lactam-enhancer combination of cefepime (FEP) and zidebactam (ZID). ZID is a novel β-lactam enhancer with a dual action of binding to Gram-negative penicillin-binding ...protein 2 (PBP2) and β-lactamase inhibition. WCK 5222 is being developed as a new therapeutic option for the treatment of complicated multidrug-resistant Gram-negative pathogen infections. We investigated the effect of renal impairment on the pharmacokinetics (PK) and safety of WCK 5222 in 48 subjects based on Cockcroft-Gault-estimated creatinine clearance (CL
). We enrolled mild (
= 6; CL
, 60 to <90 ml/min), moderate (
= 6; CL
, 30 to <60 ml/min), and severe (
= 6; CL
, <30 ml/min; not on dialysis) impairment, end-stage renal disease (ESRD) on hemodialysis (HD) (
= 6), and matched normal controls (
= 24; CL
, ≥90 ml/min). Healthy control subjects and mild and moderate renal impairment subjects received a single 60-min intravenous (i.v.) infusion of 3 g WCK 5222 (2 g FEP/1 g ZID); severe renal impairment and HD subjects received a single 60-min i.v. infusion of 1.5 g WCK 5222 (1 g FEP plus 0.5 g ZID). Body and renal clearance decreased, and plasma half-life (
) and the area under the concentration-time curve from time zero extrapolated to infinity (AUC
h µg/ml) increased in a graded relationship with severity of renal impairment for both FEP and ZID. Our findings suggest that dose adjustments for WCK 5222 will be required according to the degree of renal impairment. Overall, WCK 5222 (FEP-ZID) was found to be safe and well tolerated in subjects with normal and impaired renal function. (This study has been registered at ClinicalTrials.gov under identifier NCT02942810.).
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•A LC–MS/MS method was validated for buprenorphine, norbuprenorphine and naloxone.•The LLOQ of buprenorphine and norbuprenorphine was 20pg/mL.•The LLOQ of naloxone was 1pg/mL (the ...lowest LLOQ reported for biological samples).•The method was successfully applied in clinical pharmacokinetic study.
A simple, sensitive and rapid liquid chromatography/electrospray ionization tandem mass spectrometry (LC–ESI-MS/MS) method was developed and validated for simultaneous quantification of naloxone, buprenorphine and its metabolite norbuprenorphine in human plasma. Human plasma samples were extracted using a single step liquid–liquid extraction, and then separated on an Imtakt Unison UK-C18 column (2.1×50mm, 3μm) using alkaline mobile phases with gradient elution. All of the analytes were detected in positive ion mode using multiple reaction monitoring (MRM). The method was validated and the specificity, linearity, lower limit of quantitation, precision, accuracy, recoveries and stability were determined. The linear range was 20–10000pg/mL for buprenorphine and norbuprenorphine; and 1–500pg/mL for naloxone. The correlation coefficient (R2) values for all three analytes were ≥0.995. The precision and accuracy for intra-day and inter-day were <11.0%. The recoveries were >63% and matrix effects were tracked by the deuterated internal standards (IS) with the IS-normalized matrix factor ranging from 0.96 to 1.33 for all three analytes. The validated method was successfully applied in a clinical pharmacokinetic study with low dose administration of sublingual buprenorphine and naloxone.
Abstract
Background
Dalbavancin is a semi-synthetic glycopeptide with a long half-life, making it a promising alternative for infections requiring prolonged therapy such as complicated Staphylococcus ...aureus bacteremia. A critical pharmacokinetic consideration with prolonged treatment is the unbound or “free” concentration-time profile, as free antibiotic concentrations may correlate with tissue penetration and therapeutic effects better than total drug. Dalbavancin’s plasma protein binding (PB) remains poorly studied and has been reported to range between 93-99%. A reliable and validated free drug assay is needed to link dalbavancin concentrations with patient outcomes.
Methods
The ultracentrifugation technique was used to determine free dalbavancin concentrations in plasma at two concentrations (50 and 200 µg/mL) in duplicate. Centrifuge tubes and pipette tips were treated for 24 hours before use with Tween 80 to assess adsorption. PB centrifugation conditions: 400,000 g (106,000 RPM in TLA-120.1 rotor) for 4 hours at 37°C. Dalbavancin concentrations were analyzed from the plasma samples (total) and middle layer samples (free) by liquid chromatography – tandem mass spectrometry (LC/MS/MS) with isotopically labeled internal standard. Warfarin served as a positive control with known high protein binding.
Results
Measurement of free dalbavancin was sensitive to adsorption onto plastic. Treatment of tubes and pipette tips with ≥2% Tween 80 effectively prevented drug loss during PB experiments (Figure 1). Addition of 2% Tween 80 did not affect PB results of warfarin. In PB experiments with 2% Tween 80 coated tubes, the free fraction of dalbavancin was 0.96% (95% CI: 0.94-0.98) at 50 µg/mL and 1.11% (95% CI: 1.08-1.13) at 200 µg/mL.
Figure 1. Percent Free Dalbavancin vs Varying Concentrations of Tween 80 for Pretreatment of Tubes
Conclusion
By the ultracentrifugation method, dalbavancin’s PB was estimated to be approximately 99%. Given dalbavancin’s high PB, accurate measurement of free dalbavancin concentrations should be a key consideration in future exposure-response studies, especially clinical trials. Future investigations should also determine if the active fraction is best predicted by the free or total fraction, as this remains a subject of debate.
Supported by NIAID/NIH grant UM1AI104681. Content is solely the authors’ responsibility and does not represent official NIH views.
Disclosures
Thomas L. Holland, MD, Aridis (Consultant)Basilea Pharmaceutica (Consultant)Lysovant (Consultant) Thomas L. Holland, MD, Aridis (Individual(s) Involved: Self): Consultant; Basilea Pharmaceutica (Individual(s) Involved: Self): blinded adjudication, Consultant, Other Financial or Material Support; Genentech (Individual(s) Involved: Self): Consultant; Lysovant (Individual(s) Involved: Self): Consultant; Motif Bio (Individual(s) Involved: Self): Consultant Thomas Lodise, Jr., PharmD, PhD, Astra-Zeneca (Consultant)Bayer (Consultant)DoseMe (Consultant, Advisor or Review Panel member)ferring (Consultant)genentech (Consultant)GSK (Consultant)Melinta (Consultant)merck (Consultant, Independent Contractor)nabriva (Consultant)paratek (Consultant, Advisor or Review Panel member, Speaker’s Bureau)shionogi (Consultant, Advisor or Review Panel member, Speaker’s Bureau)Spero (Consultant)tetraphase (Consultant)Venatrox (Consultant) Thomas Lodise, Jr., PharmD, PhD, Melinta Therapeutics (Individual(s) Involved: Self): Consultant; Merck (Individual(s) Involved: Self): Consultant, Scientific Research Study Investigator; Paratek (Individual(s) Involved: Self): Consultant; Shionogi (Individual(s) Involved: Self): Consultant, Speakers’ bureau; Spero (Individual(s) Involved: Self): Consultant; Tetraphase Pharmaceuticals Inc. (Individual(s) Involved: Self): Consultant
A sensitive and specific method for the quantification of JWH-018, JWH-073, and JWH-250 and the qualitative identification of JWH-019 in whole blood was developed and validated. Samples fortified ...with JWH-018-d9 and JWH-073-d9 underwent liquid-liquid extraction and were analyzed by liquid chromatography-positive ion electrospray ionization-tandem mass spectrometry. Two transitions were monitored for all analytes except JWH-250, for which there was only one available transition. JWH-019 did not meet the stringent requirements for quantitative analysis, and thus this method is only appropriate for the qualitative identification of this compound in whole blood. The linear range was 0.1-20 µg/L for all quantitative analytes. The maximum average within- and between-run imprecision was 7.9% and 10.2%, respectively, and all controls quantified within 8.2% of target concentrations. Process efficiency, a measurement that takes into effect extraction efficiency and matrix effect, was ≥ 32.0% for all quantitative analytes; similar results were obtained for the deuterated internal standards. All analytes were stable at room, refrigerated, and frozen temperatures for at least 30 days. The method was used to quantify JWH-018 and JWH-073 in a blood specimen collected from a person known to have used an herbal incense blend containing these substances.
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