Measured Plasma Concentrations Research Articles

Pharmacokinetic exposure and treatment outcomes of lenvatinib in patients with renal cell carcinoma and differentiated thyroid carcinoma.

After initial approval of lenvatinib for radioiodine-refractory differentiated thyroid cancer (DTC), it has also shown promising outcomes in among others metastatic renal cell carcinoma (mRCC). Given that trial populations typically do not represent routine clinical care populations, questions arise about how applicable trial outcomes are in clinical practice. This study aims to compare the pharmacokinetics (PK), toxicity patterns, and survival data of lenvatinib in a real-world cohort with DTC and mRCC to those observed in pivotal clinical trials. Patients were included when diagnosed with DTC or mRCC, had received current or prior treatment with lenvatinib, and had at least one available lenvatinib plasma concentration measurement. A descriptive comparison was made between the baseline characteristics, PK data, toxicity and survival data in this real-world cohort and those described in the phase III trials. Overall, 29 patients with mRCC and 35 patients with DTC were included. For mRCC, median time to treatment discontinuation (mTTD) was shorter than observed in the phase III trial (7.5 versus 11.0 months) with fewer dose-limiting toxicities, likely because 66% of the patients started with a reduced dose. mRCC patients were more pretreated and had a worse performance status than trial participants. This was resembled in overall lower PK exposure in mRCC patients. For DTC, mTTD was longer in our cohort (17.1 versus 13.8 months), with similar toxicity patterns and PK exposure as in the phase III trial. Our data suggests that patient characteristics and outcomes in routine clinical care deviate from clinical trials and show the need for alternative treatment strategies to manage tolerability to lenvatinib.

Prenatal Exposure to PFAS and the Association With Neurobehavioral and Social Development During Childhood

Exposure to per- and polyfluoroalkyl substances (PFAS) is ubiquitous and may be associated with neurodevelopmental toxicity. However, epidemiological studies report mixed results on the risks of gestational PFAS exposure for children’s neurobehavioral impairment. We aimed to examine the associations between prenatal PFAS exposure and children’s neurobehavioral and social problems.We measured plasma concentrations of perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), and perfluorohexane sulphonate (PFHxS) in first-trimester blood from 757 women from the Canadian Maternal-Infant Research on Environmental Chemicals (MIREC) study. Children were assessed at 3–4 years with the Behavior Assessment System for Children-2 (BASC-2) and the Social Responsiveness Scale-2 (SRS-2) (n = 756 and 496, respectively). We used multivariable linear regression to examine associations between individual and summed log2-transformed PFAS and scores on these assessments. Effect modification by sex was evaluated through interaction terms and stratified analyses.In the sample combining both sexes, a doubling of maternal PFOA was significantly associated with lower T-scores on the following SRS-2 scales: Social Motivation, DSM-Social Communication, and SRS Total score (B ranging from -1.08 to -0.78), suggesting lesser impairments with higher exposure. In sex-stratified analysis, PFOA was related to significantly lower T-scores in boys for these BASC-2 scales: Behavioral Symptoms Index, Externalizing Problems, Aggression, and Hyperactivity (B ranging from -1.32 to -1.03). In girls, however, PFAS were significantly associated more problem behaviors. For instance, in girls, PFOA was associated with higher Anxiety (B = 1.84, 95% CI: 0.36, 3.32) and Hyperactivity (B = 1.08, 95% CI: -0.13, 2.30), whereas PFOS and ∑PFAS were associated with higher T-scores for Externalizing Problems and Hyperactivity (B ranging from 0.95 to 1.17).In conclusion, we did not observed strong associations between prenatal exposure to the PFAS evaluated and children’s neurobehavioral and social development in this population with low exposure levels. The results show mixed findings, depending on children’s sex, neurodevelopmental outcome, and specific PFAS.

The effect of carbamazepine, a strong CYP3A inducer, on the pharmacokinetics of zongertinib in healthy male volunteers.

Zongertinib (BI 1810631) is a potent, selective, and epidermal growth factor receptor (EGFR) wild-type sparing human epidermal growth factor receptor 2 (HER2) inhibitor. Based on invitro data, the oxidative hepatic metabolism of zongertinib is principally driven by cytochrome P450 (CYP) 3A4/5. Therefore, zongertinib may be affected by strong CYP3A inducers, like carbamazepine. This study aimed to investigate the effect of multiple oral doses of carbamazepine on the pharmacokinetics of a single oral dose of zongertinib in healthy male subjects. This open-label, two-period, fixed-sequence clinical drug-drug interaction study examined the pharmacokinetics of a single 60-mg oral dose of zongertinib in the absence or presence of multiple oral doses of carbamazepine. The extent of drug-drug interaction was estimated using the adjusted geometric mean ratios (and 90% confidence intervals [CIs]) for the test treatment (zongertinib in the presence of carbamazepine) versus the reference treatment (zongertinib alone) for areas under the plasma concentration-time curve from time 0 to infinity and to the last quantifiable time point (AUC0-∞, AUC0-tz) and maximum measured plasma concentration (Cmax). Sixteen subjects (all Caucasian males) received zongertinib alone in Study Period 1, and 15 of them received both zongertinib and carbamazepine in Study Period 2. Upon co-administration with carbamazepine in Study Period 2, AUC0-∞ and AUC0-tz of zongertinib were both reduced to 36.5% (90% CI: 32.0%-41.6% for AUC0-∞ and 31.9%-41.7% for AUC0-tz). The Cmax of zongertinib was reduced to 56.4% (90% CI: 45.1%-70.6%). Zongertinib exposure was reduced by 63.5% when coadministered with the strong CYP3A inducer, carbamazepine.

Identification and Evaluation of Angiogenesis-Related Proteins That Predict Major Adverse Cardiovascular Events in Patients with Peripheral Artery Disease.

The most common cause of death in patients with peripheral artery disease (PAD) are major adverse cardiovascular events (MACEs), including myocardial infarction (MI) and stroke. However, data on biomarkers that could be used to help predict MACEs in patients with PAD to guide clinical decision making is limited. Angiogenesis-related proteins have been demonstrated to play an important role in systemic atherosclerosis and may act as prognostic biomarkers for MACEs in patients with PAD. In this study, we evaluated a large panel of angiogenesis-related proteins and identified specific biomarkers associated with MACEs in patients with PAD. We conducted a prognostic study using a prospectively recruited cohort of 406 patients (254 with PAD and 152 without PAD). Plasma concentrations of 22 circulating angiogenesis-related proteins were measured at baseline, and the cohort was followed for 2 years. The primary outcome was 2-year MACEs (composite of MI, stroke, or death). Plasma protein concentrations were compared between PAD patients with and without 2-year MACEs using Mann-Whitney U tests. Differentially expressed proteins were further investigated in terms of their prognostic potential. Specifically, Cox proportional hazards analysis was performed to determine the independent association between differentially expressed proteins and 2-year MACEs, controlling for all baseline demographic and clinical characteristics, including existing coronary artery disease and cerebrovascular disease. Kaplan-Meier analysis was conducted to assess 2-year freedom from MACEs in patients with low vs. high levels of the differentially expressed proteins based on median plasma concentrations. The mean age of the cohort was 68.8 (SD 11.1), and 134 (33%) patients were female. Two-year MACEs occurred in 63 (16%) individuals. The following proteins were significantly elevated in PAD patients with 2-year MACEs compared to those without 2-year MACEs: endostatin (69.15 [SD 58.15] vs. 51.34 [SD 29.07] pg/mL, p < 0.001), angiopoietin-like protein 4 (ANGPTL4) (0.20 [SD 0.09] vs. 0.12 [SD 0.04] pg/mL, p < 0.001), and ANGPTL3 (51.57 [SD 21.92] vs. 45.16 [SD 21.90] pg/mL, p = 0.001). Cox proportional hazards analysis demonstrated that these three proteins were independently associated with 2-year MACEs after adjusting for all baseline demographic and clinical characteristics: endostatin (HR 1.39 [95% CI 1.12-1.71] p < 0.001), ANGPTL4 (HR 1.35 [95% CI 1.08-1.68], p < 0.001), and ANGPTL3 (HR 1.35 [95% CI 1.12-1.63], p < 0.001). Over a 2-year follow-up period, patients with higher levels of endostatin, ANGPTL4, and ANGPTL3 had a lower freedom from MACEs. Supplementary analysis demonstrated that these three proteins were not significantly associated with 2-year MACEs in patients without PAD. Among a panel of 22 angiogenesis-related proteins, endostatin, ANGPTL4, and ANGPTL3 were identified to be independently and specifically associated with 2-year MACEs in patients with PAD. Measurement of plasma concentrations of these proteins can support MACE risk stratification in patients with PAD, thereby informing clinical decisions on multidisciplinary referrals to cardiologists, neurologists, and vascular medicine specialists and guiding aggressiveness of medical treatment, thereby improving cardiovascular outcomes in patients with PAD.

Intraoperative Use of Sodium Bicarbonate Ringer's Solution Instead of Sodium Lactate Ringer's Solution to Reduce Endothelial Glycocalyx Degradation and Improve Postoperative Recovery During Cardiopulmonary Bypass Cardiac Surgery: A Single-Center Prospective Cohort Study.

To investigate the effect of sodium bicarbonate Ringer's solution (BRS) on the degradation of endothelial glycocalyx components in patients undergoing cardiopulmonary bypass (CPB) during cardiac surgery, and to evaluate its impact on endothelial glycocalyx preservation and postoperative recovery. A total of eight patients scheduled for elective CPB heart surgery were included and randomly divided into two groups: the sodium lactate Ringer's solution (LRS) group and the BRS group. ELISA was used to measure plasma concentrations of syndecan-1, matrix metalloproteinase-9 (MMP-9), matrix metalloproteinase-3 (MMP-3), IL-6, IL-8, TNF-α, and TGF-β at predefined time points: T0 (before induction of anesthesia), T3 (immediately after weaning from CPB), T5 and T6 (24 and 72hours postoperatively). Serum creatinine concentrations were measured within 48hours postoperatively. The incidence of postoperative delirium (POD) was assessed three days after surgery. Postoperative mechanical ventilation time, duration of stay in the intensive care unit and hospital stay were also documented. The BRS group had significantly lower plasma concentrations of syndecan-1 at T3 (7.98 [7.43, 8.92] ng/mL vs 9.54 [8.4, 10.73] ng/mL, P < 0.001) and T5 (4.20 [3.31, 4.96] ng/mL vs 5.40 [3.95, 6.55] ng/mL, P = 0.001) in comparison with the LRS group (P<0.01). Syndecan-1 levels in both groups were similar at T6 (3.18 [2.88, 3.5]ng/mL vs 3.12 [2.77, 3.45] ng/mL, P > 0.05). Additionally, MMP-9, MMP-3, IL-6 and IL-8 were significantly lower at T3 and T5 in the BRS group (P<0.05 and P<0.01, respectively). However, no significant differences were observed between the two groups in the incidence of acute kidney injury (AKI) or POD (P > 0.05). BRS has the potential to reduce glycocalyx degradation in patients undergoing heart valve surgery with CPB. However, both groups demonstrated similar post-postoperative clinical outcomes, including the rates of AKI and POD.

Plasma Concentration as a Proxy for Perilymph Drug Levels: Preclinical and Clinical Dexamethasone Measures with a Long-Acting Formulation for Precise Delivery to the Round Window Membrane.

To use animal pharmacokinetic data and FluidSIM modeling to estimate human dexamethasone perilymph concentrations from plasma concentration measurements over time following a single intratympanic administration of SPT-2101. Perilymph and plasma dexamethasone concentrations were measured in guinea pigs and African green monkeys over 3 to 6 weeks post-intratympanic administration of SPT-2101. Plasma concentrations of dexamethasone were measured in Ménière's disease patients post-intratympanic administration of SPT-2101. FluidSIM was trained on the correlations of animal plasma and animal perilymph levels, allowing the human perilymph drug time course for SPT-2101 to be predicted from measured human plasma dexamethasone concentrations. Tertiary care neurotology clinic in Perth, Australia. Nine adults with unilateral definite Ménière's disease per Barany Society criteria. Intratympanic SPT-2101, a single injection of a long-acting gel formulation of dexamethasone precisely delivered at the round window. Estimated dexamethasone levels in human perilymph following a single administration of SPT-2101 at the round window over time. Perilymph dexamethasone concentrations were above estimated therapeutic levels for up to 35 days in guinea pigs and at least 21 days in African green monkeys. In human subjects, plasma dexamethasone concentrations were detected for 2 weeks post-administration. Animal middle ear, plasma and perilymph drug interrelationships were compared to FluidSIM simulations, providing rationale for correlating dexamethasone concentrations in the respective compartments. Comparable simulations of human plasma concentrations predicted perilymph dexamethasone therapeutic levels in humans for 23-55 days. Sustained release dexamethasone from SPT-2101 precisely delivered at the round window provides prolonged and durable estimated perilymph concentrations in clinical subjects.

Ultra-Sensitive Quantification of Coproporphyrin-I and -III in Human Plasma Using Ultra-Performance Liquid Chromatography Coupled to Quadrupole Time-of-Flight Mass Spectrometry.

Organic anion transporting polypeptides (OATP) 1B1 and 1B3 are expressed in liver cells and are involved in drug uptake in the liver. OATP1B activity varies due to polymorphisms and is decreased by OATP1B inhibitors. Variability of OATP1B activity impacts the pharmacokinetics of OATP1B substrate drugs through drug-drug interactions. Lately, coproporphyrin-I (CP-I) and -III (CP-III) have been featured as quantitative endogenous biomarkers for evaluating the activity of OATP1B. CP-III has been reported to be transported not only by OATP1B but also by OATP2B1 in vitro. We have established a highly sensitive assay for the simultaneous measurement of CP-I and CP-III using a small volume of human plasma. The sample was pretreated by solid-phase extraction and analyzed by ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS). This method that uses 100 μL of plasma met the acceptance criteria of the US Food and Drug Administration guidance for bioanalytical method validation, and the lower limit of quantification was 0.01 ng/mL for both coproporphyrins. The clinical application of the method was evaluated by measuring plasma CP-I and CP-III concentrations in healthy volunteers and rheumatoid arthritis (RA) patients. The measured concentrations were within the calibration range (0.01-50 ng/mL). Using this novel method to measure plasma concentrations of CP-I and CP-III may contribute to the evaluation of the activities of OATP1B1, OATP1B3, and OATB2B1 in healthy individuals and patients with various clinical conditions including RA.

Determining the Pharmacokinetic Properties of Two Different Doses of Meloxicam in Barred Owls (Strix varia).

Anthropogenic activities have negatively affected many birds, including owls. The Wildlife Hospital of Louisiana (WHL) has seen a 3.2-fold increase in barred owl (Strix varia) cases over the past eight years (2023, 134; 2015, 42). Because most of these animals present with traumatic injuries, analgesics should be considered in their treatment plan. To date, no study has measured the pharmacokinetics of an analgesic in barred owls. The goals of this study were to determine the harmonic means, times to maximum concentration, and elimination half-lives for single 1 mg/kg and 2 mg/kg intramuscular doses of meloxicam. Twelve barred owls (1 mg/kg, n = 6; 2 mg/kg, n = 6) admitted to the WHL and determined to be clinically normal based on examination and blood work were recruited for this study. Meloxicam was administered intramuscularly, and blood samples were collected intermittently over 12 h to measure plasma concentrations using high-performance liquid chromatography. Both doses had rapid elimination half-lives (1 mg/kg, 0.99 ± 0.1 h; 2 mg/kg, 1.07 ± 0.43 h) and were below the limits of quantification (0.1 µg/mL) by 6-12 h. Based on these results, 1 and 2 mg/kg doses of meloxicam were found to produce plasma concentrations below therapeutic concentrations for less than four hours, making current twice-daily recommended dosing intervals unlikely to provide desired analgesia.

Therapeutic drug monitoring (TDM) of β-lactam/β-lactamase inhibitor (BL/BLI) drug combinations: insights from a pharmacometric simulation study.

The emergence of β-lactamase-producing bacteria has led to the use of β-lactam (BL) antibiotic and β-lactamase inhibitor (BLI) drug combinations. Despite therapeutic drug monitoring (TDM) being endorsed for BLs, the impact of TDM on BLIs remains unclear. Evaluate whether BLIs are available in effective exposures at the site of infection and assess if TDM of BLIs could be of interest. Population pharmacokinetic models for 9 BL and BLI compounds were used to simulate drug concentrations at infection sites following EMA-approved dose regimens, considering plasma protein binding and tissue penetration. Predicted target site concentrations were used for probability of target attainment (PTA) analysis. Using EUCAST targets, satisfactory (≥90%) PTA was observed for BLs in patients with typical renal clearance (CrCL of 80 mL/min) across various sites of infection. However, results varied for BLIs. Avibactam achieved satisfactory PTA only in plasma, with reduced PTAs in abdomen (78%), lung (73%) and prostate (23%). Similarly, tazobactam resulted in unsatisfactory PTAs in intra-abdominal infections (79%), urinary tract infections (64%) and prostatitis (34%). Imipenem-relebactam and meropenem-vaborbactam achieved overall satisfactory PTAs, except in prostatitis and high-MIC infections for the latter combination. This study highlights the risk of solely relying on TDM of BLs, as this can indicate acceptable exposures of the BL while the BLI concentration, and consequently the combination, can result in suboptimal performance in terms of bacterial killing. Thus, dose adjustments also based on plasma concentration measurements of BLIs, in particular for avibactam and tazobactam, can be valuable in clinical practice to obtain effective exposures at the target site.

Intestinal distribution of anionic, cationic, and neutral polymer-stabilized nanocarriers measured with a lanthanide (europium) tracer assay

Nanocarriers, more commonly called nanoparticles (NPs), have found increasing use as delivery vehicles which increase the oral bioavailability of poorly water-soluble and peptide therapeutics. Therapeutic bioavailability is commonly assessed by measuring plasma concentrations that reflect the absorption kinetics. This bioavailability is a convolution of the gastrointestinal distribution of the NP vehicle, the release rate of the encapsulated therapeutic cargo, and the absorption-metabolism-distribution kinetics of the released therapeutic. The spatiotemporal distribution of the NP vehicle in the gastrointestinal tract is not well studied and is a buried parameter in PK studies used to measure the effectiveness of an NP formulation. This work is a study of the intestinal distribution and fate of orally dosed NPs in male CD-1 mice over 24 h. NPs have identical hydrophobic cores – composed of poly(styrene) homopolymer, a naphthalocyanine dye, and oleate-coated europium oxide colloids – with one of four different surface stabilizers: neutral poly(styrene)-block-poly(ethylene glycol) (PS-b-PEG), moderately negative hydroxypropyl methylcellulose acetate succinate (HPMCAS), highly negative poly(styrene)-block-poly(acrylic acid) (PS-b-PAA), and highly cationic adsorbed chitosan HCl on PS-b-PAA stabilized NPs. NP hydrodynamic diameters are all below 200 nm, with some variation attributable to the molecular properties of the stabilizing polymer. The encapsulated hydrophobic europium oxide colloids do not release soluble europium ions, enabling the use of highly sensitive inductively coupled plasma mass spectrometry (ICP-MS) to detect NP concentrations in digested biological tissues.Highly anionically-charged PAA and cationically-charged chitosan stabilized NPs showed statistically significant increased retention compared to the neutral PEG-stabilized NPs at p < 0.05 significance and (1-β) > 0.95 power. HPMCAS-stabilized NPs showed statistically insignificant greater retention than PEG-stabilized NPs, and all NP formulations showed clearance from the intestines within 24 h. Different surface charges preferentially reside in different segments of the intestines, where cationic chitosan-stabilized NPs showed increased retention in the small intestines (ileum) and anionic PAA-stabilized NPs in the large intestines (caecum and colon). Modifying the surface charge of a NP can be used to modulate mucoadhesion, total retention, and intestinal segment specific retention, which enables the rational design of delivery vehicles that maximize residence times in appropriate locations.

Association between Inflammatory and Metabolic Biomarkers and Common Mental Disorders among Adults: 2015 Health Survey of São Paulo, SP, Brazil.

Recent studies suggest that plasma inflammatory biomarker concentrations may represent valuable indicators for the diagnosis and prognosis of mental disorders. At the same time, metabolic alterations may contribute to the development and progression of systemic low-grade inflammation. Background/Objectives: This study evaluated the association between plasma inflammatory biomarkers and common mental disorders (CMD), exploring the relationship between metabolic biomarkers, metabolic syndrome (MetS), and inflammatory biomarkers in younger and older adults. Methods: This cross-sectional study used data from the 2015 Health Survey of São Paulo with a Focus on Nutrition Study. The occurrence of CMD was assessed through the Self-Reporting Questionnaire (SRQ-20). Blood samples were used to measure plasma concentrations of inflammatory and cardiometabolic biomarkers. MetS was defined according to the International Diabetes Federation Consensus. The Mann-Whitney test compared inflammatory biomarker concentrations across CMD groups and cardiometabolic conditions, and logistic regression models explored associations between inflammatory biomarker concentration and CMD. Results: The sample included 575 participants, 22.6% (n = 130) of whom had CMD. Concentrations of plasminogen activator inhibitor 1, C-reactive protein (CRP), and the systemic low-grade inflammation score varied significantly among CMD groups. CRP concentrations were positively associated with the presence of CMD, independent of confounding factors. Participants with insulin resistance, dyslipidemia, and MetS exhibited significantly higher CRP concentrations than individuals without these conditions. Conclusions: The findings suggest that increased plasma CRP concentrations may be a potential risk factor for CMD. Higher CRP concentrations were observed in individuals with insulin resistance, dyslipidemia, and MetS. Future interventional studies should explore these hypotheses in diverse populations.

Pharmacokinetics of single dose levobupivacaine after peri-incisional subcutaneous infiltration in anaesthetized domestic pigs.

Increasing use of pigs as models in translational research, and growing focus on animal welfare are leading to better use of effective analgesics and anaesthetics when painful procedures are performed. However, there is a gap in basic knowledge such as pharmacokinetics of different anaesthetics in these species. The main objective of our study was to determine the pharmacokinetics of levobupivacaine in domestic pigs. Twelve female grower pigs weighing 31.17 ± 4.6 kg were subjected to general anaesthesia and experimental surgery, at the end of which they received 1 mg/kg levobupivacaine via peri-incisional subcutaneous infiltration. Plasma samples were collected before administration of levobupivacaine and at 0.5, 1, 2, 4, 8, 12, 24 and 48 h thereafter. Concentrations of levobupivacaine were determined by liquid chromatography coupled with tandem mass spectrometry. Following single dose of levobupivacaine, all animals had measurable plasma concentrations 0.5 h after drug administration, with most peak concentrations observed at the 1-h time point. In all 12 animals, levobupivacaine was below the limit of quantification 48 h after drug administration. The mean maximum plasma concentration, area under the curve and half-life were determined to be 809.98 μg/l, 6552.46 μg/l h and 6.25 h, respectively. Plasma clearance, volume of distribution and weight-normalized volume of distribution were 4.41 l/h, 35.57 l and 1.23 l/kg, respectively. Peak plasma concentrations in our study were well below concentrations that were found to produce toxicity in pigs.

Loading Dose of Ceftazidime Needs to Be Increased in Critically Ill Patients: A Retrospective Study to Evaluate Recommended Loading Dose with Pharmacokinetic Modelling.

To rapidly achieve ceftazidime target concentrations, a 2 g loading dose (LD) is recommended before continuous infusion, but its adequacy in critically ill patients, given their unique pharmacokinetics, needs investigation. This study included patients from six ICUs in Saint-Etienne and Paris, France, who received continuous ceftazidime infusion with plasma concentration measurements. Using MONOLIX and R, a pharmacokinetic (PK) model was developed, and the literature on ICU patient PK models was reviewed. Simulations calculated the LD needed to reach a 60 mg/L target concentration and assessed ceftazidime exposure for various regimens. Among 86 patients with 223 samples, ceftazidime PK was best described by a one-compartment model with glomerular filtration rate explaining clearance variability. Typical clearance and volume of distribution were 4.45 L/h and 88 L, respectively. The literature median volume of distribution was 37.2 L. Simulations indicated that an LD higher than 2 g was needed to achieve 60 mg/L in 80% of patients, with a median LD of 4.9 g. Our model showed a 4 g LD followed by 6 g/day infusion reached effective concentrations within 1 h, while a 2 g LD caused an 18 h delay in achieving target steady state.

Evaluation of the effects and plasma concentration of the platelet inhibitor ticagrelor, after crushed and non-crushed intake, after cardiac arrest and after semi-urgent coronary artery bypass surgery

Background Ticagrelor, used in acute coronary syndrome (ACS), can be administered via nasogastric tube when oral intake is impossible. We investigated platelet inhibition and pharmacokinetics in resuscitated ACS patients and those undergoing semi-urgent coronary artery bypass graft (CABG) surgery. Our study aimed to assess platelet inhibition with use of the Platelet Function Analyser (PFA) and measured plasma concentrations of ticagrelor and its active metabolite in these ACS patients. Methods We included resuscitated cardiac arrest patients (STEMI/NSTEMI) and semi-urgent CABG patients. Crushed ticagrelor tablets were administered using a nasogastric tube. PFA closure time (CT) was determined with CT longer than 113 s as reference range. Plasma concentrations of ticagrelor and its active metabolite were measured after protein precipitation, by using liquid chromatography with mass spectrometry detection. Results In 20 resuscitated patients, 89% showed platelet inhibition at 24 h and 92% at day 4. For semi-urgent CABG patients, 85% exhibited platelet inhibition at 24 h and 84% at day 4. For ticagrelor in resuscitated patients, the median time to peak plasma concentration (Tmax) was 100 h [8; 100] for a median maximal concentration (Cmax) of 615.5 ng/mL [217.5; 1385.0]. For AR-C124910XX median Tmax was 100 h [8; 100] for a Cmax of 131.0 ng/mL [52.1; 177.7]. Among 20 patients undergoing semi-urgent CABG, Tmax for ticagrelor was 100 h [100; 100] for a median Cmax of 857.0 ng/ml [496.8; 1157.5]. For AR-C124910XX, median Tmax was 100 h [43; 100] for a Cmax of 251.0 ng/ml [173.0; 396.5]. Conclusion Crushed ticagrelor via nasogastric tube achieved targeted platelet inhibition. Pharmacokinetics aligned with previous studies. EudraCT number: 2013-004191-35; Study protocol code: AGO/2013/011; EC/2014/1061; ClinicalTrial.gov identifier: NCT02341729

Study of risk factors and clinical management of patients with clinical non-response due to low plasma levels of anti-tubercular drugs.

This study was carried out to assess the role of therapeutic drug monitoring of crucial first-line anti-tubercular drugs: rifampicin (R) and isoniazid (H) among 75 non-responding proven drug-sensitive tuberculosis patients on treatment followed by intervention in field conditions. The intervention was done in the form of either an increase in the dosage of R and H in patients with minimally low drug levels or a modification of the regimen in a certain group of patients with significantly low drug levels by augmenting it with three or four second-line drugs in addition to standard first-line drugs. This study also aimed to determine the relationship between the measured plasma concentration of anti-tubercular drugs and various demographic, microbiological, radiological, and malabsorption factors and the presence of co-morbidities affecting them. The study also focused on the clinical impact of the intervention for low plasma levels of anti-TB drugs on TB treatment outcomes. In our study overall, 85.5% of patients had low levels of any drug. In 85.3% of patients, R levels were low, and in 39.1%, H levels were low. On univariate analysis, low body mass index (BMI), hypoalbuminemia, bilateral disease on chest X-rays, and the presence of cavities were found to be significantly associated with low drug levels, while none of the factors were independently significantly associated. Low BMI, pulmonary tuberculosis and disseminated tuberculosis, far-advanced disease and bilateral disease on chest X-ray, presence of cavities, and only low R levels were associated with unfavorable outcomes, with none of the factors found to be significant on multivariate analysis. In our study, it was seen that the treatment outcome was favorable in 59.6% of patients in whom this intervention was done by augmenting the treatment regimen with three/four second-line drugs along with increasing the dose of R and H. To conclude, various factors may be associated with low plasma levels of anti-tubercular drugs. If such patients show clinical non-response after >6 months of treatment and have significantly low drug levels, with an absence of drug resistance, their treatment regimen may need augmentation with three/four second-line drugs along with an increase in the dose of R and H, which may lead to a favorable outcome.

Quantification of the Plasma Concentration of Vadadustat by High-Performance Liquid Chromatography with Ultraviolet Detection and Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry.

An inexpensive, simple, and accurate plasma concentration measurement system is needed to actively conduct pharmacokinetic and pharmacodynamic analyses of vadadustat, hypoxia-inducible factor-prolyl hydroxylase inhibitor, in clinical settings. In this study, the authors aimed to develop a method for measuring vadadustat in human plasma that could be applied for therapeutic drug monitoring using high-performance liquid chromatography with ultraviolet detection (HPLC-UV) in a clinical setting. Plasma samples (100 μL) were pretreated with acetonitrile using butyl paraoxybenzoate as an internal standard. Chromatographic separation was performed on a SunShell PFP C18 column (2.6 μm, 4.6 mm × 150 mm). The mobile phase consisted of (A) 20 mM of phosphate buffer (pH 2.4) and (B) acetonitrile (60:40, v/v), delivered isocratically at a flow rate of 1 mL/min. The analytes were detected by UV absorbance at a wavelength of 220 nm, and the column temperature was 40°C. To evaluate the applicability of HPLC-UV in a clinical setting, blood samples were collected at 19 time points from 7 patients who had been taking vadadustat. The calibration curve was linear over the concentration range of 0.2-150 mcg/mL (R2 > 0.99). Intra-assay and interassay accuracy, precision, and stability met the Food and Drug Administration recommendations. The vadadustat plasma concentrations of patients analyzed using the current HPLC-UV method were almost equal to those measured using ultra-performance liquid chromatography-tandem mass spectrometry (mean difference: 0.13 mcg/mL). Large variability in the dose-adjusted plasma concentrations of vadadustat at 12 hours after administration was observed between patients (coefficient of variation = 57.6%). This HPLC-UV method is a simple, accurate quantification method for evaluating plasma concentrations in patients taking vadadustat in a clinical setting.

Plasma concentrations of buprenorphine administered via matrix-type transdermal patches applied at three different anatomical locations in healthy adult horses.

Anatomical location-dependent differences in transdermal opioid penetration are well described in human patients. Although this has been investigated in horses with fentanyl, there is no literature available on location-dependent plasma buprenorphine concentrations when administered as a transdermal matrix-type patch. This study aims to compare the plasma concentrations achieved from the matrix-type transdermal buprenorphine patches placed at different anatomical sites (metacarpus, gaskin, and ventral tail base) in healthy adult horses. This is a randomized experimental study with a Latin square design. Six adult horses were given each of three treatments with a minimum 10-day washout period. For each treatment, two 20 μg h-1 matrix-type buprenorphine patches were applied to the ventral aspect of the tail base (TailTDP), metacarpus region (MetacarpusTDP), or gaskin region (GaskinTDP). Whole blood samples (for determination of buprenorphine concentration) and physiological variables were collected before (0 h) and at 0.5, 2, 4, 6, 8, 10, 12, 16, 24, 32, 48, 56, 72, 96 and 120 h after patches were applied. The patches were removed 96 h following placement and were analyzed for residual buprenorphine content. Buprenorphine concentrations were measured in plasma by LC-MS/MS. A mixed-effects model was used to analyze the physiological variables. Between the three treatment groups, there was no change in physiological variables across timepoints as compared to baseline and when compared to each other in a single horse and between horses (p > 0.3). When comparing all three locations, the buprenorphine uptake was observed to be more consistent with respect to measurable plasma concentrations >0.1 ng ml-1 when applied to the ventral aspect of the tail base. In the TailTDP group, the mean plasma buprenorphine concentrations were >0.1 ng ml-1 from 2 to 32 h. The highest group mean was 0.25 ng ml-1 noted at 4 h. The metacarpal and gaskin regions presented more erratic and inconsistent buprenorphine uptake and plasma concentrations as compared to the ventral aspect of the tail base. Further research must be directed at investigating the optimal dose, achievable duration of analgesia, change in measurable plasma concentrations, and behavioral and systemic effects.

Plasma epinephrine and norepinephrine responses to extreme heat exposures in young and older adults.

Hyperthermia is known as a hyperadrenergic state, yet there is a lack of data on the sympathetic responses to ambient heat stress in humans. Therefore, we investigated the plasma epinephrine and norepinephrine concentrations of healthy young and older adults exposed to 3 h of very hot and dry, as well as hot and humid, heat, both with accompanying activities of daily living. We hypothesized that older adults, compared with young adults, would have augmented increases in epinephrine and norepinephrine concentrations secondary to increased thermal strain. Young (n = 20) and older (n = 18) participants underwent two 3-h heat exposures on different days: very hot and dry [47°C and 15% relative humidity (RH)] and hot and humid (41°C and 40% RH). To mimic heat generation comparable to activities of daily living, participants performed seven 5-min bouts of light cycling (approximately 3 METS) dispersed throughout the heat exposure. We measured plasma concentrations of epinephrine and norepinephrine at baseline, end, and 2-h postheat exposure. There was a group-wide increase in epinephrine from baseline to the end of the heat exposure (Δ19 ± 27 pg/mL; P < 0.001) in the hot and humid condition, but not in the very hot and dry condition (Δ6 ± 19 pg/mL; P = 0.10). There were group-wide decreases in norepinephrine concentrations from baseline to the end of the heat exposure in both the very hot and dry (Δ-131 ± 169 pg/mL; P < 0.001) and the hot and humid (Δ-138 ± 157 pg/mL; P < 0.001) conditions, with both returning to near baseline at 2-h postexposure. These data suggest that ambient heating with accompanying bouts of light intermittent exercise may lead to decreases in circulating concentrations of norepinephrine.NEW & NOTEWORTHY Herein we present plasma epinephrine and norepinephrine concentrations to 3 h of very hot and dry, as well as hot and humid, heat exposures with accompanying activities of daily living in young and older participants. We found 1) increased plasma concentrations of epinephrine in young and older adults following the hot and humid, but not the very hot and dry exposures and 2) decreased concentrations of norepinephrine in both groups following exposure to both conditions.

Population pharmacokinetics of TLD-1, a novel liposomal doxorubicin, in a phase I trial.

TLD-1 is a novel pegylated liposomal doxorubicin (PLD) formulation aiming to optimise the PLD efficacy-toxicity ratio. We aimed to characterise TLD-1's population pharmacokinetics using non-compartmental analysis and nonlinear mixed-effects modelling. The PK of TLD-1 was analysed by performing a non-compartmental analysis of longitudinal doxorubicin plasma concentration measurements obtained from a clinical trial in 30 patients with advanced solid tumours across a 4.5-fold dose range. Furthermore, a joint parent-metabolite PK model of doxorubicinentrapped, doxorubicinfree, and metabolite doxorubicinol was developed. Interindividual and interoccasion variability around the typical PK parameters and potential covariates to explain parts of this variability were explored. Medians standard deviations of dose-normalised doxorubicinentrapped+free Cmax and AUC0-∞ were 0.342 0.134mg/L and 40.1 18.9mg·h/L, respectively. The median half-life (95h) was 23.5h longer than the half-life of currently marketed PLD. The novel joint parent-metabolite model comprised a one-compartment model with linear release (doxorubicinentrapped), a two-compartment model with linear elimination (doxorubicinfree), and a one-compartment model with linear elimination for doxorubicinol. Body surface area on the volumes of distribution for free doxorubicin was the only significant covariate. The population PK of TLD-1, including its release and main metabolite, were successfully characterised using non-compartmental and compartmental analyses. Based on its long half-life, TLD-1 presents a promising candidate for further clinical development. The PK characteristics form the basis to investigate TLD-1 exposure-response (i.e., clinical efficacy) and exposure-toxicity relationships in the future. Once such relationships have been established, the developed population PK model can be further used in model-informed precision dosing strategies. ClinicalTrials.gov-NCT03387917-January 2, 2018.

The efficacy of wound catheter infusion with local anesthetics for the treatment of postoperative pain in children: A systematic review.

Wound catheter infusion (WCI) with local anesthetics (LA) is a regional anesthesia technique, which has shown to produce effective postoperative analgesia in adults, without any adverse effects on wound healing. To investigate the efficacy and safety of WCI with LA for the treatment of postoperative pain in children, we conducted a systematic review of literature published until 2020. The literature search included articles concerning subcutaneous WCI with LA, in the surgical wound, as treatment of postoperative pain, in children <18 years of age. Exclusion criteria were studies describing peripheral nerve blocks, intercostal, abdominal or thoracic wall blocks and single local anesthetic infiltration of the surgical wound. The articles were appraised for quality and only randomized controlled trials with a Jadad score ≥3 were included for evaluation of results concerning postoperative pain scores and opioid use. All relevant original studies, including observational studies and case reports, were assessed for adverse events and measurements of LA plasma concentrations during WCI. A total of 1907 articles were found, leading to 92 relevant abstracts selected for further review. After exclusion of articles of which full texts could not be retrieved or because of exclusion criteria, 28 articles remained. Thirteen articles described randomized controlled trials, of which 10 were assessed as good or excellent in quality. Due to the small number and heterogeneity of the studies, the data could not be pooled. Instead, results were described per type of procedure: abdominal surgery, extremity surgery, thoracic surgery and iliac crest bone harvesting. Reduced pain scores and opioid needs were demonstrated after abdominal and extremity surgery. In five studies, plasma levels of LA were measured, which all remained below toxic thresholds. In all relevant studies, no serious adverse events concerning the use of WCI were reported.