Range Of Serum Concentrations Research Articles

Tocilizumab Dose Tapering Based on a Model-Based Algorithm is Feasible in Clinical Practice: A Short Communication.

Tocilizumab in the treatment of rheumatoid arthritis (RA) is a potential candidate for concentration-guided tapering because the standard dose of tocilizumab results in a wide range of serum concentrations, usually above the presumed therapeutic window, and an exposure-response relationship has been described. However, no clinical trials have been published to date on this subject. Therefore, the objective of this study was to assess the feasibility of the tapering of intravenous (iv) tocilizumab with the use of a pharmacokinetic model-based algorithm in RA patients. A randomized controlled trial with a double-blind design and follow-up of 24 weeks was conducted. RA patients who received the standard of tocilizumab for at least the past 24 weeks, which is 8 mg/kg every 4 weeks, were included. Patients with a tocilizumab serum concentration above 5 mg/L at trough were randomized between concentration-guided dose tapering, referred to as therapeutic drug monitoring (TDM), or the standard 8 mg/kg dose. In the TDM group, the tocilizumab dose was tapered with a recently published model-based algorithm to achieve a target concentration of 4-6 mg/L after 20 weeks of dose tapering. Twelve RA patients were included and 10 were randomized between the TDM and standard dose group. The study was feasible regarding the predefined feasibility criteria and patients had a positive attitude toward therapeutic drug monitoring. In the TDM group, the tocilizumab trough concentration within patients decreased on average by 24.5 ± 18.3 mg/L compared with a decrease of 2.8 ± 12 mg/L in the standard dose group. None of the patients in the TDM group reached the drug range of 4-6 mg/L. Instead, tocilizumab concentrations of 1.6 and 1.5 mg/L were found for the 2 patients who completed follow-up on the tapered dose. No differences in RA disease activity were observed between the 2 study groups. This study was the first to show that it is feasible to apply a dose-reduction algorithm based on a pharmacokinetic model in clinical practice. However, the current algorithm needs to be optimized before it can be applied on a larger scale.

Quantitative assessment of daratumumab in serum via intact light chain measurement using liquid chromatography-high resolution mass spectrometry: a method suitable for therapeutic drug monitoring.

Daratumumab, a pivotal treatment for multiple myeloma, exhibits considerable inter-patient variability in pharmacological clinical outcomes, likely attributed to serum concentration that may underscore the need for its therapeutic drug monitoring. This study aims to develop and validate a straightforward analytical method for quantifying daratumumab in serum, focusing on intact light chain determination, using liquid chromatography high-resolution mass spectrometry. The sample preparation involved immunoglobulin enrichment using Melon gel followed by a reduction step to dissociate the light from the heavy chains of immunoglobulins. The latter were then separated using a MabPac RP 2.1 × 50 mm chromatographic column and the intact light chains were detected and quantified using a Q Exactive Orbitrap mass spectrometer operating in ESI-positive ion mode at 17 500 resolution. The method demonstrated excellent linearity (R2 > 0.992) across a serum concentration range of 100 to 2000 μg mL-1 and good precision and accuracy: intra- and interday relative errors ranged from -5.1% to 6.5%, with a relative standard deviation of less than 5.8%. Clinical suitability was confirmed by analyzing 80 clinical samples from multiple myeloma patients treated with 1800 mg of daratumumab. 99% of the samples fell within the analytical range with a mean daratumumab concentration evaluated before the next administration (Ctrough) of 398 μg mL-1. These findings highlighted that intact light chain monoclonal antibody quantification could be a valid and robust alternative to either immunoassays or to LC-MS/MS targeting peptides for measuring daratumumab in clinical samples, positioning it as a suitable method for therapeutic drug monitoring applications.

Chronic use of Phenytoin Induced Ataxia: A Case Series of Six Patients

Published on:June 2022 Journal of Young Pharmacists, 2022; 14(2):249-252 Case Report | doi:10.5530/jyp.2022.14.47 Authors: Niharika Pathakamuri1, Sujit Kumar Sah2,*, Atiqulla Shariff2, Siddartha Ningappa Dhurappanavar2, Jalapa Pradhan2, Anjali Pradhan2, Sai Siddharth Matad2, Sinchana Shivukumar2, Dibaneja Khonglein2, Meghna Gosi2, Veer Sangmesh Patil31Department of Pharmacy Practice, TVM College of Pharmacy, Rajiv Gandhi University of Health Sciences, Ballari, Karnataka, INDIA.2Department of Pharmacy Practice, JSS College of Pharmacy, JSS Academy of Higher Education and Research, SS Nagar, Mysuru, Karnataka, INDIA.3Department of Medicine, VIMS Hospital, Vijayanagar Institute of Medical Sciences, Ballari, Karnataka, INDIA. Abstract: Phenytoin-induced ataxia increased the risk of morbidity by 10% to 50% and could be life-threatening but rarely fatal. We reported six cases of phenytoin-induced ataxia, experienced with cerebellar signs of ataxia. All study patients were found with elevated phenytoin serum concentrations (range: 30-40 mcg/ml). Assessment of SARA (Scale for the Assessment and Rating of Ataxia) scale indicated mild ataxia among all patients. Naranjo’s algorithm shows 50% of patients had definite and another 50% had probable relation between phenytoin exposure and ataxia. Ataxia resulted in the withdrawal of phenytoin among five patients and dose reduction in one patient. All patients were treated with alternative antiseizure medications along with supportive treatment and they were symptomatically better within 1-6 weeks duration of treatment. Hence, this study concluded that phenytoin-induced ataxia is common at a plasma concentration of 30 to 40 mcg/ml. Prescribers and pharmacists need to focus on monitoring phenytoin serum levels and providing appropriate counseling to prevent their toxicity.Key words: Ataxia, Chronic use, Naranjo’s algorithm, Neurotoxicity, Phenytoin, Scale for the assessment and rating of ataxia.

A sensitive and robust bioanalytical assay for pharmacokinetic analysis of ROR1xCD3 bispecific T cell engager (NVG-111) in a first-in-human study.

e19505 Background: Receptor tyrosine kinase-like Orphan Receptor-1 (ROR1) is widely expressed on hematological and solid tumors. NVG-111, a first in class humanized tandem scFv ROR1xCD3 bispecific antibody elicits potent killing of ROR1+ tumor cells in vitro and in vivo. This bispecific T-cell engager (TCE) is being evaluated in a first in human, Phase I trial in patients with relapsed/refractory chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). The predicted therapeutic dose and steady state serum concentrations of NVG-111 were estimated by allometric scaling using relevant doses from a murine PK study. To assess free drug levels in patients following 21 days of continuous infusion of NVG-111, a bespoke, sensitive pharmacokinetics (PK) assay with high levels of specificity and sensitivity was developed. Methods: Anti-idiotype (anti-ID) antibodies directed to anti-ROR1 (αROR1-ID) and anti-CD3 (αCD3-ID) were generated by mouse immunization or by phage display from customized libraries. A proof-of-concept sandwich ELISA assay was developed using αCD3-ID to capture NVG-111 and detection by biotinylated hROR1-streptavidin-HRP. Gyrolab and Quanterix Simoa high sensitivity ELISA platforms were used to detect NVG-111 by αCD3-ID capture and αROR1-ID detection. The mesoscale discovery electrochemiluminescence assay (MSD-ECLA) was developed using a reversed format; NVG-111 capture with αROR1-ID and detection with αCD3-ID. Results: Allometric scaling predicted a theoretically relevant therapeutic dose and steady state serum concentration of 1ng/mL NVG-111 in humans, which was just at the level of sensitivity of a conventional ELISA under non-matrix conditions. Transferring the format to Quanterix Simoa had limited success due to high background levels in all configurations evaluated. The Gyrolab platform increased sensitivity to 75pg/mL, but suboptimal individual human sera matrix selectivity limited assay validity. Assessment of MSD-ECLA provided the best signal/noise, enhanced human disease and healthy sera selectivity, and a dynamic sensitivity range of 250pg/mL to 32ng/mL, which enabled the development of a GCLP qualified PK assay. The MSD-ECLA assay was employed to measure NVG-111 concentrations in CLL or MCL subjects dosed with 0.3-30µg/day NVG-111. MSD-ECLA detected drug in patients receiving NVG-111, with a range of steady-state serum concentrations (Cavg.ss) of 168-610pg/mL. This was in-line with the predicted drug levels from the single species allometric scaling, albeit with observed levels being marginally lower than expected. Conclusions: Development, custom optimization and validation of a highly sensitive MSD-ECLA PK assay has enabled GCLP-compliant measurement of circulating NVG-111 in CLL or MCL patients treated with at least 10µg/day cIV NVG-111.

Limited Dose-Dependent Effects of Vedolizumab on Various Leukocyte Subsets.

OBJECTIVES:The anti-α4β7 integrin antibody vedolizumab (VDZ) is successfully used for the treatment of inflammatory bowel diseases. However, only a subgroup of patients respond to therapy. VDZ is administered at a fixed dose, leading to a wide range of serum concentrations in patients. Previous work from our group showed a dose-dependent preferential binding of VDZ to effector compared with regulatory CD4+ T cells. Therefore, we aimed to determine the dose-dependent binding profile of VDZ to other leukocyte subsets.METHODS:We characterized α4β7 integrin expression on CD8+ T cells, CD19+ B cells, CD14+ monocytes, natural killer cells, and eosinophils from patients with inflammatory bowel disease and healthy controls. We studied the binding of VDZ to these cells at different concentrations and investigated the functional consequences for dynamic adhesion and transmigration in vitro.RESULTS:The expression of α4β7 differed between the analyzed leukocyte subsets and was significantly higher on eosinophils from inflammatory bowel disease patients compared with controls. Almost all α4β7-expressing cells from these subsets were bound by VDZ at a concentration of 10 μg/mL. Dynamic cell adhesion was significantly impaired in all subsets, but there were no dose-dependent differences in the inhibition of adhesion.DISCUSSION:Our data suggest that α4β7-expressing CD8+ T cells, CD19+ B cells, CD14+ monocytes, natural killer cells, and eosinophils are a target of VDZ. However, there do not seem to be concentration-dependent differences, regarding the effects on these cells in the clinically relevant range. Thus, the reported exposure-efficacy characteristic of VDZ can probably mainly be attributed to CD4+ T-cell subsets.

Valproic Acid Serum Concentration and Incidence of Toxicity in Pediatric Patients.

In certain pediatric patients on valproic acid, therapeutic range (50-100 μg/mL) is maximized or exceeded to achieve better seizure control. This study compared incidence of common valproic acid adverse effects (thrombocytopenia, hepatotoxicity, and hyperammonemia) across maintenance concentration and age group. One hundred twenty-four children on maintenance valproic acid between January 2013 and January 2021 were eligible for inclusion. Fifty-six patients were maintained in concentration range 50 to 80 μg/mL, an additional 44 between 80 and 100 μg/mL and 24 between 100 and 120 μg/mL. Forty-one patients were prepubescent, 57 pubescent, and 26 postpubescent. There were no statistically significant differences observed in the primary endpoint of thrombocytopenia across serum concentration range (P = .093) or age group (P = .628). No significant differences in hepatic dysfunction (P = .099) or hyperammonemia (P = .548) were observed in serum concentration groups. Similarly, age group analysis observed no difference in hepatic dysfunction (P = .615) or hyperammonemia (P = .369). Serum valproic acid levels >100 μg/mL can be considered in select pediatric patients based on this study.

Primary hypothyroidism and quality of life.

In the 1970s, treatment with thyroid extract was superseded by levothyroxine, a synthetic L form of tetraiodothyronine. Since then, no major innovation has emerged for the treatment of hypothyroidism. The biochemical definition of subclinical hypothyroidism is a matter of debate. Indiscriminate screening for hypothyroidism has led to overdiagnosis and treatment initiation at lower serum levels of thyroid-stimulating hormone (TSH) than previously. Adverse health effects have been documented in individuals with hypothyroidism or hyperthyroidism, and these adverse effects can affect health-related quality of life (QOL). Levothyroxine substitution improves, but does not always normalize, QOL, especially for individuals with mild hypothyroidism. However, neither studies combining levothyroxine and liothyronine (the synthetic form of tri-iodothyronine) nor the use of desiccated thyroid extract have shown robust improvements in patient satisfaction. Future studies should focus not only on a better understanding of an individual's TSH set point (the innate narrow physiological range of serum concentration of TSH in an individual, before the onset of hypothyroidism) and alternative thyroid hormone combinations and formulations, but also on autoimmunity and comorbidities unrelated to hypothyroidism as drivers of patient dissatisfaction. Attention to the long-term health consequences of hypothyroidism, beyond QOL, and the risks of overtreatment is imperative.

The Serum Concentration of Vancomycin as a Diagnostic Predictor of Nephrotoxic Acute Kidney Injury in Critically Ill Patients.

The impact of serum concentrations of vancomycin is a controversial topic. Results: 182 critically ill patients were evaluated using vancomycin and 63 patients were included in the study. AKI occurred in 44.4% of patients on the sixth day of vancomycin use. Vancomycin higher than 17.53 mg/L between the second and the fourth days of use was a predictor of AKI, preceding AKI diagnosis for at least two days, with an area under the curve of 0.806 (IC 95% 0.624–0.987, p = 0.011). Altogether, 46.03% of patients died, and in the Cox analysis, the associated factors were age, estimated GFR, CPR, and vancomycin between the second and the fourth days. Discussion: The current 2020 guidelines recommend using Bayesian-derived AUC monitoring rather than trough concentrations. However, due to the higher number of laboratory analyses and the need for an application to calculate the AUC, many centers still use therapeutic trough levels between 15 and 20 mg/L. Conclusion: The results of this study suggest that a narrower range of serum concentration of vancomycin was a predictor of AKI in critically ill septic patients, preceding the diagnosis of AKI by at least 48 h, and it can be a useful monitoring tool when AUC cannot be used.

1183. Serum Bactericidal Activity Induced by Live Attenuated Pertussis Vaccine BPZE1 is Comparable to Boostrix™

BackgroundIn a Phase 2b, multi-center, placebo-controlled, randomized study, intranasal BPZE1 induced mucosal and serum antibodies to pertussis antigens and protected against subsequent colonization following attenuated challenge with BPZE1 3 months later. BoostrixTM also induced serum but not mucosal antibodies and did not protect against BPZE1 challenge. We have evaluated the induction of serum bactericidal activity (SBA) for Bordetella pertussis by BPZE1 or Boostrix vaccination. A previous study showed that Boostrix induction of SBA is dependent on Prn whereas B. pertussis infection induces SBA targeting Prn and other antigens.MethodsA convenience set of subjects who had a broad range of Prn and PT IgG serum concentrations from treatment groups who received BPZE1+BPZE1 or Boostrix+Placebo (Day 1 and 85 vaccination) were randomly selected to assess SBA using B. pertussis strain B1917. Three timepoints (baseline, 28 days following first and second vaccination) were analyzed and interpolated 50% killing titers determined. The relationship to Prn IgG concentration was assessed.ResultsBPZE1 and Boostrix elicited similar and significant increases in SBA following vaccination. BPZE1 and Boostrix elicit anti-Prn IgG, with Boostrix eliciting higher concentrations. A greater SBA response relative to PRN IgG was observed for BPZE1 compared to Boostrix. SBA-Prn correlations were high post-Boostrix (0.74) as previously reported; correlation was lower (0.35) following BPZE1, suggesting the involvement of broader antigenic protection beyond Prn alone.Table of GMT and GMFR in SBA and Prn IgG ConclusionIn this exploratory investigation, the novel intranasal live-attenuated pertussis vaccine BPZE1 induced SBA titers that were similar to Boostrix using a B. pertussis strain representative of current disease isolates. SBA-Prn correlations were high post-Boostrix, consistent with prior reports showing Prn is the acellular vaccine antigen that mediates SBA. In contrast, BPZE1 bactericidal antibodies appear broader than Prn which may be important given the global rise of Prn-deficient B. pertussis strains.Disclosures All Authors: No reported disclosures

Residual homing of α4β7-expressing β1+PI16+ regulatory T cells with potent suppressive activity correlates with exposure-efficacy of vedolizumab

ObjectiveThe anti-α4β7 integrin antibody vedolizumab is administered at a fixed dose for the treatment of IBDs. This leads to a wide range of serum concentrations in patients and previous studies...

Per-and Polyfluoroalkyl Substances (PFAS) Concentrations in Serum and Drinking Water in Pregnant Women from the Greater Cincinnati Area HOME Study

BACKGROUND AND AIM: The occurrence, fate, and transport of PFAS in the environment is understood, but the contribution of drinking water to serum PFAS concentrations in humans is poorly defined. METHODS: We examined data from a prospective pregnancy and birth cohort (HOME Study) in Cincinnati, Ohio. We quantified PFOA and PFOS in sera of 227 pregnant women at 16 weeks gestation between 2003 and 2006. Tap water was collected from the participants’ homes within one month of blood collection. We mapped serum and tap water PFAS concentrations using ArcGIS and examined clustering via spatial hotspot analyses for each participant. RESULTS:The median (range) of PFOA serum concentration in pregnant HOME Study participants between 2003-2006 was 5.4 (0.5-24.5) ng/ml, which is over twice the geometric mean serum concentration of 2.4 ng/l as measured in a representative sample of pregnant women in NHANES 2003 and 2004. Median PFOA drinking water concentrations in samples collected from participants’ homes were 3.7 ng/l in 2003, 4.5 ng/l in 2004, 6.4 ng/l in 2005 and 11.0 ng/l in 2006. For each doubling of water PFOA concentration, serum PFOA increased by 0.6 ng/l (95% CI: 0.02, 1.20) after adjusting for water source type (bottled/filtered vs tap water). For every doubling of water PFOS, serum PFOS increased 0.95 ng/l (95%CI: -0.10, 2.00). CONCLUSIONS:Drinking water is an important contributing source of PFAS exposure in pregnant women. This research adds to the literature, helping to delineate the relationship between drinking water and circulating serum concentrations of PFAS in pregnant women. The views expressed in this abstract are those of the authors and do not necessarily reflect the views or policies of the U.S. EPA. KEYWORDS: PFAS, drinking water, pregnant women, HOME Study, Cincinnati

The impact of hepatic and renal function on panitumumab exposures in patients with metastatic RAS wild-type colorectal cancer

PurposePanitumumab is a human monoclonal antibody targeting the epidermal growth factor receptor for the treatment of wild-type RAS metastatic colorectal cancer (mCRC). Currently, no dedicated clinical studies have evaluated the effect of organ impairment on the pharmacokinetics of panitumumab. Here, we present data from late phase studies of panitumumab in patients with mCRC and analyses of the effect of hepatic or renal impairment on the exposure of panitumumab.MethodsFrom three multicenter, open-label, phase 2 and phase 3 studies, 349 and 351 patients were included in hepatic and renal function subgroup analyses, respectively. Patients who received IV panitumumab and serum exposures were compared to patients with varying degrees of hepatic and renal organ dysfunction.ResultsThe Cmax and Ctrough values for patients with mild (n = 119) and moderate (n = 4) hepatic impairment were within the range of serum concentrations of panitumumab for the normal hepatic function subgroup. The distributions of serum concentration of panitumumab in patients with mild (n = 85) or moderate (n = 19) renal impairment were similar to the serum concentrations of panitumumab in the normal renal function subgroup. Population pharmacokinetic modeling and covariate analysis results were also consistent with lack of any significant effect of renal or hepatic impairment on the pharmacokinetics of panitumumab. Additionally, real-world evidence from case studies of patients with mCRC and severe hepatic or renal impairment, which is a rare patient population to study, indicated lack of clinically relevant differences in exposure of panitumumab compared with patients with mCRC and normal hepatic or renal function.ConclusionsMild-to-moderate hepatic or renal dysfunction had no clinically meaningful impact on the pharmacokinetics of panitumumab in patients with mCRC. No dose adjustments for panitumumab are warranted in patients with mCRC with mild-to-moderate hepatic or renal dysfunction.Trial registrationClinicalTrials.gov; NCT00083616, NCT00089635, NCT00113763

Per- and Polyfluoroalkyl Substances (PFAS) Concentrations in Serum and Drinking Water in Pregnant Women from the Greater Cincinnati Area HOME Study

Background: The occurrence, fate, and transport of PFAS in the environment is understood, but the contribution of drinking water to serum PFAS concentrations in humans is poorly defined. Methods: We examined data from a prospective pregnancy and birth cohort (HOME Study) in Cincinnati, Ohio. We quantified PFOA and PFOS in sera of 227 pregnant women at 16 weeks gestation between 2003 and 2006. Tap water was collected from the participants’ homes within one month of blood collection. We mapped serum and tap water PFAS concentrations using ArcGIS and examined clustering via spatial hotspot analyses for each participant. Results: The median (range) of PFOA serum concentration in pregnant HOME Study participants between 2003-2006 was 5.4 (0.5-24.5) ng/ml, which is over twice the geometric mean serum concentration of 2.4 ng/l as measured in a representative sample of pregnant women in NHANES 2003 and 2004. Median PFOA drinking water concentrations in samples collected from participants’ homes were 3.7 ng/l in 2003, 4.5 ng/l in 2004, 6.4 ng/l in 2005 and 11.0 ng/l in 2006. For each doubling of water PFOA concentration, serum PFOA increased by 0.6 ng/l (95% CI: 0.02, 1.20) after adjusting for water source type (bottled/filtered vs tap water). For every doubling of water PFOS, serum PFOS increased 0.95 ng/l (95%CI: -0.10, 2.00).Conclusions: Drinking water is an important contributing source of PFAS exposure in pregnant women. This research adds to the literature, helping to delineate the relationship between drinking water and circulating serum concentrations of PFAS in pregnant women.The views expressed in this abstract are those of the authors and do not necessarily reflect the views or policies of the U.S. EPA.

Should the Vancomycin Minimal Inhibitory Concentration be used as an Infant Critical Care Regular Criteria?

Vancomycin is the first-line antibiotic used for the treatment of staphylococcal infections. Because of its narrow therapeutic window and the pharmacokinetics variability, vancomycin trough serum concentration should be monitored. However, due to the increased cases of staphylococcus' commensal species infections and the case of vancomycin resistance, the minimal inhibitory concentration should be considered on antimicrobial therapy. This article aimed to show the importance of the minimal inhibitory concentration to infants on vancomycin therapy as regular criteria. Three infants in the use of vancomycin, hospitalized in the same maternity hospital, and that had at least one blood culture performed during the intensive-care-unit hospitalization were included in the study. Vancomycin serum concentrations were determined by particleenhanced- turbidimetric inhibition-immunoassay. The vancomycin minimal inhibitory concentration data were interpreted by following the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST). The trough serum concentration range of 10 to 20 mg.L-1 was considered therapeutic. All three patients had at least one infection by S. epidermidis, being one patient exhibit vancomycin- resistant S. epidermidis infection. All patients had stoppages in the vancomycin treatment, and the minimal inhibitory concentration was performed for only one patient. The data obtained from these patients also showed the need to perform therapeutic monitoring by using minimal inhibitory concentration values, because, although the serum concentrations were within the reference range, they are insufficient to guarantee patient therapeutic success.

Safety range of free valproic acid serum concentration in adult patients

BackgroundTherapeutic drug monitoring (TDM) is recommended during valproic acid (VPA) use, and total serum concentration has been widely adopted. However, the free form of VPA is responsible for its pharmacologic and toxic effects, and the total and free concentrations are highly discordant because of VPA’s highly protein bound and saturable binding characteristics. Therefore, free VPA monitoring is increasingly advocated. Nevertheless, the correlation between free VPA concentration and associated adverse effects remains unknown.ObjectiveTo determine the optimal safety range of free VPA concentration in adult patients.Materials and methodsThis prospective cohort study enrolled adult patients undergoing VPA therapy with TDM. Patient characteristics, VPA use, and adverse effects (thrombocytopenia, hyperammonemia, and hepatotoxicity) were recorded. A multivariate logistic regression model was applied to identify the predictors of adverse effects, and the receiver operating characteristic curve was applied to locate the cutoff point of free VPA concentration.ResultsA total of 98 free serum concentrations from 51 patients were included for final analysis. In total, 31 (31.6%), 27 (27.6%), and 4 (4.1%) episodes of hyperammonemia, thrombocytopenia, and hepatotoxicity were observed, respectively. Free VPA concentration was a predicting factor for thrombocytopenia but not for hyperammonemia. A free VPA concentration of >14.67 mcg/mL had the greatest discriminating power (area under the curve = 0.77) for the occurrence of thrombocytopenia.ConclusionsA free VPA serum concentration of 14.67 mcg/mL had the optimal discriminating power for the occurrence of thrombocytopenia. Ammonemia should be monitored even if free VPA concentration is within the safety range.

Using l-Carnitine as a Pharmacologic Probe of the Interpatient and Metabolic Variability of Sepsis.

The objective of this review is to discuss the therapeutic use and differential treatment response to Levo-carnitine (l-carnitine) treatment in septic shock, and to demonstrate common lessons learned that are important to the advancement of precision medicine approaches to sepsis. We propose that significant interpatient variability in the metabolic response to l-carnitine and clinical outcomes can be used to elucidate the mechanistic underpinnings that contribute to sepsis heterogeneity. A narrative review was conducted that focused on explaining interpatient variability in l-carnitine treatment response. Relevant biological and patient-level characteristics considered include genetic, metabolic, and morphomic phenotypes; potential drug interactions; and pharmacokinetics (PKs). Despite promising results in a phase I study, a recent phase II clinical trial of l-carnitine treatment in septic shock showed a nonsignificant reduction in mortality. However, l-carnitine treatment induces significant interpatient variability in l-carnitine and acylcarnitine concentrations over time. In particular, administration of l-carnitine induces a broad, dynamic range of serum concentrations and measured peak concentrations are associated with mortality. Applied systems pharmacology may explain variability in drug responsiveness by using patient characteristics to identify pretreatment phenotypes most likely to derive benefit from l-carnitine. Moreover, provocation of sepsis metabolism with l-carnitine offers a unique opportunity to identify metabolic response signatures associated with patient outcomes. These approaches can unmask latent metabolic pathways deranged in the sepsis syndrome and offer insight into the pathophysiology, progression, and heterogeneity of the disease. The compiled evidence suggests there are several potential explanations for the variability in carnitine concentrations and clinical response to l-carnitine in septic shock. These serve as important confounders that should be considered in interpretation of l-carnitine clinical studies and broadly holds lessons for future clinical trial design in sepsis. Consideration of these factors is needed if precision medicine in sepsis is to be achieved.

Ultrasmall Gold Nanoparticle Cellular Uptake: Influence of Transient Bionano Interactions.

Ultrasmall nanoparticles are attracting an increasing interest for a variety of biomedical applications, from therapeutic targeting to imaging, in virtue of the peculiar behavior shown in vivo (i.e., efficient renal clearance, low liver accumulation, etc.). In evaluating their potential to overcome some of the challenges that larger particles have faced, it is important to understand their mechanisms of interaction with the cell membrane in relation to the biological environment and their tendency to transiently interact with biomolecules. In this work, the mechanism of cellular uptake across a range of serum concentrations is investigated using 2 nm gold nanoparticles with different surface chemistries as a model. The data suggest that despite their ultrasmall size, for these nanoparticles, internalization occurs via energy-dependent processes, and the surface chemistry could play a key role in determining the modality of the transient protein interaction, especially in conditions close to the in vivo scenario (large excess of the protein content). These aspects might be exploited to define novel targeting strategies.

Isoform-specific Inhibition of N-methyl-D-aspartate Receptors by Bile Salts

The N-methyl-D-aspartate subfamily of ionotropic glutamate receptors (NMDARs) is well known for its important roles in the central nervous system (CNS), e.g. learning and memory formation. Besides the CNS, NMDARs are also expressed in numerous peripheral tissues including the pancreas, kidney, stomach, and blood cells, where an understanding of their physiological and pathophysiological roles is only evolving. Whereas subunit composition increases functional diversity of NMDARs, a great number of endogenous cues tune receptor signaling. Here, we characterized the effects of the steroid bile salts cholate and chenodeoxycholate (CDC) on recombinantly expressed NMDARs of defined molecular composition. CDC inhibited NMDARs in an isoform-dependent manner, preferring GluN2D and GluN3B over GluN2A and GluN2B receptors. Determined IC50 values were in the range of bile salt serum concentrations in severe cholestatic disease states, pointing at a putative pathophysiological significance of the identified receptor modulation. Both pharmacological and molecular simulation analyses indicate that CDC acts allosterically on GluN2D, whereas it competes with agonist binding on GluN3B receptors. Such differential modes of inhibition may allow isoform-specific targeted interference with the NMDAR/bile salt interaction. In summary, our study provides further molecular insight into the modulation of NMDARs by endogenous steroids and points at a putative pathophysiological role of the receptors in cholestatic disease.

Comparison of in-situ forming composite using PLGA-PEG-PLGA with in-situ forming implant using PLGA: In-vitro, ex-vivo, and in-vivo evaluation of naltrexone release

An in-situ forming composite (ISFC) of naltrexone (NTX) was prepared using PLGA-PEG-PLGA (triblock) and N-methyl-2-pyrrolidone (NMP) for decreasing the initial burst release. The supercritical CO2 method was used to achieve the ring-opening polymerization of the triblock. The Box-Behnken design was used to achieve the minimal initial burst release of NTX in the in-vitro release medium. In-vitro, ex-vivo, and in-vivo studies of the ISFC were compared with an in-situ forming implant (ISFI) composed of copolymer PLGA 504H. The equivalency of ISFC and Vivitrol® were compared by sampling the concentration of NTX in rabbit blood. The results of the in-vitro release evaluation showed that the initial burst release for the ISFC (5.69 ± 0.27%) was significantly lower than that for the ISFI (17.45 ± 1.07%). The Cmax of NTX (15.16 ± 2.46 ng/mL) from the ISFC was significantly (p < 0.05) lower than that of the ISFI (24.46 ± 2.9 ng/mL) and Vivitrol® (21.11 ± 2.89 ng/mL). The bioavailability and the range of serum concentration of NTX for the ISFC formulation was similar to that of Vivitrol®. The results suggested that the ISFC could be used as a new type of sustained-release formulation with a smaller initial burst release than the ISFI.

In-vitro, ex-vivo, and in-vivo evaluation of buprenorphine HCl release from an in situ forming gel of PLGA-PEG-PLGA using N‑methyl‑2‑pyrrolidone as solvent

An in situ forming gel (ISFG) of buprenorphine (BP) was prepared using PLGA-PEG-PLGA (triblock) and N‑methyl‑2‑pyrrolidone as solvent for decreasing the initial burst release. Supercritical CO2 method was used for ring opening polymerization of triblock. The optimum formulation of ISFG was achieved based on a minimum initial burst release of BP in the in-vitro release media using Box-Behnken design. In-vitro, ex-vivo, and in-vivo studies of ISFG were compared with an in situ forming implant (ISFI) composed of copolymer PLGA 504H (similar to RBP-6000). The initial burst release from in vitro media for the ISFG (6.19 ± 0.31%) was significantly lower than that for the ISFI (13.45 ± 1.14%) because the thermosensitive property of the triblock and hydrogen bonding between the NMP molecules and the PEG of the triblock prevented the NMP from diffusing rapidly into the release medium. The Cmax of BP (6.95 ± 0.98 ng/mL) from the ISFG was significantly (p < 0.05) lower than those from the ISFI (8.19 ± 1.02). Furthermore, the AUC, the range of serum concentration (C) of BP for the ISFG (AUC = 2721.38 ± 69, C = 1.87–7.12) formulation were similar to those for ISFI (AUC = 2727.36 ± 71, C = 1.75–10). The results suggest that the ISFG can be used as a new type of sustained-release injection formulation with a smaller initial burst release than the ISFI.