Maximum Drug Concentration Research Articles

Pharmacokinetics and pharmacodynamics of sacubitril/valsartan in peritoneal dialysis patients.

There is little information on the pharmacokinetics and pharmacodynamics of sacubitril/valsartan (SV) in patients with peritoneal dialysis (PD) complicated with hypertension or heart failure (HF). This study was designed to evaluate the pharmacokinetics and pharmacodynamics of SV in PD patients with complications of hypertension or HF. This was an open-label and cross-sectional study investigating PD patients diagnosed with hypertension or New York Heart Association (NYHA) Class II-IV HF. The concentrations of valsartan, sacubitril, and sacubitrilat (LBQ657) were measured by ultra-performance liquid chromatography tandem mass spectrometry in plasma, urine and peritoneal dialysate samples. Pharmacodynamics were evaluated by comparing changes in mean sitting systolic blood pressure (msSBP), mean sitting diastolic blood pressure (msDBP), mean sitting heart rate (msHR), N-terminal-pro B-type natriuretic peptide (NT-proBNP) and left ventricular ejection fraction (LVEF). Forty patients with PD were enrolled including 27 (67.5%) patients with hypertension, 4 (10%) patients with HF and 9 (22.5%) patients with both hypertension and HF. This study included three treatment cohorts: 50mg twice daily (BID), 100mg once daily (QD) and 100mg BID. The plasma maximum drug concentrations in the 100mg BID group were 1995 ± 1499ng/mL for valsartan, 171 ± 148ng/mL for sacubitril and 13686 ± 7418ng/mL for LBQ657. The 24h recovery rate of LBQ657 was 3.77% in urine and 2.23% in peritoneal dialysate. After taking SV, msSBP and msDBP decreased by 19.25±10.32mmHg and 10.10±8.00mmHg from baseline, respectively. NT-proBNP decreased by 1436.50 (0.00-18198.00) from baseline, while LVEF increased by 5.00 (-0.25-9.25) from baseline after SV treatment. PD and residual renal function contributed only to a minor degree to the elimination of LBQ657. Additionally, a dose of 100mg BID SV is safe and effective in patients with PD with complications of hypertension or HF.

In vitro to in vivo acetaminophen hepatotoxicity extrapolation using classical schemes, pharmacodynamic models and a multiscale spatial-temporal liver twin.

In vitro to in vivo extrapolation represents a critical challenge in toxicology. In this paper we explore extrapolation strategies for acetaminophen (APAP) based on mechanistic models, comparing classical (CL) homogeneous compartment pharmacodynamic (PD) models and a spatial-temporal (ST), multiscale digital twin model resolving liver microarchitecture at cellular resolution. The models integrate consensus detoxification reactions in each individual hepatocyte. We study the consequences of the two model types on the extrapolation and show in which cases these models perform better than the classical extrapolation strategy that is based either on the maximal drug concentration (Cmax) or the area under the pharmacokinetic curve (AUC) of the drug blood concentration. We find that an CL-model based on a well-mixed blood compartment is sufficient to correctly predict the in vivo toxicity from in vitro data. However, the ST-model that integrates more experimental information requires a change of at least one parameter to obtain the same prediction, indicating that spatial compartmentalization may indeed be an important factor.

Pharmacokinetics and bioequivalence study of montelukast sodium oral soluble film and chewable tablet in healthy Chinese volunteers: randomized trials under fasting and fed conditions.

The oral soluble film (OSF) is a new drug delivery system. Whether montelukast sodium OSF has similar pharmacokinetic (PK) properties and bioequivalence to chewable tablet (CT) should be investigated. This study, conducted at Haikou People's Hospital, consisted of two trials: a randomized, open-label, single-dose, 3-sequence, 3-period crossover trial under fasting conditions and a randomized, open-label, single-dose, 2-sequence, 2-period crossover trial under fed conditions. Healthy volunteers were randomized 1:1:1 to receive single-dose oral montelukast sodium OSF without water, OSF, or CT with water in the fasting trial, and 1:1 to receive OSF or CT with water in the fed trial in each period, with a 7-day washout period. Randomization was performed according to random number tables generated using computer. Blood samples were collected over a 24-h period. Plasma drug concentrations were tested using high-performance liquid chromatography-tandem mass spectrometry. The primary PK parameters were maximum plasma drug concentration (Cmax), area under the plasma drug concentration-time curve (AUC) from t=0 to the last quantifiable concentration (AUC0-t), and AUC from t=0 to infinity (AUC0-∞). The other PK parameters included time to Cmax (Tmax), terminal elimination rate constant (λz), and half-life (t1/2). Safety was also assessed. Analysis of variance on log-transformed primary PK parameters was applied to analyze the bioequivalence between the OSF and CT. The bioequivalence margin was 80-125%. From November 2018 to January 2019, 30 subjects were included in each trial. The PK parameters between OSF and CT were numerically similar. All 90% confidence intervals (CIs) of the geometric mean ratio (GMR) for the primary PK parameters fell within 80-125%, confirming the bioequivalence of montelukast sodium OSF and CT under fasting and fed conditions. In the fasting trial, 6 (20%) adverse events (AEs) were reported, including 3 (10%) cases after OSF administration without water and 3 (10%) after OSF administration with water, with no serious AEs. No AEs were recorded in the fed trial. Montelukast sodium OSF is bioequivalent to CT, with acceptable safety. The OSF is an alternative option of CT. ClinicalTrials.gov identifiers: NCT05528198 (the fasting trial) and NCT05531994 (the fed trial).

In-vitro and in-vivo evaluation of sustained-release buprenorphine using in-situ forming lipid-liquid crystal gels

AimsSustained-release systems reduce the incidence of drug side effects and the need for frequent drug consumption, thus increasing patient compliance with treatment. In this study, we aimed to produce sustained-release buprenorphine (BP) using lipid-liquid crystal gels. Main methodsThe three experimental groups in this study included: group I: lipid-liquid crystal formulation 5 (F5) containing BP, group II: BP-free F5, group III: BP solution in NMP, and group IV: control (no treatment). The formulations were injected subcutaneously into the rabbits' back neck. Key findingsThe results showed that the time required to reach the drug's maximum concentration (Tmax) was longer in group I than in group III. The maximum BP concentration (Cmax) and the constants of the drug removal rate and drug absorption rate (Ka) were significantly higher in group III compared to group I. The half-life (t1/2) of the drug in blood circulation was significantly longer in group I than in group III. Histopathological analysis revealed no histological abnormalities in the skin and heart in group I (BP-containing F5); however, mild hyperemia was observed in interstitial vessels in group III (BP-containing NMP). The kidney and liver tissues showed normal structure in the control group, as well as groups I and II. However, in the group receiving BP-containing NMP, significant congestion, tissue damage, necrosis, and fibrosis were observed in the kidney and liver. SignificanceThe results showed that the lipid-liquid crystal system can be used to design slow-release platforms for BP, minimizing the side effects associated with the use of its conventional forms.

Pharmacokinetics, metabolite profiling, safety, and tolerability of inhalation aerosol of 101BHG-D01, a novel, long-acting and selective muscarinic receptor antagonist, in healthy Chinese subjects.

101BHG-D01 is a novel, long-acting, selective muscarinic receptor antagonist for the treatment of chronic obstructive pulmonary disease (COPD). A single-site, randomized, double-blind, placebo-controlled and dose-escalation study of 101BHG-D01 inhalation aerosol was conducted to evaluate its pharmacokinetics, metabolite profiling, safety and tolerability following the single inhaled doses ranged from 20 to 900μg in healthy Chinese subjects. After inhalation, 101BHG-D01 was absorbed rapidly into plasma with the time to maximum concentration about 5min, and eliminated slowly with the terminal phase half-life about 30h. The cumulative excretion rates of 101BHG-D01 in feces and urine were about 30% and 2%, respectively, which showed the study drug was mainly excreted in feces. The maximum drug concentration and area under the plasma concentration-time curve increased with dose escalation in the range of 20-600μg, but their values increased out of proportion to the whole studied doses. The main metabolic pathways were loss of phenyl group and hydroxylation. No metabolite that presented at greater than 10 percent of total drug-related exposure was observed. 101BHG-D01 was safe and well tolerated after administration. The study results indicate that 101BHG-D01 is a good candidate for the treatment of COPD and enable further clinical development in subsequent studies in patients. Clinical Trial Registration: http://www.chinadrugtrials.org.cn; Identifier: CTR20192058.

High-Dose Intermittent Treatment with the Multikinase Inhibitor Sunitinib Leads to High Intra-Tumor Drug Exposure in Patients with Advanced Solid Tumors

Patients with advanced cancer refractory to standard treatment were treated with sunitinib at a dose of 300 mg once every week (Q1W) or 700 mg once every two weeks (Q2W). Tumor, skin and plasma concentrations were measured and immunohistochemical staining for tumor cell proliferation (TCP), microvessel density (MVD) and T-cell infiltration was performed on tumor biopsies before and after 17 days of treatment. Oral administration of 300 mg sunitinib Q1W or 700 mg Q2W resulted in 19-fold (range 5-35×) and 37-fold higher (range 10-88×) tumor drug concentrations compared to parallel maximum plasma drug concentrations, respectively. Patients with higher tumor sunitinib concentrations had favorable progression-free and overall survival than those with lower concentrations (p = 0.046 and 0.024, respectively). In addition, immunohistochemistry of tumor biopsies revealed an induction of T-cell infiltration upon treatment. These findings provide pharmacological and biological insights in the clinical benefit from high-dose intermittent sunitinib treatment. It emphasizes the potential benefit from reaching higher tumor drug concentrations and the value of measuring TKI tumor- over plasma-concentrations. The finding that reaching higher tumor drug concentrations provides most clinical benefit in patients with treatment refractory malignancies indicates that the inhibitory potency of sunitinib may be enforced by a high-dose intermittent treatment schedule. These results provide proof of concept for testing other clinically available multitargeted tyrosine kinase inhibitors in a high-dose intermittent treatment schedule.

An open-label, randomized, crossover study to evaluate the bioavailability of nanoemulsion versus conventional fat-soluble formulation of cholecalciferol in healthy participants

BackgroundNanoemulsion preparations of cholecalciferol available in the market claim to have better bioavailability than the conventional fat-soluble cholecalciferol. However, limited data are available in humans for such preparations. We, therefore, compared the relative bioavailability of two formulations of 60,000 IU cholecalciferol (nanoemulsion oral solution, water-miscible vitamin D3 [test] vs soft gelatin capsules [reference]) in healthy adult participants. MethodsIn this randomized, open-label, two sequence, single-dose, two-way crossover study (CTRI/2018/05/013839), Indian participants aged 18–45 years received single dose of nanoemulsion and capsule formulations, under fasting conditions. Blood samples collected over 120 h were assessed to determine cholecalciferol concentrations. Pharmacokinetic parameters (area under the concentration-time curve up to 120 h [AUC0–120h], maximum observed drug concentration [Cmax], time to reach maximum drug concentration [Tmax], terminal half-life [T½el], and terminal elimination rate constant [Kel]) were estimated using baseline corrected data and analyzed using analysis of variance. ResultsAmong the 24 eligible participants, the relative bioavailability of nanoemulsion was significantly higher than the capsules by 36% (p = 0.0001) based on AUC0–120h. Similarly, Cmax of the nanoemulsion was significantly higher by 43% (p = 0.0001) than that of the capsules. The intra-participant variability for AUC0–120h and Cmax were 23.22% and 26.51%, respectively. The Tmax, T½el, and Kel were comparable for both the formulations. No adverse effects were noted with either of the two formulations. ConclusionsNanoemulsion oral solution of cholecalciferol showed a greater bioavailability compared with soft gelatin capsules, under fasting conditions, in healthy human participants.

PHARMACEUTICAL WASTE – A NEW THREAT TO LAKE ECOSYSTEMS

According to the Basel Convention (1998), pharmaceutical waste is waste from medical care in hospitals, medical centers and clinics, waste from the production and preparation of pharmaceutical products, waste pharmaceuticals, drugs and medicines, wastes from the production, formulation and use of biocides and phytopharmaceuticals. They belong to the so-called Yellow List, and are all, without exception, regarded hazardous. A review of the results of studies on pharmaceutical wastes in water bodies (rivers and lakes) in Russia and abroad has been produced. Medicines are an integral part of medical practice. They serve the preservation of the health of the population and, as a result, enhance the quality and prolong the duration of life. On the other hand, pharmaceutical industry waste is increasingly affecting wildlife, as unused medicines are often discarded or disposed of improperly. At the beginning of the 21st century, the European Environment Agency (EEA) designated the impact of active pharmaceutical ingredients on the environment as a new environmental problem. The main pathways by which drugs reach the environment have been charted. Meanwhile, Russia has no system to regulate maximum permissible concentrations of drugs in water bodies. The purpose of this study is to work out a methodology for calculating maximum permissible concentrations of drugs in water bodies of fishery importance. An adequate correlation has been established between maximum permissible concentrations of harmful substances in water bodies of fishery importance (MPCf) and their average lethal concentrations for daphnia. Indicative MPCf values have been calculated for 12 pharmaceutical products.

Formulation and Evaluation of a Drug-in-Adhesive Patch for Transdermal Delivery of Colchicine.

Gout is one of the most prevalent rheumatic diseases, globally. Colchicine (COL) is the first-line drug used for the treatment of acute gout. However, the oral administration of COL is restricted, owing to serious adverse reactions. Therefore, this study aimed to develop a drug-in-adhesive (DIA) patch to achieve transdermal delivery of COL. We investigated the solubility of COL in different pressure-sensitive adhesives (PSAs) using slide crystallization studies. The COL-DIA patches were optimized based on in vitro skin penetration studies and evaluated by in vivo pharmacokinetics and pharmacodynamics. The results showed that the optimized COL-DIA patch contained 10% COL, Duro-Tak 87-2516 as PSA, 5% oleic acid (OA) and 5% propylene glycol (PG) as permeation enhancer, exhibiting the highest in vitro cumulative penetration amount of COL (235.14 ± 14.47 μg∙cm−2 over 48 h). Pharmacokinetic studies demonstrated that the maximum plasma drug concentration (Cmax) was 2.65 ± 0.26 ng/L and the mean retention time (MRT) was 37.47 ± 7.64 h of the COL-DIA patch, effectively reducing the drug side effects and prolonging drug activity. In addition, pharmacodynamic studies showed the patch significantly decreased the expression levels of inflammatory factors of gouty rats and reduced pathological damage in the ankle joint of rats, making it an attractive alternative to the administration of COL for the treatment of gout.

PHYSIOLOGICALLY BASED PHARMACOKINETIC (PBPK) MODELING OF THE COMBINATION OF IVACAFTOR AND LEFAMULIN IN PATIENTS WITH CYSTIC FIBROSIS

PHYSIOLOGICALLY BASED PHARMACOKINETIC (PBPK) MODELING OF THE COMBINATION OF IVACAFTOR AND LEFAMULIN IN PATIENTS WITH CYSTIC FIBROSIS

Pharmacokinetics of butorphanol following intravenous and intramuscular administration in donkeys: A preliminary study.

The pharmacokinetics of butorphanol after intravenous (IVB) and intramuscular (IMB) administration in donkeys were determined in this preliminary study. Healthy male gelded donkeys (n = 5), aged 6–12 years old, were administered 0.1 mg/kg butorphanol IV or IM in a randomized, crossover design. Blood samples were obtained at predetermined intervals for 24 h (IVB) and 48 h (IMB) after administration. Plasma butorphanol concentrations were determined by high performance liquid chromatography and pharmacokinetic parameters were calculated. Following IVB administration, mean (± SE) apparent volume of distribution, elimination half-life, total body clearance, and area under the plasma concentration time curve from time 0 to infinity (AUC0−∞) were 322 ± 50 mL/kg, 0.83 ± 0.318 h, 400 ± 114 mL/h/kg, 370 ± 131 h·ng/mL, respectively. After IMB administration, a maximum plasma drug concentration of 369 ± 190 ng/mL was reached at 0.48 ± 0.09 h. The IMB AUC0−∞ was 410 ± 60 h·ng/mL. Bioavailability of IMB was 133 ± 45%. The pharmacokinetics of butorphanol in healthy donkeys was characterized by faster elimination half-life compared to values from the equine literature.

Pharmacokinetics and Bioequivalence of 2 Safinamide Tablets in Healthy Chinese Volunteers Under Fasting and Fed Conditions.

To assess the bioequivalence of a generic safinamide tablet (test) vs a brand-name safinamide tablet (reference) and effects of food on the pharmacokinetics of safinamide in healthy Chinese subjects, a single-center, single-dose, randomized, open-label, 2-preparation, 2-period study with a 15-day washout period was undertaken. A total of 56 healthy subjects were recruited in this study (fasting, n = 28; fed, n = 28). A single dose of a 100-mg test or reference safinamide tablet was administered to each subject in a randomized sequence. Blood samples were obtained at 5minutes before drug administration and during the 120hours after dosing. The safinamide concentration in plasma was determined by high-performance liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were analyzed with noncompartmental methods. Safety was also monitored. The major pharmacokinetic parameters including maximum plasma drug concentration, area under plasma concentration-time curve (AUC) from zero to time t (AUC0-t ), and AUC from time 0 to infinity (AUC0-∞ ) were similar between the test and reference tablets under fasting and fed conditions. The 90% CIs of the test/reference ratios of log-transformed maximum plasma drug concentration, AUC from zero to time t, and AUC from time 0 to infinity all fell within the equivalence interval (80.0%-125%) whether under fasting condition or fed condition. In conclusion, the 2 formulations of safinamide tablets were bioequivalent and well tolerated under both fasting and fed conditions in healthy Chinese volunteers. High-fat food delayed the absorption of safinamide but did not affect the final bioavailability.

Assessment of the pharmacokinetics, safety, and tolerability of levothyroxine sodium in healthy Indian volunteers

Background: Few studies have assessed the pharmacokinetics of various marketed formulations of levothyroxine available in the Indian market. Here, we assessed the pharmacokinetics and safety of Thyronorm® 100 in healthy Indian volunteers.Methods: The primary and secondary objectives were to determine the pharmacokinetic profile and to monitor safety and tolerability of 600 µg of levothyroxine, respectively. Eligible subjects received a single oral dose of 6×100 µg of levothyroxine, and pharmacokinetic profiles were monitored up to 432 hours post-dose. Safety assessments included exposure of study drug and incidence of adverse events (AEs) and serious AEs. The mean plasma concentration of LT4 versus time profile was presented on both untransformed and log-transformed scales.Results: Of 20 enrolled subjects, 1 was discontinued due to an AE of pain, unrelated to study drug. The mean [standard deviation (SD)] age and body mass index of subjects were 35.7 (6.33) years and 25.0 (3.0) kg/m2, respectively. Following baseline correction, the mean maximum observed drug concentration (Cmax) and area under the plasma concentration-time curve measured to the last quantifiable concentration (AUC0-t) of free thyroxine were found to be 68.4 (12.09) ng/ml and 6760.0 (2065.05) ng×hr/ml, respectively, with an elimination half-life (t1/2) of 205.6 (180.26) hrs and a residual area of 24.6%. The median time to first observed maximum drug concentration (Tmax) was 2.5 (1.5-2.5) hrs.Conclusions: These parameters were in accordance with those of other marketed formulations and confirmed the pharmacokinetics and safety of Thyronorm® 100 in healthy volunteers from India.

An Open-Label Study to Evaluate the Effect of Eluxadoline on the Single-Dose Pharmacokinetics of Midazolam in Healthy Participants.

Eluxadoline is a mixed μ-opioid, κ-opioid receptor agonist, and δ-opioid receptor antagonist, approved in the United States for adults with diarrhea-predominant irritable bowel syndrome. This phase 1, single-center, open-label, single-sequence study was conducted on 30 healthy participants to establish whether steady-state eluxadoline increases systemic exposure of the cytochrome P450 (CYP) 3A4 substrate midazolam. Participants received oral midazolam 4 mg on day 1 with a 7-day washout period. On days 8-16, oral eluxadoline 100mg was administered twice daily. On day 15, midazolam 4 mg was coadministered with the eluxadoline 100-mg morning dose. Primary outcome measures were pharmacokinetic parameters of midazolam and 1-hydroxy-midazolam. The midazolam and 1-hydroxy-midazolam geometric mean ratios and 90%CIs for maximum plasma drug concentration were 99.0% (91.6-107.0) and 113.8% (104.9-123.5), respectively, and area under the plasma concentration-time curves were 90.5% (83.9-97.6) and 105.1% (99.8-110.7), respectively, demonstrating the 2 treatments were bioequivalent, and there was no clinically significant drug interaction. All treatment-emergent adverse events were treatment related, mild in intensity, with no serious adverse events. These results suggest that eluxadoline has no clinically significant effect on CYP3A4 activity and is, therefore, unlikely to affect the pharmacokinetics of other CYP3A4 substrates.

Design of Montelukast Nanocrystalline Suspension for Parenteral Prolonged Delivery.

BackgroundMontelukast (MTK), a representative leukotriene receptor antagonist, is currently being investigated as a potential candidate for treating Alzheimer’s disease. For potent and effective dosing in elderly patients, a parenteral prolonged delivery system is favored, with improved medication adherence with reduced dosage frequency.PurposeThis study aimed to design a nanocrystalline suspension (NS)-based MTK prolonged delivery system and evaluate its pharmacokinetics profile and local tolerability following subcutaneous administration.MethodsTo decelerate the dissolution rate, the amorphous MTK raw material was transformed into a crystalline state using a solvent-mediated transformation method and subsequently formulated into NS using a bead-milling technique. The MTK NSs were characterized by morphology, particle size, crystallinity, and in vitro dissolution profiles. The pharmacokinetic profile and local tolerability at the injection site following subcutaneous injection of MTK suspension were evaluated in rats.ResultsMicroscopic and physical characterization revealed that the amorphous MTK powder was lucratively transformed into a crystalline form in acidic media (pH 4). MTK crystalline suspensions with different diameters (200 nm, 500 nm, and 3 μm) were uniformly prepared using bead-milling technology, employing polysorbate 80 as suspending agent. Prepared crystalline suspensions exhibited analogous crystallinity (melting point, 150°C) and size-dependent in vitro dissolution profiles. MTK NSs with particle sizes of 200 nm and 500 nm provided a protracted pharmacokinetic profile for up to 4 weeks in rats, with a higher maximum drug concentration in plasma than the 3 μm-sized injectable suspensions. Histopathological examination revealed that MTK NS caused chronic granulomatous inflammation at the injection site, which resolved after 4 weeks.ConclusionThe MTK parenteral NS delivery system is expected to be a valuable tool for treating Alzheimer’s disease with extended dose intervals.

The efficacy and safety of mizoribine for maintenance therapy in patients with myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA)-associated vasculitis: the usefulness of serum mizoribine monitoring.

The life prognosis of elderly patients with myeloperoxidase-anti-neutrophil cytoplasmic antibodies-associated vasculitis (MPO-AAV) has been improved by reducing the corticosteroid or cyclophosphamide dose to avoid opportunistic infection. However, many elderly MPO-AAV patients experience recurrence and renal death. An effective and safer maintenance treatment method is necessary to improve the renal prognosis of MPO-AAV. Patients with MPO-AAV who reached complete or incomplete remission after induction therapy were prospectively and randomly divided into mizoribine (MZR; n = 25) and control (n = 28) groups. The primary endpoint was relapse of MPO-AAV. The patients' serum MZR concentration was measured before (C0) and 3h after taking the MZR. The maximum drug concentration (Cmax) and the serum MZR concentration curves were determined using population pharmacokinetics parameters. We also assessed the relationship between the MZR concentrations and adverse events. The observation period was 12months. Fifty-eight MPO-AAV patients from 16 hospitals in Japan were enrolled. Ten patients relapsed (MZR group, n = 6; control group, n = 4; a nonsignificant between-group difference). Changes in the serum MZR concentration could be estimated for 22 of the 25 MZR-treated patients: 2 of the 11 patients who reached a Cmax of 3μg/mL relapsed, whereas 4 of the 11 patients who did not reach this Cmax relapsed. The treatment of one patient with C0 > 1μg/mL was discontinued due to adverse events. No serious adverse events occurred. There was no significant difference in the recurrence rate of MPO-AAV between treatment with versus without MZR.

Donepezil hydrochloride-reinforced cellulose nanocrystal-aggregated gel structure for long-acting drug delivery

A donepezil hydrochloride (DPZ)-reinforced cellulose nanocrystal (CNC) hydrogel structure with pH control was developed for sustained drug delivery through subcutaneous injection. In the present study, an aggregated CNC gel was fabricated by reducing the electrostatic repulsion between CNC particles by incorporating DPZ and adjusting the pH value to 7.7. The crosslinked CNC/DPZ (cCNC/DPZ) gel exhibited immediate gelation, injection capability through a single syringe, improved viscoelasticity, and shear-thinning properties. Interactions between the CNCs and DPZ and pH regulation were assessed using several solid-state studies, and a sustained release profile of the DPZ from the cCNC/DPZ gel was also observed. In the pharmacokinetic study, a higher half-life and mean residence time and lower maximum drug concentration values were obtained in the cCNC/DPZ group than in the DPZ solution and CNC/DPZ groups after subcutaneous injection. Drug salt form-incorporated and pH-controlled CNC hydrogel systems can be safely applied to the subcutaneous delivery of DPZ.

Determination of starting dose of the T cell-redirecting bispecific antibody ERY974 targeting glypican-3 in first-in-human clinical trial

Currently, ERY974, a humanized IgG4 bispecific T cell-redirecting antibody recognizing glypican-3 and CD3, is in phase I clinical trials. After a first-in-human clinical trial of an anti-CD28 agonist monoclonal antibody resulting in severe life-threatening adverse events, the minimal anticipated biological effect level approach has been considered for determining the first-in-human dose of high-risk drugs. Accordingly, we aimed to determine the first-in-human dose of ERY974 using both the minimal anticipated biological effect level and no observed adverse effect level approaches. In the former, we used the 10% effective concentration value from a cytotoxicity assay using the huH-1 cell line with the highest sensitivity to ERY974 to calculate the first-in-human dose of 4.9 ng/kg, at which maximum drug concentration after 4 h of intravenous ERY974 infusion was equal to the 10% effective concentration value. To determine the no observed adverse effect level, we conducted a single-dose study in cynomolgus monkeys that were intravenously infused with ERY974 (0.1, 1, and 10 μg/kg). The lowest dose of 0.1 μg/kg was determined as the no observed adverse effect level, and the first-in-human dose of 3.2 ng/kg was calculated, considering body surface area and species difference. For the phase I clinical trial, we selected 3.0 ng/kg as a starting dose, which was lower than the first-in-human dose calculated from both the no observed adverse effect level and minimal anticipated biological effect level. Combining these two methods to determine the first-in-human dose of strong immune modulators such as T cell-redirecting antibodies would be a suitable approach from safety and efficacy perspectives.Clinical trial registration: JapicCTI-194805/NCT05022927.

Activity of Delafloxacin and Levofloxacin against Stenotrophomonas maltophilia at Simulated Plasma and Intrapulmonary pH Values.

ABSTRACTFluoroquinolones have become a popular treatment option for Stenotrophomonas maltophilia infections. Although levofloxacin is most commonly used, delafloxacin demonstrates comparable in vitro activity when evaluated under standard susceptibility testing conditions at neutral pH. At acidic pH, the activity of the anionic delafloxacin is improved, while the activity of the zwitterionic levofloxacin is reduced. Because the human respiratory tract has a pH of ~6.6 and is the most common site of S. maltophilia infection, it is vital to understand the activity of these agents in this environment. Therefore, levofloxacin and delafloxacin were tested against clinical S. maltophilia isolates via broth microdilution testing (n = 37) and time-kill analysis (n = 5) in neutral cation-adjusted Mueller-Hinton broth (CAMHB) (pH 7.3) and acidic CAMHB (aCAMHB) (pH 6.5). In CAMHB, MIC50 values were similar between levofloxacin and delafloxacin (8 mg/L versus 8 mg/L). In aCAMHB, levofloxacin MICs did not change, while delafloxacin MICs decreased by a median of 4 log2 dilutions (MIC50 values of 8 mg/L versus 0.25 mg/L). In time-kill analyses, levofloxacin and delafloxacin at the maximum drug concentration for the free drug (fCmax) were bactericidal against 3 and 2 isolates in CAMHB, respectively. In aCAMHB, levofloxacin was not bactericidal against any isolate, while delafloxacin was bactericidal against the same 2 isolates. Relative to CAMHB, levofloxacin activity was reduced by 2.5 log10 CFU/mL in aCAMHB, whereas delafloxacin activity was increased 2.7 log10 CFU/mL. Although the bactericidal activity of levofloxacin against S. maltophilia was attenuated in an acidic environment in this study, the increased potency of delafloxacin at pH 6.5 did not translate into improved bactericidal activity in time-kill analyses, compared to pH 7.3.IMPORTANCE Stenotrophomonas maltophilia most often infects the lungs, where the physiologic environment is naturally slightly acidic (pH ~6.6), compared to most parts of the body (such as the bloodstream), which have neutral pH values (~7.4). Pneumonia due to S. maltophilia is often treated with the antibiotic levofloxacin, despite the activity of levofloxacin being known to be impaired at acidic pH. Unfortunately, currently available methods for susceptibility testing of levofloxacin against S. maltophilia are performed at a neutral pH and therefore may not accurately represent the activity of levofloxacin at the site of infection in the lungs. A similar but newer antibiotic in the same class as levofloxacin, namely, delafloxacin, is not affected by being in an acidic environment and may actually work better at lower pH values. Therefore, the purpose of this study was to investigate whether one drug might be better than the other in this setting by testing each agent’s ability to kill S. maltophilia at pH 7.3 and pH 6.5. These findings could then be used to design confirmatory studies that may ultimately impact which drug is given to patients with lung infections due to S. maltophilia.

Neuroprotection against supra-lethal ‘stroke in a dish’ insults by an anti-excitotoxic receptor antagonist cocktail

The goal of this study was to identify cocktails of drugs able to protect cultured rodent cortical neurons against increasing durations of oxygen-glucose deprivation (OGD). As expected, a cocktail composed of an NMDA and AMPA receptor antagonists and a voltage gated Ca2+ channel blocker (MK-801, CNQX and nifedipine, respectively) provided complete neuroprotection against mild OGD. Increasingly longer durations of OGD necessitated increasing the doses of MK-801 and CNQX, until these cocktails ultimately failed to provide neuroprotection against supra-lethal OGD, even at maximal drug concentrations. Surprisingly, supplementation of any of these cocktails with blockers of TRPM7 channels for increasing OGD durations was not neuroprotective, unless these blockers possessed the ability to inhibit NMDA receptors. Supplementation of the maximally effective cocktail with other NMDA receptor antagonists augmented neuroprotection, suggesting insufficient NMDAR blockade by MK-801. Substitution of MK-801 in cocktails with high concentrations of a glycine site NMDA receptor antagonist caused the greatest improvements in neuroprotection, with the more potent SM-31900 superior to L689,560. Substitution of CQNX in cocktails with AMPA receptor antagonists at high concentrations also improved neuroprotection, particularly with the combination of SYM2206 and NBQX. The most neuroprotective cocktail was thus composed of SM-31900, SYM2206, NBQX, nifedipine and the antioxidant trolox. Thus, the cumulative properties of antagonist potency and concentration in a cocktail dictate neuroprotective efficacy. The central target of supra-lethal OGD is excitotoxicity, which must be blocked to the greatest extent possible to minimize ion influx.