Maximum Drug Concentration Research Articles

Safety, Tolerability, and Pharmacokinetics of the Monoamine Oxidase B Inhibitor, HEC122505, and its Major Metabolite After Single- andMultiple- Ascending Dose, and Food Effect Study in Healthy Chinese Subjects.

HEC122505 is a potent and selectively monoamine oxidase B inhibitor that is safe and well-tolerated in preclinical models of Parkinson's disease. The objectives of single ascending dose and multiple dose pharmacokinetic trials of HEC122505 oral tablets were to determine the safety and tolerability of HEC122505, and to examine the food effect on thepharmacokinetic parameters of HEC122505 and its major metabolite HEC129870. The phase I study (NCT04625361) consisted of three arms: single ascending dose study (5, 20, 50, 100, 200, 300 or 400 mg HEC122505 tablets or placebo), multiple ascending dose study (20, 50 or 100 mg HEC122505 tablets or placebo once daily), and food effect (100 mg HEC122505 tablets single dose after a high-fat, high-calorie meal). All subjects completed all trial arms and were analyzed as planned. Pharmacokinetic analysis showed that HEC122505 rapidly absorbed with the time to peak plasma concentration (Tmax) ranged from 0.5 to 1.75h. In addition, maximum plasma drug concentration (Cmax) and area under the plasma concentration-time curve (AUC) increased in a dose proportional manner. Food effect study showed that a high-fat, high-calorie meal had no significant effect on the pharmacokinetics ofHEC122505 and its major metabolite HEC129870, suggesting that HEC122505 could be administered in both fasted and fed state in clinical trials. The subsequent multiple-dose study evaluated doses from 20 to 100mg dose once daily for up to 8days. HEC122505 reached steady state after approximately 5days with a once daily dose. In these studies, all dose of HEC122505 was generally safe and well tolerated. No grade ≥ 3 drug related adverse events (AEs) occurred. HEC122505 was generally safe and well tolerated in the single ascending dose (ranging from 5 to 400 mg) and multiple ascending dose (50 to 200 mg once daily doses) studies. All the drug related adverse events (AEs) were Grade ≤ 2. There were no deaths, no subjects discontinued the trial due to AEs, and there were no other serious AEs. The safety and pharmacokinetic profile support once daily administration of HEC122505.

Safety, Tolerability, and Pharmacokinetics of Voriconazole for Injection in Two Preparations in Chinese Healthy Adult Volunteers.

Voriconazole is a second-generation, synthetic, triazole antifungal drug based on the structure of fluconazole. We compared the safety, tolerability, and pharmacokinetic characteristics of voriconazole for injection (200mg) manufactured by at a dose of 6mg/kg in Chinese healthy adult volunteers. This was a single-center, randomized, open, 2-preparation, single-dose, 2-period, 2-sequence, crossover bioequivalence clinical trial. Twenty-four eligible, healthy, male, and female volunteers were assigned randomly to one of 2 dose-sequence groups (test-reference group or reference-test group) in a 1:1 block. The voriconazole concentration in plasma was determined by protein precipitation and high-performance liquid chromatography-tandem mass spectrometry. The main PK parameters were calculated on the basis of a noncompartmental model. The ratio of the geometric mean of the maximum plasma drug concentration, area under the plasma concentration-time curve from time 0 to the last time of quantifiable concentration, and area under the plasma concentration-time curve from time 0 to infinity of the test preparation, and the reference preparation was 100.4%, 102%, and 102.2%, respectively. The 90% confidence intervals were between 80% and 125%, indicating that the 2 preparations were bioequivalent. The adverse events experienced by healthy adult volunteers were mild. Both preparations had a good safety profile.

Investigation of pharmacokinetic drug interaction between clesacostat and DGAT2 inhibitor ervogastat in healthy adult participants.

Co-administration of clesacostat (acetyl-CoA carboxylase inhibitor, PF-05221304) and ervogastat (diacylglycerol O-acyltransferase inhibitor, PF-06865571) in laboratory models improved non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) end points and mitigated clesacostat-induced elevations in circulating triglycerides. Clesacostat is cleared via organic anion-transporting polypeptide-mediated hepatic uptake and cytochrome P450 family 3A (CYP3A); invitro clesacostat is identified as a potential CYP3A time-dependent inactivator. Invitro ervogastat is identified as a substrate and potential inducer of CYP3A. Prior to longer-term efficacy trials in participants with NAFLD, safety and pharmacokinetics (PK) were evaluated in a phase I, non-randomized, open-label, fixed-sequence trial in healthy participants. In Cohort 1, participants (n = 7) received clesacostat 15 mg twice daily (b.i.d.) alone (Days 1-7) and co-administered with ervogastat 300 mg b.i.d. (Days 8-14). Mean systemic clesacostat exposures, when co-administered with ervogastat, decreased by 12% and 19%, based on maximum plasma drug concentration and area under the plasma drug concentration-time curve during the dosing interval, respectively. In Cohort 2, participants (n = 9) received ervogastat 300 mg b.i.d. alone (Days 1-7) and co-administered with clesacostat 15 mg b.i.d. (Days 8-14). There were no meaningful differences in systemic ervogastat exposures when administered alone or with clesacostat. Clesacostat 15 mg b.i.d. and ervogastat 300 mg b.i.d. co-administration was overall safe and well tolerated in healthy participants. Cumulative safety and no clinically meaningful PK drug interactions observed in this study supported co-administration of these two novel agents in additional studies exploring efficacy and safety in the management of NAFLD.

Pharmacokinetics, metabolite profiling, safety and tolerability of YZJ-4729 tartrate, a novel G protein-biased μ-opioid receptor agonist, in healthy Chinese subjects.

Objective: YZJ-4729 is a novel G protein-biased μ-opioid receptor agonist for the treatment of acute pain in adult patients who require intravenous opioid analgesic therapy. The aim of this study was to assess the pharmacokinetics, metabolite profiling, safety and tolerability of YZJ-4729 in healthy Chinese subjects following the single intravenous doses ranged from 0.2mg to 6mg. Methods: This single-center, randomized, double-blind, placebo-controlled clinical study was conducted in 54 healthy male and female Chinese subjects after single ascending doses of YZJ-4729 tartrate (0.2, 0.5, 1.5, 3, 4.5, and 6mg). Subjects in each cohort were assigned randomly to receive a single intravenous dose of YZJ-4729 tartrate injection or placebo at a ratio of 4:1. Pharmacokinetic characteristics, metabolite profiling, safety and tolerability profiles of the study drug were evaluated. Results: Overall, YZJ-4729 was safe and well tolerated in healthy Chinese subjects. The study drug reached peak plasma concentrations nearly at the end of the infusion. After administration, YZJ-4729 was eliminated rapidly with a terminal elimination half-life of 0.862-2.50h, and excreted little in human excreta. The maximum drug concentration and area under the plasma concentration-time curve increased with dose escalation across the entire dose range. YZJ-4729 experienced extensive metabolism in human body. A total of 19 metabolites were identified and the characteristic metabolic pathways involved hydroxylation, ketone formation, N-dealkylation and glucuronide conjugation. Metabolite M10 was the most abundant circulating metabolite, and represented over 10% of total drug-related systemic exposure. Further PK and safety evaluation of M10 was necessary. Conclusion: The clinical study results laid a foundation for the further clinical studies of YZJ-4729 in patients. Clinical Trial Registration: http://www.chinadrugtrials.org.cn, identifier CTR20222574.

Novel bioequivalent oral disintegrating tablet of aripiprazole prepared by direct compression technique with shortened disintegration time

Herein, we aimed to formulate a novel oral disintegrating tablet (ODT) of aripiprazole (ARP) capable of rapid disintegration using a direct compression technique. Different ODTs were fabricated with directly compressible excipients, and their disintegration time, wettability (water absorption ratio and wetting time), and mechanical properties (hardness and friability) were evaluated. The optimized ODT comprised F-Melt® type C, Prosolv® SMCC HD90, and Na croscarmellose (10 mg of ARP in a 130 mg tablet). The ODT with 3.1–5.2 kp hardness exhibited rapid disintegration (14.1–17.2 sec), along with appropriate mechanical strength (friability < 0.24%). In a bioequivalent study in Korean healthy subjects (randomized, single-dose, two-period crossover design, n = 37), the novel ODT offered the equivalent pharmacokinetic profile to that of a conventional immediate release tablet (Otsuka, Abilify®, Japan), despite different disintegration and dissolution profiles. The 90% confidence intervals of the geometric mean test to reference ratios considering the area-under-the-curve and maximum plasma drug concentrations were 1.0306–11051 and 0.9448–1.1063, respectively, satisfying FDA regulatory criteria for bioequivalence. The novel ART ODT was physicochemically stable under the accelerated storage condition (40 °C, RH75%) for 24 weeks. Therefore, the novel ARP-loaded ODT is expected to be an alternative to oral ARP therapy, providing improved patient adherence.

Preparation, In-vitro, Ex-vivo, and Pharmacokinetic Study of Lasmiditan as Intranasal Nanoemulsion-based In Situ Gel.

Lasmiditan (LAS) is a recently developed antimigraine drug and was approved in October, 2019 for the treatment of acute migraines; however, it suffers from low oral bioavailability, which is around 40%. This study aimed to improve the LAS bioavailability via formulation as nanoemulsionbased in situ gel (NEIG) given intranasally and then compare the traditional aqueous-LASsuspension (AQS) with the two successful intranasal prepared formulations (NEIG 2 and NEIG 5) in order to determine its relative bioavailability (F-relative) via using rabbits. Two successfully prepared nanoemulsion (NE) formulas, a and b, were selected for the incorporation of different percentages of pH-sensitive in situ gelling polymer (Carbopol 934) to prepare NEIGs 1, 2, 3, 4, 5, and 6. The pH, gelation capacity, gel strength, and viscosity were predicted for the prepared NEIGs. The release (in vitro) and the nasal permeation (ex vivo) were determined for NEIG 2 and 5, and then both were subjected to pharmacokinetics in vivo studies. Eighteen male rabbits weighing 2.0 to 2.5 kg were employed in the parallel design study. The body surface area (BSA) normalization method was applied for LAS dose calculation. Serial blood samples were taken out and subjected to drug analysis using the HPLC method previously developed and validated by L. Santosh Kumar. Primary pharmacokinetics parameters, including maximum drug concentration in plasma (Cmax), time to reach C-max (T-max), and area under the concentration-time curve from time zero to affinity (AUCt0-∞) were calculated. Both NE (a and b), together with NEIG (2 and 5) formulas, were subjected to the stability study. Finally, a nasal ciliotoxicity study was carried out to evaluate the nasal toxicity of developed NEIGs 2 and 5. The results showed that NEIGs 2 and 5 could be selected as the optimized NEIGs as both achieved 100% permeation within 20 min and then released within 25 and 35 min, respectively, thus achieving 3.3 folds with higher permeation percentages as compared to the AQS. Both NEIGs 2 and 5 exerted comparable release and permeation values as the corresponding NE a and b with more residence time in order to overcome the normal nasal physiological clearance. The values of C-max, Tmax, and AUC0- ∞ for NEIG 2 and NEIG 5 were 8066±242 ng/ml, 0.75±0.05 h, 19616.86±589 ng. h/ml, and 7975.67±239 ng/ml, 1.0±0.05 h, 17912.36±537 ng. h/ml, respectively, compared to the traditional AQS, which is equal to 4181.09±125 ng/ml, 2±0.2 h, and 8852.27±266 ng. h/ml, respectively. It was discovered that NEIGs 2 and 5 had better intranasal delivery of LAS and could significantly (p<0.05) achieve a higher value of permeability coefficient (3.3 folds) and 2.5 folds improvement in bioavailability when compared to AQS. The NE a, NE b, NEIG2, and NEIG5 formulations showed good stability at various temperatures. According to the nasal ciliotoxicity study, the nasal mucosal membrane, which was treated with NEIG 5, showed irritation with a bit of damage. However, damage was not observed when it was treated with NEIG 2, indicating the biocompatibility of the last one to be selected as the optimum formula. NEIG 2 and NEIG 5 are promising new intranasal formulas with a faster onset of action and greater bioavailability than the oral dosage form (AQS). Finally, the selected optimum gold formula that will be ready for further clinical study is NEIG 2.

Nose to brain delivery of flurbiprofen from a solid lipid nanoparticles-based thermosensitive in-situ gel.

Flurbiprofen, a non-steroidal anti-inflammatory drug (NSAID), has selective amyloid-lowering characteristics and can be utilized for Alzheimer's disease treatment. Oral flurbiprofen has poor brain bioavailability and high dose-related gastrointestinal adverse effects. To overcome these issues, the study aimed to formulate intranasal flurbiprofen solid lipid nanoparticles (SLN) based thermosensitive in-situ gel. SLN were formulated by the High-speed homogenization method. A 23 factorial design technique was utilized for optimization, wherein the influence of two independent variables, critical process parameters (X1 = surfactant concentration, X2 = D:L ratio) on critical quality attributes (Y1 = particle size, Y2=Percent Drug Loading, Y3=Percent Entrapment Efficiency) was ascertained at three distinct levels. The optimized SLN were then prepared into an SLN-based intranasal thermosensitive in-situ gel with Poloxamer 188 P (1.2% w/v) and Poloxamer 407 P (18% w/v). The in-vitro flurbiprofen release study demonstrated a 100% release of flurbiprofen from the SLN-based thermosensitive in-situ gel at 6 h. The ex-vivo flurbiprofen release study revealed a complete release of flurbiprofen from the SLN-based thermosensitive in-situ gel at 8 h. In the in-vivo tests, the in-situ gel (2 mg/kg) administered intranasally in rats demonstrated nearly three times greater brain bioavailability (Cmax = 490.3 ng/ml) than the oral marketed formulation of flurbiprofen, Ansaid® (10 mg/kg) (Cmax = 145.1 ng/ml). The plasma concentration obtained with intranasal in-situ gel (Cmax = 2.5 μg/ml) was lower than the oral marketed formulation (Cmax = 3.4 μg/ml). The time necessary to establish the maximal flurbiprofen concentration (Tmax) in the brain was 2 and 0.5 h for oral and intranasal formulations, respectively. Hence, the intranasal formulation could achieve maximal drug concentration in the brain in less time. Thus, flurbiprofen SLN-based thermosensitive in-situ gel can be a potential encouraging safe, non-invasive, and efficacious replacement to oral formulations for achieving direct brain targeting through nose-to-brain drug delivery, thereby treating neuroinflammatory conditions like Alzheimer's disease.

Development, Physicochemical Characteristics and Pharmacokinetics of a New Sustained-Release Bilayer Tablet Formulation of Tramadol with an Immediate-Release Component for Twice-Daily Administration.

There are some potential concerns about the currently marketed solid oral dosage forms of tramadol, including decreased adherence to immediate-release (IR) formulations due to the high number of doses taken each day and the slow rise in the blood tramadol concentration after administration of sustained-release (SR) formulations, which may not achieve a rapid analgesic effect. To overcome these potential concerns, a twice-daily double-layered tablet formulation of tramadol comprising IR and SR layers was developed. This article reports studies that assessed its physicochemical and pharmacokinetic properties. Dissolution tests of five bilayer tablet formulations (designated tablets A-E) and pharmacokinetic studies of tablets A and B were conducted to investigate the appropriate ratio of the IR/SR layers in the double-layered tablet. Additionally, pharmacokinetic studies of three finished dosage formulations (tablets C-E) were performed in healthy adult males to investigate the effect of food intake on drug absorption. Adjusting the excipients and tramadol content in the IR and SR layers of tablets A-E altered their dissolution profiles in a manner that could be predicted based on their compositions. The IR layer was released within 15min, and the SR layer was slowly released over 10h. In the pharmacokinetic study, the time to maximum plasma concentration (tmax) of tramadol after administration of tablets A (IR:SR: 20:80mg) and B (40:60mg) was shorter than that of a commercially available SR tablet, and the half-life (t1/2) was longer than that of a commercially available IR tablet. For tablets C-E, administration after food did not affect the area under theconcentration-time curve (AUC) or maximum drug concentration (Cmax) of tramadol, but the tmax was prolonged by about 1 h compared with administration in fasting conditions. The mean ± standard deviation tmax and t1/2 for tablet D (IR:SR: 35:65 mg) in the fasting condition was 1.09 ± 0.56h and 7.82 ± 0.85h, respectively. The respective values in the fed condition were 2.47 ± 1.06h and 7.12 ± 0.85h, respectively. To address the potential concerns regarding existing formulations of tramadol, a twice-daily, extended-release bilayer formulation of tramadol consisting of an IR and SR layer was developed. Pharmacokinetic studies confirmed that the plasma tramadol concentration increased quickly after administration and was maintained over a long period of time.

A first-in-human study of Brozopentyl Sodium, following single and multiple ascending intravenous infusion in Chinese healthy volunteers

BackgroundBrozopentyl Sodium (BZP), a novel agent for ischemic stroke, has shown promising results in preclinical pharmacological studies, prompting the initiation of the first-in-human investigation. PurposeThis study aimed to assess the safety, tolerability, and pharmacokinetic (PK) characteristics of BZP in Chinese healthy volunteers. MethodsThe study consisted of two parts. Part I was a single-center, randomized, single-blinded, placebo-controlled, single-ascending study with six BZP dose cohorts (SAD: 25, 50, 100, 200, 300, and 400 mg). Part II was a single-center, randomized, single-blinded, placebo-controlled, multi-dose- and dose-elevated study with three BZP dose cohorts (MAD: 50, 100, and 200 mg). Doses were administered once daily on days 1 and 7 and twice daily on days 2–6. The PK properties of BZP and its bioactive metabolites, BNBP, were assessed. Safety and tolerability evaluations were also conducted. ResultsIn the SAD study, BZP reached peak plasma concentrations (Tmax) at the end of administration, with median Tmax values ranging from 1 to 1.03 h, while BNBP reached Tmax between 1.25 to 1.38 h. The terminal half-lives (T1/2) were approximately 8 h for BZP and 15 h for BNBP. In the MAD study, steady-state plasma concentrations of BZP were reached by day 5. There was minimal accumulation of both BZP and BNBP after 7 days of administration. The area under the plasma concentration-time curve from 0 to time of the last measurable concentration (AUC0-t) and maximum plasma drug concentration (Cmax) showed dose-proportional increases for BZP but not for BNBP in both study parts. Single and multiple doses of BZP demonstrated a good safety profile and were well-tolerated. ConclusionBZP displayed safety, good tolerability and predictable PK characteristics following both single and multiple ascending intravenous administrations. These findings provide a basis for further clinical development of BZP for ischemic stroke patients.

Assessment of CYP3A-mediated drug interaction via cytokine (IL-6) elevation for mosunetuzumab using physiologically-based pharmacokinetic modeling.

Mosunetuzumab is a CD3/CD20 bispecific antibody. As an on-target effect, transient elevation of interleukin-6 (IL-6) occurs in early treatment cycles. A physiologically-based pharmacokinetic (PBPK) model was developed to assess potential drug interaction caused by IL-6 enzyme suppression on cytochrome P450 3A (CYP3A) during mosunetuzumab treatment. The model's performance in predicting IL-6 CYP3A suppression and subsequent drug-drug interactions (DDIs) was verified using existing clinical data of DDIs caused by chronic and transient IL-6 elevation. Sensitivity analyses were performed for a complete DDI risk assessment. The IL-6 concentration- and time-dependent CYP3A suppression during mosunetuzumab treatment was simulated using PBPK model with incorporation of invitro IL-6 inhibition data. At clinically approved doses/regimens, the DDI at maximum CYP3A suppression was predicted to be a midazolam maximum drug concentration in plasma (Cmax ) and area under the plasma drug concentration-time curve (AUC) ratio of 1.17 and 1.37, respectively. At the 95th percentile of IL-6 concentration level or when gut CYP3A suppression was considered, the predicted DDI risk for mosunetuzumab remained low (<2-fold). The PBPK-based DDI predictions informed the mosunetuzumab product label to monitor, in early cycles, the concentrations and toxicities for sensitive CYP3A substrates with narrow therapeutic windows.

Abstract A032: Cell membrane coated- Biomimetic biodegradable nanoparticles for tumor targeted delivery of THP-doxorubicin using polylactic acid based redox responsive polymer

Abstract Chemotherapy is a widely used systemic treatment modality for cancer treatment as it kills the rapidly dividing cells. However, the administered chemo-drugs cause systemic toxicity, have fast degradation rate at physiological conditions hence low bioavailability and poor tumor accumulation. These shortcomings can be mitigated by the use of tumor targeting drug delivery systems. The nanoparticles can further be tailor made according to physiological conditions of the tumor microenvironment. Herein, the redox responsive polymer has been synthesized by introducing the disulphide linkage in the polymer. The drug release profile indicated the release of the drug is more efficient in presence of 10mM Dithiothreitol(reducing agent for disulphide linkage) when compared to 0mM dithiothreitol. In this context, this study investigates the therapeutic efficacy of THP-doxorubicin encapsulated in polylactic acid based redox responsive nanoparticle(NP) whose surface have been modified with tumor (4T1) and macrophage (J774) cell membranes. The coated cell membrane provides advantages such as immune escape, long blood circulation time, specific molecular recognition and cell targeting. The prepared nanoparticles have a hydrodynamic size of 210±10 nm with zeta potential of -30±3 mV. The cellular internalization studies of free drug vs the cell membrane coated NPs (CMNPs) were done and it was confirmed that CMNPs were internalized more efficiently in one hour drug incubation study. The same was confirmed when cancer cell proliferation inhibition assay was done, and half maximal inhibitory concentration of free drug, uncoated NPs and CMNPs were 0.31µM , 0.463µM and 0.137µM respectively. This study provides the synthesis and characterization of redox responsive polymer, preparation of cell membrane coated nanoparticles and in-vitro studies for the same. This study has a future scope in the field of personalized medicine at much cheaper price when compared to active targeting methods by antibodies, CART, proteins etc. Citation Format: Harshdeep Kaur, Harpal Singh, Neetu Singh. Cell membrane coated- Biomimetic biodegradable nanoparticles for tumor targeted delivery of THP-doxorubicin using polylactic acid based redox responsive polymer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A032.

Nanocrystalline solid dispersions: an emerging approach for oral bioavailability enhancement of anticancer drugs using lapatinib ditosylate as the case drug

The bioavailability of lapatinib ditosylate, an active anticancer agent against breast neoplasms, is constrained by its poor bioavailability due to poor aqueous solubility. So, the study’s objective was to develop its nanocrystalline solid dispersion (NSD) in order to improve its oral bioavailability. The process of wet media milling followed by lyophilization was used to prepare NSDs of the drug. Using polyvinyl pyrrolidone (PVP), and sodium dodecyl sulfate (SDS) as combination stabilizers, the resultant NSD demonstrated the smallest particle size and a sufficient stability during formulation screening. Differential scanning calorimetry, and powder X-ray diffraction techniques confirmed the crystalline state of the dispersion. Scanning electron microscopic analysis of optimized NSD revealed evenly distributed rod-shaped crystals of lapatinib ditosylate. The molecular-level interaction in the formulated dispersion was confirmed by NMR analysis. The formulated NSD has enhanced aqueous solubility of lapatinib ditosylate, by 3.68 folds. It also exhibited improved drug release as well as enhanced in vitro anticancer activity in the MCF-7 cell line. Similar findings were derived from in vivo pharmacokinetic investigations, where, compared to pure drug, the maximum plasma drug concentration (Cmax), and area under the curve (AUC), of formulated NSD, increased by 2.45, and 2.56, times respectively for lapatinib ditosylate. All these pharmacokinetic parameters were found to be improved in formulation LP, when compared to the marketed formulation, Tykerb. Thus, this study demonstrated a commercially viable method for increasing the oral bioavailability of anticancer drug, lapatinib ditosylate through the screening and optimization of stabilizers in nanocrystalline solid dispersion.

Pharmacokinetics and Tolerability of Zibotentan in Patients with Concurrent Moderate Renal and Moderate Hepatic Impairment.

Zibotentan, a selective endothelin A receptor antagonist, is in development for chronic liver and kidney disease. The pharmacokinetics (PK) of zibotentan were previously investigated in patients with either renal impairment or hepatic impairment, but the impact of both pathologies on PK was not evaluated. This study evaluated the PK and tolerability of a single oral dose of zibotentan in participants with concurrent moderate renal impairment and moderate hepatic impairment versus control participants. Twelve participants with moderate renal and hepatic impairment and 11 healthy matched control participants with no clinically significant liver or kidney disease were enrolled in an open-label, parallel-group study design. After administration of a single oral dose of zibotentan 5 mg, blood and urine sampling was performed. Pharmacokinetic parameters were determined for each of the two cohorts and compared. Comparisons between the cohorts were based on the geometric least squares mean ratio for the primary endpoints, which were area under the plasma concentration-time curve (AUC) from time zero to infinity (AUC∞) and from time zero to the time of the last measurable concentration (AUClast), and maximum plasma drug concentration (Cmax) on Day 1 through 120 h post-dose. Secondary endpoints included apparent total body clearance (CL/F) on Day 1 through 120 h post-dose. Safety endpoints were assessed up to discharge. In total, 11 participants with concurrent moderate renal and hepatic impairment, and 11 controls, completed the study. Zibotentan was generally well tolerated, and no new clinically significant safety findings were observed. Total exposure (AUC∞ and AUClast) was approximately 2.10-fold higher in participants with concurrent moderate renal and hepatic impairment versus controls, while Cmax and total nonrenal body clearance were similar among all groups. A regression-based post hoc analysis, comparing exposure and CL/F in patients with concurrent impairment to patients with either renal or hepatic impairment alone, showed that CL/F with concurrent impairment was approximately half of that in controls and was positively correlated with reduction of renal function. Inclusion of the data on concurrent moderate renal and hepatic impairment in the regression analysis led to a narrower confidence interval for the predicted mean CL/F in participants with moderate hepatic impairment. The presented findings advance the understanding of the PK of zibotentan in both renal impairment and hepatic impairment, with and without overlapping pathologies, and will thus increase the confidence of dose selection in future studies, particularly in vulnerable patient populations with concurrent renal and hepatic impairment. ClinicalTrials.gov identifier: NCT05112419.

Numerical Mechanistic Modelling of Drug Release from Solvent-Removal Zein-Based In Situ Gel.

The development of effective drug delivery systems remains a focus of extensive research to enhance therapeutic outcomes. Among these, in situ forming gels (ISG) have emerged as a promising avenue for controlled drug release. This research focuses on the mathematical modeling of levofloxacin HCl (Lv) release from zein-based ISG using the cup method, aiming to mimic the environment of a periodontal pocket. The drug release behavior of the ISGs was investigated through experimental observations and numerical simulations employing forward and central difference formula. Notably, the experimental data for drug release from the 20% w/w zein-based ISG formulations closely aligned with the simulations obtained from numerical mechanistic modeling. In summary, 20% w/w zein-based ISG formulations demonstrated nearly complete drug release with the maximum drug concentration at the edge of the matrix phase values consistently around 100-105%, while 25% w/w zein-based ISG formulations exhibited somewhat lower drug release extents, with values ranging from 70-90%. Additionally, the rate of drug transport from the polymer matrix to the external phase influenced initial release rates, resulting in a slower release. The utilization of glycerol formal as a solvent extended drug release further than dimethyl sulfoxide, thanks to denser matrices formed by high-loading polymers that acted as robust barriers to solvent removal and drug diffusion. Furthermore, UV-vis imaging was utilized to visualize the matrix formation process and solvent diffusion within the ISGs. The imaging results offered valuable insights into the matrix formation kinetics, controlled drug release mechanisms, and the influence of solvent properties on drug diffusion. The combination of mathematical modeling and experimental visualization provides a comprehensive understanding of drug release from zein-based ISGs and offers a foundation for tailored drug delivery strategies.

Optimal Treatment of Prostate Cancer Based on State Constraint

As a new tumor therapeutic strategy, adaptive therapy involves utilizing the competition between cancer cells to suppress the growth of drug-resistant cells, maintaining a certain tumor burden. However, it is difficult to determine the appropriate time and drug dose. In this paper, we consider the competition model between drug-sensitive cells and drug-resistant cells, propose the problem of drug concentration, and provide two state constraints: the upper limit of the maximum allowable drug concentration and the tumor burden. Using relevant theories, we propose the best treatment strategy. Through a numerical simulation and quantitative analysis, the effects of drug concentrations and different tumor burdens on treatments are studied, and the effects of cell-to-cell competitive advantage on cell changes are taken into account. The clinical dose titration method is further simulated; the results show that our therapeutic regimen can better suppress the growth of drug-resistant cells, control the tumor burden, limit drug toxicity, and extend the effective treatment time.

Bioequivalence study of ticagrelor in normal, healthy Indian subjects under fasting conditions: A randomized, blinded, crossover study

Objectives: The objectives of this study were to evaluate the bioequivalence and safety profiles of the test drug and reference drug of 90 mg ticagrelor tablets under fasting conditions. Methods: This was a randomized, blinded, balanced, two-treatment, two-period, two-sequence, single-dose, crossover bioequivalence study in normal, healthy adults. Subjects were randomized to receive a single dose of test or reference drug (ticagrelor 90 mg oral) under fasting conditions with a 16-day washout period. The primary pharmacokinetic variables were peak plasma concentration (Cmax), area under the plasma concentration (AUC) time curve measured to the last quantifiable concentration (AUCT), and time to maximum drug concentration (Tmax). Bioequivalence was concluded if 90% confidence intervals (CIs) of the geometric mean ratio of the test/reference drugs AUCT and Cmax are within the predefined range of 80%–125%. Adverse events (AEs) were also assessed. Results: Forty-two healthy adult males were enrolled, but 4 withdrew and 38 subjects successfully completed the study. There was no difference between the test and reference drugs regarding pharmacokinetic parameters. The median (range) Tmax was 1.67 h (1–4 h) and 2 h (1–4.5 h) for the test and reference products, respectively. The estimated 90% CIs of the geometric mean ratio for AUCT and Cmax satisfied the predefined bioequivalence criteria of 80%–125%. On analysis of variance, no significant “sequence” and “period” effects were observed for the pharmacokinetic parameters. No AEs were reported in the study. Conclusion: Our findings indicate that the test product is bioequivalent to the reference product and safe and well-tolerated in healthy Indian adults.

Effect of Fluid Flow Direction on Intravitreal Injections of Drugs into Eye

The amount of drug in the eye depends on various factors such as genetics, layers structure, temperature distribution, and aqueous humor flow field. The heat transfer, fluid flow field, and drug delivery in the eye are numerically simulated using a three-dimensional model. The results are compared with experimental data on human and rabbit eyes. The effect of ambient temperature on the flow field in standing and supine positions was investigated. Then the transfer of drug concentration by intravitreal injection method was simulated using the obtained flow field. The results showed that the temperature distribution and the position of the eye relative to the direction of gravity have a significant role in the process of concentration transfer in the anterior segment of the eye. The results showed that in an intravitreal injection method, the drug has a significant concentration in the posterior part of the eye. In the intravitreal injection method with the injection of 1.25 mg of the drug, the maximum concentration in the vitreous humor is 1575.5 μg/ml, and the drug vanishes into the eye after 30 days. In this case, the maximum drug concentration in the aqueous humor is 30.16 μg/ml, which occurs after 1.5 days.

Population Pharmacokinetic Modeling and Stochastic Simulations to Support Pediatric Dose Selection of Pimavanserin.

Pimavanserin is a selective serotonin-modulating agent with inverse agonist/antagonist activity at the 5-hydroxytryptamine2A (5-HT2A ) receptor. The safety and efficacy of pimavanserin 34mg once daily were studied in adults with hallucinations and delusions associated with Parkinson's disease psychosis and other neuropsychiatric conditions. This analysis used model-based simulations of pimavanserin steady-state exposures to identify a dose that generated pediatric exposures comparable with adult exposures achieved with 34mg pimavanserin. A population pharmacokinetics model was developed using pooled plasma drug concentration (ie, actual) data from 13 clinical studies, including a phase1 study of adolescent pediatric patients (aged 13-17years) with various psychiatric conditions. Stochastic simulations were performed to predict exposures in a virtual (ie, simulated) group of pediatric patients (aged 5-17years). Steady-state measures of the area under the plasma concentration-time curve (AUC) and maximum drug concentration (Cmax ) were simulated for relevant age and weight stratifications and compared with simulated exposures in adults (aged 18-49years). The simulated mean AUC ranged from 47.41 to 54.73ng d/mL and the mean Cmax ranged from 41.13 to 50.07ng/mL in adults receiving pimavanserin 34mg. The simulated mean (SD) Cmax of 56.54(24.58)ng/mL with pimavanserin 34mg in patients aged 10-17years was similar to that in adults. Pimavanserin 20mg yielded a mean (SD) Cmax of 45.30(21.31)ng/mL in patients aged 5-9years and 49.18(22.91)ng/mL in the pediatric patient weight group of 14-25kg, which are values close to the Cmax in adults treated with 34mg. Pimavanserin 20 and 34mg in pediatric patients aged 5-9 and 10-17years, respectively, yielded exposures similar to daily pimavanserin 34mg in adults aged 18-49years.

Localized pollution of veterinary antibiotics in watersheds receiving treated effluents from swine farms

Swine excrement is discharged into surface waters mainly as effluent in Asian countries. As swine production consumes more antibiotics and less water than humans, a mismatch of the size of swine farms and that of the rivers receiving their effluent could create severe pollution by antibiotics. However, little is known about the occurrence of antibiotics in such rivers. We therefore monitored seven veterinary drugs, six human drugs (including a metabolite), three drugs for both use (including a metabolite), and major water qualities at 30 sites in Japanese watersheds where swine outnumber humans and where their excrement is largely treated on-site by aerobic biological wastewater processes. The compositions of veterinary drugs differed substantially among sites, unlike human drugs, indicating various patterns of use among swine farms. Median concentrations at the 30 sites were <1 ng/L for seven out of the ten drugs used in livestock, whereas maximum concentrations were >1000 ng/L for three and 100–1000 ng/L for four of them, giving median–maximum among the sites of >3 log for two and 2–3 log for six of them. The spatial distribution ranges of concentrations of veterinary drugs were wider than those of human drugs (mostly <1.5 log) and other analytes (mostly <1 log), despite the correlation between those of total veterinary drugs and nitrogen, attributable to fewer swine farms than households, the intensive animal husbandry, and the various drug-use patterns among the farms. The range of maximum concentrations of veterinary drugs in the watersheds was comparable to those reported in other Asian watersheds with less strict management of swine excrement, attributable to their slow decay in conventional wastewater treatment on swine farms. Thus, attention should be paid to hot-spot pollution of antibiotics on large Asian swine farms adjacent to streams with limited dilution capacity.

Modelling how increased Cathepsin B/L and decreased TMPRSS2 usage for cell entry by the SARS-CoV-2 Omicron variant may affect the efficacy and synergy of TMPRSS2 and Cathepsin B/L inhibitors

The SARS-CoV-2 Omicron variant harbours many mutations in its spike protein compared to the original SARS-CoV-2 strain, which may alter its ability to enter cells, cell tropism, and response to interventions blocking virus entry. To elucidate these effects, we developed a mathematical model of SARS-CoV-2 entry into target cells and applied it to analyse recent in vitro data. SARS-CoV-2 can enter cells via two pathways, one using the host proteases Cathepsin B/L and the other using the host protease TMPRSS2. We found enhanced entry efficiency of the Omicron variant in cells where the original strain preferentially used Cathepsin B/L and reduced efficiency where it used TMPRSS2. The Omicron variant thus appears to have evolved to use the Cathepsin B/L pathway better but at the expense of its ability to use the TMPRSS2 pathway compared to the original strain. We estimated >4-fold enhanced efficiency of the Omicron variant in entry via the Cathepsin B/L pathway and >3-fold reduced efficiency via the TMPRSS2 pathway compared to the original or other strains in a cell type-dependent manner. Our model predicted that Cathepsin B/L inhibitors would be more efficacious and TMPRSS2 inhibitors less efficacious in blocking Omicron variant entry into cells than the original strain. Furthermore, model predictions suggested that drugs simultaneously targeting the two pathways would exhibit synergy. The maximum synergy and drug concentrations yielding it would differ for the Omicron variant compared to the original strain. Our findings provide insights into the cell entry mechanisms of the Omicron variant and have implications for intervention targeting these mechanisms.