The influence of dead space in blood sampling needle on FVIII level and pharmacokinetic profiles in children with hemophilia

OBJECTIVE

To investigate the influence of the dead space in disposable blood sampling needle on activated partial thromboplastin time (APTT), FVIII level and pharmacokinetic (PK) profiles in children with hemophilia.

METHODS

Children (<18 years) with severe hemophilia A were enrolled. After three days' washout-period, blood samples were collected at pre-dose, 1 h, 3 h, 9 h, 24 h and 48 h post-infusion. At each timepoint, two 2 mL vacuum tubes with 3.2% trisodium citrate were used. The first tube was signed as 'non-standard' (NS) and the second tube was signed as 'standard' (S). FVIII activities were evaluated by one-stage assay. WAPPS-Hemo was used to generate PK profiles like half-life time (t1/2), clearance (CL), trough level and time to 1, 2 and 5IU/dL after a dose of 50 ± 10IU/dL. The FVIII activities at 9 h and 24 h post-infusion were put into WAPPS and thus brought four combinations by true or biased FVIII level that used.

RESULT

Compared with standard-collected blood samples, prolonged APTT results (P-values < 0.01) and decreased FVIII activity (P-values < 0.05) were revealed in those non-standard blood samples. The corresponding bias was in positive relation to both APTT-S (r = 0.44, P < 0.0001) and FVIII-S level(r = 0.68, P < 0.001). The FVIII bias percentage got larger as FVIII-S level reduced (r = -0.24, P < 0.01). During the four combinations of FVIII activity at 9 h and 24 h, statistically longer t1/2, lower CL and longer time to 1, 2 or 5IU/dL were observed in 9H-S&24H-S group and 9H-NS&24H-S group.

CONCLUSION

While using vacuum tubes for clotting indicators and PK profiles, the dead space of blood sampling needle should be eliminated in advance.

Investigation of pharmacokinetics and immunogenicity of magnetosomes

Magnetosomes are iron oxide or iron sulphide nano-sized particles surrounded by a lipid bilayer synthesised by a group of bacteria known as magnetotactic bacteria (MTB). Magnetosomes have become a promising candidate for biomedical applications and could be potentially used as a drug-carrier. However, pharmacokinetics and immunogenicity of the magnetosomes have not been understood yet which preclude its clinical applications. Herein, we investigated the pharmacokinetics of magnetosomes including Absorption, Distribution, Metabolism, and Elimination (ADME) along with its immunogenicity in vitro and in vivo. The magnetosomes were conjugated with fluorescein isothiocyanate (Mag-FITC) and their conjugation was confirmed through fluorescence microscopy and its absorption in HeLa cell lines was evaluated using flow cytometry analysis. The results revealed a maximum cell uptake of 97% at 200 µg/mL concentration. Further, the biodistribution of Mag-FITC was investigated in vivo by a bioimaging system using BALB/c mice as a subject at different time intervals. The Mag-FITC neither induced death nor physical distress and the same was eliminated post 36 h of injection with meagre intensities left behind. The metabolism and elimination analysis were assessed to detect the iron overload which revealed that magnetosomes were entirely metabolised within 48-h interval. Furthermore, the histopathology and serum analysis reveal no histological damage with the absence of any abnormal biochemical parameters. The results support our study that magnetosomes were completely removed from the blood circulation within 48-h time interval. Moreover, the immunogenicity analysis has shown that magnetosomes do not induce any inflammation as indicated by reduced peaks of immune markers such as IL 1β, IL 2, IL 6, IL8, IFN γ, and TNF α estimated through Indirect ELISA. The normal behaviour of animals with the absence of acute or chronic toxicities in any organs declares that magnetosomes are safe to be injected. This shows that magnetosomes are benign for biological systems enrouting towards beneficial biomedical applications. Therefore, this study will advance the understanding and application of magnetosomes for clinical purposes.

Novel protocol for multiple-dose oral administration of the L-type Ca2+ channel blocker isradipine in mice: A dose-finding pharmacokinetic study

Studies in genetically modified animals and human genetics have recently provided new insight into the role of voltage-gated L-type Ca2+ channels in human disease. Therefore, the inhibition of L-type Ca2+ channels in vivo in wildtype and mutant mice by potent dihydropyridine (DHP) Ca2+ channel blockers serves as an important pharmacological tool. These drugs have a short plasma half-life in humans and especially in rodents and show high first-pass metabolism upon oral application. In the vast majority of in vivo studies, they have therefore been delivered through parenteral routes, mostly subcutaneously or intraperitoneally. High peak plasma concentrations of DHPs cause side effects, evident as DHP-induced aversive behaviors confounding the interpretation of behavioral readouts. Nevertheless, pharmacokinetic data measuring the exposure achieved with these applications are sparse. Moreover, parenteral injections require animal handling and can be associated with pain, discomfort and stress which could influence a variety of physiological processes, behavioral and other functional readouts. Here, we describe a noninvasive oral application of the DHP isradipine by training mice to quickly consume small volumes of flavored yogurt that can serve as drug vehicle. This procedure does not require animal handling, allows repeated drug application over several days and reproducibly achieves peak plasma concentrations over a wide range previously shown to be well-tolerated in humans. This protocol should facilitate ongoing nonclinical studies in mice exploring new indications for DHP Ca2+ channel blockers.

Physiologically based modeling of LNP-mediated delivery of mRNA in the vascular system

RNA therapeutics are an emerging, powerful class of drugs with potential applications in a wide range of disorders. A central challenge in their development is the lack of clear pharmacokinetic (PK)-pharmacodynamic relationship, in part due to the significant delay between the kinetics of RNA delivery and the onset of pharmacologic response. To bridge this gap, we have developed a physiologically based PK/pharmacodynamic model for systemically administered mRNA-containing lipid nanoparticles (LNPs) in mice. This model accounts for the physiologic determinants of mRNA delivery, active targeting in the vasculature, and differential transgene expression based on nanoparticle coating. The model was able to well-characterize the blood and tissue PKs of LNPs, as well as the kinetics of tissue luciferase expression measured by ex vivo activity in organ homogenates and bioluminescence imaging in intact organs. The predictive capabilities of the model were validated using a formulation targeted to intercellular adhesion molecule-1 and the model predicted nanoparticle delivery and luciferase expression within a 2-fold error for all organs. This modeling platform represents an initial strategy that can be expanded upon and utilized to predict the in vivo behavior of RNA-containing LNPs developed for an array of conditions and across species.

Induction of hepatic CYP3A4 expression by cholesterol and cholic acid: Alterations of gene expression, microsomal activity, and pharmacokinetics

Human cytochrome P450 3A4 (CYP3A4) is a drug-metabolizing enzyme that is abundantly expressed in the liver and intestine. It is an important issue whether compounds of interest affect the expression of CYP3A4 because more than 30% of commercially available drugs are metabolized by CYP3A4. In this study, we examined the effects of cholesterol and cholic acid on the expression level and activity of CYP3A4 in hCYP3A mice that have a human CYP3A gene cluster and show human-like regulation of the coding genes. A normal diet (ND, CE-2), CE-2 with 1% cholesterol and 0.5% cholic acid (HCD) or CE-2 with 0.5% cholic acid was given to the mice. The plasma concentrations of cholesterol, cholic acid and its metabolites in HCD mice were higher than those in ND mice. In this condition, the expression levels of hepatic CYP3A4 and the hydroxylation activities of triazolam, a typical CYP3A4 substrate, in liver microsomes of HCD mice were higher than those in liver microsomes of ND mice. Furthermore, plasma concentrations of triazolam in HCD mice were lower than those in ND mice. In conclusion, our study suggested that hepatic CYP3A4 expression and activity are influenced by the combination of cholesterol and cholic acid in vivo.

Coadministration of fluconazole to boost subtherapeutic sirolimus concentrations: A case report

Individual sirolimus whole blood concentrations are highly variable, critically influenced by the concomitant use of cytochrome P450 (CYP) 3A inducers or inhibitors, and also modulated by food. Therapeutic drug monitoring is therefore recommended, especially at treatment start or in circumstances that can influence sirolimus exposure. In this case report, we highlight the challenge of achieving therapeutic sirolimus concentrations and present pragmatic solutions with regimen adaptions, pharmacokinetic enhancement (use of a drug-drug interaction), concentration monitoring, and subsequent modeling of population pharmacokinetics to support treatment decisions. In a 69-year-old female patient with allogeneic hematopoietic stem cell transplantation, tacrolimus concentrations were stable until she developed cerebral toxoplasmosis with tonic-clonic seizures. During treatment of this acute infection, tacrolimus concentrations dropped to subtherapeutic levels and remained largely unaffected by dose increases. Only the simultaneous administration of the CYP3A4 inhibitor fluconazole and a shortening of the sirolimus dosing intervals to a (non-approved) twice-daily administration led to successful control of the concentrations, which ultimately even made a dose reduction possible. This intervention resulted in an increase of sirolimus mean trough concentration to 5.85 ng/mL, i.e., into the desired target range. Additionally, a higher ratio of sirolimus trough levels/daily dose from 26.9 to 109 ng/mL/mg/kg/day was achieved with the initiation of fluconazole. Thus, this case report describes the use of clinical pharmacological concepts and pharmacokinetic modeling to optimize treatment strategies in an individual patient. This strategy could be generalized to other CYP inhibitors and other treatment regimens.

Recombinant factor IX Fc for the treatment of hemophilia B

Current hemophilia B treatment guidelines recommend routine prophylaxis with factor IX (FIX) replacement products, tailored to maintain plasma activity at levels that will prevent bleeds. However, plasma FIX activity may not be the primary determinant or best indicator of hemostatic efficacy due to its extravascular distribution. FIX replacement therapy has evolved to include extended half-life (EHL) products that provide effective bleed protection when administered at intervals of 7 days or longer. rFIXFc is a recombinant fusion protein with an extended circulation time. rFIXFc has a biodistribution profile consistent with distribution into extravascular space, where it may support hemostasis at sites of vessel injury independent of circulating plasma activity levels. The safety and efficacy of rFIXFc prophylaxis is well established in adults, adolescents and children including previously untreated patients with hemophilia B, with substantial evidence from clinical trials and real-world clinical practice. This review describes the pharmacokinetic characteristics of rFIXFc, summarizes available safety and efficacy data, and evaluates the use of rFIXFc in special populations. Current hemophilia B treatment challenges, including target FIX plasma levels, perioperative use, and management of patients with comorbidities, are discussed together with the potential role of EHL products in the future treatment landscape of hemophilia B.

Pharmacokinetic and pharmacodynamic properties of once-weekly insulin icodec in individuals with type 1 diabetes

AIMS

To investigate the pharmacokinetic/pharmacodynamic properties of once-weekly insulin icodec in individuals with type 1 diabetes (T1D).

MATERIALS AND METHODS

In this randomized, open-label, two-period crossover trial, 66 individuals with T1D (age 18-64 years; glycated haemoglobin ≤75 mmol/mol [≤ 9%]) were to receive once-weekly icodec (8 weeks) and once-daily insulin glargine U100 (2 weeks) at individualized fixed equimolar total weekly doses established during up to 10 weeks' run-in with glargine U100 titrated to pre-breakfast plasma glucose (PG) of 4.4-7.2 mmol/L (80-130 mg/dL). Insulin aspart was used as bolus insulin. Blood sampling for icodec pharmacokinetics was performed from the first icodec dose until 35 days after the last dose. The glucose infusion rate at steady state was assessed in glucose clamps (target 6.7 mmol/L [120 mg/dL]) at 16-52 h and 138-168 h after the last icodec dose and 0-24 h after the last glargine U100 dose. Icodec pharmacodynamics during 1 week were predicted by pharmacokinetic-pharmacodynamic modelling. Hypoglycaemia was recorded during the treatment periods based on self-measured PG.

RESULTS

Icodec reached pharmacokinetic steady state on average within 2-3 weeks. At steady state, model-predicted daily proportions of glucose infusion rate during the 1-week dosing interval were 14.3%, 19.6%, 18.3%, 15.7%, 13.1%, 10.6% and 8.4%, respectively. Rates and duration of Level 2 hypoglycaemic episodes (PG <3.0 mmol/L [54 mg/dL]) were 32.8 versus 23.9 episodes per participant-year of exposure and 33 ± 25 versus 30 ± 18 min (mean ± SD) for icodec versus glargine U100.

CONCLUSIONS

The pharmacokinetic/pharmacodynamic properties of icodec suggest its potential to provide basal coverage in a basal-bolus insulin regimen in people with T1D.

Agreement Between Two-Concentration and One-Concentration Area Under the Curve (AUC) Estimates When Using Bayesian Modeling to Dose Vancomycin in Patients With Obesity

BACKGROUND

Vancomycin Bayesian modeling provides 24-hour area under the curve (AUC24) estimations. However, the agreement between two-concentration and one-concentration Bayesian estimates in patients with obesity is unknown.

OBJECTIVE

The purpose of this study was to determine the agreement between two-concentration and one-concentration Bayesian AUC24 estimates in patients with obesity receiving vancomycin.

METHODS

This retrospective within-subjects cohort study included patients with obesity and two vancomycin concentrations. The first concentration was hidden from dosing software to record the one-concentration AUC24. AUC24 estimates were categorized into 1 of 3 groups: <400, 400 to 600, or >600 mg*h/L. Patients were excluded for vancomycin duration less than 48 hours or renal dysfunction. The primary outcome was AUC24 agreement with two versus one concentration. Secondary outcomes included the AUC24 category, matching of AUC24 categorization, and correlation between two-concentration versus one-concentration AUC24. AUC24 estimate agreement was assessed by Bland Altman plot and bias via linear regression. Statistical analyses were performed using SPSS (version 20.0).

RESULTS

A total of 31 patients were included. The mean difference in AUC24 between two versus one concentration was 11.4 mg*h/L (95% limits of agreement = -72 to 95 mg*h/L). Linear regression indicated the presence of proportional bias at higher AUC24 values (β = 0.16; P = 0.015). Matching of AUC24 categorization with two versus one concentration was 87% (27/31 patients).

CONCLUSION AND RELEVANCE

This study demonstrated overall agreement between AUC24 estimates when using two versus one vancomycin concentration in patients with obesity, though proportional bias was detected at higher AUC24. Future studies with larger sample sizes are needed to confirm these results.

Pharmacokinetic behaviour and pharmacokinetic-pharmacodynamic integration of doxycycline in rainbow trout (Oncorhynchus mykiss) after intravascular, intramuscular and oral administrations

OBJECTIVE

Doxycycline (DO) has been used in fish for a long time, but there are some factors that have not yet been clarified regarding its pharmacokinetic (PK) and pharmacodynamic (PD) properties. Therefore, the aim of this study was to investigate the PK and PK/PD targets of DO after 20 mg/kg intravascular (IV), intramuscular (IM) and oral (OR) gavage administration in rainbow trout (Oncorhynchus mykiss).

METHODS

Plasma samples were collected at specific time points and subsequently analysed by HPLC-ultraviolet. The PK/PD indices were calculated based on the MIC90 (Aeromonas hydrophila and Aeromonas sobria) values obtained for the respective bacteria and the PK parameters obtained for DO following both IM and OR administration.

RESULTS

After IV administration, the elimination half-life (t1/2 ʎz), area under the concentration vs. time curve (AUC), apparent volume of distribution at steady-state and total body clearance of DO were 34.81 h, 723.82 h µg/mL, 1.24 L/kg and 0.03 L/kg/h, respectively. The t1/2λz of the DO was found to be 37.39 and 39.78 h after IM, and OR administration, respectively. The bioavailability was calculated 57.02% and 32.29%, respectively, after IM and OR administration. The MIC90 of DO against A. hydrophila and A. sobria was 4 µg/mL. The PK/PD integration showed that DO (20 mg/kg dose) for A. hydrophila and A. sobria with MIC90 ≤4 µg/mL achieved target AUC/MIC value after IM administration.

CONCLUSIONS

These results suggest that when rainbow trout was treated with 20 mg/kg IV and IM administered DO, therapeutically effective concentrations were reached in the control of infections caused by A. hydrophila and A. sobria.

Pharmacokinetics and tissue residues of albendazole sulphoxide and its metabolites in donkey after intramuscular injection

BACKGROUND

Various anti-parasitic drugs are used to control donkey parasitic diseases. The abuse of donkey drugs leads to the disposition of residues in the edible parts of treated donkeys.

OBJECTIVES

The aim of this study was to (1) analyse the pharmacokinetics of ABZSO to serve as reference for the dosage regimen in donkey; and (2) calculate the withdrawal times of the ABZSO in the tissue of the donkey.

METHODS

The concentrations of ABZSO and its metabolites in plasma and tissues were determined using high-performance liquid chromatography with an ultraviolet detector. Pharmacokinetic analysis was performed by the programme 3p97.

RESULTS

The plasma concentrations of ABZSO and ABZSO2 concentration-time data in donkey conformed to the absorption one-compartment open model. Thet 1 / 2 k e ${{{t1}} \!\mathord{/ {\vphantom { {2{{k}_{\mathrm{e}}}}}}}}$ of ABZSO was 0.67 h, whereas the t1/2 k e was 12.93 h; the Cmax and the Tp were calculated as 0.58 μg mL-1 and 3.01 h. The Vd/F of ABZSO was estimated to be 10.92 L kg-1; the area under the curve (AUC) was 12.81 μg mL-1 h. The Cmax and AUC values of ABZSO were higher than those of ABZSO2; however, t1/2 K e and Vd/F were lower. Other pharmacokinetics parameters were similar between the two metabolites.

CONCLUSIONS

The results revealed that ABZSO2 was the main metabolite of ABZSO in donkey plasma. The concentrations of ABZSO and its chief metabolite (ABZSO2) were detected in liver, kidney, skin and muscle; however, ABZ-SO2NH2 was only detected in liver and kidney. The results also revealed that the depletion of ABZSO and its metabolite in donkey was longer, especially in skin.

A 13.2 mg epinephrine intranasal spray demonstrates comparable pharmacokinetics, pharmacodynamics, and safety to a 0.3 mg epinephrine autoinjector

Background

Recent acute anaphylaxis guideline updates have identified remaining unmet needs based on currently available therapeutic options as a critical focus.

Objective

We compared the pharmacokinetic, pharmacodynamic, safety, and tolerability profiles of intranasal epinephrine with intramuscular epinephrine administered by autoinjector and manual syringe.

Methods

An open-label, 3-period crossover study was conducted in 116 healthy adult volunteers to assess the bioavailability of a single 13.2 mg intranasal dose of epinephrine compared to a 0.3 mg intramuscular autoinjector and a 0.5 mg manual syringe. Patients with epinephrine concentrations of 50, 100, and 200 pg/mL at 10, 20, 30, and 60 minutes after dosing were also evaluated.

Results

Pharmacokinetic parameters for the 13.2 mg intranasal dose exceeded those of the 0.3 mg autoinjector with a rapid and higher maximum observed concentration (intranasal, 429.4 pg/mL; autoinjector, 328.6 pg/mL) and greater systemic exposure (AUC0-360; intranasal, 39,060 pg∙min/mL; autoinjector, 17,440 pg∙min/mL). Similar results were observed compared to the 0.5 mg manual syringe. Pharmacokinetic parameters for opposite-nostril and same-nostril dosing were higher than both intramuscular doses, except time to reach maximum observed concentration, which was bracketed between the 2 intramuscular doses (intranasal opposite and same nostril, 20 minutes; autoinjector, 14.9 minutes; manual syringe, 45 minutes). Similar effects on blood pressure and heart rate were observed for intranasal and autoinjector administration. Intranasal epinephrine was safe and well tolerated. No serious or unexpected adverse events were reported, confirming results from earlier clinical studies.

Conclusions

Bidose epinephrine spray addresses the unmet medical and patient needs for a needle-free, convenient, and effective dose-delivery system for self-administration of epinephrine that is as good as or better than the 0.3 mg autoinjector.

Combined impact of hypoalbuminemia and pharmacogenomic variants on voriconazole trough concentration: data from a real-life clinical setting in the Chinese population

Voriconazole (VRC) displays highly variable pharmacokinetics impacting treatment efficacy and safety. To provide evidence for optimizing VRC therapy regimens, the authors set out to determine the factors impacting VRC steady-state trough concentration (Cmin) in patients with various albumin (Alb) level. A total of 275 blood samples of 120 patients and their clinical characteristics and genotypes of CYP2C19, CYP3A4, CYP3A5, CYP2C9, FMO3, ABCB1, POR, NR1I2 and NR1I3 were included in this study. Results of multivariate linear regression analysis demonstrated that C-reactive protein (CRP) and total bilirubin (T-Bil) were predictors of the VRC Cmin adjusted for dose in patients with hypoalbuminemia (Alb < 35 g/L) (R2 = 0.16, P < 0.001). Additionally, in patients with normal albumin level (Alb ≥ 35 g/L), it resulted in a significant model containing factors of the poor metabolizer (PM) CYP2C19 genotype and CRP level (R2 = 0.26, P < 0.001). Therefore, CRP and T-Bil levels ought to receive greater consideration than genetic factors in patients with hypoalbuminemia.

Population pharmacokinetic-pharmacodynamic model of subcutaneous bupivacaine in a novel extended-release microparticle formulation

The objective of this study was to develop a population pharmacokinetic-pharmacodynamic model of subcutaneously administered bupivacaine in a novel extended-release microparticle formulation for postoperative pain management. Bupivacaine was administered subcutaneously in the lower leg to 28 healthy male subjects in doses from 150 to 600 mg in a phase 1 randomized, placebo-controlled, double-blind, dose-ascending study with two different microparticle formulations, LIQ865A and LIQ865B. Warmth detection threshold was used as a surrogate pharmacodynamic endpoint. Population pharmacokinetic-pharmacodynamic models were fitted to plasma concentration-effect-time data using non-linear mixed-effects modelling. The pharmacokinetics were best described by a two-compartment model with biphasic absorption as two parallel absorption processes: a fast, zero-order process and a slower, first-order process with two transit compartments. The slow absorption process was found to be dose-dependent and rate-limiting for elimination at higher doses. Apparent bupivacaine clearance and the transit rate constant describing the slow absorption process both appeared to decrease with increasing doses following a power function with a shared covariate effect. The pharmacokinetic-pharmacodynamic relationship between plasma concentrations and effect was best described by a linear function. This model gives new insight into the pharmacokinetics and pharmacodynamics of microparticle formulations of bupivacaine and the biphasic absorption seen for several local anaesthetics.

Biotransformation and disposition characteristics of HSK7653, a novel long-acting dipeptidyl peptidase-4 inhibitor for the treatment of type 2 diabetes

AIM

To investigate the metabolism and disposition characteristics of HSK7653 in healthy male Chinese participants.

METHODS

A single oral dose of 80 μCi (25 mg) [14C]HSK7653 capsules was administered to six healthy participants, and blood, plasma, urine and faeces were collected. Quantitative and qualitative analysis was conducted to investigate the pharmacokinetics, blood-to-plasma ratio, mass balance and metabolism of HSK7653.

RESULTS

The drug was well absorbed and reached a maximum concentration at 1.25 h. The drug-related components (HSK7653 and its metabolites) were eliminated slowly, with a half-life (t1/2) of 111 h. Unchanged HSK7653 contributed to more than 97% of the total radioactivity in all plasma samples. The blood-to-plasma ratio (0.573-0.845) indicated that HSK7653 did not tend to distribute into blood cells. At 504 h postdose, up to 95.9% of the dose was excreted, including 79.8% in urine and 16.1% in faeces. Most of the radioactivity (75.5% dose) in excreta was unchanged HSK7653. In addition, nine metabolites were detected in urine and faeces. The most abundant metabolite was M6-2, a dioxidation product of HSK7653, which accounted for 4.73% and 2.63% of the dose in urine and faeces, respectively. The main metabolic pathways of HSK7653 in vivo included oxidation, pyrrole ring opening and sulphonamide hydrolysation.

CONCLUSION

HSK7653 was well absorbed, slightly metabolized and slowly excreted in humans. The high plasma exposure and long t1/2 of HSK7653 may contribute to its long-lasting efficacy as a long-acting dipeptidyl peptidase-4 inhibitor.

Sofosbuvir-velpatasvir in children 3-17 years old with hepatitis C virus infection

BACKGROUND

The safety and efficacy of sofosbuvir-velpatasvir in children aged 3-17 years with chronic hepatitis C virus (HCV) infection of any genotype were evaluated.

METHODS

In this Phase 2, multicenter, open-label study, patients received once daily for 12 weeks either sofosbuvir-velpatasvir 400/100 mg tablet (12-17 years), 200/50 mg low dose tablet or oral granules (3-11 years and ≥17 kg), or 150/37.5 mg oral granules (3-5 years and <17 kg). The efficacy endpoint was sustained virologic response 12 weeks after therapy (SVR12). Dose appropriateness was confirmed by intensive pharmacokinetics in each age group.

FINDINGS

Among 216 patients treated, 76% had HCV genotype 1% and 12% had genotype 3. Rates of SVR12 were 83% (34/41) among 3-5-year-olds, 93% (68/73) among 6-11-year-olds, and 95% (97/102) among 12-17-year-olds. Only two patients experienced virologic failure. The most common adverse events were headache, fatigue, and nausea in 12-17-year-olds; vomiting, cough, and headache in 6-11-year-olds; and vomiting in 3-5-year-olds. Three patients discontinued treatment because of adverse events. Four patients had serious adverse events; all except auditory hallucination (n = 1) were considered unrelated to study drug. Exposures of sofosbuvir, its metabolite GS-331007, and velpatasvir were comparable to those in adults in prior Phase 2/3 studies. Population pharmacokinetic simulations supported weight-based dosing for children in this age range.

INTERPRETATION

The pangenotypic regimen of sofosbuvir-velpatasvir is highly effective and safe in treating children 3-17 years with chronic HCV infection.

Effect of Hepatic Impairment on Trilaciclib Pharmacokinetics

Trilaciclib is a first-in-class, intravenous cyclin-dependent kinase 4 and 6 inhibitor approved for reducing the incidence of chemotherapy-induced myelosuppression in adult patients with extensive-stage small cell lung cancer receiving a platinum/etoposide-containing or topotecan-containing regimen. No dose adjustment is recommended for participants with mild hepatic impairment (HI) based on previous population pharmacokinetic (PK) analysis. This open-label, parallel-group study examined the impact of moderate and severe HI on the PK of trilaciclib. The study employed a reduced study design. Participants with moderate (Child-Pugh B, n = 8) and severe (Child-Pugh C, n = 5) HI and matched healthy controls (n = 11) received a single intravenous dose of trilaciclib 100 mg/m2. The unbound fraction of trilaciclib was comparable between the HI groups and the matched healthy control group. The unbound trilaciclib extent of exposure (i.e., area under the concentration-time curve) in participants with moderate and severe HI was ∼40% and ∼60% higher, respectively, compared with healthy matched controls based on Child-Pugh classification. Ad hoc analysis using National Cancer Institute classification showed similar results. The US Food and Drug Administration-approved trilaciclib dose of 240 mg/m2 should be reduced by ∼30%, to 170 mg/m2, for patients with moderate or severe HI.

Enhanced oral bioavailability of levormeloxifene and raloxifene by nanoemulsion: simultaneous bioanalysis using liquid chromatography-tandem mass spectrometry

Aim & objective: Levormeloxifene (L-ORM) and raloxifene (RAL) are selective estrogen receptor modulators used in the treatment of postmenopausal osteoporosis and breast cancer. Here, we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous estimation of both drugs. Materials & methods: A quality-by-design (QbD) approach was used for the optimization of the nanoemulsion, and US FDA guidelines were followed for method validation. Results: Multiple reaction monitoring transitions were used for L-ORM (459.05→98.50), RAL (475.00→112.02) and internal standard (180.10→110.2). Analytes were resolved in a C18 column with 80:20 v/v% acetonitrile (ACN), 0.1% formic acid in triple-distilled water as a mobile phase. The developed method was linear over a concentration range of 1-600 ng/ml. Pharmacokinetic results of free L-ORM-RAL and the L-ORM-RAL nanoemulsion showed Cmax of free L-ORM - 70.65 ± 16.64, free RAL 13.53 ± 2.72, L-ORM nanoemulsion 65.07 ± 14.0 and RAL-nanoemulsion 59.27 ± 17.44 ng/ml. Conclusion: Future findings will contribute to the treatment of postmenopausal osteoporosis and breast cancer using L-ORM and RAL.

Aloe-emodin: Progress in Pharmacological Activity, Safety, and Pharmaceutical Formulation Applications

Aloe-emodin (AE) is an anthraquinone derivative and a biologically active component sourced from various plants, including Rheum palmatum L. and Aloe vera. Known chemically as 1,8-dihydroxy-3-hydroxymethyl-anthraquinone, AE has a rich history in traditional medicine and is esteemed for its accessibility, safety, affordability, and effectiveness. AE boasts multiple biochemical and pharmacological properties, such as strong antibacterial, antioxidant, and antitumor effects. Despite its array of benefits, AE's identity as an anthraquinone derivative raises concerns about its potential for liver and kidney toxicity. Nevertheless, AE is considered a promising drug candidate due to its significant bioactivities and cost efficiency. Recent research has highlighted that nanoformulated AE may enhance drug delivery, biocompatibility, and pharmacological benefits, offering a novel approach to drug design. This review delves into AE's pharmacological impacts, mechanisms, pharmacokinetics, and safety profile, incorporating insights from studies on its nanoformulations. The goal is to outline the burgeoning research in this area and to support the ongoing development and utilization of AE-based therapies.

Pharmacokinetics of tranexamic acid (TXA) delivered by expeditious routes in a swine model of polytrauma and hemorrhagic shock

OBJECTIVE

Hemorrhage is the leading cause of preventable death in civilian trauma centers and on the battlefield. One of the emerging treatment options for hemorrhage in austere environments is tranexamic acid (TXA). However, the landscape is not amenable to the current delivery standard. This study compared the pharmacokinetics of TXA via a standard 10-minute intravenous infusion (IV infusion), intravenous rapid push over 10 s (IV push), and intramuscular injection (IM) in a swine polytrauma and hemorrhagic shock model (trauma group) compared to uninjured controls (control group).

METHODS

Thirty swine were randomized to the trauma or control group. Following anesthesia, the trauma group experienced a simulated blast injury and 40% controlled hemorrhage. Subjects in both groups were then randomized to receive 1 g/10 mL TXA via IV infusion, IV push, or IM. Animals were monitored for four hours with serial blood sampling. Serum TXA concentrations were measured by liquid chromatography with tandem mass spectrometry (LC-MS/MS) and analyzed.

RESULTS

The time to maximum TXA concentration (Tmax) was not affected by trauma in IV infusion or IV push, but was affected in the IM administration with Tmax significantly slower than the control group (p = 0.016). The minimum effective serum concentration of TXA (Ceff, 10 µg/mL) was reached in less than one minute with IV infusion and instantaneously with IV push. Despite lower bioavailability, the time to reach Ceff (Teff) was achieved via IM administration in less than 10 minutes for both groups (6.4 minutes trauma vs. 2.1 minutes control).

CONCLUSIONS

In austere prehospital environments, an alternative to intravenous infusion of a life-saving medication is desired. Administration of TXA via all three methods reached the level needed to cause substantial inhibition of fibrinolysis within 10 minutes. The IV push method showed similar pharmacokinetics to IV infusion of TXA but can be delivered quickly without sacrificing an access site for 10 minutes.

Enantiomer-Specific Cardiovascular Effects of the Ketone Body 3-Hydroxybutyrate

BACKGROUND

The ketone body 3-hydroxybutyrate (3-OHB) increases cardiac output (CO) by 35% to 40% in healthy people and people with heart failure. The mechanisms underlying the effects of 3-OHB on myocardial contractility and loading conditions as well as the cardiovascular effects of its enantiomeric forms, D-3-OHB and L-3-OHB, remain undetermined.

METHODS AND RESULTS

Three groups of 8 pigs each underwent a randomized, crossover study. The groups received 3-hour infusions of either D/L-3-OHB (racemic mixture), 100% L-3-OHB, 100% D-3-OHB, versus an isovolumic control. The animals were monitored with pulmonary artery catheter, left ventricle pressure-volume catheter, and arterial and coronary sinus blood samples. Myocardial biopsies were evaluated with high-resolution respirometry, coronary arteries with isometric myography, and myocardial kinetics with D-[11C]3-OHB and L-[11C]3-OHB positron emission tomography. All three 3-OHB infusions increased 3-OHB levels (P<0.001). D/L-3-OHB and L-3-OHB increased CO by 2.7 L/min (P<0.003). D-3-OHB increased CO nonsignificantly (P=0.2). Circulating 3-OHB levels correlated with CO for both enantiomers (P<0.001). The CO increase was mediated through arterial elastance (afterload) reduction, whereas contractility and preload were unchanged. Ex vivo, D- and L-3-OHB dilated coronary arteries equally. The mitochondrial respiratory capacity remained unaffected. The myocardial 3-OHB extraction increased only during the D- and D/L-3-OHB infusions. D-[11C]3-OHB showed rapid cardiac uptake and metabolism, whereas L-[11C]3-OHB demonstrated much slower pharmacokinetics.

CONCLUSIONS

3-OHB increased CO by reducing afterload. L-3-OHB exerted a stronger hemodynamic response than D-3-OHB due to higher circulating 3-OHB levels. There was a dissocitation between the myocardial metabolism and hemodynamic effects of the enantiomers, highlighting L-3-OHB as a potent cardiovascular agent with strong hemodynamic effects.

Investigation of the drug-drug interaction and incompatibility mechanism between Aconitum carmichaelii Debx and Pinellia ternata (Thunb.) Breit

ETHNOPHARMACOLOGICAL RELEVANCE

The combination of Aconitum carmichaelii Debx (Chuanwu, CW) and Pinellia ternata (Thunb.) Breit (Banxia, BX) forms an herbal pair within the eighteen incompatible medicaments (EIM), indicating that BX and CW are incompatible. However, the scientific understanding of this incompatibility mechanism, especially the corresponding drug-drug interaction (DDI), remains complex and unclear.

AIM OF THE STUDY

This study aims to explain the DDI and potential incompatibility mechanism between CW and BX based on pharmacokinetics and cocktail approach.

MATERIALS AND METHODS

Ultraperformance liquid chromatography-tandem mass spectrometry methods were established for pharmacokinetics and cocktail studies. To explore the DDI between BX and CW, in the pharmacokinetics study, 10 compounds were determined in rat plasma after administering CW and BX-CW herbal pair extracts. In the cocktail assay, the pharmacokinetic parameters of five probe substrates were utilized to assess the influence of BX on cytochrome P450 (CYP) isoenzyme (dapsone for CYP3A4, phenacetin for CYP1A2, dextromethorphan for CYP2D6, tolbutamide for CYP2C9, and omeprazole for CYP2C19). Finally, the DDI and incompatibility mechanism of CW and BX were integrated to explain the rationality of EIM theory.

RESULTS

BX not only enhances the absorption of aconitine and benzoylaconine but also accelerates the metabolism of mesaconitine, benzoylmesaconine, songorine, and fuziline. Moreover, BX affects the activity of CYP enzymes, which regulate the metabolism of toxic compounds.

CONCLUSIONS

BX altered the activity of CYP enzymes, consequently affecting the metabolism of toxic compounds from CW. This incompatibility mechanism may be related to the increased absorption of these toxic compounds in vivo.

Amoxicillin-clavulanate Breakpoints Against Enterobacterales: Rationale for Revision by the Clinical and Laboratory Standards Institute

Amoxicillin-clavulanate (AMC) is among the most frequently prescribed antibiotics globally. It has broad antibacterial activity against gram-positive, gram-negative, and anaerobic bacteria, and has been utilized to treat infections caused by a broad range of pathogens. AMC breakpoints against Enterobacterales were initially set in the 1980s but since then increases in antibiotic resistance, advances in pharmacokinetic (PK)/pharmacodynamic (PD) analyses, and publication of additional clinical data prompted a reassessment by the Clinical and Laboratory Standards Institute (CLSI) Subcommittee on Antimicrobial Susceptibility Testing. Based on this contemporary reappraisal, the CLSI retained the Enterobacterales breakpoints but revised comments regarding dosing associated with use of the AMC breakpoints in the 2022 supplement of M100. This viewpoint provides insight into the CLSI breakpoint reevaluation process and summarizes the data and rationale used to support these revisions to the AMC Enterobacterales breakpoint.

Effects of Quinidine or Rifampin Co-administration on the Single-Dose Pharmacokinetics and Safety of Rilzabrutinib (PRN1008) in Healthy Participants

This open-label, phase 1 study was conducted with healthy adult participants to evaluate the potential drug-drug interaction between rilzabrutinib and quinidine (an inhibitor of P-glycoprotein [P-gp] and CYP2D6) or rifampin (an inducer of CYP3A and P-gp). Plasma concentrations of rilzabrutinib were measured after a single oral dose of rilzabrutinib 400 mg administered on day 1 and again, following a wash-out period, after co-administration of rilzabrutinib and quinidine or rifampin. Specifically, quinidine was given at a dose of 300 mg every 8 hours for 5 days from day 7 to day 11 (N = 16) while rifampin was given as 600 mg once daily for 11 days from day 7 to day 17 (N = 16) with rilzabrutinib given in the morning of day 10 (during quinidine dosing) or day 16 (during rifampin dosing). Quinidine had no significant effect on rilzabrutinib pharmacokinetics. Rifampin decreased rilzabrutinib exposure (the geometric mean of Cmax and AUC0-∞ decreased by 80.5% and 79.5%, respectively). Single oral doses of rilzabrutinib, with or without quinidine or rifampin, appeared to be well tolerated. These findings indicate that rilzabrutinib is a substrate for CYP3A but not a substrate for P-gp.

Cannabidiol Bioavailability Is Nonmonotonic with a Long Terminal Elimination Half-Life: A Pharmacokinetic Modeling-Based Analysis

Background: Oral and inhalation-based cannabidiol (CBD) administration has been clinically evaluated for various therapeutic indications, alongside widespread off-label use. However, the long-term exposure kinetics and varied bioavailability have not been fully characterized. Methods: Human CBD plasma concentration-time profiles from six studies evaluating the oral administration of Epidiolex® and three studies evaluating inhalation-based delivery were obtained. A four-compartment pharmacokinetic (PK) model with Weibull-based oral absorption kinetics was employed to describe the long-term PKs of CBD. Furthermore, a Cedergreen-Ritz-Streibig model was applied to evaluate nonmonotonic oral bioavailability. Results: CBD was extensively distributed into tissue compartments with varied kinetics resulting in a long plasma terminal elimination half-life of >134 h in humans. For once-a-day oral dosing, the plasma trough concentrations require >70 days to reach a steady state. The oral bioavailability of CBD for different doses administered in fasted state follows a nonmonotonic pattern with an inverted U-shaped profile. Oral administration of CBD under fed state or subjects with hepatic impairment yields higher oral bioavailability with varied exposure. In contrast, inhalation-based delivery of CBD, while delivering a similar systemic delivered dose compared with oral dosing due to high device losses, bypasses first-pass metabolism and can be efficient. Conclusion: CBD PKs vary across different doses due to nonmonotonic oral bioavailability, and inhalation-based delivery could minimize such variability in humans. The delayed attainment of steady state and prolonged terminal half-life, resulting from differential but extensive tissue distribution, needs to be considered when dosing CBD in the long term. These fundamental findings are critical for establishing dose-exposure relationship for further clinical evaluation of novel CBD-based therapies.

The effect of renal function on the pharmacokinetics and pharmacodynamics of enavogliflozin, a potent and selective sodium-glucose cotransporter-2 inhibitor, in type 2 diabetes

AIMS

To explore the effect of renal function on the pharmacokinetic (PK) and pharmacodynamic (PD) profile and safety of enavogliflozin, a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, in patients with type 2 diabetes mellitus (T2DM).

METHODS

An open-label, two-part clinical trial was conducted in T2DM patients, stratified by renal function: Group 1, normal renal function; Group 2, mild renal impairment (RI); Group 3, moderate RI; and Group 4, severe RI. In Part A, Groups 2 and 4 received enavogliflozin 0.5 mg once. In Part B, Groups 1 and 3 received enavogliflozin 0.5 mg once daily for 7 days. Serial blood and timed urine samples were collected to analyse the PK and PD characteristics of enavogliflozin. Pearson's correlation coefficients were calculated to assess the correlations between PK or PD parameters and creatinine clearance (CrCL).

RESULTS

A total of 21 patients completed the study as planned. The area under the curve (AUC) for enavogliflozin was not significantly correlated with CrCL, although the maximum concentration slightly decreased as renal function decreased. By contrast, daily urinary glucose excretion (UGE) was positively correlated with CrCL after both single- (r = 0.7866, p < 0.0001) and multiple-dose administration (r = 0.6606, p = 0.0438).

CONCLUSIONS

Systemic exposure to oral enavogliflozin 0.5 mg was similar among the patients with T2DM regardless of their renal function levels. However, the glucosuric effect of enavogliflozin decreased with RI. Considering the UGE observed and approved therapeutic use of other SGLT2 inhibitors, the efficacy of enavogliflozin with regard to glycaemic control could be explored in patients with mild and moderate RI (estimated glomerular filtration rate ≥30 or ≥45 mL/min/1.73 m2) in a subsequent larger study.

Diagnostic value of qualitative and quantitative enhancement parameters on contrast-enhanced mammography

PURPOSE

To determine whether qualitative and quantitative enhancement parameters obtained from contrast-enhanced mammography (CEM) can be used in predicting malignancy.

METHODS

After review board approval, consecutive 136 suspicious lesions with definite diagnosis were retrospectively analyzed on CEM. Acquisition was routinely started with craniocaudal view and ended with mediolateral oblique view of the affected breast. Lesion conspicuity (low, moderate, high), internal enhancement pattern (homogeneous, heterogeneous, rim), contrast-to-noise ratio (CNR), percentage of signal difference (PSD) and relative enhancement from early to late view were analyzed. PSD and relative enhancements were used to determine patterns of descending, steady or ascending enhancements. Receiver operating characteristic analysis, Cohen's kappa statistics and Spearman correlation tests were used.

RESULTS

There were 29 benign and 107 malignant lesions. 64% of the malignant lesions exhibited high conspicuity compared to 14% of the benign lesions (P < 0.001). CNR values were higher in malignant lesions compared to benign ones (P ≤ 0.004). CNR from early view yielded 82% sensitivity, 72% specificity and PSD yielded 79% sensitivity, 65% specificity. Descending pattern and rim enhancement observed in 44% and 21% of breast cancers, respectively, and both provided 96% positive predictive value for malignancy.

CONCLUSION

Diagnostic accuracy of quantitative parameters was higher than that of qualitative parameters. High CNR, rim enhancement, and descending pattern were features commonly seen in malignant lesions, while low CNR, homogeneous enhancement, and ascending pattern were commonly seen in benign lesions.

Phase 1, placebo-controlled, single ascending dose trial to evaluate the safety, pharmacokinetics and effect on altered states of consciousness of intranasal BPL-003 (5-methoxy-N,N-dimethyltryptamine benzoate) in healthy participants

AIMS

To investigate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of BPL-003, a novel intranasal benzoate salt formulation of 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), in healthy participants.

METHODS

In all, 44 psychedelic-naïve participants enrolled in the double-blind, placebo-controlled single ascending dose study (1-12 mg BPL-003). Concentrations of 5-MeO-DMT and its pharmacologically active metabolite, bufotenine, were determined in plasma and urine. PD endpoints included subjective drug intensity (SDI) rating, the Mystical Experience Questionnaire (MEQ-30) and the Ego Dissolution Inventory (EDI).

RESULTS

BPL-003 was well tolerated at doses up to 12 mg. There were no serious adverse events (AEs), and most AEs were mild; the most common being nasal discomfort, nausea, headache and vomiting. 5-MeO-DMT was rapidly absorbed and eliminated; the median time to peak plasma concentration was approximately 8-10 min and the mean terminal elimination half-life was <27 min. 5-MeO-DMT systemic exposure increased approximately dose-proportionally, while plasma bufotenine concentrations and urinary excretion of 5-MeO-DMT and bufotenine were negligible. The intensity of the SDI ratings was associated with plasma 5-MeO-DMT concentrations. MEQ-30 and EDI scores generally increased with the BPL-003 dose; 60% of participants had a 'complete mystical experience' at 10 and 12 mg doses. Profound and highly emotional consciousness-altering effects were observed with BPL-003, with a rapid onset and short-lasting duration.

CONCLUSION

The novel intranasal formulation of BPL-003 was well tolerated with dose-proportional increases in PK and PD effects. The short duration of action and induction of mystical experiences suggest clinical potential, warranting further trials.

CLINICAL TRIAL REGISTRATION

NCT05347849.

Questioning methadone split-dosing for analgesia among hospitalized patients with opioid use disorder

Methadone is hypothesized to provide greater analgesic coverage when split into two or more divided doses. However, empirical data are lacking, and our anecdotal experience at a safety-net hospital among patients with opioid use disorder suggests that it may not be straightforward. Guidelines and clinicians should exercise appropriate caution when recommending this strategy.

Tenofovir Douche as HIV Preexposure Prophylaxis for Receptive Anal Intercourse: Safety, Acceptability, Pharmacokinetics, and Pharmacodynamics (DREAM 01)

BACKGROUND

Despite highly effective HIV preexposure prophylaxis (PrEP) options, no options provide on-demand, nonsystemic, behaviorally congruent PrEP that many desire. A tenofovir-medicated rectal douche before receptive anal intercourse may provide this option.

METHODS

Three tenofovir rectal douches-220 mg iso-osmolar product A, 660 mg iso-osmolar product B, and 660 mg hypo-osmolar product C-were studied in 21 HIV-negative men who have sex with men. We sampled blood and colorectal tissue to assess safety, acceptability, pharmacokinetics, and pharmacodynamics.

RESULTS

The douches had high acceptability without toxicity. Median plasma tenofovir peak concentrations for all products were several-fold below trough concentrations associated with oral tenofovir disoproxil fumarate (TDF). Median colon tissue mucosal mononuclear cell (MMC) tenofovir-diphosphate concentrations exceeded target concentrations from 1 hour through 3 to 7 days after dosing. For 6-7 days after a single product C dose, MMC tenofovir-diphosphate exceeded concentrations expected with steady-state oral TDF 300 mg on-demand 2-1-1 dosing. Compared to predrug baseline, HIV replication after ex vivo colon tissue HIV challenge demonstrated a concentration-response relationship with 1.9 log10 maximal effect.

CONCLUSIONS

All 3 tenofovir douches achieved tissue tenofovir-diphosphate concentrations and colorectal antiviral effect exceeding oral TDF and with lower systemic tenofovir. Tenofovir douches may provide a single-dose, on-demand, behaviorally congruent PrEP option, and warrant continued development. Clinical Trials Registration . NCT02750540.

Effect of Poly(ethylene glycol) Configuration on Microbubble Pharmacokinetics

Microbubbles (MBs) hold substantial promise for medical imaging and therapy; nonetheless, knowledge gaps persist between composition, structure, and in vivo performance, especially with respect to pharmacokinetics. Of particular interest is the role of the poly(ethylene glycol) (PEG) layer, which is thought to shield the MB against opsonization and rapid clearance but is also known to cause an antibody response upon multiple injections. The goal of this study was, therefore, to elucidate the role of the PEG layer in circulation persistence of MBs in the naïve animal (prior to an adaptive immune response). Here, we directly observe the number and size of individual MBs obtained from blood samples, unifying size and concentration into the microbubble volume dose (MVD) parameter. This approach enables direct evaluation of the pharmacokinetics of intact MBs, comprising both the lipid shell and gaseous core, rather than separately assessing the lipid or gas components. We examined the in vivo circulation persistence of 3 μm diameter phospholipid-coated MBs with three different mPEG2000 content: 2 mol % (mushroom), 5 mol % (intermediate), and 10 mol % (brush). MB size and concentration in the blood were evaluated by a hemocytometer analysis over 30 min following intravenous injections of 20 and 40 μL/kg MVD in Sprague-Dawley rats. Interestingly, pharmacokinetic analysis demonstrated that increasing PEG concentration on the MB surface resulted in faster clearance. This was evidenced by a 1.6-fold reduction in half-life and area under the curve (AUC) (p < 0.05) in the central compartment. Conversely, the AUC in the peripheral compartment increased with PEG density, suggesting enhanced MB trapping by the mononuclear phagocyte system. This was supported by an in vitro assay, which showed a significant rise in complement C3a activation with a higher PEG content. In conclusion, a minimal PEG concentration on the MB shell (mushroom configuration) was found to prolong circulation and mitigate immunogenicity.

Using the Dynamic Well-stirred Model to Extrapolate Hepatic Clearance of OATP Substrates without Assuming Albumin-Mediated Hepatic Drug Uptake

Extrapolating in vivo hepatic clearance from in vitro uptake data is a known challenge, especially for OATP substrates, and the well-stirred model (WSM) commonly yields systematic under-predictions for those anionic drugs hypothetically due to "albumin-mediated hepatic drug uptake". In the present study, we demonstrate that the WSM incorporating the dynamic free fraction (f D), a measure of drug protein binding affinity, performs reasonably well in predicting hepatic clearance of OATP substrates. For a selection of anionic drugs including atorvastatin, fluvastatin, pravastatin, rosuvastatin, pitavastatin, cerivastatin, and repaglinide, this dynamic well-stirred model (dWSM) correctly predicts hepatic plasma clearance within 2-fold error for six out of seven OATP substrates examined. The geometric mean of clearance ratios between the predicted and the observed values falls in the range of 1.21-1.38. As expected, the WSM with unbound fraction (f u) systematically under-predicts hepatic clearance with greater than 2-fold error for five out of seven drugs, and the geometric mean of clearance ratios between the predicted and the observed values is in the range of 0.20-0.29. The results suggest that, despite its simplicity, the dWSM operates well for transporter-mediated uptake clearance, and that clearance under-prediction of OATP substrates may not necessarily be associated with the chemical class of the anionic drugs, nor is it a result of albumin-mediated hepatic drug uptake as currently hypothesized. Instead, the superior prediction power of the dWSM confirms the utility of the dynamic free fraction in clearance prediction and the importance of drug plasma binding kinetics in hepatic uptake clearance. Significance Statement The traditional well-stirred model (WSM) consistently under predicts OATP-mediated hepatic uptake clearance, hypothetically due to the albumin-mediated hepatic drug uptake. In this manuscript, we apply the dynamic well-stirred model (dWSM) to extrapolate hepatic clearance of the OATP substrates, and our results show significant improvements in clearance prediction without assuming "albumin-mediated hepatic drug uptake".

Pharmacokinetics of tilmicosin in plasma, urine and feces after a single intragastric administration in donkey (Equus asinus)

Tilmicosin, a macrolide antibiotic, has the potential to treat bacterial infections in donkeys. However, the pharmacokinetics of tilmicosin in donkeys have not been reported. The aim of this study was to investigate the pharmacokinetics of tilmicosin in donkey plasma, urine, and feces after a single intragastric administration to determine the suitability of tilmicosin for donkeys. A total of 5 healthy male donkeys with similar body weights were selected. The donkeys were administered a single dose of 10 mg · kg-1 body weight (BW) tilmicosin by gavage. The concentrations of tilmicosin in plasma, urine, and feces were determined. The results showed that after a single intragastric administration of 10 mg · kg-1 body weight, tilmicosin in donkey plasma reached a maximum concentration of 11.23 ± 5.37 mg · L-1 at 0.80 ± 0.10 h, with a half-life of 14.49 ± 7.13 h, a mean residence time of 28.05 ± 3.05 h, a Cl/F of 0.48 ± 0.18 L · kg-1 · h-1, and a Vd/F of 9.28 ± 2.63 Lkg-1. The percentage of tilmicosin excreted through the urine of donkeys is 2.47%, and the percentage excreted through the feces is 66.43%. Our study provides data to inform the use of tilmicosin in donkeys.

Simultaneous assessment of absorption and pharmacokinetic characteristics of four active flavonoids from Chimonanthus nitens Leaf Granules using LC-MS determination: in vivo and in vitro

A sensitive UPLC-HRMS method was developed and validated for simultaneous quantification of four active flavonoids from Chimonanthus nitens Leaf Granules (CNLG) in biological matrix. The method was utilized in pharmacokinetic study of the four flavonoids in rats as well as other evaluation assays in vitro. It was revealed that rutin, nicotiflorin, and astragalin had poor oral bioavailability in rats possibly due to low intestinal permeability and metabolism in intestinal flora. Kaempferol underwent rapid glucuronidation and sulphation in rat plasma with medium permeability coefficient. The results provided valuable data for future research and development of CNLG flavonoids.

Method development and validation for the estimation of gedatolisib in mouse plasma by tandem mass spectrometry and its application to pharmacokinetics studies

A simple and a sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of gedatolisib in mouse plasma. The extraction technique involved a simple precipitation method to extract gedatolisib and idelalisib (internal standard) from mouse plasma. A clean chromatographic separation of gedatolisib and the internal standard was achieved on an Atlantis dC18 column using an isocratic mobile phase (10 mm ammonium formate and acetonitrile; 30:70% v/v, both supplemented with 0.1% formic acid) delivered at a flow rate of 0.7 ml/min. The total run time was 2.0 min, and gedatolisib and idelalisib were eluted at 0.80 and 0.95 min, respectively. Gedatolisib was monitored at m/z 616.40 → 488.20 and idelalisib at 416.05 → 176.10. All the required parameters for the method validation were performed as per US Food and Drug Administration guidelines, and the results were within the acceptance criteria. The method was accurate and proved to be precise at a linearity range of 1.33-2667 ng/ml. The accuracy for gedatolisib in mouse plasma was in the ranges 0.99-1.06% (intra-day) and 0.96-1.04% (inter-day). Gedatolisib appeared to be stable in a series of stability conditions. Gedatolisib showed a good intravenous profile when administered through a solution formulation.

Assessing potential drug-drug interactions between clofazimine and other frequently used agents to treat drug-resistant tuberculosis

Clofazimine is included in drug regimens to treat rifampicin/drug-resistant tuberculosis (DR-TB), but there is little information about its interaction with other drugs in DR-TB regimens. We evaluated the pharmacokinetic interaction between clofazimine and isoniazid, linezolid, levofloxacin, and cycloserine, dosed as terizidone. Newly diagnosed adults with DR-TB at Klerksdorp/Tshepong Hospital, South Africa, were started on the then-standard treatment with clofazimine temporarily excluded for the initial 2 weeks. Pharmacokinetic sampling was done immediately before and 3 weeks after starting clofazimine, and drug concentrations were determined using validated liquid chromatography-tandem mass spectrometry assays. The data were interpreted with population pharmacokinetics in NONMEM v7.5.1 to explore the impact of clofazimine co-administration and other relevant covariates on the pharmacokinetics of isoniazid, linezolid, levofloxacin, and cycloserine. Clofazimine, isoniazid, linezolid, levofloxacin, and cycloserine data were available for 16, 27, 21, 21, and 6 participants, respectively. The median age and weight for the full cohort were 39 years and 52 kg, respectively. Clofazimine exposures were in the expected range, and its addition to the regimen did not significantly affect the pharmacokinetics of the other drugs except levofloxacin, for which it caused a 15% reduction in clearance. A posteriori power size calculations predicted that our sample sizes had 97%, 90%, and 87% power at P < 0.05 to detect a 30% change in clearance of isoniazid, linezolid, and cycloserine, respectively. Although clofazimine increased the area under the curve of levofloxacin by 19%, this is unlikely to be of great clinical significance, and the lack of interaction with other drugs tested is reassuring.

Saliva monitoring of prednisolone in children with first onset steroid-sensitive nephrotic syndrome: Is it possible?

AIMS

Prednisolone is the cornerstone of treatment for idiopathic nephrotic syndrome in children, but is associated with marked side-effects. Therapeutic drug monitoring using saliva would be a patient-friendly option to monitor prednisolone treatment. To assess the feasibility of saliva monitoring, we described the pharmacokinetics (PK) of unbound prednisolone in plasma and saliva of children with first onset steroid-sensitive nephrotic syndrome (SSNS).

METHODS

Children (age 2-16 years) with SSNS participating in a randomized, placebo-controlled trial with levamisole were treated with an 18-week tapering schedule of prednisolone. Five serial samples were collected at 4 (saliva) and 8 weeks (saliva and plasma) after first onset. A nonlinear mixed-effects model was used to estimate the PK parameters of unbound prednisolone and the saliva-to-plasma ratio. Monte Carlo simulations were performed to assess the predictive performance of saliva monitoring.

RESULTS

From 39 children, 109 plasma and 275 saliva samples were available. Estimates (relative squared error) of unbound plasma clearance and volume of distribution were 93 (5%) L h-1 70 kg-1 and 158 (7%) L 70 kg-1, respectively. Typical saliva-to-plasma ratio was 1.30 (8%). Monte Carlo simulations demonstrated that on basis of 4 saliva samples and a single plasma sample unbound plasma area-under-the-concentration-time curve can be predicted within 20% imprecision in 79% of the patients compared to 87% based on 4 plasma samples.

CONCLUSION

Saliva proved to be a reliable and patient-friendly option to determine prednisolone plasma exposure in children with SSNS. This opens opportunities for further PK and pharmacodynamics studies of prednisolone in a variety of paediatric conditions.

Cefadroxil and cephalexin pharmacokinetics and pharmacodynamics in children with musculoskeletal infections

Cephalexin, a first-generation cephalosporin, is the first-line oral therapy for children with musculoskeletal infections due to methicillin-susceptible Staphylococcus aureus (MSSA). Cefadroxil, a similar first-generation cephalosporin, is an attractive alternative to cephalexin given its longer half-life. In this study, we describe the comparative pharmacokinetics (PK) and pharmacodynamics (PD) of cephalexin and cefadroxil in children with musculoskeletal infections. Children aged 6 months to 18 years with a musculoskeletal infection were enrolled in a prospective, open-label, crossover PK study and given single oral doses of cefadroxil (50-75 mg/kg up to 2,000 mg) and cephalexin (50 mg/kg up to 1,375 mg). Population PK models were developed and used for dosing simulations. Our primary PD target was the achievement of free antibiotic concentrations above the minimum inhibitory concentration (fT >MIC) for 40% of the day for MICs ≤ 4 mg/L. PK of cephalexin (n = 15) and cefadroxil (n = 14) were best described using a one-compartment, first-order absorption model, with a lag time component for cefadroxil. PK parameters were notable for cefadroxil's longer half-life (1.61 h) than cephalexin's (1.10 h). For pediatric weight bands, our primary PD target was achieved by cephalexin 25 mg/kg/dose, maximum 750 mg/dose, administered three times daily and cefadroxil 40 mg/kg/dose, maximum 1,500 mg/dose, administered twice daily. More aggressive dosing was required to achieve higher PD targets. Among children with musculoskeletal infections, oral cephalexin and cefadroxil achieved PD targets for efficacy against MSSA. Given less frequent dosing, twice-daily cefadroxil should be further considered as an alternative to cephalexin for oral step-down therapy for serious infections due to MSSA.

A rapid and sensitive LC-MS/MS method for quantifying oxycodone, noroxycodone, oxymorphone and noroxymorphone in human plasma to support pharmacokinetic drug interaction studies of oxycodone

A sensitive and reliable LC-MS/MS method was developed and validated for the quantification of oxycodone and metabolites in human plasma. The method has a runtime of 6 min and a sensitivity of 0.1 μg/L for all analytes. Sample preparation consisted of protein precipitation. Separation was performed on a Kinetix biphenyl column (2.1 × 100 mm, 1.7 μm), using ammonium formate 5 mm in 0.1% aqueous formic acid and methanol LC-MS grade 100% in gradient elution at a flow rate of 0.4 ml/min. Detection was performed in multiple reaction monitoring mode using positive electrospray ionization. The method was linear over the calibration range of 0.1-25.0 μg/L for oxycodone, noroxycodone and noroxymorphone and 0.1-5.0 μg/L for oxymorphone. The method demonstrated good performance in terms of intra- and interday accuracy (86.5-110.3%) and precision (CV 1.7-9.3%). The criteria for the matrix effect were met (CV < 15%) except for noroxymorphone, for which an additional method was applied to compensate for the matrix effect. Whole blood samples were stable for 4 h at room temperature. Plasma samples were stable for 24 h at room temperature and 3 months at -20°C. Furthermore, the method was successfully applied in a pharmacokinetic drug interaction study of oxycodone and enzalutamide in patients with prostate cancer.

Extracellular Vesicles as Surrogates for the Regulation of the Drug Transporters ABCC2 (MRP2) and ABCG2 (BCRP)

Drug efflux transporters of the ATP-binding-cassette superfamily play a major role in the availability and concentration of drugs at their site of action. ABCC2 (MRP2) and ABCG2 (BCRP) are among the most important drug transporters that determine the pharmacokinetics of many drugs and whose overexpression is associated with cancer chemoresistance. ABCC2 and ABCG2 expression is frequently altered during treatment, thus influencing efficacy and toxicity. Currently, there are no routine approaches available to closely monitor transporter expression. Here, we developed and validated a UPLC-MS/MS method to quantify ABCC2 and ABCG2 in extracellular vesicles (EVs) from cell culture and plasma. In this way, an association between ABCC2 protein levels and transporter activity in HepG2 cells treated with rifampicin and hypericin and their derived EVs was observed. Although ABCG2 was detected in MCF7 cell-derived EVs, the transporter levels in the vesicles did not reflect the expression in the cells. An analysis of plasma EVs from healthy volunteers confirmed, for the first time at the protein level, the presence of both transporters in more than half of the samples. Our findings support the potential of analyzing ABC transporters, and especially ABCC2, in EVs to estimate the transporter expression in HepG2 cells.

First-In-Human Study on Pharmacokinetics, Safety, and Tolerability of Single and Multiple Escalating Doses of PA9159 Nasal Spray, a Highly Potent Glucocorticoid in Healthy Chinese Volunteers

OBJECTIVE

PA9159 (previously named VSG159) is a structurally novel and highly potent glucocorticoid that plays a role in the late development of autoimmune and inflammatory diseases. The current first-in-human ascending-dose study of the PA9159 nasal spray was conducted in healthy Chinese volunteers to evaluate its pharmacokinetics, safety, and tolerability. In addition, the effects of PA9159 on serum cortisol secretion were investigated.

METHODS

This was a double-blinded, randomized, placebo-controlled clinical study that included four single-dose groups in the single ascending dose cohort (SAD) and two multiple-dose groups in the multiple ascending dose cohort (MAD), with dose ranges of 10-80 μg and 20-40 μg, respectively. PA9159 was administered bilaterally via nasal spray once only or once daily for seven days. Pharmacokinetic, safety, and tolerability profiles were evaluated.

RESULTS

A total of 60 participants completed the study. PA9159 doses of up to 80 μg in the SAD and up to 40 μg in the MAD were shown to be safe and tolerable. The most common treatment-related AEs were mild and transient local nasal AEs. Morning serum cortisol levels approximately remained unchanged in both the single-dose and multiple-dose groups. PA9159 was quantified in 41.8% (368/880) of the samples in all treatment groups, including 25.2% (105/416) of the SAD and 56.7% (263/464) of the MAD. The majority (>80.0%) of PA9159 plasma concentrations ranged from 0.5 to 2 pg/mL in determined samples. The mean AUC0-t of PA9159 in the SAD was 0.91, 1.39±0.68, 11.40±9.91, and 46.30±25.80 h*pg/mL in the 10 to 80 ug single group. The mean terminal half-life time (t1/2) was 8.43 h and 8.97±2.28 h in 40 ug and 80 ug single group, respectively. The mean AUCss of PA9159 in the MAD was 31.70±7.04, 44.20±20.60 h*pg /mL, and the t1/2 was 16.00±4.18 h, 21.20±10.20 h in the 20 ug and 40 ug multiple groups, respectively. The median Tmax was approximately 6 hours in both the SAD and MAD cohorts.

CONCLUSIONS

The PA9159 nasal spray was generally safe and well tolerated, and the effects of PA9159 on serum cortisol levels were limited. The plasma concentration and systemic exposure to PA9159 were very low. These findings support the necessity for further clinical studies on PA9159 nasal spray in patients suffering from allergic rhinitis.

Scutellarein: a review of chemistry and pharmacology

OBJECTIVES

To get a better understanding of the scientific values of flavone scutellarein (SCT), and to encourage its applications in human health, the current review systematically summarizes the natural observation, biosynthesis, synthesis, pharmacology, pharmacokinetics, and recent synthetic advances.

KEY FINDINGS

Scientific sources to search for references included Google Scholar, Scopus, Web of Science, PubMed, Sci-Finder, and journal websites. The references have been collected from the 1970s to the present. "Scutellarein" is the most meaningful keyword to search for publications, in which it was used alone or in combination with other keywords.

SUMMARYS

SCT as a hydrophobic flavonoid can be found in various medicinal plants of the families Lamiaceae, Compositae, and Verbenaceae. Flavone SCT has drawn much interest due to its wide pharmacological effects, such as anticancer, anti-inflammation, antioxidant, antiobesity, and vasorelaxant. The SCT treatments also possessed a lot of positive results in the neuron, liver, heart, lung, kidney, bone, and skin protective experiments, and human sperm function enhancement. Its underlying mechanism of action may relate to the apoptotic program and cytokine inhibition by regulating a panel of the signaling pathway, e.g., NF-κB (nuclear factor kappa B)/MAPK (mitogen-activated protein kinase), IκBa (nuclear factor of kappa light polypeptide gene enhancer in B cells inhibitors alpha)/NF-κB, TRAF2 (tumor necrosis factor receptor-associated factor 2)/NF-κB, and PTEN (phosphatase and tension homologue deleted on chromosome 10)/Akt (protein kinase B)/NF-κB. In addition, the metabolic actions and synthetic derivative promotions of SCT were mostly based on the substitution of hydroxyl groups. Collectively, the studies that aim to highlight the role of scutellarein in preclinical and clinical treatments are urgently needed. More and more experiments to improve its bioavailability are expected.

Pharmacokinetics of Nitazoxanide Dry Suspensions After Single Oral Doses in Healthy Subjects: Food Effects Evaluation and Bioequivalence Study

Nitazoxanide (NTZ) is an effective antiparasitic drug with potent antiviral and antimicrobial activity. This randomized, open-label, 2-sequence, 2-period crossover trial was designed to evaluate the bioequivalence (BE) of the NTZ dry suspension in healthy subjects and investigated the effect of food intake on the pharmacokinetic (PK) properties of tizoxanide (an active metabolite of NTZ, TIZ). Sixty healthy Chinese subjects were enrolled and received a single dose of 500 mg/25 mL of preparations on days 1 and 4 under overnight fasting or fed conditions, respectively. The plasma concentration of TIZ was determined using high-performance liquid chromatography/tandem mass spectrometry. PK parameters were calculated using WinNonlin 8.2 and BE was evaluated using SAS 9.4. The 90% confidence intervals for the geometric mean ratio (test/reference) of maximum concentration (Cmax), the area under the curve from time 0 to the time of the last quantifiable concentration (AUC0-t), and the area under the curve from time 0 to extrapolation to infinity (AUC0-∞) were all within the equivalent interval of 80%-125%, compliant with BE requirements. In comparison with fasting, on taking the reference and test preparations of the NTZ dry suspension after a meal, the AUC0-t increased by 48.9% and 47.3%, respectively, the AUC0-∞ increased by 48.4% and 48.3%, respectively, and the post-meal Tmax was prolonged by 1.8-2 hours. Our results demonstrate that the test and reference preparations were bioequivalent. High-fat meals significantly improve the degree of drug absorption and delay the rate of drug absorption.

Preclinical and phase I studies of an antisense oligonucleotide drug targeting IGF-1R in liver cancer

Aim: To evaluate a novel antisense oligonucleotide drug targeting human IGF-1R in preclinical and phase I studies of liver cancer. Materials & methods: The tolerability and safety of an investigational new drug were evaluated in a dose-escalation trial involving 17 patients with advanced liver cancer after preclinical assessment of pharmacokinetics and pharmacodynamics. Results: The drug exposure levels in the phase I trial were determined by the in vivo efficacy with pharmacokinetics evaluation in rats and rhesus monkeys. This clinical study showed that the maximum tolerated dose was 3.96 mg/kg, and the dose-limiting toxicity dose was 4.4 mg/kg. Conclusion: The drug was safe and tolerable in patients with advanced liver cancer. Clinical Trial Registration: ChiCTR2100044235 (www.chictr.org.cn).

Role for Carboxylic Acid Moiety in NSAIDs: Favoring the Binding at Site II of Bovine Serum Albumin

The molecular structures of nonsteroidal anti-inflammatory drugs (NSAIDs) vary, but most contain a carboxylic acid functional group (RCOOH). This functional group is known to be related to the mechanism of cyclooxygenase inhibition and also causes side effects, such as gastrointestinal bleeding. This study proposes a new role for RCOOH in NSAIDs: facilitating the interaction at the binding site II of serum albumins. We used bovine serum albumin (BSA) as a model to investigate the interactions with ligands at site II. Using dansyl-proline (DP) as a fluorescent site II marker, we demonstrated that only negatively charged NSAIDs such as ibuprofen (IBP), naproxen (NPX), diflunisal (DFS), and ketoprofen (KTP) can efficiently displace DP from the albumin binding site. We confirmed the importance of RCOO by neutralizing IBP and NPX through esterification, which reduced the displacement of DP. The competition was also monitored by stopped-flow experiments. While IBP and NPX displaced DP in less than 1 s, the ester derivatives were ineffective. We also observed a higher affinity of negatively charged NSAIDs using DFS as a probe and ultrafiltration experiments. Molecular docking simulations showed an essential salt bridge between the positively charged residues Arg409 and Lys413 with RCOO-, consistent with the experimental findings. We performed a ligand dissociation pathway and corresponding energy analysis by applying molecular dynamics. The dissociation of NPX showed a higher free energy barrier than its ester. Apart from BSA, we conducted some experimental studies with human serum albumin, and similar results were obtained, suggesting a general effect for other mammalian serum albumins. Our findings support that the RCOOH moiety affects not only the mechanism of action and side effects but also the pharmacokinetics of NSAIDs.

Improving the pharmacokinetics, biodistribution and plasma stability of monobodies

Cancer is a leading cause of death worldwide. Several targeted anticancer drugs entered clinical practice and improved survival of cancer patients with selected tumor types, but therapy resistance and metastatic disease remains a challenge. A major class of targeted anticancer drugs are therapeutic antibodies, but their use is limited to extracellular targets. Hence, alternative binding scaffolds have been investigated for intracellular use and better tumor tissue penetration. Among those, monobodies are small synthetic protein binders that were engineered to bind with high affinity and selectivity to central intracellular oncoproteins and inhibit their signaling. Despite their use as basic research tools, the potential of monobodies as protein therapeutics remains to be explored. In particular, the pharmacological properties of monobodies, including plasma stability, toxicity and pharmacokinetics have not been investigated. Here, we show that monobodies have high plasma stability, are well-tolerated in mice, but have a short half-life in vivo due to rapid renal clearance. Therefore, we engineered monobody fusions with an albumin-binding domain (ABD), which showed enhanced pharmacological properties without affecting their target binding: We found that ABD-monobody fusions display increased stability in mouse plasma. Most importantly, ABD-monobodies have a dramatically prolonged in vivo half-life and are not rapidly excreted by renal clearance, remaining in the blood significantly longer, while not accumulating in specific internal organs. Our results demonstrate the promise and versatility of monobodies to be developed into future therapeutics for cancer treatment. We anticipate that monobodies may be able to extend the spectrum of intracellular targets, resulting in a significant benefit to patient outcome.

Impact of Dietary Fat and Oral Delivery System on Cannabigerol Pharmacokinetics in Adults

Background and Aims: Cannabigerol (CBG) is a nonintoxicating cannabinoid synthesized in the Cannabis sativa plant that is incorporated into dietary supplements. This study investigated the influence of dietary fat and an emulsified delivery vehicle on CBG pharmacokinetics (PKs) after oral ingestion by adults. Materials and Methods: Consented participants were enrolled in a double-crossover pilot study and were blinded to the delivery vehicle type (isolate or emulsification) and isocaloric meal condition (low-fat=<5 g fat/meal or high-fat [HF]=>30 g fat/meal). The concentration of CBG in human plasma was measured after a single 25 mg dose of CBG using liquid chromatography-tandem mass spectrometry (LC-MS/MS). PK parameters were calculated using noncompartmental analysis. Results: The PKs of the two delivery systems (emulsified vs. non-emulsified) were significantly impacted by the HF meal condition. Participants in the HF meal group exhibited significantly higher area under the plasma concentration time curve from time 0 to last quantifiable value, maximum concentration, and terminal half-life. Participants in the HF meal group also had a significantly lower terminal elimination rate constant and time to maximum concentration (Tmax), in addition to decreased Tmax variation. The threshold for bioequivalence between conditions was not met. An exploratory aim correlated anthropometric measures and previous day's dietary intake on PK parameters which yielded inconsistent results across dietary fat conditions. Conclusions: In aggregate, dietary fat had a greater effect on CBG PKs than the emulsified delivery vehicle. This supports accounting for dietary intake in development of therapeutics and administration guidelines for orally delivered CBG.

Pharmacokinetics of long-acting lenacapavir in participants with hepatic or renal impairment

Lenacapavir is a novel, first-in-class, multistage inhibitor of HIV-1 capsid function approved for the treatment of multidrug-resistant HIV-1 infection in combination with other antiretrovirals for heavily treatment-experienced people with HIV. Two Phase 1, open-label, parallel-group, single-dose studies assessed the pharmacokinetics (PK) of lenacapavir in participants with moderate hepatic impairment [Child-Pugh-Turcotte (CPT) Class B: score 7-9] or severe renal impairment [15 ≤ creatinine clearance (CLcr) ≤29 mL/min] to inform lenacapavir dosing in HIV-1-infected individuals with organ impairment. In both studies, a single oral dose of 300 mg lenacapavir was administered to participants with normal (n = 10) or impaired (n = 10) hepatic/renal function who were matched for age (±10 years), sex, and body mass index (±20%). Lenacapavir exposures [area under the plasma concentration-time curve from time 0 to infinity (AUCinf) and maximum concentration (Cmax)] were approximately 1.47- and 2.61-fold higher, respectively, in participants with moderate hepatic impairment compared to those with normal hepatic function, whereas lenacapavir AUCinf and Cmax were approximately 1.84- and 2.62-fold higher, respectively, in participants with severe renal impairment compared to those with normal renal function. Increased lenacapavir exposures with moderate hepatic or severe renal impairment were not considered clinically meaningful. Lenacapavir was considered generally safe and well tolerated in both studies. These results support the use of approved lenacapavir dosing regimen in patients with mild (CPT Class A: score 5-6) or moderate hepatic impairment as well as in patients with mild (60 ≤ CLcr ≤ 89 mL/min), moderate (30 ≤ CLcr ≤ 59 mL/min), and severe renal impairment.

One-Year Clinical Outcomes of Subcutaneous Infliximab Maintenance Therapy Compared With Intravenous Infliximab Maintenance Therapy in Patients With Inflammatory Bowel Disease: A Prospective Cohort Study

BACKGROUND

Although the pharmacokinetic profile of subcutaneous (SC) infliximab (IFX) is superior to conventional intravenous (IV) IFX, long-term efficacy and safety of SC IFX in patients with inflammatory bowel disease (IBD) have not been reported yet. This study aimed to evaluate long-term clinical outcomes of IBD patients treated with SC IFX compared with those of IBD patients treated with IV IFX during maintenance therapy.

METHODS

This prospective cohort study enrolled 61 IBD patients in clinical remission who received scheduled IFX maintenance therapy. Of them, 38 patients were switched to SC IFX, while 23 patients continued IV IFX with dose optimization. Enrolled patients were followed up for 1 year. The primary outcome was durable remission defined as clinical remission (Crohn's disease, Harvey-Bradshaw index <5; ulcerative colitis, partial Mayo score <2) and biochemical remission (C-reactive protein <0.5 mg/dL) with IFX trough level ≥3 µg/mL throughout the follow-up period.

RESULTS

One-year clinical remission, 1-year biochemical remission, and mucosal healing did not differ between the IV and SC IFX groups (n = 20 of 23 vs 33 of 38; P = 1.000; n = 22 of 23 vs 34 of 38; P = .641; and n = 10 of 18 vs 17 of 25; P = .414, respectively). During follow-up, the number of patients with IFX trough level <3 μg/mL was significantly lower in the SC IFX group (n = 0 of 38, 0%) than in the IV IFX group (n = 10 of 23, 43%) (P < .001). The SC IFX group showed higher 1-year durable remission than the IV IFX group (n = 31 of 38, 82% vs n = 11 of 23, 48%; P = .013). The incidence of IFX-related adverse events did not differ significantly between both groups (26% vs 39%; P = .446).

CONCLUSION

The SC IFX switch induced a higher 1-year durable remission rate than continuing IV IFX in patients with IBD during scheduled maintenance therapy, showing similar safety.

Interspecies variability in protein binding of antibiotics basis for translational PK/PD studies-a case study using cefazolin

For antimicrobial agents in particular, plasma protein binding (PPB) plays a pivotal role in deciphering key properties of drug candidates. Animal models are generally used in the preclinical development of new drugs to predict their effects in humans using translational pharmacokinetics/pharmacodynamics (PK/PD). Thus, we compared the protein binding (PB) of cefazolin as well as bacterial growth under various conditions in vitro. The PB extent of cefazolin was studied in human, bovine, and rat plasmas at different antibiotic concentrations in buffer and media containing 20-70% plasma or pure plasma using ultrafiltration (UF) and equilibrium dialysis (ED). Moreover, bacterial growth and time-kill assays were performed in Mueller Hinton Broth (MHB) containing various plasma percentages. The pattern for cefazolin binding to plasma proteins was found to be similar for both UF and ED. There was a significant decrease in cefazolin binding to bovine plasma compared to human plasma, whereas the pattern in rat plasma was more consistent with that in human plasma. Our growth curve analysis revealed considerable growth inhibition of Escherichia coli at 70% bovine or rat plasma compared with 70% human plasma or pure MHB. As expected, our experiments with cefazolin at low concentrations showed that E. coli grew slightly better in 20% human and rat plasma compared to MHB, most probably due to cefazolin binding to proteins in the plasma. Based on the example of cefazolin, our study highlights the interspecies differences of PB with potential impact on PK/PD. These findings should be considered before preclinical PK/PD data can be extrapolated to human patients.