Multiple-dose Pharmacokinetic Study Research Articles

JSKN003, A NOVEL BIPARATOPIC ANTI-HER2 ANTIBODY-DRUG CONJUGATE, EXHIBITS POTENT ANTITUMOR EFFICACY

Abstract In human advanced solid tumors, expression of HER2 protein has been reported in various tumor tissues and a variety of cultured tumor cell lines including breast cancer, gastric cancer, pancreatic cancer, lung cancer, colorectal cancer, and ovarian cancer. Due to the critical roles of HER2 in carcinogenesis, two main targeted therapies have been developed in the past two decades to block the HER2-driven pathways, which include small molecule compounds that inhibit the tyrosine kinase activity of the intracellular domain, and mono-antibodies (mAbs) that target the extracellular domain (ECD) of the receptors. JSKN003 is an antibody-drug conjugate (ADC) comprised of a recombinant, humanized anti-human epidermal growth factor receptor 2 (HER2) bispecific antibody conjugated to a topoisomerase I inhibitor via a dibenzocyclooctyne tetrapeptide linker. The anti-HER2 component, KN026, is a recombinant, humanized bispecific antibody that targets both extra-cellular domains II (pertuzumab binding site) and IV (trastuzumab binding site) of HER2. JSKN003 showed high affinity binding to human HER2 with KDs of 2.209 E-10M, which is comparable to its parental antibody KN026 and bound to NCI-N87 and BxPC-3 cells in a concentration-dependent manner. At the same time JSKN003 showed more extensive and faster internalization than DS8201 on NCI-N87 cells. As expected, JSKN003 showed directly inhibits growth by targeting HER2 positive tumor model (NCI-N87 and BT474 cell models). The single dose and multiple dose pharmacokinetics study in cynomolgus monkey indicated that JSKN003, total antibody and DXd had general linear dynamic characteristics, and pharmacokinetics parameters showed no significant differences between males and females in the range 0.3-30 mg/kg. The HNSTD (highest non-severely toxic dose) of JSKN003 was determined as 30mg/kg in cynomolgus monkeys. These preclinical data suggest that JSKN003 could potentially benefit patients with tumors co-expressing HER2 through improved drug selectivity and efficacy. JSKN003’s safety, tolerability and preliminary anti-tumor activity are currently being evaluated in a first-in-human phase I study in advanced stage solid tumors in Australia (NCT05494918) using a BOIN design. This ADC is targeted on the subjects who has HER2 expression and/or HER2-gene mutation and may address an unmet medical need for these patients.

A One Health perspective on comparative cannabidiol and cannabidiolic acid pharmacokinetics and biotransformation in humans and domestic animals

The goal of pharmacokinetic (PK) studies is to provide a basis for appropriate dosing regimens with novel therapeutic agents. With a knowledge of the desired serum concentration for optimum pharmacological effect, the amount and rate of drug administration can be tailored to maintain that concentration based on the 24-hour PK modeling (eg, every 24 hours, every 12 hours) to achieve therapeutic ranges. This dosing and PK information are tailored to maintain that concentration. Typically, these optimum serum concentrations pertain across species. Single-dose PK modeling provides fundamental parameters to suggest dosing regimes. Multiple-dose PK studies provide information on steady-state serum levels to assure that desired therapeutic levels are maintained during chronic administration. Clinical trials using dosing suggested by these PK determinations provide proof that the compound is producing the desired therapeutic effect. A number of PK studies with cannabinoids in humans and domestic animals have been conducted with the goal of determining appropriate clinical use with these plant-derived products. The following review will focus on the PK of cannabidiol (CBD) and the lesser-known precursor of CBD, cannabidiolic acid (CBDA). Although Δ9-tetrahydrocannabinol (THC) has profound pharmacological effects and may be present at variable and potentially violative concentrations in hemp products, PK studies with THC will not be a major consideration. Because, in domestic animals, hemp-CBD products are usually administered orally, that route will be a focus. When available, PK results with CBD administered by other routes will be summarized. In addition, the metabolism of CBD across species appears to be different in carnivorous species compared with omnivorous/herbivorous species (including humans) based on current information, and the preliminary information related to this will be explained with the therapeutic implication being addressed in Currents in One Health by Ukai et al, JAVMA, May 2023.

A Single- and Multiple-Dose Pharmacokinetic Study of Oral Perampanel in Healthy Chinese Subjects.

Perampanel is a once-daily oral anti-seizure medication indicated for focal-onset seizures and generalized tonic-clonic seizures. This study investigated the single- and multiple-dose pharmacokinetics of perampanel in healthy Chinese adults. Study 052 (NCT03424564) was a phase I, single-center, open-label, parallel-group study. In the single-dose part of the study, subjects received a single oral dose of perampanel 2, 4, or 8 mg. In the multiple-dose part, subjects received once-daily oral perampanel 2 mg on Days 1-7 and 4 mg on Days 8-21. Pharmacokinetic parameters were determined from perampanel plasma concentrations using non-compartmental analysis. Dose proportionality after single doses of perampanel was assessed. Safety and tolerability were evaluated. In the single-dose part (N=30), median time to reach maximum concentration (tmax) was 0.75-1.0h, mean terminal elimination phase half-life (t½) was 85.6-122h, mean maximum observed concentration (Cmax) was 77.9-276 ng/mL, and mean area under the concentration-time curve from time zero to time of the last quantifiable concentration (AUC(0-t)) was 4070-15100 ng·h/mL. Single-dose pharmacokinetics were linear for perampanel 2-8 mg. In the multiple-dose part (N=12), Day 21 steady-state (4 mg/day) parameters were median time at which the highest drug concentration occurs at steady state (tss,max), 1.25h; mean t½, 109h; mean maximum observed concentration at steady state (Css,max), 453ng/mL; and mean area under the concentration-time curve over the dosing interval on multiple dosing (AUC(0- τ)), 7540 ng·h/mL. For single- and multiple-dose perampanel, the most common treatment-emergent adverse events were dizziness and somnolence. Single- and multiple-dose pharmacokinetics of perampanel in healthy Chinese adults revealed rapid perampanel absorption, slow elimination, and a linear relationship with single perampanel doses of 2-8 mg. Findings were consistent with previous studies of perampanel pharmacokinetics in other ethnic/racial populations of healthy subjects. Single and multiple doses of perampanel were generally safe and well tolerated. NCT03424564; registered February 2018.

Pharmacokinetic study of single and multiple oral administration of glutamine in healthy Beagles.

Glutamine is an amino acid that is mainly used for the treatment of gastrointestinal diseases in clinic, but there is a lack of such medicine in veterinary clinic, and its research in dogs has never been seen. This study aimed to investigate the pharmacokinetics of single and multiple administration of glutamine (Gln) tablets in Beagles. Twenty-four healthy Beagles were randomly selected for the pharmacokinetic study of a single dose of low (120 mg/kg), medium (240 mg/kg), and high (360 mg/kg) Gln tablets. After 7 days of washout period, six Beagles in the medium group were selected for a multiple-dose pharmacokinetic study, 240 mg/kg twice a day for 7 days. The Gln concentration in plasma was determined by a validated UPLC-MS/MS method. The results of single oral administration of different doses of Gln tablets showed that Cmax, AUC0→t, AUC0→∝ had a certain linear relationship with the dosage. T-tests were performed for single and multiple administration of Tmax, Cmax, t1/2λz, AUC0→t, and AUC0→∝, and the results showed no significant differences (p > 0.05). Therefore, Gln tablets were absorbed quickly by oral administration, and there was no accumulation in Beagles after 7 days of administration.

Clinical pharmacokinetics of kavalactones after oral dosing of standardized kava extract in healthy volunteers

Ethnopharmacological relevancePiper methysticum G. Forst. (Piperaceae), commonly known as kava, has been used as a traditional beverage for centuries for its relaxing properties. Kavalactones are considered to be the major constituents responsible for kava's beneficial effects. Despite the extensive use of kava, clinical pharmacokinetic data is not available in the literature; therefore, the findings of this study will be critical for the dosage calculations for future clinical evaluation of kava. Aim of the studyThe aim of the current study is to examine the clinical pharmacokinetics of six major kavalactones following oral dosing of flavokavain A/B-free standardized kava extract capsules in healthy volunteers using two dosage regimens. Materials and methodsA sensitive, reliable, and specific ultra-high pressure liquid chromatography-mass spectrometry (UPLC-MS/MS) method was developed and validated for the simultaneous quantification of six major kavalactones (kavain, dihydrokavain, methysticin, dihydromethysticin, yangonin, and desmethoxyyangonin) and two flavokavains (A and B) in human plasma. Pharmacokinetic profiles were assessed in ten healthy volunteers after oral doses of standardized kava product, and plasma samples were analyzed for six kavalactones and two flavokavains using the validated UPLC-MS/MS method. Concentration-time data was subjected to pharmacokinetic analysis. ResultsThe systemic exposure of the kavalactones was found to be in the following order: dihydrokavain > dihydromethysticin > kavain > methysticin > yangonin. Desmethoxyyangonin was quantifiable only at a couple of time points, while flavokavain A and flavokavain B were not present in any of the plasma samples. Fast absorption of five kavalactones was observed with time to reach the maximum plasma concentration of 1–3 h. A dose proportionality in pharmacokinetics was established from 75 to 225 mg of kavalactone doses. In the multiple-dose study, a significant reduction in the extent of absorption of kavalactones with food was observed. ConclusionSingle and multiple-dose clinical pharmacokinetic studies for kava were performed in healthy volunteers, and higher exposure to the kavalactones was observed after single-dosing (225 mg), while a longer duration of exposure was observed after three times a day (3 x 75 mg) dosing.

Population Pharmacokinetics of Intraperitoneal Gentamicin and the Impact of Varying Dwell Times on Pharmacodynamic Target Attainment in Patients with Acute Peritonitis Undergoing Peritoneal Dialysis.

While the use of intraperitoneal (i.p.) gentamicin is common in the treatment of peritoneal dialysis (PD)-related infections, the ability of these regimens to attain pharmacodynamic target indices of interest in blood and dialysate has not been widely reported. Pharmacokinetic (PK) data were obtained and analyzed from a multiple-dose PK study of i.p. gentamicin with 24 patients who received the drug at 0.6 mg/kg dose of body weight. The probability of target attainment (PTA) for indices of treatment success (i.p. peak/MIC ratio > 10) and toxicity (plasma area under the concentration-time curve [AUC] < 120 mg·h/L) was determined for 0.3- to 1.2-mg/kg i.p. regimens every 24 h for dwell times of 2 to 6 h and for the duration of a 2-week course. In the peritoneum, successful PTA was achieved by all of the simulated regimens up to an MIC of 1 mg/L and by doses equal to or greater than 0.6 mg/kg up to the MIC of 2 mg/L. At the susceptibility breakpoint of 4 mg/L, only the highest dose of 1.2 mg/kg is likely to provide adequate PTA. The probability of achieving exposure below the threshold of 120 mg·h/L in the daily AUC in plasma seems acceptable for all regimens at or below 0.6 mg/kg. Based on the model we developed, a gentamicin dose of 0.6 mg/kg is sufficient to treat organisms with an MIC of ≤2 mg/L without the risk of significant systemic exposure. The 1.2-mg/kg dose necessary to reach the pharmacodynamic target for efficacy at the clinical breakpoint of 4 mg/L is likely to produce early toxic levels of exposure that are expected to be detrimental to the renal system.

Pharmacokinetic Characterization and Bioavailability Barrier for the Key Active Components of Botanical Drug Antitumor B (ATB) in Mice for Chemoprevention of Oral Cancer.

This study aims to characterize the pharmacokinetic (PK) profiles and identify important bioavailability barriers and pharmacological pathways of the key active components (KACs) of Antitumor B (ATB), a chemopreventive agent. KACs (matrine, dictamine, fraxinellone, and maackiain) of ATB were confirmed using the antiproliferative assay and COX-2 inhibition activities in oral cancer cells. The observed in vitro activities of KACs were consistent with their cell signaling pathways predicted using the in silico network pharmacology approach. The pharmacokinetics of KACs were determined after i.v., i.p., and p.o. delivery using ATB extract and a mixture of four KACs in mice. Despite good solubilities and permeabilities, poor oral bioavailabilities were estimated for all KACs, mostly because of first-pass metabolism in the liver (for all KACs) and intestines (for matrine and fraxinellone). Multiple-dose PK studies showed 23.2-fold and 8.5-fold accumulation of dictamine and maackiain in the blood, respectively. Moreover, saliva levels of dictamine and matrine were found significantly higher than their blood levels. In conclusion, the systemic bioavailabilities of ATB-KACs were low, but significant levels of dictamine and matrine were found in saliva upon repeated oral administration. Significant salivary concentrations of matrine justified its possible use as a drug-monitoring tool to track patient compliance during chemoprevention trials.

Antimicrobial dosing in prolonged intermittent renal replacement therapy: a systematic review

AbstractAimThe research aim was to conduct a systematic review of the literature regarding the pharmacokinetics (PK) and dosing of antimicrobials in prolonged intermittent renal replacement therapy (PIRRT), a hybrid form of dialysis becoming increasingly utilised in critical care.MethodsA literature review was performed using PubMed from database inception to October 2020 according to the PRISMA guidelines. All papers published in English language were included in the review. Two researchers independently conducted literature searches, screened abstracts and full text and came to agreement as to which articles were suitable for inclusion before compiling the relevant data into a spreadsheet. The types of papers retrieved varied between case reports, single and multiple dose pharmacokinetic studies and Monte Carlo simulations.ResultsA total of 149 articles were found in the initial literature review and via other sources. Of these papers, 50 articles were deemed eligible for inclusion. These studies included one to 34 patients. PIRRT settings varied between institutions, including filter surface area, duration of PIRRT and type of dialyser used. With the exception of vancomycin and meropenem, few antimicrobials had sufficient data available from which reasonable empiric dosing regimens can be recommended.ConclusionThere is limited data to guide dosing of antimicrobials during PIRRT. More studies are required to understand how dosing can be optimised in this population of critically ill patients.

Pharmacokinetics and Safety of Rifamycin SV after Single and Multiple Doses of MMX® Modified Release Tablets in Healthy Male and Female Volunteers.

The primary objective of this single- and multiple-dose pharmacokinetic study was the investigation of rifamycin SV’s pharmacokinetic profile in plasma and urine. All the 18 enrolled healthy men and post-menopausal women received modified release tablets containing 600 mg of the oral non-absorbable antibiotic, rifamycin SV, according to a multiple dose regimen: one tablet three times a day (daily intake: 1800 mg) for 14 consecutive days. Blood sampling and urine collection were performed up to 24 h post-dose after the first dose on Days 1 and 7. On average, on Day 1, Cmax,0–24 was 5.79 ± 4.24 ng/mL and was attained in a median time of 9 h. On Day 7, all the subjects had quantifiable levels of rifamycin SV in plasma at each sampling time. After a peak concentration attained 2 h post-dose (mean ± SD concentration: 10.94 ± 16.41 ng/mL), rifamycin SV decreased in plasma to levels similar to those of Day 1. The amounts of rifamycin SV excreted in urine paralleled the plasma concentration at the corresponding times. On Day 1, the total amount excreted in urine was 0.0013%, and was 0.0029% on Day 7. The study results confirmed those of the previous Phase I study: the systemic absorption of rifamycin SV was also proved negligible after 7 days of the 600 mg t.i.d. dose regimen of the newly formulated tablets, currently under development for the treatment of several small and large intestinal pathologies, including diarrhea-predominant irritable bowel syndrome, hepatic encephalopathy, and others. Registered at ClinicalTrials.gov with the identifier NCT02969252, last updated on 26JAN18.

Safety, Tolerability and Pharmacokinetics of Bencycloquidium Bromide, a Novel Inhaled Anticholinergic Bronchodilator, in Healthy Subjects: Results from Phase I Studies

BackgroundBencycloquidium bromide (BCQB) is a novel inhaled anticholinergic bronchodilator with high selectivity for muscarinic M3 receptor. BCQB's potential utility of for therapy in Chronic obstructive pulmonary disease (COPD) has been indicated in pre-clinical studies. PurposeTo investigate the initial safety, tolerability and pharmacokinetics of BCQB delivered via pressurised Metered Dose Inhaler (pMDI) in healthy subjects. MethodsThis study consisted of single-ascending-dose (SAD), multiple-ascending-dose (MAD) tolerability study periods, and single- plus multiple-dose pharmacokinetic study periods. Randomized, double-blind, placebo-controlled, dose-escalating tolerability and pharmacokinetic studies were conducted. Seventy-two healthy subjects were assigned 3:1 (BCQB: placebo) to 7 single-dose cohorts (125, 250, 500, 750, 1125, 1500 and 2000 μg) and 2 multiple-dose cohorts (1500 μg/d and 2000 μg/d). In the pharmacokinetic periods, 12 subjects were allocated three-way crossover to receive single dose of 250, 750 or 2000 μg BCQB, respectively. Subsequently, the same 12 subjects received multiple dose of 750 μg/d and 1000 μg/d for 7 days. Pharmacokinetic, safety and tolerability assessments were performed. ResultsBCQB administered by inhalation was well tolerated, especially with favorable cardiovascular safety profile. BCQB was rapidly absorbed into plasma after inhalation through pMDI, with peak concentrations achieved within 5 to 10 minutes. Repeated inhalation caused certain degree of accumulation with the accumulation ratio RCmax 2.50, RAUC 3.49 for 3 times-a-day and RCmax 2.23, RAUC 3.44 for 4 times-a-day, respectively. Twice-a-day or even once-a-day dosage could be suggested in phase II study. Sex didn't affect the pharmacokinetics of BCQB and dose adjustments based on sex is not anticipated in clinical use. Approximately 4% of the BCQB dose excreted unchanged in urine and liver metabolism is the main biotransformation route of BCQB in human. ConclusionsThe results of our study provided the initial safety, tolerability and pharmacokinetic profiles of BCQB inhalation, and could enable further clinical development in COPD patients.

Quantitation and modeling of post-translational modifications in a therapeutic monoclonal antibody from single- and multiple-dose monkey pharmacokinetic studies using mass spectrometry.

Post-translational modifications (PTMs) of therapeutic monoclonal antibodies (mAbs) are important product quality attributes (PQAs) that can potentially impact drug stability, safety, and efficacy. The PTMs of a mAb may change remarkably in the bloodstream after drug administration compared to in vitro conditions. Thus, monitoring in vivo PTM changes of mAbs helps evaluate the criticality of PQAs during the product risk assessment. In addition, quantitation of the subject exposures to PTM variants helps assess the impact of PTMs on the safety and efficacy of therapeutic mAbs. Here, we developed an immunocapture-liquid chromatography/mass spectrometry (LC/MS) method to quantify in vivo PTM changes a therapeutic mAb overtime in single- and multiple-dose monkey pharmacokinetic (PK) studies. We also built mathematical models to predict the in vivo serum concentrations of PQAs, the subject exposures to PQAs, and the relative abundance of PQAs in single- and multiple-dose regimens. The model predictions are in good agreement with the experimental results. The immunocapture-LC/MS method and mathematical models enable bioanalytical chemists to quantitatively assess the criticality of PQAs during drug development.

S-amlodipine–bisoprolol combination therapy caused elevated transaminases and triglyceride levels in healthy Chinese subjects: a randomized controlled, open-label, multiple-dose pharmacokinetic interaction study

ABSTRACTIntroduction: S-amlodipine is main anti-hypertensive active enantiomer of amlodipine. Bisoprolol is a β-blocker particularly suitable for hypertensive patients with sinus tachycardia. We evaluated the pharmacokinetic interaction between S-amlodipine and bisoprolol in healthy Chinese subjects.Areas covered: Thirty-two subjects were randomly divided into two equal groups. Subjects in group A were administered S-amlodipine 5 mg for 10 days followed by S-amlodipine 5 mg plus bisoprolol 5 mg for 7 days. Subjects in group B were administered bisoprolol 5 mg for 7 days, followed by S-amlodipine 5 mg plus bisoprolol 5 mg for 10 days. Blood samples were collected for evaluation of pharmacokinetic interaction. Tolerability was evaluated by interview, vital signs, 12-lead ECGs, physical examination, and clinical laboratory tests.Expert opinion: The geometric mean ratio (90% CI) for amlodipine AUCτ,ss and Css-max during the monotherapy and combination therapy periods were 1.0389 (0.9879, 1.0926) and 1.0213 (0.9556, 1.0915). For bisoprolol, it was 1.0193 (0.9834, 1.0566) and 0.9989 (0.9133, 1.0925). Most adverse events were mild-moderate. There was high incidence of elevated alanine aminotransferase, aspartate aminotransferase, and triglyceride.This study found no pharmacokinetic interaction between S-amlodipine and bisoprolol. Alanine aminotransferase, aspartate aminotransferase, and triglycerides should be closely monitored.

&lt;p&gt;Pharmacokinetics of fixed-dose combination of atorvastatin and metformin compared with individual tablets&lt;/p&gt;

Purpose: The aims of this study was to investigate the mutual pharmacokinetic interactions between steady-state atorvastatin and metformin and the effect of food on the fixed-dose combined (FDC) tablet of atorvastatin and metformin extended release (XR).Subjects and methods: Study 1, an open-labeled, fixed sequence, multiple-dose pharmacokinetic drug-drug interaction study, was divided into 2 parts. Atorvastatin (40 mg) or metformin (1,000 mg) XR tablets were administered once daily via mono- or co-therapy for 7 days. Plasma levels of atorvastatin and 2-OH-atorvastatin, were quantitatively determined for 36 h in part A (n=50) while metformin plasma concentration was measured up to 24 h in part B (n=16) after the last dosing. Study 2, a randomized, open-labeled, single-dose, two-treatment, two-period, two-sequence crossover study, involved 27 healthy subjects to investigate the impact of food intake on the pharmacokinetics of a combined atorvastatin/metformin XR 20/500 mg (CJ-30056 20/500 mg) tablet.Results: After multiple doses of mono- or co-therapy of atorvastatin (40 mg) and metformin (1,000 mg) XR, the 90% confidence intervals (CIs) of the geometric mean ratios (GMRs) for the peak plasma concentration at steady state (Cmax,ss) and area under the plasma concentration–time curve during the dosing interval at steady state (AUCτ,ss) were 1.07 (0.94–1.22) and 1.05 (0.99–1.10) for atorvastatin, 1.06 (0.96–1.16) and 1.16 (1.10–1.21) for 2-OH-atorvastatin, and 1.00 (0.86–1.18) and 0.99 (0.87–1.13) for metformin, respectively. Food delayed time to reach maximum concentration (tmax), decreased atorvastatin Cmax by 32% with a GMR (90% CI) of 0.68 (0.59–0.78), and increased metformin AUCt by 56% with a GMR (90% CI) of 1.56 (1.43–1.69).Conclusion: No clinically relevant pharmacokinetic interaction was seen when atorvastatin was co-administered with metformin. Food appeared to change the absorption of atorvastatin and metformin from an FDC formulation. These alterations were in accordance with those described with the single reference drugs when ingested with food.

A selective LC-MS/MS method for simultaneous quantification of Artemether, Lumefantrine and their principle metabolites in human plasma

We have developed and validated a sensitive, selective and reproducible reversed-phase high-performance liquid chromatography method coupled with electrospray ionization mass spectrometry (HPLC–ESI-MS/MS) for the simultaneous quantitation of artemether (ART), dihydroartemisinin (DHA), lumefantrine (LUM) and desbutyl-lumefantrine (DBL) in human plasma. Mefloquine was used as an internal standard (IS). The analytes were extracted by protein precipitation procedure and separated on a reversed-phase Zorbax SB-Ciano column with a mobile phase composed of acetonitrile and 20mM aqueous ammonium formate containing 0.5% (v/v) formic acid. Multiple reaction monitoring was performed in the positive ion mode using the transitions m/z 316.3→m/z 163.1 (ART), m/z 302.3→m/z 163.1 (DHA), m/z 530.3→m/z 512.2. (LUM), m/z 472.2→m/z 454.1 (DBL) and m/z 379.1→m/z 361.1(MQ) to quantify the drugs. Calibration curves in spiked plasma were linear (r2 ≥ 0.9992) over the range of 5–1500 ng/mL for ART/ DHA and 5–5,000 ng/mL for LUM/DBL. The lower limit of quantitation (LLOQ) was 10 ng/mL ART/ DHA and 5 ng/mL for LUM/ DBL. The mean R.S.D. values for the intra-run precision were 2.2% , 3.8%, 1.9% and 4.7% and for the inter-run precision were 3.2%, 3.6% , 4.4% and 3.5% for ART, DHA, LUM and DBL, respectively. The mean percentage recovery values were 93.2%, 98.5%, 97.1% and 99.4% for ART, DHA, LUM and DBL, respectively. No matrix effect was detected for all the analytes and the IS. The validated method was successfully applied to determine the plasma concentrations of ART, DHA, LUM and DBL in pregnant and non-pregnant women volunteers in a multiple-dose pharmacokinetics study over the course of 336 hours.

Effects of Intrinsic Factors on the Clinical Pharmacokinetics of Vortioxetine.

Vortioxetine is an antidepressant agent with multimodal activity that is approved for the treatment of major depressive disorder at doses of 5 to 20mg once daily. Vortioxetine is a medium-clearance drug that undergoes extensive metabolism via several cytochrome P450 isozymes. A series of single- and multiple-dose pharmacokinetic studies were performed to evaluate the impact of intrinsic (ie, subject-related) factors, such as age, sex, race, and renal and hepatic function, on the pharmacokinetics of vortioxetine. The point estimates on the ratios and their 90% confidence intervals (CIs) for the central values of AUC (area under the concentration-time curve) and Cmax (maximum plasma concentration) were obtained by taking the antilog of the differences and 90%CIs in the log-transformed least-squares means. The results demonstrate that there were no clinically meaningful differences (defined as exposure difference between 50% and 2-fold change) in the exposure to vortioxetine (as assessed by AUC and Cmax ) between elderly and younger subjects, men and women, and blacks and whites and among subjects with varying degrees of renal or hepatic impairment. These results suggest that no dosing adjustments of vortioxetine are required for the intrinsic factors investigated in these studies.

Identify super quality markers from prototype-based pharmacokinetic markers of Tangzhiqing tablet (TZQ) based on in vitro dissolution/ permeation and in vivo absorption correlations

BackgroundA quality marker (Q-marker) is defined as an inherent chemical compound that is used for the quality control of a drug. Its biological activities are closely related to safety and therapeutic effects. Generally, a multiple-component herbal medicine may have many Q-markers. We therefore proposed a concept of “super Q-marker” satisfying both the criterion of Q-markers and PK-markers to be used in more effective quality control of herbal medicine. PurposeThe first aim was to find suitable prototype-based PK-markers from Tangzhiqing tablets (TZQ), a Chinese patent medicine. Then super Q-markers were expected to be identified from the prototype-based PK-markers based on an in vitro-in vivo correlation study. MethodsPotentially eligible prototype-based PK-markers were identified in a single- and multiple-dose pharmacokinetic study on TZQ in 30 healthy volunteers. The in vitro dissolution and permeation profiles of the prototype-based PK-markers of TZQ were evaluated by the physiologically-based drug dissolution/absorption simulating system (DDASS). An in vitro-in vivo correlation analysis was conducted between the dissolution/permeation behaviors in DDASS and the actual absorption profiles in human to test the transferability and traceability of the promising super Q-markers for TZQ. ResultsIn human, plasma paeoniflorin and nuciferine as prototype-based PK-markers exhibited the appropriate pharmacokinetic properties, including dose-dependent systemic exposure (AUC, Cmax) and a proper elimination half-life (1∼3h). In DDASS, it was predicted that paeoniflorin and nuciferine are highly permeable but the absorption rates are primarily limited by the dissolution rates. Moreover, the established in vitro-in vivo correlations of paeoniflorin and nuciferine were in support of the super Q-markers features. ConclusionPaeoniflorin and nuciferine are identified as the super Q-markers from the prototype-based PK-markers of TZQ based on findings from a combination of in vitro, in vivo, and in vitro-in vivo correlation studies. This method is practical for optimal identification of qualified Q-markers, thus helping improve the quality control of herbal medicines.

A VALIDATED LC-MS/MS METHOD FOR PHARMACOKINETIC STUDY OF BRIVARACETAM IN HEALTHY RABBITS

Objective: A liquid chromatography-tandem mass spectrophotometric (LC–MS/MS) method was developed for quantification of brivaracetam in rabit plasma employing liquid-liquid extraction with ethyl acetate.Methods: Developed method was validated for specificity, precision, accuracy, recovery, and stability characteristics. Chromatographic separation was achieved on Chromolith C18column (100 mmx4.6 mmx5 µm) with 0.1% formic acid, adjusted to pH 3.2 as an isocratic mobile phase with a flow rate of 1.0 ml/min. the developed method was applied to assess pharmacokinetics parameters like Cmax, Tmax, t1/2 and AUC of brivaracetam in healthy rabbits.Results: The developed method was linear over the range of 0.16 to 8µg/ml. The regression equation for the analysis was Y=0.0053x+0.0018 with coefficient of correction (r2) = 0.998. The % mean recovery for brivaracetam was found to be between 95.7% to 106.5%. The mean intraday and inter-day precision of the method was found to be 0.77 to 3.72% for quality control standards. Brivaracetam showed Tmax of 1.025±0.061 and mean Cmax, AUC0®t andAUC0®a for Test formulation is 92.7±4.4, 496.21±26.4 and 504.20±30.68 respectively.Conclusion: A highly specific, rugged and rapid method with sufficiently low LLOQ was developed for analysis of routine samples of a single dose or multiple dose pharmacokinetic studies with any marketing formulation of brivaracetam.

Pharmacokinetics of colistin methanesulfonate (CMS) in healthy Chinese subjects after single and multiple intravenous doses

The high prevalence of extensively drug-resistant Gram-negative pathogens has forced clinicians to use colistin as a last-line therapy. Knowledge on the pharmacokinetics of colistin methanesulfonate (CMS), an inactive prodrug, and colistin has increased substantially; however, the pharmacokinetics in the Chinese population is still unknown due to lack of a CMS product in China. This study aimed to evaluate the pharmacokinetics of a new CMS product developed in China in order to optimise dosing regimens. A total of 24 healthy subjects (12 female, 12 male) were enrolled in single- and multiple-dose pharmacokinetic (PK) studies. Concentrations of CMS and formed colistin in plasma and urine were measured, and PK analysis was conducted using a non-compartmental approach. Following a single CMS dose [2.36 mg colistin base activity (CBA) per kg, 1 h infusion], peak concentrations (Cmax) of CMS and formed colistin were 18.0 mg/L and 0.661 mg/L, respectively. The estimated half-life (t1/2) of CMS and colistin were 1.38 h and 4.49 h, respectively. Approximately 62.5% of the CMS dose was excreted via urine within 24 h after dosing, whilst only 1.28% was present in the form of colistin. Following multiple CMS doses, colistin reached steady-state within 24 h; there was no accumulation of CMS, but colistin accumulated slightly (RAUC = 1.33). This study provides the first PK data in the Chinese population and is essential for designing CMS dosing regimens for use in Chinese hospitals. The urinary PK data strongly support the use of intravenous CMS for serious urinary tract infections.

A selective LC-MS/MS method for simultaneous quantification of Artemether, Lumefantrine and their principle metabolites in human plasma

We have developed and validated a sensitive, selective and reproducible reversed-phase high-performance liquid chromatography method coupled with electrospray ionization mass spectrometry (HPLC–ESI-MS/MS) for the simultaneous quantitation of artemether (ART), dihydroartemisinin (DHA), lumefantrine (LUM) and desbutyl-lumefantrine (DBL) in human plasma. Mefloquine was used as an internal standard (IS). The analytes were extracted by protein precipitation procedure and separated on a reversed-phase Zorbax SB-Ciano column with a mobile phase composed of acetonitrile and 20mM aqueous ammonium formate containing 0.5% (v/v) formic acid. Multiple reaction monitoring was performed in the positive ion mode using the transitions m/z 316.3→ m/z 163.1 (ART), m/z 302.3→ m/z 163.1 (DHA), m/z 530.3→ m/z 512.2. (LUM), m/z 472.2→ m/z 454.1 (DBL) and m/z 379.1→ m/z 361.1(MQ) to quantify the drugs. Calibration curves in spiked plasma were linear ( r 2 ≥ 0.9992) over the range of 5–1500 ng/mL for ART/ DHA and 5–5,000 ng/mL for LUM/DBL. The lower limit of quantitation (LLOQ) was 10 ng/mL ART/ DHA and 5 ng/mL for LUM/ DBL. The mean R.S.D. values for the intra-run precision were 2.2% , 3.8%, 1.9% and 4.7% and for the inter-run precision were 3.2%, 3.6% , 4.4% and 3.5% for ART, DHA, LUM and DBL, respectively. The mean percentage recovery values were 93.2%, 98.5%, 97.1% and 99.4% for ART, DHA, LUM and DBL, respectively. No matrix effect was detected for all the analytes and the IS. The validated method was successfully applied to determine the plasma concentrations of ART, DHA, LUM and DBL in pregnant and non-pregnant women volunteers in a multiple-dose pharmacokinetics study over the course of 336 hours.

A Randomized Multiple Dose Pharmacokinetic Study of a Novel PDE10A Inhibitor TAK-063 in Subjects with Stable Schizophrenia and Japanese Subjects and Modeling of Exposure Relationships to Adverse Events

BackgroundPhosphodiesterase 10A (PDE10A) is selectively expressed in medium spiny neurons of the striatum. TAK-063 is a selective inhibitor of PDE10A in clinical development for the treatment of schizophrenia.ObjectivesSafety, tolerability, and pharmacokinetics (PK) of TAK-063 were evaluated following multiple rising oral doses, and PK/adverse event (AE) models were developed to characterize the relationship between TAK-063 exposure and incidence of specific AEs.MethodsHealthy Japanese subjects (HJS) aged 20–55 years and subjects with stable schizophrenia (SSS) aged 18–55 years were enrolled and randomized to either TAK-063 or placebo. Study medication was administered as a tablet once daily (at night) with food over a 7-day period.ResultsTAK-063 and placebo groups consisted of 62 and 15 subjects, respectively. A majority of subjects (71 of 77) completed the study. AEs were mostly of mild or moderate severity, and no deaths were reported. The most common AE was somnolence. For equivalent doses, the rate of extrapyramidal syndromes (EPS) was higher in SSS than in HJS. PK parameters were comparable between HJS and SSS at equivalent doses. The incidence of somnolence and EPS symptoms increased with exposure, and this was described with the PK/AE model. A maximum tolerated dose was not determined.ConclusionsMultiple doses of TAK-063 were safe and well tolerated. PK/AE models characterized the incidence of somnolence and EPS with increasing TAK-063 exposure, and simulations suggested that a once-daily dose range of up to 30 mg would be suitable for future studies.ClinicalTrials.gov IdentifierNCT01879722.Electronic supplementary materialThe online version of this article (doi:10.1007/s40268-017-0214-8) contains supplementary material, which is available to authorized users.