The everchanging Sky-Tower - an apparent giant.

For over a quarter-century, the Sky-Tower has dominated the skyline of Auckland Tamaki Makaurau. Despite its imposing height, observers anecdotally report odd fluctuations in how big it appears. From certain angles, it can look positively stumpy. Such misperceptions can be bewildering and perilous when it happens whilst driving. Here, we characterise this strange illusion in the hopes of better understanding its cause.

In Vitro and Clinical Pharmacokinetic Studies of the Effects of Iron-containing Agents on Vadadustat, an Oral Hypoxia-inducible Factor-Prolyl Hydroxylase Inhibitor.

PURPOSE: Vadadustat is an oral hypoxia-inducible factor-prolyl hydroxylase inhibitor approved in Japan for the treatment of anemia in chronic kidney disease. This study investigated drug-drug interactions between vadadustat and oral iron supplements or iron-containing phosphate binders commonly used in Japanese clinical practice by conducting in vitro mechanistic and clinical pharmacokinetic studies. METHODS: In the in vitro assessment, chelate formation of vadadustat with iron-containing agents was investigated in water and in a fed-state simulated intestinal fluid. Chelate formation was assessed by observation of a chelate-specific color, and the concentration of vadadustat was determined. In the single-dose, open-label, randomized, crossover clinical study, healthy male participants received 150 mg of vadadustat with or without oral iron-containing agents. Pharmacokinetic data were collected for up to 24 hours after vadadustat administration. Participants were monitored for adverse events during the study. FINDINGS: Vadadustat formed a chelate precipitate with ferrous sulfate and ferric nitrate, as shown by development of a specific bright orange color in water. The proportions of vadadustat dissolved in the supernatant were 2% and 18%, respectively. Vadadustat did not form a chelate precipitate in a fed-state simulated intestinal fluid in the presence of sodium ferrous citrate, ferric citrate hydrate, or sucroferric oxyhydroxide; the proportion of vadadustat in supernatant ranged from 63% to 89%. In the clinical pharmacokinetic study, coadministration of vadadustat with sodium ferrous citrate, ferric citrate hydrate, sucroferric oxyhydroxide, or ferrous sulfate decreased the AUC0-∞ by 54.0% to 89.7% and Cmax by 42.1% to 91.9%. No serious adverse events were reported. IMPLICATIONS: Chelate formation of vadadustat with iron-containing agents was confirmed by in vitro analysis and depended on the type of iron-containing agent. The AUC0-∞ and Cmax of vadadustat decreased when coadministered with oral iron-containing agents. Our data suggest that the decreases in AUC0-∞ and Cmax are a result of chelation in the gastrointestinal tract; therefore, coadministration of iron-containing agents with vadadustat should use a dosing interval. ClinicalTrials.gov Identifier: NCT03645863.

Pharmacokinetic profile of edaravone: a comparison between Japanese and Caucasian populations.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) affects persons of all races, and there continues to be a need for effective therapies to treat the disease. OBJECTIVE: To compare the pharmacokinetics (PK) of edaravone between Japanese and Caucasian populations. METHODS: Data from five PK studies among Japanese and Caucasian healthy volunteers were pooled and evaluated. In population PK (PPK) modelling, compartment models and other models with linear elimination were evaluated for appropriateness. Covariate effects by race, sex, weight, and age were investigated to explain variability in PK parameters. Simulations of the final PPK model were performed using a virtual population based on ALS clinical trials. RESULTS: The analysis included 86 subjects. A three-compartment model with Michaelis-Menten plus linear elimination was selected as the best fit model. Race was statistically detected as a covariate for the second peripheral volume of distribution (V2), indicating a 26% increase for Caucasian subjects compared to Japanese subjects. However, based on simulation of PPK model for a virtual ALS population, the small difference of V2 was associated with a difference of Ctau around 1 ng/mL after infusion, which was minimal compared to Cmax of approximately 1000 ng/ml. CONCLUSION: The PPK analyses demonstrated no clinically relevant difference in the PK profiles of edaravone by race, sex, weight, or age.

Evaluation of pharmacokinetic and pharmacodynamic interactions of canagliflozin and teneligliptin in Japanese healthy male volunteers.

OBJECTIVES: To investigate the pharmacokinetic/pharmacodynamic interactions of the antidiabetic agents canagliflozin (a sodium-glucose cotransporter-2 inhibitor) and teneligliptin (a dipeptidyl peptidase-4 inhibitor) in Japanese healthy adult men. METHODS: Open-label, one-way crossover study used canagliflozin (200 mg/day p.o.) and teneligliptin (40mg/day p.o). A single dose of object drug (either canagliflozin or teneligliptin) was administered on day 1 followed by washout and continuous administration of precipitant drug (days 1 - 9). Both drugs were concomitantly administered on day 7. RESULTS: No changes in AUC0 - 72h and Cmax were observed for canagliflozin+teneligliptin versus monotherapy; geometric mean ratios for AUC0 - 72h and Cmax were 0.982 and 0.982 for the plasma concentration of canagliflozin and 0.983 and 0.976 for the plasma concentration of teneligliptin, respectively. Plasma concentrations of active and total glucagon-like peptide-1 (GLP-1) increased with canagliflozin+teneligliptin versus teneligliptin alone. Mean AUC0.5 - 4h increased post-meal, on combination therapy, from 9.6 to 12.5 pmol·h/l (active GLP-1) and from 21.5 to 32.3 pmol·h/l (total GLP-1). Adverse events developed in four subjects; all were mild and resolved but one subject withdrew due to generalized erythema. CONCLUSIONS: GLP-1 levels increased with the canagliflozin+teneligliptin combination, and no PK interaction was observed. This combination may show favorable antidiabetic effects without increasing systemic exposure.

Effect of ketoconazole on the pharmacokinetics of the dipeptidyl peptidase-4 inhibitor teneligliptin: an open-label study in healthy white subjects in Germany.

OBJECTIVE: The aim of this study was to examine the effect of ketoconazole, a potent cytochrome P450 (CYP) 3A4 and P-glycoprotein (P-gp) inhibitor, on teneligliptin pharmacokinetics and to evaluate the safety of combined administration of teneligliptin with ketoconazole. METHODS: This open-label, fixed-sequence study was conducted in 16 healthy adult volunteers in Germany. On day 1, under fasting conditions, 20 mg of teneligliptin was administered to evaluate the pharmacokinetics of teneligliptin alone. For 3 days (days 8-10), 400 mg of ketoconazole was administered once daily. On day 11, teneligliptin 20 mg and ketoconazole 400 mg were concurrently administered, and for 2 days (days 12 and 13), ketoconazole was administered once daily. The pharmacokinetic parameters (Cmax, Tmax, AUC, terminal t½, apparent total plasma clearance, and Vd during the terminal phase) of teneligliptin on days 1 and 11 were calculated. The safety profile was evaluated based on adverse events and clinical findings. To investigate the role of human P-gp in membrane permeation of teneligliptin, an in vitro study was performed to measure the transcellular transport of teneligliptin across monolayers of human P-gp-expressing cells and control cells. RESULTS: For Cmax and AUC, the geometric least squares mean ratios (90% CIs) of teneligliptin with ketoconazole to teneligliptin alone were 1.37 (1.25-1.50) and 1.49 (1.39-1.60), respectively. There was no change in t½ of the terminal elimination phase. In addition, the tolerability of teneligliptin coadministered with ketoconazole was acceptable. The in vitro study revealed corrected efflux ratios for teneligliptin of 6.81 and 5.27 at teneligliptin concentrations of 1 and 10 µM, respectively. CONCLUSIONS: Because the exposure to teneligliptin in combined administration with ketoconazole, a potent CYP3A4 and P-gp inhibitor, was less than twice that of administration of teneligliptin alone, it is suggested that combined administration of teneligliptin with drugs and foods that inhibit CYP3A4 should not cause a marked increase in exposure. The results of our in vitro study suggest that teneligliptin is a substrate of P-gp. CLINICAL TRIAL REGISTRATION: EudraCT No. 2009-016652-51.

Tolerability, pharmacokinetics and pharmacodynamics of TA-8995, a selective cholesteryl ester transfer protein (CETP) inhibitor, in healthy subjects.

AIMS: Two double-blind, randomized studies were conducted to assess the tolerability, pharmacokinetics and pharmacodynamics of oral TA-8995, a new cholesteryl ester transfer protein (CETP) inhibitor, in healthy subjects. METHODS: Study 1: Subjects received single doses of TA-8995 or placebo (fasted). Doses were 5, 10, 25, 50 (fed/fasted), 100 and 150 mg (Caucasian males, 18-55 years), 25 mg (Caucasian males, > 65 years and Caucasian females, 18-55 years), 25, 50, 100 and 150 mg (Japanese males, 18-55 years). Study 2: Caucasian males (18-55 years) received 1, 2.5, 10 or 25 mg once daily TA-8995 or placebo for 21-28 days. Blood and urine for pharmacokinetics and/or pharmacodynamics were collected. Tolerability was assessed by adverse events, vital signs, electrocardiograms and laboratory safety tests. RESULTS: Peak TA-8995 concentrations occurred approximately 4 h post-dose. Mean half-lives ranged from 81 to 166 h, without an obvious dose relationship. Exposure increased less than proportionally to dose. TA-8995 was not excreted in urine. Following 2.5 to 25 mg once daily dosing, TA-8995 demonstrated nearly complete inhibition of CETP activity (92-99%), increased high density lipoprotein-cholesterol (HDL-C) by 96 to 140% and decreased low density liporotein-cholesterol (LDL-C) by 40% to 53%. There were dose-related increases in apolipoproteins A-1 and E, HDL2-C and HDL3-C, and decreases in apolipoprotein B and lipoprotein A. There was no evidence of significant effects of age, gender, ethnicity or food on pharmacokinetics or pharmacodynamics. All doses were well tolerated. CONCLUSIONS: TA-8995 is a potent CETP inhibitor and warrants further investigation.

Metabolism and disposition of the dipeptidyl peptidase IV inhibitor teneligliptin in humans.

1. The absorption, metabolism and excretion of teneligliptin were investigated in healthy male subjects after a single oral dose of 20 mg [(14)C]teneligliptin. 2. Total plasma radioactivity reached the peak concentration at 1.33 h after administration and thereafter disappeared in a biphasic manner. By 216 h after administration, ≥90% of the administered radioactivity was excreted, and the cumulative excretion in the urine and faeces was 45.4% and 46.5%, respectively. 3. The most abundant metabolite in plasma was a thiazolidine-1-oxide derivative (designated as M1), which accounted for 14.7% of the plasma AUC (area under the plasma concentration versus time curve) of the total radioactivity. The major components excreted in urine were teneligliptin and M1, accounting for 14.8% and 17.7% of the dose, respectively, by 120 h, whereas in faeces, teneligliptin was the major component (26.1% of the dose), followed by M1 (4.0%). 4. CYP3A4 and FMO3 are the major enzymes responsible for the metabolism of teneligliptin in humans. 5. This study indicates the involvement of renal excretion and multiple metabolic pathways in the elimination of teneligliptin from the human body. Teneligliptin is unlikely to cause conspicuous drug interactions or changes in its pharmacokinetics patients with renal or hepatic impairment, due to a balance in the elimination pathways.

Ursodeoxycholic acid protects concanavalin A-induced mouse liver injury through inhibition of intrahepatic tumor necrosis factor-alpha and macrophage inflammatory protein-2 production.

Ursodeoxycholic acid (UDCA) is widely used for the therapy of liver dysfunction. In this study, we investigated the protective effect of UDCA in concanavalin A-induced mouse liver injury. The treatment with UDCA at oral doses of 50 and 150 mg/kg at 2 h before concanavalin A injection significantly reduced the elevated plasma levels of aminotransferases and the incidence of liver necrosis compared with concanavalin A-injected control group without affecting the concentrations of liver hydrophobic bile acids. UDCA significantly inhibited elevated levels of tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein-2 (MIP-2), and interleukin 6 (IL-6) in blood of concanavalin A-injected mice. To clarify the influence of UDCA on production of cytokines, we examined intrahepatic mRNA expressions and the protein levels of TNF-alpha, MIP-2, interferon-gamma (IFN-gamma), IL-4, IL-6, and IL-10 at 1 h after concanavalin A injection. The treatment with UDCA significantly decreased the intrahepatic levels of TNF- alpha and MIP-2, whereas this compound showed no clear effect on IFN-gamma, IL-4, IL-6, or IL-10. Furthermore, UDCA significantly decreased myeloperoxidase activity as well as MIP-2 level in the liver and histological examination of liver tissue revealed that intrasinusoidal accumulation of neutrophils was decreased markedly by UDCA. In addition, UDCA significantly inhibited the production of TNF-alpha and MIP-2 when cultured with nonparenchymal and lymph node cells. In conclusion, these findings suggest that UDCA protects concanavalin A-induced liver injury in mice by inhibiting intrahepatic productions of TNF-alpha and MIP-2, and the infiltration of neutrophils into the liver.

Protective effects of ursodeoxycholic acid on chenodeoxycholic acid-induced liver injury in hamsters.

AIM: To investigate the effects of ursodeoxycholic acid (UDCA) on chenodeoxycholic acid (CDCA)-induced liver injury in hamsters, and to elucidate a correlation between liver injury and bile acid profiles in the liver. METHODS: Liver injury was induced in hamsters by administration of 0.5% (w/w) CDCA in their feed for 7 d. UDCA (50 mg/kg and 150 mg/kg) was administered for the last 3 d of the experiment. RESULTS: At the end of the experiment, serum alanine aminotransferase (ALT) increased more than 10 times and the presence of liver injury was confirmed histologically. Marked increase in bile acids was observed in the liver. The amount of total bile acids increased approximately three-fold and was accompanied by the increase in hydrophobic bile acids, CDCA and lithocholic acid (LCA). UDCA (50 mg/kg and 150 mg/kg) improved liver histology, with a significant decrease (679.3 +/- 77.5 U/L vs 333.6 +/- 50.4 U/L and 254.3 +/- 35.5 U/L, respectively, P < 0.01) in serum ALT level. UDCA decreased the concentrations of the hydrophobic bile acids, and as a result, a decrease in the total bile acid level in the liver was achieved. CONCLUSION: The results show that UDCA improves oral CDCA-induced liver damage in hamsters. The protective effects of UDCA appear to result from a decrease in the concentration of hydrophobic bile acids, CDCA and LCA, which accumulate and show the cytotoxicity in the liver.