Impact of Chiral Bioanalytical Methods on the Bioequivalence of Ibuprofen Products Containing Ibuprofen Lysinate and Ibuprofen Base.

The purpose was to assess the impact of the use of a chiral bioanalytical method on the conclusions of a bioequivalence study that compared two ibuprofen suspensions with different rates of absorption. A comparison of the conclusion of bioequivalence between a chiral method and an achiral approach was made. Plasma concentrations of R-ibuprofen and S-ibuprofen were determined using a chiral bioanalytical method; bioequivalence was tested for R-ibuprofen and for S-ibuprofen separately and for the sum of both enantiomers as an approach for an achiral bioanalytical method. The 90% confidence interval (90% CI) that would have been obtained with an achiral bioanalytical method (90% CI: Cmax: 117.69-134.46; AUC0 (t) : 104.75-114.45) would have precluded the conclusion of bioequivalence. This conclusion cannot be generalized to the active enantiomer (90% CI: Cmax : 103.36-118.38; AUC0 (t) : 96.52-103.12), for which bioequivalence can be concluded, and/or the distomer (90% CI: Cmax : 132.97-151.33; AUC0 (t) : 115.91-135.77) for which a larger difference was observed. Chiral bioanalytical methods should be required when 1) the enantiomers exhibit different pharmacodynamics and 2) the exposure (AUC or Cmax ) ratio of enantiomers is modified by a difference in the rate of absorption. Furthermore, the bioequivalence conclusion should be based on all enantiomers, since the distomer(s) might not be completely inert, in contrast to what is required in the current regulatory guidelines. In those cases where it is unknown if the ratio between enantiomers is modified by changing the rate of absorption, chiral bioanalytical methods should be employed unless enantiomers exhibit the same pharmacodynamics. Chirality 28:429-433, 2016. © 2016 Wiley Periodicals, Inc.

Ibuprofen lysinate, quicker and less variable: relative bioavailability compared to ibuprofen base in a pediatric suspension dosage form.

OBJECTIVES: To assess and compare the bioavailability of ibuprofen enantiomers (R and S) of two different pediatric suspensions: the first one with ibuprofen lysinate (Algidrin® Pediátrico, FARDI S.A., Barcelona, Spain) and the second one with ibuprofen base (Dalsy®, Abbott Laboratories S.A., Madrid, Spain). METHODS: A randomized, open-label, single-dose, balanced, crossover study under fasting conditions was performed at the CIM-Sant Pau. 24 healthy volunteers received a single dose of ibuprofen lysinate (Algidrin® Pediátrico, FARDI S.A.) and ibuprofen base (Dalsy®, Abbott Laboratories S.A.) equivalent to 400 mg of ibuprofen. 18 blood samples were drawn and ibuprofen enantiomer plasma concentrations were determined using an enantioselective analytical method. An analysis of variance (ANOVA) model was used, and the 90% confidence intervals (CI) were calculated; further analyses were made regarding rate of absorption and variability. RESULTS: The pharmacokinetic parameters (Algidrin® Pediátrico vs. Dalsy® (Mean±SD)) were: S-enantiomer: Cmax=22.39±5.33 vs. 19.97±3.19 µg/mL; AUC0t=74.83±16.69 vs. 74.64±14.80 µg×h/mL, and AUC0∞=77.46±19.33 vs. 76.98±17.13 µg×h/mL; and for R-enantiomer: Cmax=21.74±3.76 vs. 15.20±2.03 µg/mL; AUC0t=57.55±10.17 vs. 46.13±9.61 µg×h/mL, and AUC0∞ value was 58.49±10.57 vs. 47.03±10.02 µg×h/mL. The tmax (Median) for S-enantiomer (active) were: 0.5 vs. 1.33 hours (p=0.001) and for R-enantiomer: 0.5 vs. 1.0 hours (p=0.004). Ibuprofen pharmacokinetic values may vary under fed state and in pediatric population. CONCLUSIONS: While S-ibuprofen shows a similar bioavailability for AUC0t, AUC0∞, and Cmax, R-ibuprofen shows suprabioavailability for the lysinate formulation. The rate of absorption of the ibuprofen lysinate suspension is quicker and less variable than that of the ibuprofen base reference suspension and it exhibits a shorter tmax, which is of particular interest for achieving a rapid and homogeneous analgesic and antipyretic effect.

Ritonavir boosting dose reduction from 100 to 50 mg does not change the atazanavir steady-state exposure in healthy volunteers.

OBJECTIVES: To evaluate the pharmacokinetics, tolerability and safety of 300 mg of atazanavir boosted with 100 or 50 mg of ritonavir, both once daily, at steady state. METHODS: This was a single-blind, multiple-dose, crossover, sequence-randomized trial. Thirteen healthy HIV-1-negative men received witnessed once-daily doses of atazanavir (300 mg) and 100 or 50 mg of ritonavir for 10 days (15 day washout). Atazanavir and ritonavir plasma concentrations were determined for 24 h on day 10. Log-transformed individual pharmacokinetic parameters were compared between treatments (analysis of variance); the difference between treatments on the log scale and 95% CIs were calculated. Fasting cholesterol, triglycerides, glucose and bilirubin plasma levels were measured at the beginning and end of each period and compared (Wilcoxon signed rank test). Gastrointestinal symptoms and other events were recorded. RESULTS: Ritonavir C(max) and the AUC0₋24 were lower after the 50 mg booster dose than after 100 mg [geometric mean ratio (GMR) (95% CI), 0.40 (0.31-0.51) and 0.35 (0.29-0.42), respectively]. No differences were observed in atazanavir exposure with 50 or 100 mg of ritonavir [GMR C(max) (95% CI), 1.00 (0.79-1.28); GMR AUC0₋24 (95% CI), 0.98 (0.79-1.21)]. Atazanavir trough concentration was >0.15 mg/L in all volunteers. Total and low-density lipoprotein cholesterol increased 0.40 mM (P = 0.01) and 0.37 mM (P = 0.003) from their corresponding baseline value during the 100 mg dosing period; there were no significant changes on 50 mg. Mild increases in bilirubin were detected on day 10 after both treatments without differences between treatments. CONCLUSIONS: In spite of higher exposure to ritonavir with 100 mg, atazanavir exposure was equivalent; the lipid profile was better under the lower booster dose (50 mg).

First-in-Human Randomized Trial to Assess Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of the KDM1A Inhibitor Vafidemstat.

BACKGROUND: Vafidemstat, an inhibitor of the histone lysine-specific demethylase KDM1A, corrects cognition deficits and behavior alterations in rodent models. Here, we report the results from the first-in-human trial of vafidemstat in healthy young and older adult volunteers. A total of 110 volunteers participated: 87 were treated with vafidemstat and 23 with placebo. OBJECTIVES: The study aimed to determine the safety and tolerability of vafidemstat, to characterize its pharmacokinetic and pharmacodynamic profiles, to assess its central nervous system (CNS) exposure, and to acquire the necessary data to select the appropriate doses for long-term treatment of patients with CNS disease in phase II trials. METHODS: This single-center, randomized, double-blind, placebo-controlled phase I trial included a single and 5-day repeated dose-escalation and open-label CNS penetration substudy. Primary outcomes were safety and tolerability; secondary outcomes included analysis of the pharmacokinetics and pharmacodynamics, including chemoprobe-based immune analysis of KDM1A target engagement (TE) in peripheral blood mononuclear cells (PBMCs) and platelet monoamine oxidase B (MAOB) inhibition. CNS and cognitive function were also evaluated. RESULTS: No severe adverse events (AEs) were reported in the dose-escalation stage. AEs were reported at all dose levels; none were dose dependent, and no significant differences were observed between active treatment and placebo. Biochemistry, urinalysis, vital signs, electrocardiogram, and hematology did not change significantly with dose escalation, with the exception of a transient reduction of platelet counts in an extra dose level incorporated for that purpose. Vafidemstat exhibits rapid oral absorption, approximate dose-proportional exposures, and moderate systemic accumulation after 5 days of treatment. The cerebrospinal fluid-to-plasma unbound ratio demonstrated CNS penetration. Vafidemstat bound KDM1A in PBMCs in a dose-dependent manner. No MAOB inhibition was detected. Vafidemstat did not affect the CNS or cognitive function. CONCLUSIONS: Vafidemstat displayed good safety and tolerability. This phase I trial confirmed KDM1A TE and CNS penetration and permitted characterization of platelet dynamics and selection of phase IIa doses. TRIAL REGISTRATION: EUDRACT No. 2015-003721-33, filed 30 October 2015.

Randomized, open-label, blinded-endpoint, crossover, single-dose study to compare the pharmacodynamics of torasemide-PR 10 mg, torasemide-IR 10 mg, and furosemide-IR 40 mg, in patients with chronic heart failure.

PURPOSE: Diuretics are the primary treatment for the management of chronic heart failure (HF) symptoms and for the improvement of acute HF symptoms. The rate of delivery to the site of action has been suggested to affect diuretic pharmacodynamics. The main objective of this clinical trial was to explore whether a prolonged release tablet formulation of torasemide (torasemide-PR) was more natriuretically efficient in patients with chronic HF compared to immediate-release furosemide (furosemide-IR) after a single-dose administration. Moreover, the pharmacokinetics of torasemide-PR, furosemide-IR, and torasemide-IR were assessed in chronic HF patients as well as urine pharmacodynamics. METHODS: Randomized, open-label, blinded-endpoint, crossover, and single-dose Phase I clinical trial with three experimental periods. Torasemide-PR and furosemide-IR were administered as a single dose in a crossover fashion for the first two periods, and torasemide-IR 10 mg was administered for the third period. Blood and urine samples were collected at fixed timepoints. The primary endpoint was the natriuretic efficiency after administration of torasemide-PR and furosemide-IR, defined as the ratio between the average drug-induced natriuresis and the average drug recovered in urine over 24 hours. RESULTS: Ten patients were included and nine completed the study. Here, we present the results from nine patients. Torasemide-PR was more natriuretically efficient than furosemide-IR (0.096 ± 0.03 mmol/µg vs 0.015 ± 0.0007 mmol/µg; P < 0.0001). Mictional urgency was lower and more delayed with torasemide-PR than with furosemide-IR. CONCLUSION: In a study with a limited sample size, our results suggest that 10 mg of torasemide-PR is more natriuretically efficient than 40 mg of furosemide-IR after single-dose administration in patients with chronic HF over a 24-hour collection period. Further studies are necessary to evaluate potential pharmacodynamic differences between torasemide formulations and to assess its impact on clinical therapeutics.