Pharmacokinetic and pharmacodynamic relationships of bilastine were reliably described with the use of an indirect response pharmacodynamic model; this led to an accurate prediction of the pharmacodynamic activity of bilastine.
Methadone is an opiate drug that has been identified as an in-vitro substrate of the efflux pump P-glycoprotein (P-gp), active in the intestinal epithelium and in the blood-brain barrier (BBB), among other sites. The objective of this study was to test in vivo, in the rat model, the role of P-gp modulation on the analgesic effect and brain uptake of methadone, as well as identify the most relevant site via dual oral and intravenous (i.v.) experiments. The P-gp specific inhibitor (valspodar or PSC833) was preadministered (10 mg kg(-1) i.v.) to test groups. Analgesia was measured using the tailflick test. The ED50 for oral methadone (2, 3, 6 and 8 mg kg(-1)) decreased three-fold in valspodar groups compared with controls (2.23 +/- 0.002 mg kg(-1) and 6.07 +/- 0.07 mg kg(-1); P < 0.0001). The overall analgesic effect (% antinociception) was elevated 3.1 times in pretreated compared with control rats (90.65% +/- 0.22 vs 29.23% +/- 14.0; P < 0.01) after 6 mg kg(-1) oral methadone and 2.8 times after i.v. (0.35 mg kg(-1)) administration (91.75% +/- 4.27 vs 32.45% +/- 9.0; P < 0.01). The brain:plasma distribution ratio was higher in pretreated animals and AUCbrain (overall brain concentration) was 6 times higher after oral methadone and 4 times higher after i.v. compared with controls, disproportionally increased relative to plasma, implying an active process at the BBB. P-gp, and hence substrate comedication, plays a critical role in the evolution of the methadone analgesic effect and in its brain uptake, independent of the administration route.
We investigated the pattern of distribution of intertidal soft-bottom fauna in streams and lagoons of the Uruguayan coast at three spatial scales. The Rı´o de la Plata and the Atlantic Ocean produce on this coast a large-scale gradient in salinity, defining a freshwater (west), an estuarine (central) and a marine (east) region. Within each region, there are several streams and coastal lagoons (sites) that define a second scale of variability. A third scale is given by intertidal gradients within each site. Species richness and total abundance was low in the freshwater west region and high in the central and east regions. The community in the west region was characterized by the clam Curbicula fluminea; in the other regions, it was dominated mainly by the polychaete Heteromastus similis. The polychaete Nephtys fluviatilis was more abundant in the east region, while another polychaete, Laeonereis acuta, characterized the central region. Sediment fractions did not vary significantly at this scale. At the scale of the sites, species richness and total macrofaunal abundance were higher in coastal lagoons than in streams. Coarse sands were more common in coastal lagoons, while medium and fine sand characterized the sediment in streams. Within each site, species richness and total abundance increased towards the lower intertidal level; the macrofauna of the upper levels were a subsample of the fauna occurring at the lower levels. There was also a significantly lower proportion of fine sand at the upper level. At regional scales, the observed patterns may be indirectly or directly related to the gradient in salinity, through differential physiological tolerance to osmotic stress. At the scale of the sites, variability may be explained mainly by geomorphological and sedimentological differences between lagoons and streams. Variation among levels may be related to gradients in desiccation, colonization and predation.
Background and objectivesBilastine is a novel second-generation antihistamine for the symptomatic treatment of allergic rhinitis and urticaria. The objective of this study was to evaluate the pharmacokinetics, pharmacodynamics, and tolerability of bilastine following single and multiple oral doses in healthy Japanese subjects. The pharmacokinetic and pharmacodynamic profiles were compared with those reported in Caucasian subjects.MethodsIn a single-blind, randomized, placebo-controlled, parallel-group, single- and multiple-ascending dose study, bilastine tablets were administered at single doses of 10, 20, and 50 mg (Part I), and once daily for 14 days at 20 and 50 mg (Part II).ResultsAfter single oral doses, maximum plasma concentrations (C
max) were reached at 1.0–1.5 h postdose. Plasma exposure [C
max and area under the plasma concentration-time curve (AUC)] increased dose-proportionally at single doses of 10–50 mg. In repeated-dose administration, no remarkable differences were observed between Day 1 and Day 14 for C
max or AUC. For inhibitory effects on wheal and flare response, bilastine 20 and 50 mg showed significant inhibition from 1.5 h after administration as compared with placebo, and the significant effect persisted for 24 h after administration. The rates of adverse events (AEs) were comparable between bilastine and placebo in both Part I and Part II. In addition, no dose- or administration period-dependent tendency of increase in rate of AEs or worsening of severity was observed.ConclusionBilastine exhibits similar single- and multiple-dose pharmacokinetic and pharmacodynamic characteristics in healthy Japanese subjects compared with those observed in Caucasian subjects in previous studies.Electronic supplementary materialThe online version of this article (doi:10.1007/s40261-016-0447-2) contains supplementary material, which is available to authorized users.
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