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Linerixibat, an oral small-molecule ileal bile acid transporter inhibitor under development for cholestatic pruritus in primary biliary cholangitis, was designed for minimal absorption from the intestine (site of pharmacological action). This study characterized the pharmacokinetics, absorption, metabolism, and excretion of [ 14 C]-linerixibat in humans after an intravenous microtracer concomitant with unlabeled oral tablets and [ 14 C]-linerixibat oral solution. Linerixibat exhibited absorption-limited flip-flop kinetics: longer oral versus intravenous half-life (6-7 hours vs. 0.8 hours). The short intravenous half-life was consistent with high systemic clearance (61.9 l/h) and low volume of distribution (16.3 l). In vitro studies predicted rapid hepatic clearance via cytochrome P450 3A4 metabolism, which predicted human hepatic clearance within 1.5-fold. However, linerixibat was minimally metabolized in humans after intravenous administration: ∼80% elimination via biliary/fecal excretion (>90%-97% as unchanged parent) and ∼20% renal elimination by glomerular filtration (>97% as unchanged parent). Absolute oral bioavailability of linerixibat was exceedingly low (0.05%), primarily because of a very low fraction absorbed (0.167%; fraction escaping first-pass gut metabolism (fg) ∼100%), with high hepatic extraction ratio (77.0%) acting as a secondary barrier to systemic exposure. Oral linerixibat was almost entirely excreted (>99% recovered radioactivity) in feces as unchanged and unabsorbed linerixibat. Consistent with the low oral fraction absorbed and ∼20% renal recovery of intravenous [ 14 C]-linerixibat, urinary elimination of orally administered radioactivity was negligible (<0.04% of dose). Linerixibat unequivocally exhibited minimal gastrointestinal absorption and oral systemic exposure. Linerixibat represents a unique example of high CYP3A4 clearance in vitro but nearly complete excretion as unchanged parent drug via the biliary/fecal route. SIGNIFICANCE STATEMENT: This study conclusively established minimal absorption and systemic exposure to orally administered linerixibat in humans. The small amount of linerixibat absorbed was eliminated efficiently as unchanged parent drug via the biliary/fecal route. The hepatic clearance mechanism was mispredicted to be mediated via cytochrome P450 3A4 metabolism in vitro rather than biliary excretion of unchanged linerixibat in vivo., (Copyright © 2021 by The Author(s).)

This study investigated the kinetics of quetiapine and its metabolite 7-hydroxyquetiapine in guinea pig blood and hair roots during the whole time course of absorption and elimination after intragastric administration of three dosages (25 mg/kg, 50 mg/kg, 100 mg/kg). The mean maximum concentration (C max ) values of quetiapine in the blood of the low-, medium- and high-dose groups were 334.4, 849.0, and 2751.1 ng/mL, respectively, and those of 7-hydroxyquetiapine were 75.6, 175.5, and 173.7 ng/mL, respectively. The corresponding mean Cmax values of quetiapine in hair roots were 2.0, 5.9, and 14.7 ng/mg, and those of 7-hydroxyquetiapine were 1.0, 1.8, and 6.4 ng/mg. The mean half-lives of quetiapine at the three dosages in blood were 3.8 h, 5.0 h, and 6.0 h, and those in hair roots were 48.2 h, 41.5 h, and 162.3 h; for 7-hydroxyquetiapine, the values were 2.9 h, 4.1 h, and 4.2 h in blood and 77.1 h, 103.6 h, and 385.9 h in hair roots. The levels of quetiapine in blood and hair roots were higher than those of 7-hydroxyquetiapine, and there were significant positive correlations (p<0.05) between the concentrations of quetiapine and 7-hydroxyquetiapine in hair roots and the respective doses within 24 h and 48 h. Quetiapine and 7-hydroxyquetiapine could still be detected in some guinea pigs even after 28 days, which means that drugs remain in the hair roots longer than in the blood. This finding shows that hair roots could be a good alternative or supplemental matrix to common biological samples such as blood and urine, as hair roots substantially extend the detection window from days to months. Moreover, quetiapine and 7-hydroxyquetiapine were detected within 15min after administration in hair roots, which also suggests that the drug enters the hair roots quickly. Therefore, hair root analysis may be a good choice to detect acute poisoning and single-dose administration if other matrices are unavailable or to provide complementary information for other matrices., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Adenosine, an endogenous nucleoside, modulates the release of monoamines, e.g., noradrenaline, serotonin, and dopamine in the brain. Both nonselective and selective stimulation of adenosine receptors produce symptoms of depression in some animal models. Therefore, the main objective of our study was to assess the influence of a selective adenosine A 1 receptor antagonist (DPCPX) and a selective adenosine A 2A receptor antagonist (DMPX) on the activity of agomelatine and tianeptine., Methods: The forced swim test (FST) and tail suspension test (TST) were performed to assess the effects of DPCPX and DMPX on the antidepressant-like activity of agomelatine and tianeptine. Drug serum and brain levels were analyzed using HPLC., Results: Co-administration of agomelatine (20 mg/kg) or tianeptine (15 mg/kg) with DMPX (3 mg/kg), but not with DPCPX (1 mg/kg), significantly reduced the immobility time both in the FST and TST in mice. These effects were not associated with an enhancement in animals' spontaneous locomotor activity. The observed changes in the mouse behavior after concomitant injection of DMPX and the tested antidepressant agents were associated with elevated brain concentration of agomelatine and tianeptine., Conclusion: Our study shows a synergistic action of the selective A 2A receptor antagonist and the studied antidepressant drugs, and a lack of such interaction in the case of the selective A 1 receptor antagonist. The interaction between DMPX and agomelatine/tianeptine at least partly occurs in the pharmacokinetic phase. A combination of a selective A 2A receptor antagonist and an antidepressant may be a new strategy for treating depression., (Copyright © 2019 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved.)

Ziresovir (RO-0529, AK0529) is reported here for the first time as a promising respiratory syncytial virus (RSV) fusion (F) protein inhibitor that currently is in phase 2 clinical trials. This article describes the process of RO-0529 as a potent, selective, and orally bioavailable RSV F protein inhibitor and highlights the in vitro and in vivo anti-RSV activities and pharmacokinetics in animal species. RO-0529 demonstrates single-digit nM EC 50 potency against laboratory strains, as well as clinical isolates of RSV in cellular assays, and more than one log viral load reduction in BALB/c mouse model of RSV viral infection. RO-0529 was proven to be a specific RSV F protein inhibitor by identification of drug resistant mutations of D486N, D489V, and D489Y in RSV F protein and the inhibition of RSV F protein-induced cell-cell fusion in cellular assays.

The introduction of the first antidepressants in the 50s of the 20th century radically changed the treatment of depression, while providing information on pathophysiological aspects of this disease. New antidepressants drugs (agomelatine, tianeptine, vortioxetine) are providing data that give rise to pathophysiological hypotheses of depression that differ from the classic monoaminergic theory. In this sense, tianeptina, an atypical drug by its mechanism of differential action, contributes to clarify that in depression there is more than monoamines. Thus, tianeptine does not modify the rate of extracellular serotonin, so it does not increase or decrease the reuptake of serotonin. Chronic administration of tianeptine does not alter the density or affinity of more than a hundred classical receptors related to depression. Recently, a weak action of tianeptine on Mu opioid receptors has been described that could explain the release of dopamine in the limbic system and its participation in the modulation of glutamatergic mechanisms. These mechanisms support the hypothesis of the possible mechanism of action of this antidepressant. Tianeptine is an antidepressant, with anxiolytic properties, that can improve somatic symptoms. Tianeptine as a glutamatergic modulator, among other mechanisms, allows us to approach depression from a different point of view than other antidepressants., (Copyright © 2018. Publicado por Elsevier España, S.L.U.)

GSK2330672 is an inhibitor of the ileal bile acid transporter, designed to have minimal systemic exposure, and is under development as a potential therapeutic for pruritus associated with primary biliary cholangitis and other cholestatic liver diseases. A phase 1, double-blind, placebo-controlled, 4-period crossover study was conducted to evaluate the safety, tolerability, and pharmacokinetic/pharmacodynamic characteristics of GSK2330672 in healthy Japanese participants. Sixteen healthy male participants received single oral doses of GSK2330672 (10-180 mg) or placebo in each period. No serious adverse events and no adverse events leading to study discontinuation or withdrawal were reported. Drug-related adverse events reported included gastrointestinal symptoms (mostly diarrhea) and positive fecal occult blood tests, and were all mild and resolved without any interventions. GSK2330672 was undetectable in the majority of participants' plasma. Pharmacodynamic observations included a tendency for total serum bile acids to reduce and for serum 7α-hydroxy-4-cholesten-3-one, a key intermediate of bile acid synthesis, to increase with increasing doses of GSK2330672. In the context of recently published indications of potential efficacy for cholestatic pruritus in non-Japanese populations, these data support further evaluations of GSK2330672 in Japanese patients., (© 2018, The American College of Clinical Pharmacology.)

Tianeptine is an atypical antidepressant with a unique mechanism of action and recently it has been also reported that its major metabolite, compound MC5, possesses pharmacological activity similar to that of the parent drug. The current study aims to investigate the pharmacokinetics (PK) of both tianeptine and MC5 after intravenous or intraperitoneal administration of the parent drug as well as the metabolic ratio of MC5 in rats. To achieve these goals an LC-MS/MS method using the small sample volume for the quantitation of tianeptine and its active metabolite MC5 in rat plasma and liver perfusate has been developed and validated. Following an intravenous administration of tianeptine pharmacokinetic parameters were calculated by non-compartmental analysis. The average tianeptine volume of distribution at steady state was 2.03 L/kg and the systemic clearance equaled 1.84 L/h/kg. The mean elimination half-lives of tianeptine and MC5 metabolite were 1.16 and 7.53 h, respectively. The hepatic clearance of tianeptine determined in the isolated rat liver perfusion studies was similar to the perfusate flow rate despite the low metabolic ratio of MC5. Mass spectrometric analysis of rat bile indicated that tianeptine and MC5 metabolite are eliminated with bile as glucuronide and glutamine conjugates. Bioavailability of tianeptine after its intraperitoneal administration was 69%. The PK model with a metabolite compartment developed in this study for both tianeptine and MC5 metabolite after two routes of administration may facilitate tianeptine dosage selection for the prospective pharmacological experiments.

Depression is a debilitating chronic illness that affects around 350 million people worldwide. Current treatments, such as selective serotonin reuptake inhibitors, are not ideal because only a fraction of patients achieve remission. Tianeptine is an effective antidepressant with a previously unknown mechanism of action. We recently reported that tianeptine is a full agonist at the mu opioid receptor (MOR). Here we demonstrate that the acute and chronic antidepressant-like behavioral effects of tianeptine in mice require MOR. Interestingly, while tianeptine also produces many opiate-like behavioral effects such as analgesia and reward, it does not lead to tolerance or withdrawal. Furthermore, the primary metabolite of tianeptine (MC5), which has a longer half-life, mimics the behavioral effects of tianeptine in a MOR-dependent fashion. These results point to the possibility that MOR and its downstream signaling cascades may be novel targets for antidepressant drug development.

Background: Pruritus (itch) is a symptom commonly experienced by patients with cholestatic liver diseases such as primary biliary cholangitis (PBC, previously referred to as primary biliary cirrhosis). Bile acids (BAs) have been proposed as potential pruritogens in PBC. The ileal bile acid transporter (IBAT) protein expressed in the distal ileum plays a key role in the enterohepatic circulation of BAs. Pharmacological inhibition of IBAT with GSK2330672 may reduce BA levels in the systemic circulation and improve pruritus., Methods: This clinical study (BAT117213 study) is sponsored by GlaxoSmithKline (GSK) with associated exploratory studies supported by the National Institute for Health Research (NIHR). It is a phase 2a, multi-centre, randomised, double bind, placebo controlled, cross-over trial for PBC patients with pruritus. The primary objective is to investigate the safety and tolerability of repeat doses of GSK2330672, and explore whether GSK2330672 administration for 14 days improves pruritus compared with placebo. The key outcomes include improvement in pruritus scores evaluated on a numerical rating scale and other PBC symptoms in an electronic diary completed twice daily by the patients. The secondary outcomes include the evaluation of the effect of GSK2330672 on total serum bile acid (BA) concentrations, serum markers of BA synthesis and steady-state pharmacokinetics of ursodeoxycholic acid (UDCA)., Discussion: BAT117213 study is the first randomised controlled crossover trial of ileal bile acid transporter inhibitor, a novel class of drug to treat pruritus in PBC. The main strengths of the trial are utility of a novel, study specific, electronic symptom diary as patient reported outcome to measure the treatment response objectively and the crossover design that allows estimating the treatment effect in a smaller number of patients. The outcome of this trial will inform the trial design of future development phase of the IBAT inhibitor drug. The trial will also provide opportunity to conduct metabonomic and gut microbiome studies as explorative and mechanistic research in patients with cholestatic pruritus., Trial Registration: EudraCT number: 2012-005531-84, ClinicalTrials.gov Identifier: NCT01899703 , registered on 3(rd) July 2013.

The mitochondrial Na(+)/Ca(2+) exchanger plays an important role in the control of cytosolic Ca(2+) cycling in excitable cells, essential for the regulation of a plethora of Ca(2+)-dependent physio-pathological events, such as apoptosis in the presence of a Ca(2+) overload. There are very few pharmacological tools available to study both physiological and pathological implications of the mitochondrial Na(+)/Ca(2+) exchanger, where the benzothiazepine CGP37157 is the best-known ligand, used since the 1980s. However, it is not an efficient blocker and lacks of selectivity, as also blocks several other cellular Ca(2+) transporters. Moreover, CGP37157 is a very lipophilic drug, showing very poor water solubility, what has hindered its therapeutic use. Attempting to improve its pharmacokinetic profile as well as its potency and selectivity, we herein describe the synthesis of new CGP37157 analogs, where the benzene-fused ring has been replaced by a pyridine. On top of a better water solubility and lower log P value, some of these new pyridothiazepine derivatives also presented a higher capacity to regulate the mitochondrial Ca(2+) clearance, while keeping the neuroprotective properties presented in the head compound CGP37157., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Omapatrilat (OMA), which simultaneously inhibits the angiotensin-converting enzyme (ACE) and the neutral endopeptidase (neprilysin (NEP)), is widely used in experimental protocols related to hypertension and heart failure. The penetration of OMA across the blood-brain barrier (BBB) and the effects of ACE/NEP inhibition on the recovery from ischaemic stroke have not yet been investigated. Angiotensin (Ang) I injected intracerebroventricularly (ICV) or intravenously (IV) is converted to Ang II by ACE and induces an immediate increase in blood pressure. The pressor responses to OMA administered ICV, orally or IV were studied in male Wistar rats instrumented with an ICV and arterial and venous catheters. OMA infused ICV rapidly appeared in the systemic circulation and more effectively attenuated the systemic than the central pressor responses to Ang I. OMA administered orally (5, 25, 100 μmol/kg body weight) or IV (0.5, 1, 5, 25 μmol/kg body weight) completely abolished increases in blood pressure to IV Ang I up to 2 h after treatment. The pressor responses to ICV Ang I were not altered, indicating that systemically administered OMA does not cross the BBB. To study the effects of ACE and NEP inhibition in the brain on the recovery from ischaemic stroke, OMA was infused ICV over a 5-day period before and 24 h after the occlusion of the middle cerebral artery (MCAO) for 90 min. ICV application of OMA had no effect on infarction volume and marginally improved neurological outcome. We demonstrate for the first time that simultaneous inhibition of ACE and NEP in the brain tissue does not alter the recovery from ischaemic stroke.

Background: Tianeptine is widely used for controlling depressive symptoms., Objective: The aim of this study was to evaluate the bioequivalence between the generic (test) formulation containing tianeptine sodium 12.5 mg and the branded (reference) formulation Stablon® with regard to their pharmacokinetic profiles., Methods: A randomized, two-sequence, two-treatment crossover study was conducted in healthy male Korean volunteers. All of the enrolled subjects were allocated to one of two sequence groups. They were administered a tablet of the test or reference formulation and then administered the alternative formulation after a 7-day washout period. The blood samples were taken before dosing and at 0.33, 0.67, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, and 10 hours after dosing. The plasma concentrations of tianeptine were analyzed using high-performance liquid chromatography with tandem mass spectrometer. Tolerability was assessed throughout the study., Results: The pharmacokinetic parameters were assessed in the 40 subjects who completed the study. The tianeptine C(max) for the test formulation was 283.13 ± 57.58 ng/mL (mean ± SD) and that for the reference formulation was 272.50 ± 59.00 ng/mL. The AUC(last) of tianeptine was 803.24 ± 180.94 ng×h/mL for the test formulation and 792.27 ± 180.93 ng×h/mL for the reference formulation. The geometric mean ratio (%) of the test to reference formulation was 104.04 (90% CI, 99.66 - 108.61) for C(max) and 101.30 (98.01 - 104.71) for AUC(last). Clinically significant adverse events were not reported during the study., Conclusion: The test and reference formulations of tianeptine were bioequivalent with regard to the pharmacokinetic parameters of Cmax and AUC(last). Both formulations were tolerated by all of the participants.

Background/aims: The in vivo metabolic profile of a benzopyridooxathiazepine (BPT) derivative, a potent tubulin polymerization inhibitor with a promising in vitro activity, was investigated., Methods: The quantification of the BPT derivative and the identification of metabolites in the plasma of Wistar rats after i.p. and oral administration of 10 mg/kg were performed by the HPLC-mass spectrometry method., Results: Following a single i.p. dose of the BPT derivative, the plasma concentrations showed a biexponential decay (with a rapid decline) followed by a slow decay with a terminal half-life of 77.90 min. The area under the concentration-time curve from time 0 to infinity (AUC0-∞) was 18.90 µg/ml·min. After oral administration, the plasmatic concentrations reached a peak of 0.06 μg/ml at 35 min and then decayed with a half-life of 108 min. The AUC0-∞ was 10.25 µg/ml·min, representing 54.2% of the relative bioavailability. The compound was well distributed in the body, and its elimination seemed to be fast, regardless of the administration route. The major metabolic pathways were demethylation and hydroxylation reactions, both followed by conjugation with glucuronic acid., Conclusion: In rats, the BPT derivative is well distributed and undergoes extensive metabolism, leading to several metabolites. With promising in vitro activity and very good oral bioavailability, this compound seems to be an attractive candidate for further development as an anticancer agent., (© 2014 S. Karger AG, Basel.)

In the present study, the in vitro metabolic behavior of a benzopyridooxathiazepine (BZN), a potent tubulin polymerization inhibitor, was investigated by liquid chromatography-UV detection (LC-UV). First, simple and fast LC-UV methods have been optimized and validated to evaluate the pharmacokinetic profile of BZN using rat liver microsomes or hepatocytes primary cultures suspensions. Whatever the medium investigated, baseline resolution between the internal standard and BZN was achieved in a run time less than 15min using a Symmetry ODS column (150mm×4.6mm i.d., 5μm) and a mobile phase consisting of acetonitrile/water/formic acid 60:40:0.1 (v/v/v). Linearity was assessed in the 0.1-50μM and in the 0.05-5μM concentration ranges, respectively, in microsomal and hepatocyte matrix. According to the novel strategy based on the build of the accuracy profile, total error of the developed methods was included within the ±10% limits of acceptance. Then, from incubation of BZN with both liver microsomes and or hepatocytes, structural informations on phase I and phase II metabolites were acquired using liquid chromatography coupled to electrospray orbitrap mass spectrometer (LC-MS). Mass spectrum, double bond equivalent and elemental composition were useful data to access to the chemical structure of each metabolite. In microsomal suspension, four main metabolites were observed including monohydroxylation and dihydroxylation of the benzopyridooxathiazepine core, demethylation of the methoxyphenyl moiety, as well as their combinations. The phase II metabolites detected in hepatocytes suspension were the glucuronide adducts of both demethylated BZN and mono-oxygenated BZN. Based on the structural elucidation of the metabolites detected, we proposed an in vitro metabolic pathway of BZN, a new tubulin polymerization inhibitor., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Introduction: Elobixibat (formerly A3309) is a first-in-class ileal bile acid transporter (IBAT) inhibitor for treatment of chronic idiopathic constipation (CIC; syn functional constipation). CIC affects up to 25% of the general population; and up to a half are unsatisfied with current therapies. There is an unmet need for safe and effective drugs to treat CIC., Areas Covered: The authors present: i) an overview of Phase II clinical trials of elobixibat in CIC, based on peer-reviewed literature and congress presentations and ii) an evaluation of the efficacy and mechanism of action of elobixibat in the treatment of CIC., Expert Opinion: Elobixibat provides a novel approach to treat chronic constipation via IBAT inhibition with enhanced delivery of bile acids to the colon. Pharmacodynamic studies show that it accelerates colonic transit, increases stool frequency, loosens stool consistency and relieves constipation-related symptoms in CIC patients. These beneficial effects are maintained for a minimum of 8 consecutive weeks of treatment. With minimal absorption and low systemic bioavailability, elobixibat is generally well tolerated and may offer the added benefit of improving serum lipid profiles through bile acid depletion.

The intestinal absorption mechanism of temocapril, an ester-type prodrug of temocaprilat, was evaluated using Caco-2 cell monolayers with or without active carboxylesterase (CES)-mediated hydrolysis. The inhibition of CES-mediated hydrolysis was achieved by pretreatment of the monolayers with bis-p-nitrophenyl phosphate (BNPP), which inhibited 94% of the total hydrolysis of temocapril in the Caco-2 cells. The remaining 6% hydrolysis was due to the presence of serine esterases, other than CES, on the cell membranes. Transport experiments under CES-inhibited conditions showed temocapril not to be a substrate for peptide transporter 1 (PEPT1) or organic anion transporting polypeptides (OATPs), but to be an inhibitor of PEPT1; P-glycoprotein (P-gp) and breast-cancer-resistant protein (BCRP) were responsible for the efflux of temocapril, which was mainly absorbed by passive diffusion at low apical pH. In Caco-2 cell monolayers with CES-mediated hydrolysis intact, temocaprilat derived from temocapril, was 2.5-fold more rapidly transported into the apical compartment than into the basolateral compartment due to the presence of microvilli on the apical membrane. In contrast, temocaprilat at low intracellular concentrations, was preferentially transported across the basolateral membrane under CES-inhibited conditions., (Copyright © 2011 Wiley-Liss, Inc.)

Intestinal absorption of temocapril, a prodrug of temocaprilat, was evaluated in an in situ rat jejunal perfusion model under various conditions of luminal pH and in the presence and absence of carboxylesterase-mediated hydrolysis. Temocapril was more easily taken up by mucosal cells at a luminal pH of 5.4 than at pH 6.4 or 7.4 and was extensively hydrolyzed to temocaprilat in mucosal cells. The hydrolysis was limited by the intrinsic clearance and the influx rate at luminal perfusate pHs of 5.4 and 7.4, respectively. Temocaprilat, derived from temocapril, was transported into both mesenteric vein and jejunal lumen according to pH partition theory. The net absorption of both temocapril and temocaprilat was highest at a luminal perfusate pH of 5.4. When both the luminal and venous fluid were at pH 7.4, temocaprilat was transported approximately 3-fold faster into the lumen than into the vein, due presumably to the greater surface area of the brush border membrane because of the presence of microvilli. Under carboxylesterase-inhibited conditions, the hydrolysis of temocapril was inhibited by only 50%. It is postulated that serine esterases located on the membranes of the epithelial cells were responsible for the residual hydrolysis. We have confirmed that temocapril is most easily absorbed in the proximal intestine after meals, due to prolongation of the gastric emptying time, the lower intraluminal pH caused by secretion of bile acid, and the interaction between serine esterases and the digesta.

The present investigation was undertaken with the objective of formulating orodispersible film(s) of the antidepressant drug tianeptine sodium to enhance the convenience and compliance by the elderly and pediatric patients. The novel film former, lycoat NG73 (granular hydroxypropyl starch), along with different film-forming agents (hydroxypropyl methyl cellulose, hydroxyethyl cellulose, and polyvinyl alcohol), in addition to three film modifiers; namely, maltodextrin, polyvinyl pyrrolidone K90 and lycoat RS780 (pregelatinized hydroxypropyl starch) were evaluated. Eight formulae were prepared by the solvent-casting method; and were evaluated for their in vitro dissolution characteristics, in vitro disintegration time, and their physico-mechanical properties. The promising orodispersible film based on lycoat NG73 (F1); showing the greatest drug dissolution, satisfactory in vitro disintegration time and physico-mechanical properties that are suitable for orodispersible films, was evaluated for its bioavailability compared with a reference marketed product (Stablon® tablets) in rabbits. Statistical analysis revealed no significant difference between the bioavailability parameters (C(max) (ng/ml), t(max) (h), AUC(0-t) (ng hml(-1)), and AUC(0-∞) (ng hml(-1))] of the test film (F1) and the reference product. The mean ratio values (test/reference) of C(max) (89.74%), AUC(0-t) (110.9%), and AUC(0-∞) (109.21%) indicated that the two formulae exhibited comparable plasma level-time profiles. These findings suggest that the fast orodispersible film containing tianeptine is likely to become one of choices for acute treatment of depression.

The new compound thienodiltiazem was synthesized and investigated regarding structure-activity relations and calcium antagonistic properties. Isometric contraction force was measured in guinea-pig papillary muscles and chronotropic activity was studied in right atria of guinea pigs. Compared to the parent drug diltiazem (CAS 42399-41-7) the thieno derivative had a more potent negative chronotropic effect on spontaneously beating right atria and a more potent inotropic effect on papillary muscles. The negative inotropic action was reversed by increasing the extracellular calcium concentration.

Objective: Recent reports have shown that genetic polymorphisms in organic anion transporting polypeptide (OATP) 1B1 have an effect on the pharmacokinetics of drugs. However, the impact of OATP1B1*1b alleles, the frequency of which is high in all ethnicities, on the pharmacokinetics of substrate drugs is not known after complete separation of subjects with OATP1B1*1a and *1b. Furthermore, the correlation between the clearances of OATP1B1 substrate drugs in individuals has not been characterized. We investigated the effect of genetic polymorphism of OATP1B1, particularly the *1b allele, on the pharmacokinetics of 3 anionic drugs, pravastatin, valsartan, and temocapril, in Japanese subjects., Methods: Twenty-three healthy Japanese volunteers were enrolled in a 3-period crossover study. In each period, after a single oral administration of pravastatin, valsartan, or temocapril, plasma and urine were collected for up to 24 hours., Results: The area under the plasma concentration-time curve (AUC) of pravastatin in *1b/*1b carriers (47.4 +/- 19.9 ng.h/mL) was 65% of that in *1a/*1a carriers (73.2 +/- 23.5 ng.h/mL) (P = .049). Carriers of *1b/*15 (38.2 +/- 15.9 ng.h/mL) exhibited a 45% lower AUC than *1a/*15 carriers (69.2 +/- 23.4 ng.h/mL) (P = .024). In the case of valsartan we observed a similar trend as with pravastatin, although the difference was not statistically significant (9.01 +/- 3.33 microg.h/mL for *1b/*1b carriers versus 12.3 +/- 4.6 microg.h/mL for *1a/*1a carriers [P = .171] and 6.31 +/- 3.64 microg.h/mL for *1b/*15 carriers versus 9.40 +/- 4.34 microg.h/mL for *1a/*15 carriers [P = .213]). The AUC of temocapril also showed a similar trend (12.4 +/- 4.1 ng.h/mL for *1b/*1b carriers versus 18.5 +/- 7.7 ng.h/mL for *1a/*1a carriers [P = .061] and 16.4 +/- 5.0 ng.h/mL for *1b/*15 carriers versus 19.0 +/- 4.1 ng.h/mL for *1a/*15 carriers [P = .425]), whereas that of temocaprilat (active form of temocapril) was not significantly affected by the haplotype of OATP1B1. Interestingly, the AUC of valsartan and temocapril in each subject was significantly correlated with that of pravastatin (R = 0.630 and 0.602, P < .01). The renal clearance remained unchanged for each haplotype for all drugs., Conclusion: The major clearance mechanism of pravastatin, valsartan, and temocapril appears to be similar, and OATP1B1*1b is one of the determinant factors governing the interindividual variability in the pharmacokinetics of pravastatin and, possibly, valsartan and temocapril.

A new, selective and sensitive high-performance liquid chromatography (HPLC) method with fluorimetric detection was developed for the determination of tianeptine (TIA) in human plasma using solid phase extraction (SPE) procedures. The method is based on the derivatization of TIA with 4-chloro-7-nitrobenzofurazan (NBD-Cl) in borate buffer of pH 8.5 to yield a yellow, fluorescent product. The HPLC separation was achieved on a Phenomenex C(18) column (250 mm x 4.6 mm) using a mobile phase of acetonitrile-10mM orthophosphoric acid (pH 2.5) (77:23, v/v) solvent system at 1 mL/min flow rate. Gabapentin (GA) was used as the internal standard. The fluorometric detector was operated at 458 nm (excitation) and 520 nm (emission). The assay was linear over the concentration range of 5-300 ng/mL. The detection limit (LOD) was found to be 2 ng/mL. The mean recovery was determined to be 88.6%. The proposed method was applied for pharmacokinetic study of 12.5mg TIA in a healthy volunteer.

This study was undertaken to evaluate a dosing time-dependent effect of temocapril, an angiotensin-converting enzyme (ACE) inhibitor, on the mortality of stroke-prone spontaneously hypertensive rats (SHRSP). Temocapril (1 mg/kg/day) prolonged the survival rate of these animals, with a maximum effect after dosing at the early resting period and a minimum effect after dosing at the early active period. The pharmacokinetics of temocaprilat, an active metabolite of temocapril, did not differ significantly between the two dosing times. However, the inhibition of ACE activity in serum and organs (brain and aorta) and the reduction of blood pressure were significantly greater after dosing at the early resting period than at the early active period. These data suggest that the effect of temocapril on the mortality of SHRSP depends on the time of dosing, with a maximum effect seen after dosing at the early resting period. Dosing time-dependent differences in the pharmacodynamics of temocapril might be involved in explaining this phenomenon.

We have recently developed five novel pyrrolo-1,5-benzoxazepines as proapoptotic agents. Their JNK-dependent induction of apoptosis in tumor cells suggested their potential as novel anticancer agents. The core structure of the apoptotic agent 6 was investigated, and the SARs were expanded with the design and synthesis of several analogues. To define the apoptotic mechanism of the new compounds and the localization of their drug target, two analogues of 6 were designed and synthesized to delineate events leading to JNK activation. The cell-penetrating compound 16 induced apoptosis in tumor cells, while its nonpenetrating analogue, 17, was incapable of inducing apoptosis or activating JNK. Plasma membrane permeabilization of tumor cells resulted in 17-induced JNK activation, suggesting that the pyrrolo-1,5-benzoxazepine molecular target is intracellular. Interestingly, compound 6 displayed cytotoxic activity against a panel of human tumor cell lines but demonstrated negligible toxicity in vivo with no effect on the animals' hematology parameters.

Temocapril is an angiotensin converting enzyme inhibitor (ACEI), a prodrug with a thiazepine ring. Its active form, temocaprilat, is slightly more potent than enalaprilat in inhibiting ACE isolated from rabbit lung. The inhibitory potency of temocaprilat on isolated rat aorta is 3 times that of enalaprilat. Temocapril is excreted in the bile and urine and can be used in patients with renal insufficiency. It reduces blood pressure without causing any significant change in heart rate or cardiac output. Temocapril has been reported to improve endothelial dysfunction in vitro by suppressing increased oxidative stress. In vivo it improves reactive hyperemia in patients with essential hypertension. It has been reported to prevent coronary vascular remodeling in vivo by suppressing local ACE and increased oxidative stress. In humans temocapril has been found to improve insulin resistance partly by increasing adiponectin levels. Cardiac remodeling was improved by temocapril not only in experiment animals but also in humans. It improves renal function and decreases urinary albumin excretion in diabetics as well as in hypertensive patients. Temocapril is currently marketed only in Japan. Considering its beneficial effects and unique pharmacokinetics, temocapril, is likely to be introduced in other countries as well.

Aims: To determine the pharmacokinetics, pharmacodynamics and tolerability of omapatrilat, a vasopeptidase inhibitor, in healthy subjects., Methods: The effects of oral omapatrilat were evaluated in healthy men in two double-blind, placebo-controlled, dose-escalation trials. In a single-dose study, subjects received omapatrilat in doses of 2.5, 7.5, 25, 50, 125, 250, or 500 mg. In a multiple-dose study, subjects received doses of 10, 25, 50, 75, or 125 mg daily for 10 days., Results: In the multiple-dose study, peak plasma concentrations (Cmax = 10-895 ng ml(-1); tmax = 0.5-2 h) of omapatrilat were attained rapidly. Omapatrilat exhibited a long effective half-life (14-19 h), attaining steady state in 3-4 days. In the single-dose study, Cmax (1-1009 ng ml(-1)) and AUC(0,t) (0.4-1891 ng ml(-1) h) were linear but not dose proportional. In the multiple-dose study, based on weighted least-squares linear regression analyses vs dose, Cmax but not AUC(0,t) was linear at the lower doses on day 10. The lowest dose of omapatrilat (2.5 mg) almost completely inhibited (> 97%) serum angiotensin converting enzyme activity at 2 h after dosing. In the multiple dose study, angiotensin converting enzyme activity was inhibited by more than 80% 24 h after all doses of omapatrilat. Inhibition of neutral endopeptidase activity was shown by increases in the daily urinary excretion of atrial natriuretic peptide and cyclic guanosine monophosphate at doses of more than 7.5 and 25 mg, respectively. In the single dose study, omapatrilat increased the daily urinary excretion of atrial natriuretic peptide dose-dependently from 10.8 +/- 4.1 (+/- SD) ng 24 h(-1) in the placebo group to 60.0 +/- 18.2 ng 24 h(-1) in the 500 mg group. Omapatrilat did not affect sodium and potassium excretion or urinary volume. Compared with placebo, omapatrilat produced a decrease in mean arterial pressure at 3 h after all doses in both the single- and multiple-dose studies., Conclusions: Omapatrilat was generally well tolerated. The pharmacokinetic and pharmacodynamic effects of omapatrilat are consistent with once-daily dosing.

Aim: To develop a sensitive and specific analytical method for the quantitative determination of omapatrilat (BMS-186716) and its metabolites (BMS-196087, 225308, 198433, and 253653) in human plasma., Methods: Methyl acrylate (MA) was selected to react with BMS-186716, 196087, and 253653 to protect the free sulfhydryl groups. High pressure liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used to detect the analytes., Results: The method was validated over the concentration range of 0.2-250 microg/L for BMS-186716, 0.5-250 microg/L for BMS-196087, 1-250 microg/L for BMS-225308, 2-250 microg/L for BMS-198433, and 10-2500 microg/L for BMS-253653. The limit of quantitation was in turn 0.2, 0.5, 1, 2, and 10 microg/L, respectively. The extraction recovery was on average 60.5 %, 88.6 %, 76.3 %, 71.2 %, and 26.6 %, respectively. Inter- and intra-day precision of quality control samples (QC) was all within 15 % and accuracy was within 85 %--115 %. The analytes in human plasma were found to be stable after three cycles of freeze-thaw and for at least 6 h at room temperature (25 oC). No significant change was found in reconstituted reagent after 24 h at room temperature and results of long-term stability showed all the analytes in human plasma were stable for at least 3 months at -30 oC freezing condition., Conclusion: This method is rapid, sensitive and specific for the pharmacokinetics study of omapatrilat and its metabolites.

Stress-induced structural and cellular alterations in the hippocampus can contribute to the pathophysiology of depression. The reversal of these alterations may be a mechanism by which antidepressants achieve their therapeutic effect. The aim of the present study was therefore to investigate the effect of tianeptine on stress-induced structural changes and alterations in cerebral metabolites. To this end, psychosocially stressed male tree shrews were treated with tianeptine. A combination of in vivo and postmortem methods was used to evaluate the antidepressant treatment on the preservation of neuronal plasticity. It was found that all stress-induced effects were prevented by the administration of tianeptine. It is concluded that these findings provide experimental evidence for recent theories that impairment of neuronal viability and neuroplasticity might be important causal factors in mood disorders, suggesting tianeptine as a potential stimulator of neural resilience.

The purpose of this study was to determine the pharmacodynamics and pharmacokinetics of omapatrilat, administered orally (25 mg) or intravenously (10 mg) in 19 New York Heart Association class II and class III congestive heart failure (CHF) patients versus 17 healthy controls matched for age, race, gender, and weight. The plasma concentrations of atrial natriuretic peptide (ANP) increased by approximately 20% and 30% in CHF and control subjects, respectively, at 4 hours after intravenous or oral omapatrilat administration. Similar elevation in the cyclic guanosine monophosphate concentration (25% to 35%) and ANP urinary excretion (21 ng/24 h to 22 ng/24 h) was seen in all treatment groups after omapatrilat administration. Angiotensin-converting enzyme activity was > 90% inhibited at 4 hours after dosing and remained approximately 60% to 70% inhibited at 24 hours after dosing. The levels of endothelin-1 and endothelin-2 remained unchanged after oral or intravenous administration of omapatrilat. The maximal reduction in seated blood pressure compared with baseline was similarfor CHF and control subjects. Clinical pharmacokinetic parameters were similar in both groups after intravenous dosing, but maximum concentration and area under the concentration-time curve were elevated in CHF patients compared with controls after oral dosing. Omapatrilat was well tolerated; differences in systemic exposure and metabolism between CHF patients and controls did not appear to be clinically significant.

Pharmacodynamic effects of combination therapy with omapatrilat and furosemide were evaluated. Two groups of 13 healthy subjects each received furosemide 20 mg dailyfor 15 days coadministered with either placebo on days 6 to 15 or omapatrilat 10 mg on days 6 to 10 and 25 mg on days 11 to 15. In the omapatrilat group, urinary excretion of atrial natriuretic peptide increased, and greater blood pressure reductions were seen compared with placebo. Concomitant omapatrilat treatment did not affect the acute diuresis, natriuresis, and kaliuresis observed with chronic administration of furosemide. Neither effective renal plasma flow nor glomerularfiltration rate changed in either treatment group. No clinically significant safety issues were observed. Daily coadministration of omapatrilat 10 or 25 mg with furosemide 20 mg does not affect the pharmacodynamics offurosemide at steady state.

Vasopeptidase inhibitors are a new class of cardiovascular drug that simultaneously inhibit both neutral endopeptidase and angiotensin-converting enzyme (ACE). They increase the availability of peptides that have vasodilatory and other vascular effects; they also inhibit production of angiotensin II. In animal models vasopeptidase inhibitors decrease blood pressure in low, medium, and high renin forms of hypertension, and they also appear to confer benefits in models of heart failure and ischaemic heart disease. Studies in human hypertension show that these agents are effective in decreasing blood pressure regardless of race or age. Experience with omapatrilat, the most clinically advanced of these drugs, has shown it to be more effective than currently available ACE inhibitors or other widely used antihypertensive agents. Studies with omapatrilat in congestive heart failure have shown beneficial effects on haemodynamics and symptoms. The vasopeptidase inhibitors appear to have safety profiles similar to ACE inhibitors, though the frequency of side-effects such as angio-oedema and cough remains to be established. Large trials with clinical endpoints, some already in progress, are needed to establish the place of this class of drug beside that of established therapies in conditions such as hypertension, heart failure, ischaemic heart disease, and nephropathy.

The objective of this study was to determine the absolute oral bioavailability and disposition of omapatrilat. This single-dose, randomized, crossover study of 20 mg intravenous and 50 mg oral [14C]omapatrilat was conducted in 12 healthy male subjects to determine the disposition and oral bioavailability of omapatrilat, an orally active vasopeptidase inhibitor. Blood samples were collected up to 120 hours, and the excreta were collected over 168 hours postdose. Plasma concentrations of omapatrilat were determined by a validated LC/MS/MS procedure. Radioactivity in blood, plasma, urine, and feces was determined by liquid scintillation counting. Urinary excretion of radioactivity averaged 80% and 64% of intravenous and oral doses, respectively; < 1% of oral dose was excreted unchanged in urine. The absolute oral bioavailability of omapatrilat averaged 31%. Total body clearance of omapatrilat (80 L/h) exceeded liver plasma flow. Apparent steady-state volume of distribution of omapatrilat (21 L/kg) was extremely high compared with total body water. Omapatrilat undergoes substantial presystemic first-pass metabolism after oral administration. Omapatrilat is eliminated primarily by metabolism, and its metabolites are eliminated primarily in urine. Extrahepatic organs may be involved in the elimination of omapatrilat. Plasma concentrations of omapatrilat exhibit a prolonged terminal elimination phase, which represents elimination from a deep compartment.

Objective: The pharmacodynamics and pharmacokinetics of omapatrilat, a member of a new class of cardiovascular compounds, the vasopeptidase inhibitors, were evaluated in subjects with hepatic cirrhosis (n = 10) and in healthy subjects (n = 10) matched for age, weight, gender and smoking history., Methods: All subjects received omapatrilat 25 mg orally once daily for 14 days. Plasma renin and urinary atrial natriuretic peptide (ANP) levels were measured to assess the effect of omapatrilat on cirrhotic subjects. The effect of omapatrilat on blood pressure as well as changes in ANP and plasma renin levels were not altered by hepatic impairment. Pharmacokinetic parameters were determined from plasma omapatrilat concentrations., Results: There were no significant differences between the two subject groups with regard to log-transformed area under the curve or maximum observed plasma concentration. Systemic accumulation was similar in the two groups., Conclusion: These results suggest, based on findings in otherwise healthy cirrhotic subjects, that no adjustment of standard dosing regimens is indicated for hypertensive patients with mild to moderate cirrhosis.

Trandolapril is the prodrug of an angiotensin-converting enzyme (ACE) inhibitor. It has been proposed that its active metabolite, trandolaprilat, is mainly excreted in bile, but this has not been clearly demonstrated. Recently it has been reported that temocaprilat, an active metabolite of the ACE inhibitor temocapril, is effectively excreted in bile via an ATP-dependent active transporter (canalicular multispecific organic anion transporter: cMOAT). To investigate whether trandolaprilat has the pharmacological ability to affect the cMOAT system in a manner similar to temocaprilat. The lipophilicity of trandolaprilat and temocaprilat was measured to determine the n-octanol-water partition coefficients. The dose-dependent inhibition of the up-take of [3H]-estradiol-17beta-D-glucuronide and [3H]-2,4-dinitrophenyl-S-glutathione, which are good substrates for cMOAT, in canalicular membrane vesicles (CMVs) prepared from Sprague-Dawley rats was determined in the presence of trandolaprilat and temocaprilat. The partition coefficient of trandolaprilat (log Po/w - 1.1) was about 30 times higher than that of temocaprilat (log Po/w - 2.5). The uptake of [3H]-estradiol-17beta-D-glucuronide and [3H]-2,4-dinitrophenyl-S-glutathione was dose-dependently inhibited by the presence of temocaprilat, but trandolaprilat had no effect on the transport of [3H]-estradiol-17beta-D-glucuronide or [3H]-2,4-dinitrophenyl-S-glutathione into CMVs even at concentrations as high as 200 microM. It could be concluded that trandolaprilat has a higher lipophilicity than temocaprilat. But the hepatobiliary excretion system via cMOAT may not contribute to the excretion of trandolaprilat in bile.

Unlabelled: Tianeptine is an antidepressant agent with a novel neurochemical profile. It increases serotonin (5-hydroxytryptamine; 5-HT) uptake in the brain (in contrast with most antidepressant agents) and reduces stress-induced atrophy of neuronal dendrites. Like the selective serotonin reuptake inhibitors (SSRIs) and in contrast with most tricyclic antidepressant agents, tianeptine does not appear to be associated with adverse cognitive, psychomotor, sleep, cardiovascular or bodyweight effects and has a low propensity for abuse. Tianeptine has a comparatively favourable pharmacokinetic profile. It is not subject to first-pass hepatic metabolism, has high bioavailability and limited distribution, and is rapidly eliminated. While this offers advantages for tianeptine over the tricyclic antidepressant agents in terms of dose titration, treatment changes and potential drug interactions, its rapid elimination makes adherence to dosage schedules more important. Tianeptine differs from most antidepressants in that it is not primarily metabolised by the hepatic cytochrome P450 system, indicating less likelihood of drug-drug interactions; this is of particular interest for elderly patients. Tianeptine, in dosages of 25 to 50 mg/day, has been investigated in patients with major depression, depressed bipolar disorder, dysthymia or adjustment disorder. It has equivalent antidepressant efficacy to several classical antidepressant agents (amitriptyline, clomipramine, imipramine, mianserin) and the SSRIs fluoxetine (in most patients), paroxetine and sertraline. Comparison with maprotiline indicated superior efficacy for tianeptine but dothiepin appeared superior in another study. Extended treatment with tianeptine decreases the incidence of relapse/recurrence of depression. Tianeptine appears to be as effective as fluoxetine, sertraline, amitriptyline, clomipramine and mianserin and more effective than maprotiline in improving associated anxiety in patients with depressive disorders. Depression and anxiety symptoms in alcohol dependant patients also respond well to tianeptine. The adverse effects associated with tianeptine are similar in many respects to those of the SSRIs and minimal in comparison with the tricyclic antidepressants. The most common adverse effects are nausea, constipation, abdominal pain, headache, dizziness and changes in dreaming. Anticholinergic effects occur less often with tianeptine than with tricyclic agents. Hepatoxicity is rare. The dosage should be decreased in elderly patients and those with severe renal failure, but adjustment is not necessary in patients with alcoholism or hepatic impairment, or those undergoing haemodialysis., Conclusions: The antidepressant efficacy and favourable tolerability and pharmacokinetic profiles of tianeptine in patients with depression, including those with associated anxiety, have been proven; the data indicate that it may have additional potential in specific subgroups of depressed patients such as the elderly and those with chronic alcoholism.

Omapatrilat is the most clinically advanced member of a new class of cardiovascular drugs, vasopeptidase inhibitors. Omapatrilat is a single molecule that simultaneously inhibits neutral endopeptidase and angiotensin-converting enzyme, thus preserving vasodilator peptides and inhibiting production of the vasoconstrictor angiotensin II. In healthy male volunteers, omapatrilat decreased blood pressure while being generally well tolerated, with no serious adverse events. This study was undertaken to determine the effect of age and gender on the pharmacodynamics of omapatrilat. Healthy male or female volunteers between the ages of 18 and 80 were given a single oral dose of omapatrilat 40 mg. Neither age nor gender affected the vasopeptidase inhibition by omapatrilat. There were no differences between subject groups in the effect of omapatrilat on supine systolic, diastolic, or mean arterial blood pressure. Based on this study of healthy subjects, it can be concluded that it is not necessary to adjust the initial dose of omapatrilat for the treatment of hypertension based solely on age or gender.

Objective: To evaluate the pharmacokinetic profiles of temocaprilat and its hypotensive effect after single and repeated dosings of temocapril in young and elderly hypertensive patients., Methods: An angiotensin-converting enzyme inhibitor, temocapril (2 mg), was given once daily for 8 days to nine young and ten elderly hypertensive patients. Pharmacokinetics of temocaprilat, an active metabolite, and its hypotensive effect were evaluated after the first and last doses., Results: The area under the plasma concentration-time curve (AUC) of temocaprilat after the first dose was significantly greater in the elderly than in the young. This parameter was elevated after the final dose in both groups. The AUC (eighth dose)/AUC (first dose) ratio in the elderly was similar to that in the young. Blood pressure (BP) tended to decrease in the young and significantly decreased in the elderly after the first dose. The hypotensive effect was not enhanced after the final dose in either group., Conclusion: These results suggest that although plasma temocaprilat concentration rises during repeated dosing, its BP-lowering effect is not enhanced in the elderly. Therefore, if a remarkable BP reduction is not detected at the initiation of treatment, the risk of hypotensive episode might be small during long-term therapy with temocapril in elderly hypertensive patients.

Omapatrilat, a potent vasopeptidase inhibitor, is currently under development for the treatment of hypertension and congestive heart failure. This study describes the plasma profile along with isolation and identification of urinary metabolites of omapatrilat from subjects dosed orally with 50 mg of [(14)C]omapatrilat. Only a portion of the radioactivity in plasma was unextractable (40-43%). Prominent metabolites identified in plasma were S-methyl omapatrilat, acyl glucuronide of S-methyl omapatrilat, and S-methyl (S)-2-thio-3-phenylpropionic acid. Omapatrilat accounted for less than 3% of the radioactivity. However, after dithiothreitol reduction all of the radioactivity was extractable and was characterized to be omapatrilat and its hydrolysis product (S)-2-thio-3-phenylpropionic acid, both apparently bound to proteins via reversible disulfide bonds. Urinary profile of radioactivity showed no parent compound but the presence of several metabolites that can be grouped into three categories. 1) Three metabolites, accounting for 56% of the urinary radioactivity, resulted from the hydrolysis of the exocyclic amide bond of omapatrilat. Two metabolites were diastereomers of S-methyl sulfoxide of (S)-2-thio-3-phenylpropionic acid, and the third was the acyl glucuronide of S-methyl (S)-2-thio-3-phenylpropionic acid. 2) One disulfide, identified as the L-cysteine mixed disulfide of omapatrilat, accounted for 8% of the radioactivity in the urine. 3) Five metabolites, derived from omapatrilat, accounted for 30% of the radioactivity in the urine. Two of these metabolites were mixtures of diastereomers of S-methyl sulfoxide of omapatrilat and the third was the S-methyl omapatrilat ring sulfoxide. The other two metabolites were S-methyl omapatrilat and its acyl glucuronide. These results indicate that omapatrilat undergoes extensive metabolism in humans.

To investigate how the interruption of the renin-angiotensin system (RAS) and reduction of blood pressure (BP) affect the lesions of chronic focal and segmental glomerulosclerosis (FGS), we studied the effects of high and low doses of angiotensin-converting enzyme inhibitors (temocapril - TEM) a newly developed ACE inhibitor with biliary tract excretion, on the hypertensive model of FGS. A high dose of TEM significantly lowered BP and suppressed both intense proteinuria and glomerular extracapillary lesions including macrophage infiltration. On the other hand, although a low dose of TEM did not significantly lower BP throughout the experimental period, it prevented renal lesions almost in the same manner as high-dose TEM with suppression of c-myc gene expression in glomeruli. These findings suggest that in PAN-induced chronic FGS, the systemic BP elevation could not be the major factor for the progression of renal damage which TEM could prevent without significant lowering of BP.

An improved analytical method for the quantitative measurement of tianeptine and its main metabolite MC5 in human plasma was designed. Extraction involved ion-paired liquid-liquid extraction of the compounds from 1.0 ml of human plasma adjusted to pH 7.0. HPLC separation was performed using a Nucleosil C18, 5 microm column (150x4.6 mm I.D.) and a mixture of acetonitrile and pH 3, 2.7 g l(-1) solution of sodium heptanesulfonate in distilled water (40:60, v/v) as mobile phase. UV detection was performed using a diode array detector in the 200-400 nm passband, and quantification of the analytes was made at 220 nm. For both tianeptine and MC5 metabolite, the limit of quantitation was 5 microg l(-1) and the calibration curves were linear from 5 to 500 microg l(-1). Intra- and inter-assay precision and accuracy fulfilled the international requirements. The recovery of tianeptine and its metabolite from plasma was, respectively, 71.5 and 74.3% at 20 microg l(-1), 71.2 and 70.8% at 400 microg l(-1). The selectivity of the method was checked by verifying the absence of chromatographic interference from pure solutions of the most commonly associated therapeutic drugs. This method, validated according to the criteria established by the Journal of Chromatography B, was applied to the determination of tianeptine and MC5-metabolite in human plasma in pharmacokinetic studies.

Background: Omapatrilat, a vasopeptidase inhibitor, preserves natriuretic peptides and inhibits the renin angiotensin aldosterone system by simultaneously inhibiting neutral endopeptidase and angiotensin-converting enzyme., Methods: Oral omapatrilat, 10 mg/d, was administered for 8 to 9 days to three groups of eight subjects with varying degrees of renal function (CLCR values, normal > or = 80; mild to moderate impairment < 80 to > or = 30; severe impairment < 30 mL/min/1.73 mL2) and to six subjects undergoing maintenance hemodialysis. Omapatrilat and its metabolites (phenylmercaptopropionic acid, S-methylomapatrilat, S-methylphenylmercaptopropionic acid, and cyclic S-oxide-omapatrilat) were quantified in plasma by a validated liquid chromatography/mass spectrometry method. The model, Cmax or AUC(0-T) = intercept + slope x CLCR, was tested for a possible linear correlation between Cmax (peak plasma concentrations) or AUC(0-T) (area under plasma concentration versus time curve) and CLCR., Results: For omapatrilat and its inactive metabolites, phenylmercaptopropionic acid, S-methylomapatrilat, and S-methylphenylmercaptopropionic acid, the median times to peak plasma concentrations (tmax) were 1.5 to 2, 2 to 3, 2.5 to 3.5, and 7 to 10 hours, respectively, and were independent of renal function. After Cmax attainment, plasma concentrations declined rapidly to about 10% of Cmax values. Cyclic S-oxide-omapatrilat, a potentially active metabolite, was undetectable at all sampling time points. Hemodialysis did not decrease circulating levels of omapatrilat. There was minimal accumulation of omapatrilat and phenylmercaptopropionic acid and moderate accumulation of the S-methylated metabolites. For omapatrilat and S-methylphenylmercaptopropionic acid, neither Cmax nor AUC(0-T) was CLCR dependent. However, AUC(0-T) for phenylmercaptopropionic acid and both the Cmax and AUC(0-T) for S-methylomapatrilat were CLCR dependent., Conclusions: The pharmacokinetics of omapatrilat, the only clinically relevant active compound studied, was independent of CLCR. For patients with reduced renal function, adjusting initial omapatrilat dose is not suggested. Hemodialysis did not significantly contribute to the clearance of omapatrilat. The long-term pharmacodynamic response to omapatrilat will dictate dose-adjustment needs.

The relationship between biliary excretion in sandwich-cultured rat hepatocytes and in vivo in rats was examined. The biliary excretion of seven model substrates in 96-h sandwich-cultured rat hepatocytes was determined by differential cumulative uptake of substrate in the monolayers preincubated in standard buffer (intact bile canaliculi) and Ca2+-free buffer (disrupted bile canaliculi). Biliary excretion in vivo was quantitated in bile duct-cannulated rats. The biliary excretion index of model substrates, equivalent to the percentage of retained substrate in the canalicular networks, was consistent with the percentage of the dose excreted in bile from in vivo experiments. The in vitro biliary clearance of inulin, salicylate, methotrexate, [D-pen2,5]enkephalin, and taurocholate, calculated as the ratio of the amount excreted into the bile canalicular networks and the area under the incubation medium concentration-time profile ( approximately 0, approximately 0, 4.1 +/- 1.0, 12.6 +/- 2.2, and 56. 2 +/- 6.0 ml/min/kg, respectively), correlated with their intrinsic in vivo biliary clearance (0.04, 0, 17.3, 34.4, and 116.9 ml/min/kg, respectively; r2 = 0.99). The model compound 264W94 was not excreted in bile either in vivo or in vitro. The glucuronide conjugate of 2169W94, the O-demethylated metabolite of 264W94, was excreted into bile in vitro when 2169W94, but not 264W94, was incubated with the monolayers; 2169W94 glucuronide undergoes extensive biliary excretion after administration of 264W94 or 2169W94 in vivo. Biliary excretion in long-term sandwich-cultured rat hepatocytes correlates with in vivo biliary excretion. The study of biliary excretion of metabolites in the hepatocyte monolayers requires consideration of the status of metabolic activities.

Compared with other angiotensin-converting enzyme (ACE) inhibitors, the elimination of temocapril is less dependent on renal function. To investigate the metabolic and antihypertensive effects of temocapril in diabetic hypertensives, 30 patients with diabetes mellitus type 2 and mild to moderate hypertension [diastolic blood pressure (BP) 90-115 mm Hg] and without azotemia (plasma creatinine < 180 microM) were evaluated in a prospective randomized double-blind placebo-controlled study. After a 4-week placebo run-in, they received temocapril, 20 mg daily (n = 19), or placebo (n = 11) for 6 weeks. Insulin sensitivity index (SI), determined by the Minimal Model method of Bergman, serum lipoproteins, plasma renin activity, fibrinogen, and microalbuminuria were assessed at the end of the placebo run-in phase and the double-blind treatment phases. Temocapril but not placebo administration produced a significant decrease in supine BP (152/92+/-5/3 vs. 162/98+/-5/2 mm Hg; p < 0.01) and increase in plasma renin (p < 0.05). Variation of SI during temocapril treatment did not reach statistical significance (0.95+/-0.2 before vs. 1.44+/-0.4 x 10(-4)/min/mU/L after treatment). During administration of temocapril or placebo, no significant changes in fasting plasma glucose, insulin, and serum levels of total triglycerides, cholesterol, lipoprotein cholesterol fractions, or fibrinogen were observed. Microalbuminuria decreased significantly on temocapril treatment (49+/-10 vs. 79+/-17 mg/24 h; p < 0.01) but not on placebo. These findings demonstrate that in hypertensive patients with diabetes mellitus type 2, short-term treatment with temocapril is neutral to insulin sensitivity, lipoprotein metabolism, and fibrinogen, and significantly reduces microalbuminuria.

The mechanism for hepatic uptake of temocaprilat, an angiotensin-converting enzyme inhibitor that is predominantly excreted into bile was studied using isolated rat hepatocytes and COS-7 cells expressing the organic anion transporting polypeptide (oatp1). The uptake of temocaprilat into isolated rat hepatocytes exhibited saturation with a Km of 20.9 microM and a Vmax of 0.21 nmol/min/mg protein. This uptake was temperature sensitive and was significantly reduced by metabolic inhibitors, a sulfhydryl-modifying reagent and an anion-exchange inhibitor, although the replacement of Na+ with Li+ in the medium did not affect the uptake. [3H]Temocaprilat uptake was inhibited by estradiol-17beta-D-glucuronide and dibromosulphophthalein, typical substrates for the Na+-independent organic anion transporter, in a concentration-dependent manner, whereas excess estradiol-17beta-D-glucuronide did not completely inhibit the uptake. Temocaprilat uptake into COS-7 cells transfected with oatp1 cDNA revealed a concentration-dependency with a Km of 46.7 microM, a value comparable with that obtained in isolated hepatocytes. The contribution of oatp1 to carrier-mediated hepatic uptake of temocaprilat was less than 50% by correcting the uptake clearance with that of estradiol-17beta-D-glucuronide. A good linear correlation was observed for the inhibitory effect of angiotensin-converting enzyme inhibitors (benazeprilat, cilazaprilat, delaprilat and enalaprilat) between isolated hepatocytes and oatp1-expressing cells. These data suggest that oatp1, along with another transporter(s), mediates the uptake of angiotensin-converting enzyme inhibitors into rat hepatocytes.

Aims: The aim of this study was to determine the potential impact of age on the pharmacokinetics of temocapril and its pharmacologically active diacid metabolite, temocaprilat, in hypertensive patients., Methods: Male and female patients with mild to moderate essential hypertension (DBP 95-114 mmHg inclusive) were allocated to two age groups: young, < or = 40 years; elderly, > or = 69 years, (n = 18 per group). In Part I of the study, subjects took a single oral tablet dose of 20 mg temocapril hydrochloride following an overnight fast. In Part II they took seven once daily oral tablet doses of 20 mg temocapril hydrochloride. Pharmacokinetic profiles were determined after the single and the last dose. Trough plasma samples were taken before each dose in Part II. Urine was collected for 24 h following the single and the last dose., Results: Steady state was reached within 1 week in both groups. Statistically significant differences were detected in AUC and AUCss for temocaprilat as well as in CL(R) for temocapril and temocaprilat, respectively, after a single dose and at steady state. All other pharmacokinetic parameters for temocapril and temocaprilat did not show any significant difference., Conclusions: The pharmacokinetic differences detected in the elderly do not require a dose adjustment per se. Nonetheless, a lower starting dose may be appropriate as elderly hypertensive patients are usually considered to be at an increased risk of first dose hypotension at the onset of treatment with an ACE inhibitor.

Aims: The aim of this study was to determine the potential influence of renal impairment on the pharmacokinetics of temocapril and its pharmacologically active diacid metabolite, temocaprilat., Methods: Non-compartmental pharmacokinetics were assessed in four groups of hypertensive patients (n=8 per group, four investigational centres) with normal (creatinine clearance determined via 24 h urine sampling, CL[CR], > or = 60 ml min-1) and impaired renal function (CL[CR] 40-59, 20-39, < 20 ml min-1) after 14 once daily oral doses of 10 mg temocapril hydrochloride., Results: For temocapril, there were no statistically significant differences in median tmax or mean Cmax, AUC(SS), t1/2,Z, CL/F between the four groups. Renal clearance, CL(R), for temocapril showed a linear decreasing trend with decreasing CL(CR) [mean (s.d.): 32.2 (10.7) to 3.7 (3.0) ml min-1]. Steady-state for temocaprilat was reached on day 5. For temocaprilat, no statistically significant differences in mean Cmax or median tma were detected. With decreasing mean CL(CR), mean AUC(SS) for temocaprilat increased statistically significantly although only 2.4-fold [mean (s.d.): 2115 (565) to 4989 (2338) ng ml-1 h] and t1/2,Z was prolonged [mean (s.d.): 15.2 (1.2) to 20.0 (7.5) h]. CL(R) for temocaprilat showed a linear decreasing trend with decreasing CL(CR) [mean (s.d.): 20.2 (4.3) to 3.0 (1.8) ml min-1]., Conclusions: These results indicate that impaired renal function has only a limited effect on the pharmacokinetics of temocapril and its active metabolite, temocaprilat. This may be attributed to the dual, i.e. renal and biliary, elimination pathway of the drug.