Pharmacological profile of a specific neutrophil elastase inhibitor,Sivelestat sodium hydrate

Imbalance between neutrophil elastase (NE) and its endogenous protease inhibitors has been considered to be one of possible mechanisms by which NE causes lung tissue destruction. It has been shown that the amount and/or activity of NE is increased in blood and bronchoalveolar lavage fluid in patients with acute lung injury. Accordingly, animals undergoing acute lung injury have increased NE activity such as in blood and bronchoalveolar lavage fluid. Sivelestat sodium hydrate (Sivelestat) is a synthetic inhibitor of NE with highly specificity to NE. Many studies have indicated that Sivelestat treatment improves inflammatory and edematous changes of lungs and survival as well as increased NE activity in several animal models of acute lung injury. Clinical studies have demonstrated that Sivelestat improves this injury that is associated with systemic inflammatory response syndrome. As compared with endogenous protease inhibitors that have high molecular mass, Sivelestat, a synthetic and low molecular weight elastase inhibitor, may be delivered to the inflammatory sites more easily and effectively and is considred to improve typical symptoms of acute lung injury. Clinical use of Sivelestat would further clarify the usefulness of this compound in clinical acute lung injury.     

Pharmacological profile of KR-33028, a highly selective inhibitor of Na+/H+ exchanger

We evaluated the cardioprotective effects of 4-cyano (benzo[b]thiophene-2-carbonyl)guanidine (KR-33028), a recently developed inhibitor of the Na+/H+ exchanger (NHE), on hypoxia-induced H9c2 cell death and on perfused rat hearts subjected to ischemia/reperfusion. KR-33028 inhibited in a concentration-dependent manner the recovery from acidosis induced by an NH4Cl prepulse in PS120 fibroblast cells expressing the human NHE-1 isoform (IC50: 2.59 microM). Treatment with KR-33028 (1-10 microM) significantly decreased hypoxia-induced necrotic cell death and apoptotic cell death in H9c2 cells. KR-33028 significantly inhibited hypoxia-induced increases in cytosolic and mitochondrial Ca2+ level and cytochrome c release, and recovered hypoxia-induced Delta psi(m) reduction. In the perfused rat hearts subjected to 30 min of ischemia and 30 min of reperfusion, KR-33028 (1-10 microM) improved cardiac contractility, decreased lactate dehydrogenase release, and increased content of tissue ATP, creatine phosphate and glycogen in a concentration-dependent manner. In addition, KR-33028 did not produce significant acute or subacute toxicity in the rats at doses tested. Our results suggest that a novel NHE-1 inhibitor KR-33028 possesses potent cardioprotective effects with minimal toxicity and that the effects may be mediated by inhibition of intracellular Ca2+ overload and mitochondrial cell death pathway.     

Anti-platelet activity of KR-32560, a novel sodium/hydrogen exchanger-1 inhibitor.

We investigated the anti-platelet effect of a newly synthesized guanidine derivative KR-32560, a sodium/hydrogen exchanger-1 (NHE-1) inhibitor, together with the elucidation of the possible mode of action. KR-32560 concentration dependently inhibited the aggregation of washed rabbit platelets induced by collagen (10 microg mL(-1)) and arachidonic acid (AA; 100 microM), with IC50 values of 25 and 46 microM, respectively. Whereas, KR-32560 showed weaker potency against aggregation induced by thrombin (0.05 UmL(-1)) and U46619 (1 microM), and had no effect on thapsigargin (0.5 microM)- or A23187 (5 microM)-induced platelet aggregation up to 50 microM. KR-32560 inhibited the collagen-induced [3H]AA liberation in a concentration-dependent manner. In addition, KR-32560 significantly suppressed TXB2 formation in AA-exposed platelets, but had no effect on production of PGD2, indicating an inhibitory effect on TXA2 synthase. This finding was supported by a TXA2 synthase assay that KR-32560 inhibited the conversion of PGH2 into TXB2 with a similar magnitude to suppression of TXB2 formation. Furthermore, KR-32560 significantly inhibited the collagen-induced [Ca2+]i mobilization and serotonin secretion. Taken together, these observations suggest that the anti-platelet activity of KR-32560 may be mediated by the inhibition of cytoplasmic Ca2+ mobilization and AA liberation.     

Pharmacological profile of parecoxib: a novel, potent injectable selective cyclooxygenase-2 inhibitor

The antinociceptive, anti-inflammatory, antipyretic effects along with gastric safety profile of parecoxib, a novel, potent selective cyclooxygenase-2 inhibiting prodrug, and those of ketorolac, a nonselective cyclooxygenase inhibitor, were evaluated in various animal models. Parecoxib (up to 20 mg/kg, i.v.) had no effect in two acute pain models, namely, the acetic acid-induced writhing (visceral pain) and the formalin test (tonic pain). However, ketorolac (up to 10 mg/kg, i.v.) showed marked antinociceptive effects in these models. In the models of carrageenan-provoked inflammatory hyperalgesia and inflammation, and in lipopolysaccharide-induced pyrexia, parecoxib significantly reversed all the behavioral changes and it was found to be more potent than ketorolac. Further, ketorolac (10 mg/kg, i.v.) produced visible gastric lesions with prominent petechiae and hemorrhagic streaks. However, parecoxib was without any effect on gastric mucosa. The present results showed that the cyclooxygenase-2 inhibitor, parecoxib, when administered parenterally, has potent antihyperalgesic, anti-inflammatory, antipyretic effects and has a better safety profile than with ketorolac, with sparing of cyclooxygenase-1 in the stomach in these animal models.     

Pharmacological profile of FR260330, a novel orally active inducible nitric oxide synthase inhibitor

In this study, we examined effects of a newly synthesized chemical compound, FR260330, (2E)-3-(4-chlorophenyl)-N-[(1S)-2-oxo-2-{[2-oxo-2-(4-{[6-(trifluoromethyl)-4-pyrimidinyl]oxy}-1-piperidinyl)ethyl]amino}-1-(2-pyridinylmethyl)ethyl]acrylamide on nitric oxide (NO) production in rat splenocytes and human colon cancer cell line, DLD-1 cells. FR260330 inhibited NOx production dose dependently in both cells. In lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) treated murine macrophage cell line, RAW264.7, Western blot analysis with gel filtration chromatography revealed FR260330 might prevent dimerization of inducible nitric oxide synthase (iNOS), but had no effect on the expression of iNOS protein. Furthermore, oral administration of FR260330 reduced NOx production dose dependently in plasma from rats exposed to LPS (IC50=1.6 mg/kg). Meanwhile, higher dose (100 mg/kg) of oral administration of FR260330 did not change mean arterial blood pressure in rats. These results suggest that FR260330 might be a useful therapeutical approach to various inflammatory diseases, in which superoxide or peroxynitrite formed from iNOS-derived NO are involved.     

Pharmacological profile of celecoxib, a specific cyclooxygenase-2 inhibitor

The pharmacological profile of celecoxib (CAS 169590-42-5, SC-58635), a specific cyclooxygenase-2 (COX-2) inhibitor, was investigated. Celecoxib inhibited COX-2-mediated prostaglandin E2 (PGE2) production in human dermal fibroblasts (IC50 = 91 nmol/l), whereas it was a weak inhibitor of COX-1-mediated PGE2 production in human lymphoma cells (IC50 = 2800 nmol/l). In in vivo studies, the effects of celecoxib were compared with those of nonsteroidal anti-inflammatory drugs (NSAIDs) in acute rat models of hyperalgesia and pyrexia. Celecoxib abrogated carrageenan-induced hyperalgesia in the hind paw accompanied by a decrease in PGE2 content in paw exudates and cerebrospinal fluid in a dose-related manner, with an ED30 = 0.81 mg/kg. Its analgesic potency was comparable to those of NSAIDs. In lipopolysaccharide-induced pyrexia, the anti-pyretic potency of celecoxib was equal to that of NSAIDs. On the other hand, in a gastric toxicity study in rats, single oral administration of celecoxib had no effect on gastric mucosa or mucosal PGE2 content at doses up to 200 mg/kg. Additionally, celecoxib did not inhibit thromboxane B2 production of calcium ionophore-stimulated peripheral blood of rats or arachidonic acid-induced aggregation of human platelets. These findings suggest that celecoxib might be a safe and effective alternative to NSAIDs for clinical use.     

Pharmacological and clinical profile of exemestane (Aromasin), a novel irreversible aromatase inhibitor

Aromatase is the rate-limiting enzyme playing a role at the final step of estrogen biosynthesis, which is attracting attention as the target enzyme of hormone therapy of postmenopausal breast cancer. Exemestane (Aromasin) is a novel steroidal irreversible aromatase inhibitor that was approved in Japan as a therapeutic drug for postmenopausal breast cancer. Exemestane selectively inhibits aromatase activity in vitro, in a time-dependent and irreversible manner, suggesting the mechanism of action that exemestane covalently binds to aromatase as a pseudo-substrate and inactivates the enzyme. In vivo studies show the inhibitory effect of exemestane on the ovarian aromatase activity and plasma estradiol level of PMSG-primed rats. In studies using DMBA-induced rat mammary tumor models, exemestane shows antitumor activity in both conventional (premenopausal) and ovariectomized, testosterone-treated postmenopausal models. Despite its steroidal structure, exemestane does not have hormonal or anti-hormonal activity, except for a slight androgenic activity. In the early and late phase II clinical trials conducted in Japan on postmenopausal breast cancer patients who received 25 mg/day of exemestane, the response rates were 31.4% and 24.2%, respectively. Blood estrogen levels were also markedly reduced. These results confirmed the clinical relevance of non-clinical study results, as well as the possibility of extrapolation to foreign trial data.     

Arylcyclopropanecarboxyl guanidines as novel, potent, and selective inhibitors of the sodium hydrogen exchanger isoform-1

A novel series of arylcyclopropanecarboxyl guanidines was synthesized and evaluated for activity against the sodium hydrogen exchanger isoform-1 (NHE-1). In biological assays conducted in an AP1 cell line expressing the human NHE-1 isoform, the starting cyclopropane 3a (IC(50) = 3.5 microM) shows inhibitory activity comparable to cariporide (IC(50) = 3.4 microM). Structure-activity relationships are used to optimize the affinity of various acyl guanidines for NHE-1 by screening the effect of substituents at both aryl and cyclopropyl rings. It is demonstrated that introduction of appropriate hydrophobic groups at the phenyl ring and a gem-dimethyl group at the cyclopropane ring enhances the NHE-1 inhibitory activity by up to 3 orders of magnitude (compound 7f, IC(50) = 0.003 microM). In addition, the gem-dimethyl series of analogues seem to display improved oral bioavailability and longer plasma half-life in rats. Furthermore, the lead benzodihydrofuranyl analogue 1 (BMS-284640) shows over 380-fold increased NHE-1 inhibitory activity as well as improved selectivity for NHE-1 over NHE-2 compared to cariporide.     

Contribution of sodium channel and sodium/hydrogen exchanger to sodium accumulation in the ischemic myocardium

Contribution of sodium channels and sodium/hydrogen exchangers (NHEs) to sodium accumulation during ischemia in the ischemic/reperfused heart was examined. Ischemia increased the myocardial sodium. Reperfusion elicited a further increase in the myocardial sodium, which was associated with little recovery of the left ventricular developed pressure (LVDP) of the perfused heart. Treatment with tetrodotoxin or dimethylamirolide (DMA) dose-dependently attenuated the ischemia- and reperfusion-induced increase in myocardial sodium and enhanced the post-ischemic recovery of the LVDP.There was an inverse relationship between the increase in myocardial sodium during ischemia and the post-ischemic recovery of the LVDP.The myocardial sodium accumulation during ischemia is mainly attributed to sodium influx through sodium channels and NHEs.     

Pharmacological profile of ramosetron,a novel therapeutic agent for IBS

Ramosetron is a potent and selective serotonin (5-HT)₃ receptor antagonist that has been shown to affect abnormal colonic function and abdominal pain in animals. Ramosetron (0.3 to 100 μg/kg, p.o.) has been found to significantly suppress abnormal defecation induced by conditioned-fear stress (CFS), restraint stress, corticotropin releasing factor (CRF) and 5-HT in rats and mice, and these effects were more potent than those of alosetron, cilansetron or loperamide. On the other hand, ramosetron (3,000 μg/kg, p. o., once daily for 7 days) did not inhibit normal defecation in dogs while tiquizium significantly inhibited it. Ramosetron (3 to 100 μg/kg, p. o.) also significantly prevented CFS-induced acceleration of colonic transit and CRF-induced abnormal water transport in rats, respectively. Moreover, ramosetron (0.3 to 3 μg/kg, p. o.) significantly suppressed restraint stress-induced decrease in colonic pain threshold, an effect not observed with loperamide. These results indicate that ramosetron produce beneficial clinical effects on IBS symptoms. Received 12 July 2006; accepted 21 August 2006     

Pharmacological profile of opicapone,a thirdgeneration nitrocatechol catechol-O-methyl transferase inhibitor,in the rat

Background and Purpose

Catechol-O-methyltransferase (COMT) is an important target in the levodopa treatment of Parkinson''s disease; however, the inhibitors available have problems, and not all patients benefit from their efficacy. Opicapone was developed to overcome those limitations. In this study, opicapone''s pharmacological properties were evaluated as well as its potential cytotoxic effects.

Experimental Approach

The pharmacodynamic effects of opicapone were explored by evaluating rat COMT activity and levodopa pharmacokinetics, in the periphery through microdialysis and in whole brain. The potential cytotoxicity risk of opicapone was explored in human hepatocytes by assessing cellular ATP content and mitochondrial membrane potential.

Key Results

Opicapone inhibited rat peripheral COMT with ED₅₀ values below 1.4 mg⋅kg⁻¹ up to 6 h post-administration. The effect was sustained over the first 8 h and by 24 h COMT had not returned to control values. A single administration of opicapone resulted in increased and sustained plasma levodopa levels with a concomitant reduction in 3-O-methyldopa from 2 h up to 24 h post-administration, while tolcapone produced significant effects only at 2 h post-administration. The effects of opicapone on brain catecholamines after levodopa administration were sustained up to 24 h post-administration. Opicapone was also the least potent compound in decreasing both the mitochondrial membrane potential and the ATP content in human primary hepatocytes after a 24 h incubation period.

Conclusions and Implications

Opicapone has a prolonged inhibitory effect on peripheral COMT, which extends the bioavailability of levodopa, without inducing toxicity. Thus, it exhibits some improved properties compared to the currently available COMT inhibitors.     

Pharmacological profile of SK&F 105809, a dual inhibitor of arachidonic acid metabolism

The effects of SK&F 105809, 6,7,-dihydro-2-[4(methylsulfinyl) phenyl]-3-(4-pyridyl) -5[H]-pyrrolo[1,2-a] imidazole, on eicosanoid metabolism, inflammatory responses, algesia and ulcer formation are described. SK&F 105809 was determined to be a prodrug for the sulfide metabolite SK&F 105561 which is an inhibitor of 5-lipoxygenase (5-LO) and prostaglandin H (PGH) synthase activities seen with both the isolated enzyme (IC50S 3 microM) and human monocyte production of the eicosanoids leukotriene B4 (LTB4, IC50 1.0 microM) and prostaglandin E2 (PGE2, IC50 0.1 microM). In-vivo conversion of SK&F 105809 to the active principle SK&F 105561 was observed in both mice and rats. SK&F 105809 inhibited LTB4 and PGE2 production in vivo in inflammatory exudates as well as the production of LTB4 and thromboxane B2 (TxB2) ex vivo in rat blood. SK&F 105809 inhibited oedema and inflammatory-cell infiltration in arachidonic acid-induced inflammation in the mouse ear and rat paw as well as in carrageenan- and monosodium urate crystal-induced peritonitis. SK&F 105809 was also effective in inhibiting mouse collagen-induced arthritis and associated acute-phase reactant protein. At the same time, these acute and chronic models of inflammation were found to be resistant to the action of selective cyclooxygenase inhibitors such as naproxen. In addition, SK&F 105809 possessed analgesic activity in phenylquinone-induced abdominal constriction assay and inhibited indomethacin-induced ulcers.     

Effects of KR-32570, a new sodium hydrogen exchanger inhibitor, on myocardial infarction and arrhythmias induced by ischemia and reperfusion

The present study was performed to evaluate the cardioprotective effects of [5-(2-methoxy-5-chloro-5-phenyl)furan-2-ylcarbonyl]guanidine (KR-32570) in rat and dog models of coronary artery occlusion and reperfusion. In addition, we sought to clarify the efficacy of KR-32570 on reperfusion-induced fatal ventricular arrhythmia. In anesthetized rats subjected to 45-min coronary occlusion and 90-min reperfusion, KR-32570 (i.v. bolus) dose-dependently reduced myocardial infarct size from 58.0% to 50.7%, 35.3%, 33.5% and 27.0% for 0.03, 0.1, 0.3 and 1.0 mg/kg, respectively (P<0.05). In anesthetized beagle dogs that underwent 1.2-h occlusion followed by 3.0-h reperfusion, KR-32570 (3 mg/kg, i.v. bolus) markedly decreased infarct size from 28.9% in vehicle-treated group to 8.0% (P<0.05), and reduced the reperfusion-induced release in creatine kinase isoenzyme MB, lactate dehydrogenase, Troponin-I and glutamic-oxaloacetic transaminase. KR-32570 dose-dependently decreased the incidence of premature ventricular contraction, ventricular tachycardia or ventricular fibrillation induced by ischemia and reperfusion in rats. Similar results were obtained in dogs with reperfusion-induced arrhythmia. In separate experiments to assess the effects of timing of treatment, KR-32570 given 10 min before or at reperfusion in rat models also significantly reduced the myocardial infarct size (40.9% and 46.1%, respectively) compared with vehicle-treated group. In all studies, KR-32570 caused no significant changes in any hemodynamic profiles. Taken together, these results indicate that KR-32570 significantly reduced the myocardial infarction and incidence of arrhythmias induced by ischemia and reperfusion in rats and dogs, without affecting hemodynamic profiles. Thus, it could be potentially useful in the prevention and treatment of myocardial injuries and lethal ventricular arrhythmias.     

Pharmacological profile of ASP8497, a novel,selective, and competitive dipeptidyl peptidase-IV inhibitor,in vitro and in vivo

Dipeptidyl peptidase (DPP)-IV is involved in the inactivation of glucagon-like peptide-1 (GLP-1), a potent insulinotropic peptide. Thus, DPP-IV inhibitors are expected to become a useful new class of antidiabetic agent. This report describes the pharmacological profile of the novel DPP-IV inhibitor, ASP8497 [(2S,4S)-4-fluoro-1-({[4-methyl-1-(methylsulfonyl)piperidin-4-yl]amino}acetyl)pyrrolidine-2-carbonitrile monofumarate], both in vitro and in vivo. ASP8497 inhibited DPP-IV in plasma from mice, dogs, and humans with median inhibition concentration (IC₅₀) values of 2.6 nM, 7.3 nM, and 6.2 nM, respectively. In contrast, ASP8497 did not potently inhibit human DPP8 or DPP9 activity (IC₅₀ = 1,700 nM and 100 nM, respectively) and exhibited selectivity against several proteases, including proline-specific proteases (IC₅₀ > 10 μM). Kinetic analysis indicated that ASP8497 is a competitive DPP-IV inhibitor. In normal mice, ASP8497 inhibited plasma DPP-IV activity even 12 h after administration. ASP8497 significantly inhibited increases in the blood glucose level during the oral glucose tolerance test (OGTT) conducted 0.5 h after administration. This was accompanied by increases in the plasma active GLP-1 and insulin levels. In addition, ASP8497 significantly inhibited increases in the blood glucose level during the OGTT conducted 8 h after administration. Furthermore, in Zucker fatty rats, ASP8497 dose dependently improved glucose tolerance with significance at doses of 1 mg/kg or higher. In contrast, ASP8497 did not cause hypoglycemia in fasted normal mice. These results indicate that ASP8497 is a potent, competitive, and selective DPP-IV inhibitor with antihyperglycemic activity.     

Pharmacological profile of novel psychoactive benzofurans

Background and Purpose

Benzofurans are newly used psychoactive substances, but their pharmacology is unknown. The aim of the present study was to pharmacologically characterize benzofurans in vitro.

Experimental Approach

We assessed the effects of the benzofurans 5-APB, 5-APDB, 6-APB, 6-APDB, 4-APB, 7-APB, 5-EAPB and 5-MAPDB and benzodifuran 2C-B-FLY on the human noradrenaline (NA), dopamine and 5-HT uptake transporters using HEK 293 cells that express the respective transporters. We also investigated the release of NA, dopamine and 5-HT from monoamine-preloaded cells, monoamine receptor-binding affinity and 5-HT_2A and 5-HT_2B receptor activation.

Key Results

All of the benzofurans inhibited NA and 5-HT uptake more than dopamine uptake, similar to methylenedioxymethamphetamine (MDMA) and unlike methamphetamine. All of the benzofurans also released monoamines and interacted with trace amine-associated receptor 1 (TA₁ receptor), similar to classic amphetamines. Most benzofurans were partial 5-HT_2A receptor agonists similar to MDMA, but also 5-HT_2B receptor agonists, unlike MDMA and methamphetamine. The benzodifuran 2C-B-FLY very potently interacted with 5-HT₂ receptors and also bound to TA₁ receptors.

Conclusions and Implications

Despite very similar structures, differences were found in the pharmacological profiles of different benzofurans and compared with their amphetamine analogues. Benzofurans acted as indirect monoamine agonists that interact with transporters similarly to MDMA. The benzofurans also interacted with 5-HT receptors. This pharmacological profile probably results in MDMA-like entactogenic psychoactive properties. However, benzofurans induce 5-HT_2B receptor activation associated with heart valve fibrosis. The pharmacology of 2C-B-FLY indicates predominant hallucinogenic properties and a risk for vasoconstriction.     

Pharmacological profile of the novel mammalian tachykinin, hemokinin 1.

1. The effects of the novel mammalian tachykinin, hemokinin 1 (HEK-1), have been investigated by radioligand binding and functional in vitro and in vivo experiments. 2. Similar to SP (K(i)=0.13 nM), HEK-1 inhibited in a concentration-dependent manner and with high affinity [(3)H]-substance P (SP) binding to human NK(1) receptor (K(i)=0.175 nM) while its affinity for [(125)I]-neurokinin A (NKA) binding at human NK(2) receptor was markedly lower (K(i)=560 nM). 3. In isolated bioassays HEK-1 was a full agonist at tachykinin NK(1), NK(2) and NK(3) receptors. In the rat urinary bladder (RUB) HEK-1 was about 3 fold less potent than SP. In the rabbit pulmonary artery (RPA) HEK-1 and in the guinea-pig ileum (GPI), HEK-1 was about 500 fold less potent than NKA and NKB, respectively. 4. The responses to HEK-1 were antagonized by GR 82334 in RUB (pK(B)=5.6+/-0.07), by nepadutant in RPA (pK(B)=8.6+/-0.04) and by SR 142801 in GPI (pK(B)=9.0+/-0.2) with apparent affinities comparable to that measured against tachykinin NK(1), NK(2) and NK(3) receptor-selective agonists, respectively. 5. Intravenous HEK-1 produced dose-related decrease of blood pressure in anaesthetized guinea-pigs (ED(50)=0.1 nmol kg(-1)) and salivary secretion in anaesthetized rats (ED(50)=6 nmol kg(-1)) with potencies similar to that of SP. All these effects were blocked by the selective tachykinin NK(1) receptor antagonist, SR 140333. 6. We conclude that HEK-1 is a full agonist at tachykinin NK(1), NK(2) and NK(3) receptors, possesses a remarkable selectivity for NK(1) as compared to NK(2) or NK(3) receptors and acts in vivo experiments with potency similar to that of SP.     

Pharmacological profile of FK881(ASP6537), a novel potent and selective cyclooxygenase-1 inhibitor

Nonsteroidal anti-inflammatory drugs (NSAIDs) are now understood to fall into one of two agent classes in clinical use. Traditional NSAIDs inhibit both cyclooxygenases-1 and 2 (COX-1, 2), which act as key enzymes catalyzing the same reaction in the production of prostaglandins (PGs), while the second class of NSAIDs selectively inhibit COX-2. Inhibition of the inducible COX-2 isoform is believed to be responsible for the therapeutic effects of NSAIDs, such as anti-inflammatory, analgesic, and antipyretic effects, while COX-1 inhibition results in side-effects on the gastrointestinal (GI) system. In the present study, however, we changed this notion that inhibiting only COX-1 causes adverse effects. We discovered FK881, a specific COX-1 inhibitor which exhibits a 650-fold ratio for human whole blood COX-1/COX-2 and rats in vivo. In rats, FK881 dose dependently inhibited carrageenan-induced paw edema (ED30: 22 mg/kg; diclofenac ED30: 3.6 mg/kg, rofecoxib ED30: 26 mg/kg) and paw swelling associated with adjuvant arthritis (ED50: 17 mg/kg; diclofenac ED50: 1.4 mg/kg, rofecoxib ED50: 1.8 mg/kg). Further, FK881 dose dependently inhibited acetic acid-induced writhing in mice (ED50: 19 mg/kg; diclofenac ED50: 14 mg/kg, rofecoxib ED50: >100 mg/kg) and adjuvant arthritis hyperalgesia in rats (ED50: 1.8 mg/kg; diclofenac ED50: 1.0 mg/kg, rofecoxib ED50: 0.8 mg/kg). However, unlike traditional NSAIDs, GI tolerability was improved, although the antipyretic effect of FK881 was weak (NOEL: >320 mg/kg; diclofenac NOEL: <1 mg/kg, rofecoxib NOEL: 100 mg/kg). These results suggest that FK881 may be useful in treating symptoms of rheumatoid arthritis and osteoarthritis.     

Pharmacological profile of ipragliflozin (ASP1941), a novel selective SGLT2 inhibitor, in vitro and in vivo

The pharmacological profile of ipragliflozin (ASP1941; (1S)-1,5-anhydro-1-C-{3-[(1-benzothiophen-2-yl)methyl]-4-fluorophenyl}-D: -glucitol compound with L: -proline (1:1)), a novel SGLT2 selective inhibitor, was investigated. In vitro, the potency of ipragliflozin to inhibit SGLT2 and SGLT1 and stability were assessed. In vivo, the pharmacokinetic and pharmacologic profiles of ipragliflozin were investigated in normal mice, streptozotocin-induced type 1 diabetic rats, and KK-A(y) type 2 diabetic mice. Ipragliflozin potently and selectively inhibited human, rat, and mouse SGLT2 at nanomolar ranges and exhibited stability against intestinal glucosidases. Ipragliflozin showed good pharmacokinetic properties following oral dosing, and dose-dependently increased urinary glucose excretion, which lasted for over 12?h in normal mice. Single administration of ipragliflozin resulted in dose-dependent and sustained antihyperglycemic effects in both diabetic models. In addition, once-daily ipragliflozin treatment over 4?weeks improved hyperglycemia with a concomitant increase in urinary glucose excretion in both diabetic models. In contrast, ipragliflozin at pharmacological doses did not affect normoglycemia, as was the case with glibenclamide, and did not influence intestinal glucose absorption and electrolyte balance. These results suggest that ipragliflozin is an orally active SGLT2 selective inhibitor that induces sustained increases in urinary glucose excretion by inhibiting renal glucose reabsorption, with subsequent antihyperglycemic effect and a low risk of hypoglycemia. Ipragliflozin has, therefore, the therapeutic potential to treat hyperglycemia in diabetes by increasing glucose excretion into urine.     

Pharmacological profiles of CS-622, a novel angiotensin converting enzyme inhibitor

CS-622 is a prodrug type ACE inhibitor with a thiazepin ring. Its active form, CS-622 diacid, was slightly more potent than enalaprilat in inhibiting ACE isolated from rabbit lung. The inhibitory potency of CS-622 diacid on isolated rat aorta was 3 times that of enalaprilat. The inhibitory action of enalaprilat was abolished quickly by washing the aortic strip with drug-free solution, whereas that of CS-622 diacid was abolished only slowly. This difference suggests that CS-622 diacid binds to vascular ACE more firmly than enalaprilat. By oral administration, CS-622 was 3 times more potent than enalapril, and its onset of action was faster than that of enalapril, suggesting that the conversion of CS-622 to its active diacid occurs faster than the conversion of enalapril. Although CS-622 diacid was only slightly more potent than enalaprilat by intravenous administration, it had a longer duration than enalaprilat. Elimination of renal excretory function potentiated the action of captopril but not that of CS-622, suggesting that unlike captopril, only a small portion of CS-622 is excreted through the kidney.     

Pharmacological and biochemical assessment of SM-10888, a novel cholinesterase inhibitor

The effects of the compound SM-10888 (9-amino-8-fluoro-1,2,3,4-tetrahydro-2,4-methanoacridine citrate) in a number of pharmacological and biochemical tests were studied and compared to those of tacrine (THA), amiridin, HP-029 and physostigmine. SM-10888 inhibited cholinesterase activity (IC50: 2.3 x 10(-7) M) in rat cortical P2 fraction with almost the same potency as THA, while SM-10888 was 2-4 times more potent than amiridin and HP-029, but about 10 times less potent than physostigmine. When given to mice p.o., SM-10888 induced central (hypothermia) and peripheral (salivation) cholinergic effects. When the ratio of the ED50 value for hypothermia to that for salivation was regarded as the index of the selectivity to the central nervous system (CNS), SM-10888 was shown to be about 3 times more selective to the CNS than the other four drugs in mice. The minimum effective dose of SM-10888 for its increasing effect on acetylcholine (ACh) content in the mouse cerebral cortex was about 10 times higher than that of physostigmine, but 5-10 times lower than those of THA, amiridin and HP-029. These results suggest that SM-10888 is an adequate drug for increasing the brain ACh content with less peripheral cholinergic side effects than THA, amiridin, HP-029 and physostigmine.