Catechol-O-methyltransferase inhibition in erythrocytes and liver by BIA 3-202 (1-[3,4-dibydroxy-5-nitrophenyl]-2-phenyl-ethanone)

The present study evaluated the relationship between the degree of catechol-O-methyltransferase (COMT) inhibition in erythrocytes and liver by BIA 3-202 (1-[3,4-dihydroxy-5-nitrophenyl]-2-phenyl-ethanone) and determined its effects upon the O-methylation of L-DOPA in rats orally treated with L-DOPA plus benserazide. The soluble form of COMT (S-COMT) in erythrocytes was endowed with the same affinity as liver S-COMT for the substrate adrenaline. BIA 3-202 inhibited erythrocytes and liver S-COMT with ED50's of 1.9 (0.7, 3.1) and 1.9 (0.5, 3.2) (95% confidence limits) mg kg(-1), respectively. BIA 3-202 reduced the L-DOPA-induced rise of 3-O-methyl-L-DOPA in the peripheral circulation, striatal dialysate levels and striatum, and increased dopamine striatal levels. In BIA 3-202-treated rats the increase in L-DOPA in peripheral blood and striatal dialysates was significantly greater than in vehicle-treated rats. It is concluded that S-COMT activity in erythrocytes may provide important information on the pharmacodynamic profile of COMT inhibitors. The novel COMT inhibitor BIA 3-202 is a potent COMT inhibitor that enhances the availability of L-DOPA to the brain by reducing its O-methylation, which may prove beneficial in patients with Parkinson's disease treated with L-DOPA.     

BIA 3-202, a novel catechol-O-methyltransferase inhibitor,reduces the peripheral O-methylation of L-DOPA and enhances its availability to the brain

The present study aims at determining the effects of the catechol-O-methyltransferase (COMT) inhibitor BIA 3-202 [1-(3,4-dihydroxy-5-nitrophenyl)-2-phenyl-ethanone] upon levels of L-3,4-dihydroxyphenylalanine (L-DOPA) and metabolites in peripheral circulation (jugular vein), whole brain, and striatal microdialysates in rats orally treated with L-DOPA plus benserazide. A low dose (3 mg/kg) of BIA 3-202 was relatively selective to inhibit liver COMT, being devoid of major significant inhibitory effects upon brain COMT. By contrast, a high dose (30 mg/kg) of BIA 3-202 markedly inhibited liver and brain COMT. BIA 3-202 (3 and 30 mg/kg) reduced the L-DOPA-induced rise of 3-O-methyl-L-DOPA in the peripheral circulation (jugular vein), brain tissue, and striatal dialysate, but failed to increase the levels of dopamine in striatal dialysates despite the increase in dopamine brain levels. However, the changes in brain levels of L-DOPA, 3-O-methyl-L-DOPA, and dopamine and in striatal dialysate levels of L-DOPA and 3-O-methyl-L-DOPA, obtained with 3 mg/kg BIA 3-202, were not different from those obtained with 30 mg/kg BIA 3-202. In conclusion, inhibition of peripheral COMT by BIA 3-202 may suffice to improve the availability of L-DOPA to the brain.     

Coadministration of β‐asarone and levodopa increases dopamine in rat brain by accelerating transformation of levodopa: A different mechanism from Madopar

The aim of the present study was to investigate the effect of coadministration of β‐asarone and levodopa (l ‐dopa) on increasing dopamine (DA) in the striatum of healthy rats. Rats were randomly divided into four groups: (i) a normal group, administered normal saline; (ii) a Madopar group, administered 75 mg/kg Madopar (l ‐dopa : benserazide, 4 : 1); (iii) an l ‐dopa group, administered 60 mg/kg l ‐dopa; and (iv) a group coadministered 15 mg/kg β‐asarone and 60 mg/kg l ‐dopa. All drugs (or normal saline) were administered intragastrically twice a day for 7 days. Then, plasma and striatum concentrations of DA, l ‐dopa, 5‐hydroxytryptamine (5‐HT), homovanillic acid (HVA), 3,4‐dihydroxyphenylacetic acid (DOPAC), tyrosine hydroxylase (TH), catechol‐O‐methyltransferase (COMT) and monoamine oxidase B (MAO‐B) were determined. In the group coadministered β‐asarone and l ‐dopa, there was a decline in plasma and striatal concentrations of l ‐dopa; however, DA and DOPAC concentrations increased in the striatum and plasma and plasma HVA concentrations increased, whereas there was no significant change in striatal levels. Concentrations of 5‐HT in the striatum and plasma were similar in the coadministered and Madopar‐treated groups. In addition, plasma and striatal COMT levels decreased after coadministration of β‐asarone and l ‐dopa, whereas there were no significant differences in MAO‐B concentrations among groups. Furthermore, coadministration of β‐asarone and l ‐dopa increased plasma TH concentrations. Altogether, β‐asarone affects the conversion of l ‐dopa to DA by modulating COMT activity and DA metabolism. The mechanism of coadministration is different from that of Madopar in Parkinson's disease (PD) treatment. Thus, the coadministration of β‐asarone and l ‐dopa may be beneficial in the treatment of PD.     

Kinetic inhibitory profile of BIA 3-202, a novel fast tight-binding,reversible and competitive catechol-O-methyltransferase inhibitor

The present study reports the kinetic inhibitory profile of 1-[3,4-dihydroxy-5-nitrophenyl]-2-phenyl-ethanone (BIA 3-202), a novel inhibitor of soluble catechol-O-methyltransferase (COMT) in rat liver. After an oral single dose (30 mg kg⁻¹), there was a time-dependent recovery of enzyme activity from 98±2% inhibition at 30 min to total recovery at 24 h after treatment. The inhibitory effect produced by BIA 3-202 on soluble COMT was reversible after gel filtration of the samples. BIA 3-202 acted as a fast inhibitor of rat liver soluble COMT, interacting immediately with the enzyme after mixing. No differences were observed in the metanephrine formation rates (in nmol mg protein⁻¹ min⁻¹) obtained without and with a 60-min preincubation with 30 nM of BIA 3-202 (1.30±0.02 and 1.35±0.03, respectively). The tight-binding nature of the inhibition produced by BIA 3-202 was evaluated by performing an Ackermann–Potter plot. The true K_i for BIA 3-202, derived from the nonlinear regression analysis, was 0.19±0.02 nM. In substrate competition studies, an increase in the concentration of adrenaline resulted in a linear increase in IC₅₀ values for BIA 3-202. In conclusion, BIA 3-202 behaves as a reversible, potent and fast tight-binding COMT inhibitor that acts competitively at the substrate binding site of rat liver soluble COMT.     

BIA 3-202, a novel catechol-O-methyltransferase inhibitor, enhances the availability of L-DOPA to the brain and reduces its O-methylation.

1-[3,4-Dihydroxy-5-nitrophenyl]-2-phenyl-ethanone (BIA 3-202) is a new long-acting catechol-O-methyltransferase (COMT) inhibitor with limited access to the brain. The present study evaluated the interference of BIA 3-202 upon levels of L-3,4-dihydroxyphenylalanine (L-DOPA) and metabolites in plasma (3-O-methyl-L-DOPA) and brain [3-O-methyl-L-DOPA, dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA)] in rats orally treated with L-DOPA (20 mg/kg) plus benserazide (30 mg/kg). At different time points (1, 3 and 6 h) after the administration of BIA 3-202 (0, 3, 10 and 30 mg/kg) or L-DOPA plus benserazide, rats were sacrificed and the right striatum was quickly dissected out and stored for the assay of L-DOPA, 3-O-methyl-L-DOPA, dopamine and amine metabolites. Levels of L-DOPA, 3-O-methyl-L-DOPA, dopamine, DOPAC and HVA in the striatum in L-DOPA plus benserazide-treated rats were higher than in vehicle-treated rats. However, this increase in striatal L-DOPA, dopamine, DOPAC and HVA was, in a dose- and time-dependent manner, even higher (P<0.05) in rats given BIA 3-202 (3, 10 and 30 mg/kg). This effect was accompanied by a marked decrease in 3-O-methyl-L-DOPA levels in the striatum of L-DOPA plus benserazide-treated rats. Increases in levels of L-DOPA and decreases in 3-O-methyl-L-DOPA levels in plasma also accompanied the administration of BIA 3-202. BIA 3-202 did not significantly affect levels of DOPAC and HVA in the striatum in vehicle-treated rats. It is concluded that administration of BIA 3-202 enhances the availability of L-DOPA to the brain by reducing its O-methylation in the periphery, which may prove beneficial in parkinsonian patients treated with L-DOPA plus an aromatic amino acid decarboxylase inhibitor.     

Enzymatic synthesis of tritium‐labelled isotopomers of L‐DOPA

The synthesis of two isotopomers of L ‐DOPA labelled selectively with tritium is reported. In the intermediate step [3S‐³H]‐, and [3′,5′‐³H₂]‐L ‐tyrosine, have been obtained using a combination of chemical and enzymatic methods. The labelled isotopomers of L ‐tyrosine, L ‐Tyr, have been converted into, [3S‐³H]‐, and [5′‐³H]‐L ‐DOPA using the enzyme mushroom tyrosinase (monophenol oxidase, EC 1.14.18.1) from Neurospora crassa. Copyright © 2005 John Wiley & Sons, Ltd.     

Naringenin attenuates CCl4‐induced hepatic inflammation by the activation of an Nrf2‐mediated pathway in rats

The possible protective effects of naringenin, a naturally occurring citrus flavonone, on carbon tetrachloride (CCl₄)‐induced liver injury in rats and the mechanism underlying its effects were investigated. Forty rats were divided into five groups. Rats in Groups I and II served as the normal and injured liver groups, respectively; Group III rats were treated with the standard drug silymarin as a positive control; and rats in Groups IV and V (naringenin‐treated groups) were administrated 50 mg/kg, p.o., naringenin for 7 days. Liver samples were collected to evaluate mRNA and protein expression, histological changes and oxidative stress. Naringenin inhibited lipid peroxidation and reduced serum levels of hepatic enzymes induced by CCl₄. In addition, naringenin increased the liver content of reduced glutathione and the activity of anti‐oxidant enzymes in rats treated with CCl₄. Naringenin attenuated liver inflammation by downregulating CCl₄‐induced activation of tumour necrosis factor (TNF)‐α, inducible nitric oxide synthase (iNOS) and cyclo‐oxygenase (COX‐2) at both the protein and mRNA levels. Naringenin treatment significantly increased NF‐E2‐related factor 2 (Nrf2) and heme oxygenase (HO‐1) expression in injured livers. In rats treated with CCl₄ alone, decreases were seen in nuclear Nrf2 expression and in the mRNA levels of its target genes (e.g. HO‐1, NQO1 and glutathione S‐transferase alpha 3 (GST‐a3)). Together, the results suggest that naringenin can protect the liver against oxidative stress, presumably by activating the nuclear translocation of Nrf2 as well as attenuating the TNF‐α pathway to elicit an anti‐inflammatory response in liver tissue.     

Pharmacokinetic–pharmacodynamic interaction between BIA 3-202, a novel COMT inhibitor, and levodopa/benserazide

BIA 3-202 is a novel catechol-O-methyltransferase (COMT) inhibitor being developed for use as a levodopa-sparing agent in Parkinsons disease. This study investigated the effect of four single oral doses of BIA 3-202 (50 mg, 100 mg, 200 mg, and 400 mg) compared with placebo on plasma concentrations of levodopa and its metabolite 3-O-methyl-levodopa (3-OMD) and on inhibition of erythrocyte COMT in healthy subjects receiving 100 mg of levodopa and 25 mg of benserazide (Madopar 125). This was a single-centre, double-blind, placebo-controlled, randomised, crossover study with five single-dose treatment periods. The washout period between doses was 2 weeks. On each treatment period, a different dose of BIA 3-202 or placebo was administered concomitantly with Madopar 125. Tolerability was assessed by recording adverse events, vital signs, continuous electrocardiogram and clinical laboratory parameters. In the study, 18 subjects (12 male and 6 female) participated. The drug combination was well tolerated. All doses of BIA 3-202 significantly increased the area under the concentration–time curve (AUC) versus placebo, ranging from 39% (95% confidence intervals, 1.06–1.69) with 50 mg to 80% (95% confidence intervals, 1.42–2.22) with 400 mg. No significant change in mean maximum plasma concentrations (C_max) of levodopa was found. Mean C_max and AUC of 3-OMD significantly decreased for all doses tested. BIA 3-202 caused a rapid and reversible inhibition of S-COMT activity, ranging from 57% (50 mg) to 84% (400 mg). In conclusion, the novel COMT inhibitor BIA 3-202 was well tolerated and significantly increased the bioavailability of levodopa and reduced the formation of 3-OMD when administered with standard release levodopa/benserazide.     

Trifluoromethanesulfonic acid,an alternative solvent medium for the direct electrophilic fluorination of DOPA: new syntheses of 6‐[18F]fluoro‐L‐DOPA and 6‐[18F]fluoro‐D‐DOPA

Previous work from this laboratory has shown that the direct fluorination of 3, 4‐dihydroxy‐phenyl‐L ‐alanine (L ‐DOPA) in anhydrous HF (aHF) or BF₃/HF with F₂ is an efficient method for the synthesis of 6‐fluoro‐L ‐DOPA. Since then, ¹⁸F‐labeled 6‐fluoro‐L ‐DOPA ([¹⁸F]6‐fluoro‐L ‐DOPA) has been used to study presynaptic dopaminergic function in the human brain and to monitor gastrointestinal carcinoid tumors. This work demonstrates that the reactivity and selectivity of F₂ toward L ‐DOPA in CF₃SO₃H is comparable with that in aHF. This new synthetic procedure has led to the production of [¹⁸F]fluoro‐L ‐DOPA and [¹⁸F]fluoro‐D‐DOPA isomers in 17±2% radiochemical yields (decay corrected with respect to [¹⁸F]F₂). The 2‐ and 6‐FDOPA isomers were separated by HPLC and subsequently characterized by ¹⁹F NMR spectroscopy. The corresponding [¹⁸F]‐FDOPA enantiomers have been obtained in clinically useful quantities by a synthetic approach that avoids the use of aHF. Copyright © 2007 John Wiley & Sons, Ltd.     

Pharmacokinetic and pharmacodynamic profiles of BIA 3-202, a novel catechol-O-methyltransferase (COMT) inhibitor, during multiple-dose administration to healthy subjects

The tolerability, pharmacodynamics, and pharmacokinetics of BIA 3-202 (50 mg, 100 mg, and 200 mg twice daily and 200 mg thrice daily), a novel catechol-O-methyltransferase (COMT) inhibitor, were investigated in healthy volunteers. BIA 3-202 was administered to four sequential groups of 8 healthy male subjects under a double-blind, randomized, placebo-controlled design. Within each group, 2 subjects were randomized to treatment with placebo. Treatment duration was 9 days: single dose on the first and last days and twice or thrice daily on days 3 to 8. BIA 3-202 was well tolerated at all dose regimens tested. Median maximum plasma BIA 3-202 concentrations were attained at 0.5 to 2.5 hours postdose. Thereafter, concentrations declined with a t1/2 of approximately 2 to 4 hours. The increase in the extent of systemic exposure, as measured by AUC0-tau, was approximately proportional to the administered dose. Steady state of plasma BIA 3-202 concentrations occurred by day 4 in all dose groups. Less than 1% of the total dose administered was excreted in urine up to 48 hours postdose. BIA 3-202 markedly reduced soluble COMT (S-COMT) activity in erythrocytes, with maximum inhibition occurring at 1 to 2 hours postdose; enzyme activity returned to baseline levels by approximately 8 hours. Inhibition of S-COMT activity appeared to increase with increasing doses of BIA 3-202 on both day 1 and day 9. In conclusion, BIA 3-202 was well tolerated in all the oral multiple-dose regimens tested. BIA 3-202 was shown to inhibit S-COMT activity in erythrocytes, and its pharmacokinetics appeared to be linear (i.e., dose independent and time invariant).     

Synthesis and activity evaluation of 3′‐floxuridinyl 4‐[3‐(3, 5‐di‐t‐butyl‐4‐methoxyphenyl)‐3‐oxo‐propenyl]benzoate: in vitro and in vivo as a potential dual‐acting antitumor prodrug

BOBA (4‐[3‐(3, 5‐di‐tert‐butyl‐4‐methoxyphenyl)‐3‐oxo‐propenyl]benzoic acid), a substituted chalcone derivative, exhibits an excellent inducing differentiation on neoplastic cellular differentiation. FUDR (5‐fluoro‐2′‐deoxyuridine, floxuridine) inhibits DNA biosynthesis and has been used extensively to treat various cancers. In our efforts to find a new dual‐action antitumor prodrug, 3′‐floxuridinyl 4‐[3‐(3, 5‐di‐t‐butyl‐4‐methoxyphenyl)‐3‐oxo‐propenyl] benzoate (3′‐O‐BOBA‐ FUDR) was synthesized, and its antiproliferative activity in vitro and antitumor efficacy in vivo were evaluated. Compared with FUDR, the antiproliferative activity of 3′‐O‐BOBA‐FUDR was improved by 3–7‐fold. In rat hepatocellular carcinoma xenografts, 3′‐O‐BOBA‐FUDR‐treated rats had smaller tumors than were found in controls. In addition, the expression of Bcl‐2 protein was significantly downgraded, whereas the expression of Bax protein was upregulated in neoplastic tissues. The early apoptotic ratio of 3′‐O‐BOBA‐FUDR‐treated rat group was increased dose‐dependently. These findings strongly support the concept that 3′‐O‐BOBA‐FUDR may be a novel and effective dual‐action antitumor prodrug. Drug Dev Res 72:1–9, 2011. © 2011 Wiley Periodicals, Inc.     

β‐asarone and levodopa co‐administration increase striatal dopamine level in 6‐hydroxydopamine induced rats by modulating P‐glycoprotein and tight junction proteins at the blood‐brain barrier and promoting levodopa into the brain

Levodopa (L‐dopa) is widely considered as one of the most effective drug constituents in the treatment of Parkinson's disease (PD), but the blood‐brain barrier (BBB) permeability of L‐dopa is <5%, which causes low efficacy. Neuroprotective effects of β‐asarone on 6‐hydroxydopamine (6‐OHDA)‐induced PD rats were demonstrated by our previous studies. Co‐administration of β‐asarone and L‐dopa has not been explored until being investigated on PD rats in this study. PD rats were divided into four groups: untreated, L‐dopa‐treated, β‐asarone‐treated and co‐administered‐treated groups. All of the treatments were administered to the rats twice per day for 30 days. The L‐dopa, dopamine (DA), 3,4‐dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), S100β and neuron‐specific enolase (NSE) levels were subsequently determined. The P‐glycoprotein (P‐gp), zonula occludens‐1 (ZO‐1), claudin‐5, occludin and actin expression was also assessed in cortex. Changes in BBB ultrastructure were observed using transmission electron microscopy. Our results showed that the co‐administered treatment increased levels of L‐dopa, DA, DOPAC and HVA in striatum, and S100β in plasma, but down‐regulated NSE, P‐gp, ZO‐1, occludin, actin and claudin‐5 in cortex. Crevices were observed between capillary endothelial cells at intercellular tight junction of the striatum in co‐administered‐treated group, while the endothelial cells in untreated group were tightly jointing each other. In addition, the correlations of L‐dopa or DA and P‐gp or tight junction proteins respectively were significantly negative in co‐administered‐ and β‐asarone‐treated groups. These findings suggest that co‐administered treatment may enhance the L‐dopa BBB permeability and attenuate brain injury, which may be beneficial to PD treatment.     

Assessment of impact of α‐Fe2O3 and γ‐Fe2O3 nanoparticles on phytoplankton species Selenastrum capricornutum and Nannochloropsis oculata

In this study, the impact of alpha‐iron oxide (α‐Fe₂O₃, 20‐40 nm) and gamma iron oxide (γ‐Fe₂O₃, 20‐40 nm) nanoparticles (NPs) on phytoplankton species Selenastrum capricornutum and Nannochloropsis oculata was investigated Characterizations of the NPs were systematically carried out by TEM, dynamic light scattering, zeta potential, X‐ray diffraction, SEM, and Fourier transformation infrared spectroscopy. Acute toxicity was tested between 0.2 and 50 mg/L for each NP for a period of 72 hours exposure. γ‐Fe₂O₃ NP inhibited development of N oculata at the rate of 54% in 0.2 mg/L group with a high mortality rate of up to 82%. α‐Fe₂O₃ NPs were less toxic that induced 97% mortality on N oculata at 10 mg/L suspensions. In contrast, α‐Fe₂O₃ NP inhibited growth of S capricornutum strongly (73%) in 0.2 mg/L group. γ‐Fe₂O₃ NPs showed similar growth inhibition (72%) on S capricornutum in 10 mg/L suspensions. Despite the differential effects, the results indicated acute toxicity of α‐Fe₂O₃ and γ‐Fe₂O₃ NPs on N oculata and S capricornutum.     

Syntheses,calcium channel modulation effects,and nitric oxide release studies of O2‐alkyl‐1‐(pyrrolidin‐1‐yl) diazen‐1‐ium‐1,2‐diolate 4‐aryl(heteroaryl)‐1,4‐dihydro‐2,6‐dimethyl‐3‐nitropyridine‐5‐carboxylates

A group of racemic 4‐aryl(heteroary)‐1,4‐dihydro‐2,6‐dimethyl‐3‐nitropyridine‐5‐carboxy‐lates possessing a potential nitric oxide donor C‐5 O²‐alkyl‐1‐(pyrrolidin‐1‐yl)diazen‐1‐ium‐1,2‐diolate ester [alkyl=(CH₂)_n, n=1–4] substituent were synthesized using a modified Hantzsch reaction. Compounds having a C‐4 2‐trifluoromethylphenyl ( 16 ), 2‐pyridyl ( 17 ), or benzofurazan‐4‐yl ( 20 ) substituent generally exhibited more potent smooth‐muscle calcium channel antagonist activity (IC₅₀ values in the 0.55 to 38.6 μM range) than related analogs having a C‐4 3‐pyridyl ( 18 ), or 4‐pyridyl ( 19 ) substituent with IC₅₀ values > 29.91 μM, relative to the reference drug nifedipine (IC₅₀=0.0143 μM). The point of attachment of C‐4 isomeric pyridyl substituents was a determinant of antagonist activity where the relative potency profile was 2‐pyridyl > 3‐pyridyl and 4‐pyridyl. Subgroups of compounds 16a–d , 17a–d , and 20a–d having alkyl spacer groups of variable chain length [–CO₂(CH₂)_nO–, n=1–4] exhibited small differences in calcium channel antagonist potency. Replacement of the ester “methyl” moiety of Bay K 8644 by an O²‐alkyl‐1‐(pyrrolidin‐1‐yl)diazen‐1‐ium‐1,2‐diolate group provided the Bay K 8644 group of analogs 16a‐d that retained the desired cardiac positive inotropic effect. The most potent compound in this group, O²‐ethyl‐1‐(pyrrolidin‐1‐yl)diazen‐1‐ium‐1,2‐diolate 1,4‐dihydro‐2,6‐dimethyl‐3‐nitro‐4‐(2‐trifluoromethylphenyl)pyridine‐5‐carboxylate ( 16b , EC₅₀=0.096 μM) is about eightfold more potent positive inotrope (cardiac calcium channel agonist) than the reference compound Bay K 8644 (EC₅₀=0.77 μM). A similar replacement of the ester “isopropyl” group in the C‐4 benzofurazan‐4‐yl group of compounds by an O²‐alkyl‐1‐(pyrrolidin‐1‐yl)diazen‐1‐ium‐1,2‐diolate ester substituent provided compounds 20 (n=1 and 4) that were approximately equipotent cardiac positive inotropes with the parent reference compound PN 202‐791 ( 3 , EC₅₀=9.40 μM). The O²‐alkyl‐1‐(pyrrolidin‐1‐yl)diazen‐1‐ium‐1,2‐diolate ester moiety present in 1,4‐dihydropyridine calcium channel modulating compounds 16–20 is not a suitable ?NO donor moiety because the percent nitric oxide released upon in vitro incubation with either l ‐cysteine, rat serum, or pig liver esterase was less than 1%. Drug Dev. Res. 60:204–216, 2003. © 2003 Wiley‐Liss, Inc.     

d‐α‐tocopheryl polyethylene glycol 1000 succinate‐containing vehicles provide no detectable chemoprotection from oxidative damage

The objective of this study was to evaluate potential protective effects of vehicles containing d ‐α‐tocopheryl polyethylene glycol 1000 succinate (TPGS), which may impact nonclinical safety assessments of oxidative processes. This was achieved by evaluating plasma, liver and adrenal gland concentrations of d ‐α‐tocopheryl succinate (TS) and d ‐α‐tocopherol as well as oxidative status of plasma following oral dosing of TPGS‐containing vehicles, intraperitoneal (IP) dosing of TS or ex vivo treatment of blood with H₂O₂. Male and female rats were dosed orally with formulations containing 5% or 40% TPGS (70 or 550 mg kg^–1 day^–1 TS, respectively) for 1 week. A control group was dosed orally with polyethylene glycol‐400 (PEG‐400; no vitamin E) and positive control animals received a single 100 mg kg^–1 day^–1 IP injection of TS. Whole blood from untreated animals was treated ex vivo with 5 or 50 mm H₂O₂, with or without TS (0.5, 5, 50 or 500 μm ) or ascorbate (1 mm ), for 1 h. Oral TPGS treatments did not affect d ‐α‐tocopherol concentrations in plasma or adrenal glands and caused only transient increases in liver. Concentrations of TS in plasma, liver and adrenal glands were undetectable in control animals, but increased in all other groups. Oral administration of TPGS did not reduce plasma lipid peroxidation in vivo. Substantially greater TS concentrations used ex vivo (100× greater than in vivo) were also unable to reduce lipid peroxidation in H₂O₂‐treated whole blood. These results provide evidence that administration of oral TPGS vehicles is unlikely to impact nonclinical safety assessments of pharmaceuticals. Copyright © 2014 John Wiley & Sons, Ltd.     

Synthesis of deuterium‐labeled 3‐O‐methyldopa and 4‐O‐methyldopa

Concise methods for the synthesis of 4‐hydroxy‐3‐[²H₃]‐methoxyphenylalanine (3‐O‐[²H₃]‐methydopa) and 3‐hydroxy‐4‐[²H₃]‐methoxyphenylalanine (4‐O‐[²H₃]‐methydopa) are described. The 3‐O‐[²H₃]‐methydopa is a valuable internal standard for the tandem MS quantification of 3‐O‐methyldopa, a metabolite of value in the diagnosis of aromatic l‐amino acid decarboxylase (AADC) deficiency. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis of deuterium‐labelled (−)‐galanthamine

The synthesis of deuterium‐labelled galanthamine is reported. 6‐[²H₃]methoxy‐N‐[²H₃]methyl‐(?)‐galanthamine was obtained in seven steps from galanthamine. The synthesis was carried out by selective O‐ and N‐demethylations. The [²H₃]‐N‐methyl and [²H₃]‐O‐methyl‐groups were introduced by selective aminoreduction and O‐methylation. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis and Antibacterial Activity of Novel 4″‐O‐Carbamoyl Erythromycin‐A Derivatives

Novel 4″‐O‐carbamoyl erythromycin‐A derivatives were designed, synthesized, and evaluated for their in‐vitro antibacterial activities. All of the 4″‐O‐carbamoyl derivatives showed excellent activity against erythromycin‐susceptible Staphylococcus aureus ATCC25923, Streptococcus pyogenes, and Streptococcus pneumoniae ATCC49619. Most of the 4″‐O‐arylalkylcarbamoyl derivatives displayed potent activity against erythromycin‐resistant S. pneumoniae encoded by the mef gene and greatly improved activity against erythromycin‐resistant S. pneumoniae encoded by the erm gene or the erm and mef genes. In particular, the 4″‐O‐arylalkyl derivatives 4c–4e and 4g were found to possess the most potent activity against all the tested erythromycin‐susceptible strains, which were comparable to those of erythromycin, clarithromycin, or azithromycin. 4″‐O‐Arylalkyl derivatives 4e and 4g were the most effective against erythromycin‐resistant S. pneumoniae encoded by the mef gene (0.25 and 0.25 µg/mL). 4″‐O‐Arylalkyl derivatives 4a and 4b exhibited significantly improved activity against erythromycin‐resistant S. pneumoniae encoded by the erm gene. In contrast, the 4″‐O‐alkylcarbamoyl derivatives hardly showed improved activity against all the tested erythromycin‐resistant strains.     

A rapid one‐step radiosynthesis of [11C]‐d‐threo‐methylphenidate

Carbon‐11 labelled d‐threo‐methylphenidate ([¹¹C]‐(1)), a radiopharmaceutical commonly used to image the dopamine transporter, has been labelled in one step using [¹¹C]‐methyl triflate. No protection of the nitrogen atom on the piperidine ring of d‐threo‐ritalinic acid·HCl was required, as O‐methylation was favored over N‐methylation by performing the methylation in buffered solutions which effectively protonate and protect the amine functionality. The reaction was effectively carried out at room temperature in solution by captive solvent ‘LOOP’ methods or using conventional glass vials. Copyright © 2010 John Wiley & Sons, Ltd.     

Investigations of Free Anthraquinones from Rhubarb Against α‐Naphthylisothiocyanate‐induced Cholestatic Liver Injury in Rats

Abstract: The protective effects of anthraquinones from Rhubarb, a Chinese herbal medicine, consisting of the root and rhizome of Rheum palmatum L., R. tanguticum Maxim. Ex Balf., or R. officinale Baill. (family Polygonaceae) were investigated and compared in rats with liver injury induced by α‐naphthylisothiocyanate. α‐Naphthylisothiocyanate was given intragastrically in rats, liver injury with cholestasis developed within 36 hrs, as indicated by characteristic serum levels of glutamate‐pyruvate transaminase, glutamic oxaloacetic transaminase, total bilirubin, direct bilirubin, alkaline phosphatase, γ‐glutamyltransferase and total bile acid. The intragastrical administration of rhein, aloe‐emodin and physione to α‐naphthylisothiocyanate‐treated rats reduced significantly the serum level of both glutamate‐pyruvate transaminase, glutamic oxaloacetic transaminase and the serum total bilirubin, direct bilirubin, alkaline phosphatase, γ‐glutamyltransferase and total bile acid. For all hepatic biochemical markers and cholestasis index, rhein was most efficient. By comparison, the administration of emodin and chrysophanol did not reduce the serum levels of hepatic enzymes glutamate‐pyruvate transaminase and glutamic oxaloacetic transaminase but decreased the levels of serum total bilirubin, direct bilirubin, alkaline phosphatase, γ‐glutamyltransferase, and total bile acid, showing their partial protective effects on cholestatic liver injury. The liver in α‐naphthylisothiocyanate‐treated rats showed cholangiolitic hepatitis characterized by intrahepatic cholestasis, necrosis of hepatocytes and biliary epithelial cells and bile obstruction. The concurrent intragastrical administration of rhein reduced the severity of all morphological alteration, especially the neutrophil infiltration and sinusoid congestion. Rhein, aloe‐emodin, and physione all exhibited protective effects on hepatocytes and cholangiocytes against α‐naphthylisothiocyanate‐induced damage, whereas emodin and chrystophanol provided partial protection.