Synthesis of 4'-hydroxypropranolol sulfate, a major non-beta-blocking propranolol metabolite in man

4'-Hydroxypropranolol sulfate was recently identified as a major metabolite of propranolol (Inderal). In order to confirm the structure and to further study disposition and biological activity, we have synthesized 8 with use of 1,4-naphthoquinone as the starting material. Reduction and alkylation with benzyl iodide gave 4-(benzyloxy)naphthol. Sulfation and chlorosulfuric acid in N,N-dimethylaniline gave potassium 1-(benzyloxy)-4-naphthol sulfate. Catalytic hydrogenation, alkylation with [[[(trifluoromethyl)sulfonyl]oxy]methyl]oxirane, and amination in isopropylamine gave 8. Racemic 8 was found to be 100-1000 times less potent than racemic propranolol as a beta-adrenergic receptor blocking agent in the dog.     

HPLC法测定米诺地尔微乳中米诺地尔的含量

摘 要 目的：建立高效液相色谱法测定米诺地尔微乳中米诺地尔的含量。方法: 色谱柱:Diamonsil C18柱（200 mm×4.6 mm,5 μm）,流动相:甲醇 水 冰醋酸 十二烷基硫酸钠 (70 ∶〖KG-*4〗30 ∶〖KG-*4〗0.03 ∶〖KG-*4〗0.045)(v/v/v/w),流速：1.0 ml·min-1,检测波长：280 nm,进样量：10 μl,柱温：30℃。结果: 米诺地尔在5.00~100.00 μg·ml-1线性关系良好（r=0.999 7）,平均回收率为99.12%,RSD为1.60%（n=9）。结论: 该方法简便,准确,灵敏,重复性好,专属性强,可用于该制剂的含量测定。     

Synthesis of N-hydroxyacetaminophen, a postulated toxic metabolite of acetaminophen, and its phenolic sulfate conjugate.

The synthesis of N-hydroxyacetaminophen (N-acetyl-N-hydroxy-p-aminophenol, 4), a postulated toxic metabolite of acetaminophen (N-acetyl-p-aminophenol, 3), and its phenolic sulfate conjugate (potassium N-acetyl-N-hydroxy-p-aminophenyl sulfate) (13) is described. Potassium p-nitrophenyl sulfate was reduced to the hydroxylamine, acetylated, and treated with sulfatase to yield N-hydroxyacetaminophen. The structures assigned are supported by the spectral data (IR, UV, MS, 1H NMR, and 13C NMR). N-Hydroxyacetaminophen was found to be moderately unstable at physiological pH and temperature, whereas it phenolic sulfate conjugate was stable.     

复方桑参米诺地尔搽剂中米诺地尔的HPLCLC定

建立了高效液相色谱法测定复方桑参米诺地尔搽剂中米诺地尔的含量。采用C18柱，流动相为甲醇．乙腈·水（40：10：50），流速1．2ml／min，检测波长230nm，内标为对乙酰氨基酚。米诺地尔在3．649。6μg／ml浓度范围内线性关系良好（r=0．9999），回收率大于98％，日内和日间RSD均小于1％。     

复方米诺地尔溶液中米诺地尔的含量测定

目的　测定复方米诺地尔溶液中米诺地尔的含量,为该药提供质量控制指标。方法　采用紫外分光光度法,测定复方米诺地尔溶液中米诺地尔的含量。结果　米诺地尔浓度在1～5mg·L-1范围内吸收度与溶液浓度呈线性关系(r =0 . 9999,n =3) ,回收率为10 1. 0 % ,RSD为0 .34% (n =6 )。结论　该法能排除干扰,可作为复方米诺地尔溶液质量控制的有效方法之一。     

HPLC-Q-TOF-MS法对米诺地尔及凝胶有关物质的分析

摘 要 目的：对米诺地尔及其凝胶的有关物质进行考察与鉴定,为标准提高提供依据。方法: 建立HPLC-Q-TOF-MS方法,色谱柱为Thermo Scientific Accucore C18柱（100 mm×2.1 mm,2.6 μm）,流动相为含0.1%甲酸的乙腈 水溶液（7∶〖KG-*2〗93）,流速为0.2 ml·min^-1 ,检测波长为230 nm;电喷雾离子源（ESI）,正离子扫描检测,一级和二级全扫描测定,质量扫描范围m/z 50~500。结果: 在建立的色谱条件下能分离出14个降解杂质,推断了其中8个杂质的结构。结论: 本方法能有效分离鉴定米诺地尔及凝胶中的有关物质,为其质量控制提供参考。     

Differences in the pharmacokinetics of 4-amino-3-chlorophenyl hydrogen sulfate, a metabolite of resatorvid, in rats and dogs

The pharmacokinetics of 4-amino-3-chlorophenyl hydrogen sulfate, M-III of resatorvid, in rats and dogs were investigated using radiolabeled M-III ([(14)C]M-III). The elimination half-life of (14)C in the plasma of rats was approximately 1/30 of that of dogs after intravenous dosing of [(14)C]M-III at 0.5 mg/kg to rats and dogs. The in vitro and in vivo plasma protein binding ratios of M-III were relatively high and were the same in both species. The intrinsic clearance (CL(int)) of M-III in rats was much higher than the glomerular filtration rate in rats. Furthermore, the concentration of [(14)C]M-III in the kidney of rats was much higher than that in the plasma. On the contrary, in dogs, the concentration of [(14)C]M-III in the kidney was very much lower than that in the plasma. These results indicated that M-III was effectively taken up into the kidney and was excreted into the urine in rats; however, in dogs, ineffective renal uptake of M-III was presumed. When [(14)C]M-III and probenecid were simultaneously and continually infused intravenously to rats, the CL(int) of M-III decreased with increasing plasma concentrations of probenecid, indicating that kidney uptake of M-III in rats was inhibited by probenecid. It was also thought that uptake by the organic anion transport system(s) in the basolateral membrane is involved in the renal uptake of M-III in rats. The pharmacokinetic differences of M-III between rats and dogs are considered to be mainly caused by the difference in the urinary excretion via the renal distribution processes.     

HPLC法测定米诺地尔搽剂中米诺地尔的含量

目的建立用于测定米诺地尔搽剂中米诺地尔含量的HPLE法。方法采用HPLC法测定,色谱柱：Hypersil ODS2 （250mm×4．6mm,5μm）,流动相：V（甲醇）：V（0．1％三乙胺水溶液）=25：75,检测波长285nm,柱温30℃,流速1mL·min^-1。结果米诺地尔在质量浓度6．6—39．6mg·L^-1内与峰面积之间呈现良好的线性关系（r=0．9996）,平均回收率为107．99％,RSD为0．99％。结论本方法简便、灵敏度高,能准确检测米诺地尔搽剂中米诺地尔的含量,可作为米诺地尔搽剂质量控制的有效测量方法。     

Endosulfan and its metabolite,endosulfan sulfate,in freshwater ecosystems of South Florida: a probabilistic aquatic ecological risk assessment

Endosulfan is an insecticide–acaricide used in South Florida and is one of the remaining organochlorine insecticides registered under the Federal Insecticide Fungicide and Rodenticide Act by the U.S.EPA. The technical grade material consists of two isomers (α-, β-) and the main environmental metabolite in water, sediment and tissue is endosulfan sulfate through oxidation. A comprehensive probabilistic aquatic ecological risk assessment was conducted to determine the potential risks of existing exposures to endosulfan and endosulfan sulfate in freshwaters of South Florida based on historical data (1992–2007). The assessment included hazard assessment (Tier 1) followed by probabilistic risk assessment (Tier 2). Tier 1 compared actual measured concentrations in surface freshwaters of 47 sites in South Florida from historical data to U.S.EPA numerical water quality criteria. Based on results of Tier 1, Tier 2 focused on the acute and chronic risks of endosulfan at nine sites by comparing distributions of surface water exposure concentrations of endosulfan [i.e., for total endosulfan (summation of concentrations of α- and β-isomers plus the sulfate), α- plus β-endosulfan, and endosulfan sulfate (alone)] with distributions of species effects from laboratory toxicity data. In Tier 2 the distribution of total endosulfan in fish tissue (whole body) from South Florida freshwaters was also used to determine the probability of exceeding a distribution of whole body residues of endosulfan producing mortality (critical lethal residues). Tier 1 showed the majority of endosulfan water quality violations in South Florida were at locations S-178 followed by S-177 in the C-111 system (southeastern boundary of Everglades National Park (ENP)). Nine surface water sampling sites were chosen for Tier 2. Tier 2 showed the highest potentially affected fraction of toxicity values (>10%) by the estimated 90th centile exposure concentration (total endosulfan) was at S-178. At all other freshwater sites there were <5% of the toxicity values exceeded. Potential chronic risk (9.2% for total endosulfan) was only found at S-178 and all other sites were <5%. Joint probability curves showed the higher probability of risk at S-178 than at S-177. The freshwater fish species which contain tissue concentrations of endosulfan (total) with the highest potential risk for lethal whole body tissue residues were marsh killifish, flagfish and mosquitofish. Based on existing surface water exposures and available aquatic toxicity data, there are potential risks of total endosulfan to freshwater organisms in South Florida. Although there are uncertainties, the presence of tissue concentrations of endosulfan in small demersal fish, is of ecological significance since these fish support higher trophic level species, such as wading birds.     

紫外分光光度法测定米诺地尔酊的含量

目的：用紫外分光光度法测米诺地尔酊中米诺地尔的含量,为该药提供质量控制方法。方法：紫外分光光度法。结果：米诺地尔浓度在０．５～６μｇ·ｍｌ－１范围内吸收度与溶液浓度呈线性关系（ｒ＝０．９９９９,ｎ＝５）,回收率为１００．４％,ＲＳＤ为０．１０％（ｎ＝５）。结论：该法能作为米诺地尔酊含量测定的方法,而且简便、准确、快速。     

高效液相色谱法测定米诺地尔搽剂中米诺地尔的含量

目的建立测定米诺地尔搽剂中米诺地尔含量的高效液相色谱(HPLC)检验方法。方法采用Nova-PaKC18色谱柱(150mm×4.6mm,5μm),流动相为甲醇-水(70∶30),流速为1.0mL/min,检测波长为285nm。结果米诺地尔在2.5～20mg/L浓度范围内含量与峰面积比呈现良好的线性关系(r=0.9999),平均回收率为99.5%,RSD为1.85%,最低检出浓度为0.5mg/L。结论本法能准确检测米诺地尔搽剂中米诺地尔的含量,因此可作为米诺地尔搽剂质量控制的有效测量方法。     

HPLC法同时测定复方米诺地尔凝胶中米诺地尔和维A酸的含量

摘 要 目的：建立HPLC法同时测定复方米诺地尔凝胶剂中的米诺地尔和维A酸含量。方法: 色谱柱：Shim Pack VP ODSC₁₈柱（250 mm×4.6 mm,5 μm）;流动相：甲醇和2%醋酸溶液进行梯度洗脱;检测波长：280 nm和350 nm;流速：1.0 ml·min^-1;柱温：35℃;进样量：10 μl。结果: 米诺地尔和维A酸分别在4.0～240.0 μg·mL^-1和0.05～3.00 μg·mL^-1的浓度范围内与峰面积呈良好的线性关系（r分别为0.999 6和0.999 3）。米诺地尔和维A酸的平均回收率分别为99.56%和99.36%,RSD分别为0.42%和0.50%（n=9）。结论:建立的测定方法简便,可行,适用于同时测定复方米诺地尔凝胶剂中米诺地尔和维A酸的含量。     

Ethyl sulfate: a metabolite of ethanol in humans and a potential biomarker of acute alcohol intake

This study identified ethyl sulfate (EtS) in human urine and compared the excretion characteristics of EtS with that of ethanol and ethyl glucuronide (EtG). Urine samples were collected from healthy subjects after a single ethanol dose, and also selected from routine clinical samples. Simultaneous analysis of EtS and EtG was performed by direct electrospray liquid chromatography-mass spectrometry in the negative ion mode, with selected-ion monitoring of the pseudomolecular ions at m/z 125 for EtS (M(w) 126 g/mol) and m/z 221 for EtG (M(w) 222 g/mol). The identity of EtS in authentic urine specimens was established by co-chromatography with reference substance, the presence of product ions (m/z 97 and 80 from m/z 125) with correct relative intensity, and a correct sulfur isotope ratio for (34)S (m/z 127). After healthy subjects drank ethanol, EtS showed a much longer, dose-dependent elimination half-life than the parent compound. No EtS was detected in urines collected after abstention from ethanol for several days prior to sampling. Among 354 consecutive clinical samples, 86 were positive for both EtS and EtG with a mean EtG/EtS molar ratio of 2.3 (median 1.7). Another three urine samples were only positive for EtS and four only for EtG. The present results confirm that sulfate conjugation is a normal but minor metabolic pathway for ethanol in humans, and EtS a common constituent in the urine after alcohol intake. It is also indicated that the concurrent determination of EtS and EtG will improve sensitivity, when being used as biomarkers of recent drinking.     

Evaluation of minoxidil

The chemistry, pharmacokinetics, mechanism of action, clinical studies, adverse effects, toxicology, indications, contraindications, drug interactions, and dosing of minoxidil, a recently approved antihypertensive agent, are reviewed. Minoxidil is an orally effective vasodilator that selectively relaxes peripheral arteriolar smooth muscle, Reflex tachycardia, renin stimulation, and sodium retention occur when minoxidil is used and so it requires the concomitant use of a diuretic and a sympathoplegic agent, usually a beta blocker. Hirsutism and pericardial effusions are additional adverse effects. Minoxidil is indicated in the management of severe hypertension in patients who do not respond to standard antihypertensive agents. In controlled and unctrolled studies, minoxidil was effective in patients with hypertension secondary to renal or renovascular disease and in patients with essential hypertension. Minoxidil is a potent antihypertensive agent with adverse effects that limit its use to patients resistant or intolerant to other drugs.     

Liquid chromatographic analysis of triamterene and its major metabolite, hydroxytriamterene sulfate, in blood, plasma, and urine

The first rapid and highly sensitive high-performance liquid chromatographic (HPLC) assay for triamterene, hydroxytriamterene, and hydroxytriamterene sulfate is reported. Plasma samples were processed by protein precipitation, while urine was used untreated. Three different solvent systems were used to analyze (a) triamterene in plasma (30% acetonitrile, pH 4.0; internal standard: furosemide; sensitivity limit: 1 ng/mL); (b) hydroxytriamterene and hydroxytriamterene sulfate in plasma (12% acetonitrile, pH 5.5; internal standard: cefamandole; sensitivity limits: 20 and 2 ng/mL, respectively) and (c) triamterene, hydroxytriamterene, and hydroxytriamterene sulfate in urine (13% acetonitrile, pH 5.3; internal standard: hydroflumethiazide; sensitivity limits: 0.04 microgram/mL, 0.5 microgram/mL, and 0.1 microgram/mL, respectively). Fluorescence detection of compounds was performed at 365-nm excitation and 440-nm emission wavelengths. Recovery of triamterene and its metabolites from plasma was complete, and calibration curves were linear. Intraday variation was less than 6% except for the lowest plasma concentration. The assay procedure has already been used in several pharmacokinetic studies.     

Isolation and identification of a new major metabolite of diflunisal in man. The sulfate conjugate

A new metabolite of diflunisal has been identified in volunteers and patients after multiple dose administration. The metabolite was isolated from human urine by silica gel chromatography and was further purified by reversed phase HPLC. Arylsulfatase from Helix pomatia and from Aerobacter aerogenes completely hydrolyzed the isolated metabolite to diflunisal, although hydrolysis by bacterial arylsulfatase was extremely slow. Electron impact mass spectra for diflunisal and its sulfate conjugate were virtually identical. Negative ion fast atom bombardment mass spectra clearly showed the quasimolecular ion [M-H]- at m/z 329 (base peak) as well as a large fragment ion (90% relative intensity) at m/z 249 corresponding to the loss of the sulfate moiety. Urinary excretion patterns in volunteers and rheumatoid arthritis patients revealed that sulfate conjugation of diflunisal is a minor metabolic pathway after single 500-mg dose administration (less than 10% of the dose), whereas it becomes a major pathway (21.3-44.3% of the dose) following multiple doses (500 mg b.i.d.). In one volunteer, who ingested 500 mg diflunisal b.i.d. for 5 weeks, it was shown that the percentage of the dose excreted as diflunisal sulfate gradually increased during the first week to approximately 30% and stayed virtually unchanged for the remaining 4 weeks of diflunisal intake. These preliminary observations are not compatible with the idea that sulfate conjugation is capacity-limited at lower substrate concentrations than glucuronide conjugation, nor do they suggest that sulfation of diflunisal is rate-limited by depletion of inorganic sulfate body stores.     

Isolation and identification of 6-desmethylnaproxen sulfate as a new metabolite of naproxen in human plasma

A new metabolite of naproxen, 6-desmethylnaproxen sulfate (6-DMNS), has been identified in plasma from normal and uremic subjects after oral administration of a single 500 mg dose of naproxen. Tentative identification was achieved by the finding of an increase in the concentration of 6-DMN upon incubation of the plasma with arylsulfatase from Helix pomatia or from Aerobacter aerogenes. More definitive identification was established through demonstration that the HPLC retention time of the conjugate is identical to that of an authentic reference sample of 6-DMNS. Unequivocal identification was accomplished by means of LC-MS after the metabolite was isolated from the plasma by protein precipitation with acetonitrile and further purified by anion-exchange and reversed phase HPLC. Plasma profiles of 6-DMNS for normal and uremic subjects, obtained by a procedure involving differential enzymatic hydrolysis using arylsulfatase from H. pomatia, revealed that 6-DMNS was present in plasma from all subjects but in relatively high concentrations only in subjects with impaired renal function and that the extent of the conjugation is related directly to the severity of the dysfunction. No evidence was found for the presence of glucuronide or sulfate conjugates of naproxen in plasma.     

Biopharmaceutical studies on drug/conjugated-metabolite interactions. I. Fate of acetaminophen sulfate,a major conjugated metabolite of acetaminophen,in rats

The plasma elimination kinetics and intestinal absorption kinetics of acetaminophen sulfate (APAPS), a major conjugated metabolite of acetaminophen (APAP), indispensable for the kinetic elucidation of drug/APAPS interactions, were examined in rats. Plasma elimination kinetics of APAPS after i.v. administration could be described by a two-compartment model with linear parameters to the dose. The deconjugation of intravenously administered APAPS, i.e., the formation of APAP, was recognized in neither plasma, urine nor bile. Approx. 80% of intravenously administered APAPS was excreted as the unchanged form in the urine in 4 h while biliary excretion was only a few percent of the dose. Plasma profiles of APAPS after oral administration showed two peaks, but the second one disappeared when the rat was pretreated with kanamycin sulfate. However, APAPS permeation through the small- and the large-intestinal walls determined in situ was not altered after kanamycin treatment. High APAPS-hydrolyzing activities present in the cecal and colonic contents and the feces, but not in the small-intestinal contents, completely disappeared after kanamycin treatment. Thus, part of the orally administered APAPS was absorbed as the unchanged form from both the small and large intestines, and considerable amounts of the remainder were absorbed from the large intestine as APAP after enzymatic hydrolysis by the intestinal microflora during transit through the lower bowel.