Identification and determination of 2-thiothiazolidine-4-carboxylic acid in urine of workers exposed to carbon disulfide

A compound was isolated from the urine of workers exposed to carbon disulfide during the production of rayon. The compound was identified as 2-thiothiazolidine-4-carboxylic acid (TTCA) by GC/MS and NMR. A HPLC method for the quantitative determination of TTCA was elaborated and applied to urine samples. The method allowed detection of TTCA concentrations in urine as low as 5 × 10^–7 M.No TTCA was detected in urine of workers occupationally exposed to organic solvents other than CS₂. High concentrations of TTCA (upto 32×10^–5 M) were shown to be present in urine of spinners exposed to CS₂ concentrations of approximately 100 mg/m³. It is suggested that the assay of urinary TTCA is suitable for detection of occupational exposure to CS₂.     

4-Acetaminophenoxyacetic acid,a new urinary metabolite of phenacetin

Summary It is shown that 4-acetaminophenoxyacetic acid (APOA) is an urinary metabolite of phenacetin. APOA was isolated by means of silica gel TLC in various solvent systems from the urine of rats, dogs, and humans, collected 24 h after p.o. treatment with phenacetin (rats and dogs: 200 mg/kg; humans: three single doses of 0.5 g). Expressed as a percentage of the dose, APOA was detected at levels of 1% in rats, 0.13% in dogs and 0.04% in humans. 4-Acetaminophenoxyacetic acid was identified as its methylester—synthetized in the reaction of APOA and diazomethene—by thin layer chromatography, UV absorbance, melting point, and mass spectroscopy.     

Phenaceturic acid,a new urinary metabolite of styrene in the rat

1. After administration of styrene to rat, phenaceturic acid, a new metabolite, was isolated. After administration of d₈-styrene to rat, deuterium-labelled phenaceturic acid was excreted in the urine.

2. Two metabolic pathways are proposed, based on mass spectra of the deuterium-labelled phenaceturic acid.

3. After a single dose of styrene (250?mg/kg), the excreted phenaceturic acid originating from styrene in the urine amounted to 1.4% dose.     

Discovery of 2-arylthiazolidine-4-carboxylic acid amides as a new class of cytotoxic agents for prostate cancer

To improve the selectivity and antiproliferative activity of previously reported serine amide phosphates (SAPs), we designed a new series of 4-thiazolidinone amides, in which the 4-thiazolidinone moiety was introduced as a phosphate mimic. However, these 4-thiazolidinone derivatives demonstrated less cytotoxicity in prostate cancer cells despite improved selectivity over RH7777 cells. To further optimize the thiazolidinone analogues in terms of cytotoxicity and selectivity, we made closely related structural modifications, which led us to the discovery of a new class of 2-arylthiazolidine-4-carboxylic acid amides. These compounds were potent cytotoxic agents with IC(50) values in the low micromolar concentration range and demonstrated enhanced selectivity in receptor-negative cells compared to SAPs and 4-thiazolidinone amides.     

Hopantenic acid beta-glucoside as a new urinary metabolite of calcium hopantenate in dogs

The metabolism of calcium hopantenate (HOPA) was studied in beagle dogs. After oral administration of 14C-labeled HOPA, 25.5% of the administered radioactivity was excreted in the urine within 24 hr, mostly in the form of unchanged drug. The only metabolite, accounting for 4.2% of the radioactivity in the urine, was isolated by HPLC. The metabolite was hydrolyzed by the treatment of beta-glucuronidase (Helix pomatia), acid phosphatase, or beta-glucosidase. These enzyme activities were not inhibited by treatment with D-glucaric acid 1,4-lactone or PO4(3-), but with D-gluconic acid 1,5-lactone, demonstrating that the metabolite is a glucose conjugate. The compound was identified as HOPA-glucoside, 4'-O-(beta-D-glucopyranosyl)-D-hopantenic acid, by GC/MS analyses after derivatization of the metabolite and the synthetic compound. This is the first reported instance of glucose conjugation to a non-acidic hydroxyl group in the metabolism of xenobiotics in mammals.     

An improved method for the determination of aryl-4-hydroxylase activity

An improved method for separation of tritiated benzo[a]pyrene from tritiated water in the aryl-4-hydroxylase assay is presented. Quantitative retention of benzo[a]pyrene was obtained with mixed cellulose acetate and nitrate filters. Enzymatic activities obtained with this modification agreed well with those determined using the standard charcoal column extraction. This modification greatly reduces the time required to perform this assay, and allows for the determination of enzyme activity in a large number of samples.     

Analytical procedure for the determination of the marijuana metabolite 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid in oral fluid specimens

The determination of the marijuana metabolite 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THCA) in oral fluid specimens is described for the first time using a Quantisal oral fluid collection device and gas chromatography with single-quadrupole mass spectrometric detection. Oral fluid specimens were confirmed for the presence of THCA using two-dimensional gas chromatography-mass spectrometry in order to achieve the low concentration levels previously reported to be present in oral fluid. The extraction efficiency for THCA from the oral fluid collection pad was determined to be 80% at a concentration of 10 pg/mL with a coefficient of variation of 8.23%. The intraday precision of the assay ranged from 3.4% to 7.9% over four concentrations; the interday precision ranged from 8.3% to 18.5%. The limit of quantitation was 2 pg/mL. The method was applied to oral fluid specimens collected from a frequent user of marijuana. Samples were collected almost immediately after the subject smoked and then at intervals of 15 and 45 min and 1, 2, and 8 h after smoking. THCA was present in all the specimens, even the initial specimen taken almost immediately after smoking. The presence of THCA minimizes the argument for passive exposure to marijuana in drug-testing cases.     

Identification and quantitation of 11-nor-delta9-tetrahydrocannabivarin-9-carboxylic acid, a major metabolite of delta9-tetrahydrocannabivarin

After incubation of delta9-tetrahydrocannabivarin with human hepatocytes, a major metabolic product was detected by gas chromatography-mass spectrometry that showed identical retention time and mass spectrum to the synthetic 11-nor-delta9-tetrahydrocannabivarin-9-carboxylic acid (11-nor-delta9-THCV-9-COOH). Analysis of human urine specimens from marijuana users and plasma samples from Marinol users showed that 11-nor-delta9-THCV-9-COOH was only present in urine specimens of marijuana users. These results supported the conclusion that identification of 11-nor-delta9-THCV-9-COOH in a donor's urine specimen indicates the use or ingestion of cannabis-related product(s) and would not explain the sole use of Marinol.     

Identification of cis-3'-hydroxycotinine as a urinary nicotine metabolite

1. cis-3'-Hydroxycotinine was detected as an S(-)-nicotine metabolite in the urine of smokers as well as in the urine of rats and hamsters dosed with nicotine.

2. The excreted amount of cis-3'-hydroxycotinine is lower than that of the trans-isomer.     

抗氧化法制备高旋光度的新型手性拆分试剂R-四氢噻唑-2-硫酮-4-羧酸

目的对R-四氢噻唑-2-硫酮-4-羧酸合成产率的影响因素进行探讨,并通过抗氧化方法优化合成工艺。方法以L-半胱氨酸和二硫化碳为起始原料,在硫酸铜作催化剂的条件下合成目的化合物,比较不同抗氧化方法的结果,并对亚硫酸钠的抗氧化进行了优化。结果产品收率提高到75%,比旋度高达[α]2D0-102.1,均比原来提高了约10%,产物的化学结构经IR和1HNMR确定证。结论优化后的方法简便、有效。     

N-hydroxyphenacetin, a new urinary metabolite of phenacetin in the rat

N-Hydroxyphenacetin has been found in the urine of rats dosed with phenacetin, extending previous reports that phenacetin is N-hydroxylated by liver microsomes in vitro. After an oral dose of phenacetin (500 mg/kg) urine was collected for 24 hr, conjugates hydrolyzed with extract of Helix pomatia, and the metabolites extracted with dichloromethane and treated with diazomethane. Methylation of N-hydroxyphenacetin produced a stable derivative, N-methoxyphenacetin, which was separated from most other metabolites by thin layer chromatography. Identification of N-methoxyphenacetin was by combined gas chromatography-mass spectrometry and comparison with the synthetic reference compound. Quantification by gas chromatography with flame-ionization detection showed that 0.023% of the dose phenacetin was recovered from urine as N-hydroxyphenacetin. It is probable that this value considerably underestimates the extent of phenacetin N-hydroxylation in vivo, inasmuch as N-hydroxyphenacetin is known to be rapidly degraded in biological systems.     

Identification of detomidine carboxylic acid as the major urinary metabolite of detomidine in the horse.

Horse urine was investigated for metabolites by chromatography and mass spectrometry following the oral administration of the large animal analgesic sedative detomidine to two stallions and intravenous administration of [3H]-detomidine to a mare. Detomidine carboxylic acid and hydroxydetomidine glucuronic acid conjugate were identified in the urine after the oral doses. In addition, traces of free hydroxydetomidine were observed. About half of the radioactivity of [3H]-detomidine was excreted in the urine in 12 h after the i.v. dose (80 micrograms/kg). Most of the excretion occurred between 5 and 12 h in contrast to urine output which was highest 2-5 h after the dosing. The major radioactive metabolite in the urine was detomidine carboxylic acid. It comprised more than two thirds of the total metabolites in all the urine fractions collected. Its excretion profile was similar to that of total radioactivity. Hydroxydetomidine glucuronide was also excreted. It contributed 10-20% of the total metabolites in the urine. The free aglycone was only seen in the samples collected during the peak urine flow. A minor metabolite was tentatively characterized as the glucuronide of N-hydroxydetomidine.     

An improved method for analysis of urinary hydroxyproline by an automated analyzer

An improved method of analysis has been devised for estimating the amount of hydroxyproline excreted into the urine. This study has been performed to overcome the difficulties accompaning mass-examinations which are indispensable in epidimiological studies. Urine samples are pretreated with a resin-charcoal mixture for elimination of interfering substances or color inhibitions, and the supernatant is treated by evaporation to avoid complications followed by pH adjustment. The residue is reconstituted with diluted HCL. After pretreatment, samples a analyzed with an automated analyzer. Linearity of standard calibration curve, and recovery and reproducibility of this assay are satisfactory. This simple procedure of analysis requires little time. This method is also useful for routine clinical examinations.