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PubMed1983

Quantitative gas chromatographic mass spectrometric determination of mandelic acid in blood plasma. Comparison of deuterated and homologous internal standards.

Quantitative gas chromatography/mass spectrometry/selected ion monitoring of mandelic acid in plasma in the lower micromolar range has been investigated using both the deuterated compound and a homologue, 2-phenyllactic acid, as internal standards. On chromatography of the TMSi-ester ethers, the latter is less stable than the former. The chromatographic isotope effect observed for deuterated mandelic acid does not suggest a carrier function for this compound. Normal plasma levels of mandelic acid are about 0.5 microM. Only a minor portion of phenyramidol is metabolized to mandelic acid. Preliminary in vivo data indicate the presence of a stereoselective transport system for D(-)-mandelic acid in gastrointestinal tract and possibly kidney.

Adult↗
PubMed1994

Urinary mandelic acid and hemoglobin adducts in fiberglass-reinforced plastics workers exposed to styrene.

OBJECTIVES: A field study was undertaken to investigate the effects of occupational styrene exposure on mandelic acid excretion and the formation of styrene-7,8-oxide hemoglobin adducts. Especially the sensitivity of a gas chromatography-mass spectrometry method for determining hemoglobin adducts was evaluated. METHODS: Over a four-week period, each individual of a group of 52 fiberglass-reinforced plastics workers was monitored once a week by the simultaneous measurement of styrene in the air and urinary postshift mandelic acid. In addition mandelic acid and hemoglobin adducts were monitored in a group of 24 unexposed referents. At the end of the monitoring period styrene-7,8-oxide adduct formation on N-terminal valine in hemoglobin was examined by gas chromatography-mass spectrometry according to the modified Edman degradation technique. RESULTS: Personal air samples showed an average styrene exposure of 31 mg.m-3. The average postshift mandelic acid was 98 mg.g creatinine-1. For workers not wearing respirators and not showing breath ethanol, the correlation coefficient between styrene and mandelic acid was 0.78. The blood samples were analyzed for styrene-7,8-oxide adducts on hemoglobin. With a detection limit of 10 pmol.g-1, no styrene-7,8-oxide adducts were found under these exposure conditions. CONCLUSION: Adduct formation in humans is less effective than in mice. In comparison with ethylene, styrene is at least 70 times less effective in forming hemoglobin adducts. Investigating adduct formation in humans at or below the exposure levels reported in this study would require a detection limit of about one order of magnitude better.

Adult↗
PubMed1983

Effect of alcohol on the kinetics of mandelic acid excretion in volunteers exposed to styrene vapour.

The effect of a dose of alcohol on the kinetics of mandelic acid excretion in four volunteers exposed to 220 mg/m3 styrene has been investigated under controlled exposure chamber conditions. Ethanol inhibited the excretion of mandelic acid, so that the peak excretion was delayed from the end of the exposure period until three hours afterwards. One hour after administration of ethanol blood mandelic acid concentrations were 56% of the levels found during the alcohol-free control exposure, and this was paralleled by a 15-fold rise in phenylethane 1,2 diol, the metabolic precursor of mandelic acid. It is suggested that the inhibition of the oxidation of this diol is related to the change in NAD +/NADH ratio produced by ethanol metabolism. The implications of this ethanol effect on the interpretation of urinary mandelic acid excretion when monitoring workers exposed to styrene are discussed.

Adult↗
PubMed1977

Urinary mandelic acid: identified in normal individuals following a single oral load of phenylethylamine.

1. An increased urinary mandelic acid was identified by gas-liquid chromatography in the urine of 3 healthy subjects following the oral ingestion of phenylethylamine. 2. The pathway for the formation of mandelic acid from phenylethylamine was suggested to involve the intermediate phenylethanolamine. The basic similarity of the metabolism of phenylethylamine and tyramine was suggested by the excretion of 4.5% of phenulethlamine as mandelic acid which correlated well to a reported 7.2% of p-tyramine excreted as p-hydroxy mandelic acid.

Humans↗
PubMed1992

Stereometabolism of ethylbenzene in man: gas chromatographic determination of urinary excreted mandelic acid enantiomers and phenylglyoxylic acid and their relation to the height of occupational exposure.

Ethylbenzene is an important industrial solvent and a key substance in styrene production. Ethylbenzene metabolism leads to the formation of mandelic acid, which occurs in two enantiomeric forms, and phenylglyoxylic acid. To decide which enantiomer is preferably formed, 70 urine samples of exposed workers were taken at the end of shifts and--after 3-pentyl ester derivatisation--gas chromatographically analysed. The R/S ratio of mandelic acid enantiomers in urine amounts to 19:1, which means that R-mandelic acid is a major metabolite and S-mandelic acid is one of the minor urinary metabolites of ethylbenzene in man. The R/S ratio is independent of ambient air concentration of ethylbenzene within the investigated range. Compared to an ethylbenzene monoexposure the height of total mandelic acid excretion is decreased in the case of coexposure to other aromatic solvents.

Benzene Derivatives↗
PubMed2002

Use of mandelic acid condensation polymer (SAMMA), a new antimicrobial contraceptive agent, for vaginal prophylaxis.

OBJECTIVE: To assess the contraceptive properties, antimicrobial activity, and safety of mandelic acid condensation polymer (SAMMA). DESIGN: Experimental study of SAMMA's in vitro and in vivo properties. SETTING: Academic research laboratories. PATIENT(S): Healthy volunteers for semen donation in an academic research environment. INTERVENTION(S): Inhibition of sperm function indicators, conception, sexually transmitted infection-causing pathogens (including HIV), and lactobacilli was evaluated. Safety indicators were studied. MAIN OUTCOME MEASURE(S): Quantitation of SAMMA's effect on microbial infectivity or multiplication and on sperm function in vitro; evaluation of contraceptive efficacy in vivo; assessment of safety in vitro and in vivo. RESULT(S): Mandelic acid condensation polymer is not cytotoxic toward lactobacilli, microbial host cells, and spermatozoa. The compound inhibits hyaluronidase and acrosin, induces sperm acrosomal loss, and is contraceptive in the rabbit model. Mandelic acid condensation polymer prevents infectivity of HIV and herpesviruses 1 and 2 and, to a lesser extent, of Chlamydia trachomatis. It inhibits the multiplication of Neisseria gonorrhoeae. Mandelic acid condensation polymer is not mutagenic, has low acute oral toxicity, and is safe in the rabbit vaginal irritation assay. CONCLUSION(S): Mandelic acid condensation polymer inhibits sperm function, is contraceptive, has broad-spectrum antimicrobial activity, and is highly safe. Further development as a microbicide is warranted.

Animals↗
PubMed1984

Urinary mandelic acid as an exposure test for ethylbenzene.

Absorption of ethylbenzene and excretion of mandelic acid were investigated under controlled conditions in six volunteers, exposed at concentrations of 18, 34, 80, and 200 mg/m3. Retention of ethylbenzene vapours in the lungs was 49 +/- 5%. Elimination of mandelic acid was found to be biphasic, with biological half-life values of 3.1 and 24.5 h. Total excreted mandelic acid accounts for 55 +/- 2% of retained ethylbenzene. The results obtained were applied to devise an exposure test for ethylbenzene, which would enable the precise evaluation of exposure at low ethylbenzene, vapour concentrations (+/- 13%). Exposures, carried out dermally, gave a rationale for the exclusion of the skin as a route of entry of ethylbenzene vapours into the body.

Adult↗
PubMed2002

A practical enantioselective fluorescent sensor for mandelic acid.

A novel optically active bisbinaphthyl fluorescent sensor, (S,S)- or (R,R)-1, is designed for the recognition of chiral alpha-hydroxycarboxylic acids. A convenient method has been developed to synthesize this compound. It is observed that (S)-mandelic acid enhances the fluorescence intensity of the (S,S)-sensor significantly more than (R)-mandelic acid does. The enantioselective fluorescent response is confirmed with the observation of a mirror image relationship for the interaction of (S,S)- and (R,R)-sensors with mandelic acid. The enantioselectivity in fluorescence response [(I(S) - I(0))/(I(R) - I(0)) = 2.49] is quite high, which makes the sensor useful for practical application. The fluorescence intensity change of the sensor is found to be linearly related to the enantiomeric composition of mandelic acid. This sensor is potentially useful for the combinatorial search of chiral catalysts for the asymmetric synthesis of alpha-hydroxycarboxylic acids.

Fluorescence↗
PubMed1996

Study of urinary mandelic acid concentration and peripheral nerve conduction among styrene workers.

The relationship between exposure to styrene and nerve conduction velocities was investigated in 32 workers occupationally exposed to styrene. There was a dose-dependent relationship between urinary mandelic acid and ulnar and peroneal motor distal latencies (MDLs). The ulnar and peroneal MDLs of subgroup B (urinary mandelic acid > or = 250 mg/l) were significantly longer than those of subgroup A (urinary mandelic acid < 250 mg/l)(p < 0.05), and the referent group (p < 0.03). After adjusting confounding factors, urinary mandelic acid had a significant positive relationship with ulnar and peroneal MDL. Our study suggests that a low level of styrene, below the 50 ppm exposure limit of the American Conference of Governmental Industrial Hygienists (ACGIH), involves the risk of inducing adverse effects on the peripheral nervous system. The study also indicated that motor distal latency is a sensitive parameter of toxic peripheral neuropathy.

Action Potentials↗
PubMedDate not supplied

[Synthesis of new mandelic acid derivatives with preservative action. Synthesis and acute toxicity study].

Starting from the antiseptic action of DL mandelic acid, there were synthesized a series of esters of the mandelic acid, esters which could have preservative action. This study present the synthesis, structure validation and the acute toxicity study, for the new synthesized compounds. The esters were obtained by acylating 4-hydroxybenzoic acid propyl, ethyl, methyl esters and salicylic acid with the DL mandelic chloride (that was protected initially by the hydroxylic group). The structure of the synthesized compounds was confirmed by quantitative elemental analysis and RMN 1H spectral measurements. The acute toxicity was determined for two of the esters, who proved to had a preservative action (previously studied) and indicated that these esters have a small toxicity.

Esters↗
PubMed1977

[Determination of mandelic acid in urine by means of gas chromatography].

The method of determining mandelic acid in urine after Engstöm was examined. It was stated that supplementing the procedure by introducing an internal standard (a-naphthol) improves the accurary of the method. In case of a full procedure for mandelic acid solutions in urine we get the range of 80 to 800 mg/l +/- 7,13%. This method detectability is sufficient for an industrial evaluation of the exposure to styrene or ethylbenzene.

Chromatography, Gas↗
PubMed1975

Vanillyl mandelic acid excretion in unilateral electroconvulsive therapy (ECT).

The twenty-four hour urinary excretion of vanillyl mandelic acid was determined in a group of eleven psychiatric patients prior to and during the day of the fifth unilateral electroconvulsive treatment. The patients were all determined by their treating psychiatrists and by psychological testing to be psychotically depressed. In ten of the eleven patients a marked decrease in excreted vanillyl mandelic acid was apparent from the pretreatment level to the fifth treatment level. In one of the eleven patients there was a slight rise from the pretreatment level to the excreted level during the fifth day of treatment. The mean pretreatment determination of vanillyl mandelic acid was 4.2 mg per twenty-four hours; the mean determination made on the fifth treatment was 2.8 mg per twenty-four hours.

Depression↗
PubMed1994

Contraceptive discovery: mandelic acid can be used as a spermicide.

Sperms can be quickly and effectively killed by the mandelic acid which is extracted from peach leaves or of the synthetic kind, according to a research project undertaken by Prof. Guo Renyu and Prof. Zhang Minru of Xi'an Medical University. This discovery has been recognized by the Ministry of Public Health. The findings of the research jointly undertaken by the Embryological and Parasitic teaching and Research Sections of Xi'an Medical University indicate that the mandelic acid is effective in killing both sperms and trichomoniasis. It is as effective in killing both sperms and trichomoniasis. It is as effective as nonoxynol-9 in devitalizing sperms and can also achieve the same clinical effect of contraception. It is 2 to 5 times as effective as metronidazole in curing trichomoniasis vaginitis. The research findings show that the mandelic acid will neither incur side-effects of mutation and malformation of fetus nor ill effects on livers, kidneys, and other viscera. It will not disturb the normal activities of bacteria in the vagina and little is to be absorbed by the body. Moreover, it will not provoke any stimulation to mucosa of the vagina.

Asia↗
PubMed1984

Styrene metabolism in man: gas chromatographic separation of mandelic acid enantiomers in the urine of exposed persons.

D- and L-mandelic acid are separated by gas chromatography as isopropyl ester or isopropyl ester-isopropyl urethane on capillary columns, coated with Chirasil -Val. For its determination in urine the isopropyl ester procedure gives better results because other components of the urine do not cause interference. Thus D- and L-mandelic acid in the urine of exposed workers could be detected and verified by means of GC/MS. Occupational styrene exposure near the MAK-value (100 ppm) results in a L/D-enantiomer-ratio in urine of nearly 1.5.

Chromatography, Gas↗
PubMed2006

[Resolution of alpha-cyclohexyl mandelic acid enantiomers by enantioselective extraction in separation system containing tartaric esters and beta-cyclodextrin].

AIM: To establish a resolution method for alpha-cyclohexyl mandelic acid enantiomers by enantioselective extraction and to observe the effects of all kinds of tartaric esters, pH, the concentration of D-tartaric esters and beta-cyclodextrin on the enantioselectivity. METHODS: Resolution of alpha-cyclohexyl mandelic acid enantiomers by enantioselective extraction with tartaric esters and beta-cyclodextrin has been studied. RESULTS: The distribution behavior of alpha-cyclohexyl mandelic acid enantiomers in the separation system was studied. The effects of all kinds of tartaric esters, pH, the concentration of D-tartaric esters and beta-cyclodextrin on the enantioselectivity has been examined in the two-phase. CONCLUSION: Results showed that the complex formed by D-iso-butyl-D-tartaric ester with R enantiomer is stabler than that with S enantiomer. With the increase of pH, the partition coefficient and separation factor decreased. The concentration of beta-cyclodextrin and D-tartaric ester had visible effect on the enantioselectivity.

Esters↗