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The effect of 1% mandelic acid bladder washouts on 40 patients who were using in-dwelling catheters was studied. The procedure appeared to benefit those colonised with Pseudomonas species but not those colonised with Proteus species. The subject of bladder irrigation is briefly reviewed.
Urinary excretion of 4-hydroxy-3 methoxy mandelic acid (VMA) was used as an index of catecholamine activity in 59 cases of ulcerative colitis compared with 59 controls and 18 cases of diarrhoea of nervous origin. No significant differences were observed between cases and controls but the level of VMA excretion was raised in nervous diarrhoea.
Conditions for separation of enantiomers of a mandelic acid derivative, methyl 2-phenyl-2-(tetrahydropyranyloxy) acetate (the analyte) were studied. Because of the presence of two chiral carbons, the analyte consists of four stereoisomers stable at ambient temperature. Chiral HPLC of the analyte resulted in four peaks, using an (S,S)-Whelk-O1 column with the mobile phase consisting of hexane and the t-butyl methyl ether (TBME). It was found that TBME dramatically changed the retention of the isomers, though it produced the best enantioseparation on (S,S)-Whelk-O1. The amount of TBME in the mobile phase influenced the degree of retention shift; 5% (v/v) TBME gave a bigger shift than 8% (v/v) and 10% (v/v). 2-Propanol did not produce the same results. The chiral separation was also tried on cellulose tris (3, 5-dimethyl phenylcarbamate) (CDMPC), but only three peaks were seen, indicating some but not full enantiomer resolution.
[Structure: see text] Syn-configured aldol products of mandelic acid esters and aldehydes were synthesized by the catalytic use of amines in the presence of titanium(IV) tert-butoxide. Used along with chiral N-methylephedrine, anti-configured alpha,beta-dihydroxyesters were isolated with a high degree of enantioselectivity for the first time.
The activities of formaldehyde and of mandelic and hippuric acids, alone and in combination, have been tested against some 300 strains of bacteria typical of those causing urinary tract infections. In a chemically defined medium, which resembles urine in many respects, formaldehyde had a mean minimal inhibitory concentration of 13 mug per ml. Activity was several fold lower in media (nutrient agar and tryptic soy agar) that contained significant amounts of protein. The activity of formaldehyde is virtually unaffected by pH in the range of 5 to 8. Mandelic and hippuric acids (2 mg per ml) have limited antimicrobial activity at acid pH values only. The combination of formaldehyde with mandelic acid (2 mg per ml) was additive, most markedly at pH 5; the formaldehyde-hippuric acid combination, however, did not appear to be additive. Our findings suggest that, at pH values between 5 and 6, an antibacterial concentration of formaldehyde will be generated from methenamine within approximately 1 hr after being excreted into the urine.
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A strain of Acinetobacter lwoffii degraded 4-hydroxymandelic and 4-hydroxy-3-methoxymandelic acids to their corresponding benzoates, which were then hydroxylated by specific monooxygenases to yield, respectively, protocatechuic and 3-O-methylgallic acids; these were substrates for meta fission dioxygenases. The product formed from 3-O-methylgallate underwent slow spontaneous cyclization at pH 7 to release methanol.
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A reversed-phase HPLC method for the simultaneous quantitative determination of mandelic acid enantiomers (MA) and phenylglyoxylic acid (PGA) in urine is described. MA and PGA were extracted with ethyl acetate from urine at acidic pH and derivatized with S-(-)-1-(1-naphthyl) ethylamine. A ZORBAX SB-C(18) column (250 mm x 4.6mm i.d., 5 microm, Agilent, USA) was used with a mobile phase composed of methanol-10 mmol/L phosphate buffer [pH 2.5 (65:35, v/v)] at a flow-rate of 0.8 ml/min. Detection was set at UV wavelength of 254 nm. The mean absolute recoveries were 94.2%, 91.9%, 92.5% and 86.3% for S-MA, R-MA, PGA and salicylic acid (I.S.), respectively. The intra- and inter-day precisions determined at three different concentrations ranged from 2.8% to 4.8%, 0.7% to 7.7% and 1.3% to 6.8%, respectively. The lower limits of detection for MA enantiomers and PGA in urine were 1 microg/ml and the lower limits of quantification were 5 microg/ml (R.S.D.<10%, n=5). The method has been applied to determine the urinary excretion of MA enantiomers and PGA from Sprague-Dawley rats after orally administered with styrene.
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This paper describes a sensitive biological monitoring method for assessing exposure to styrene. Two major metabolites of styrene, mandelic acid (MA) and phenylglyoxylic acid (PGA), were measured in urine using reversed-phase high-performance liquid chromatography with a variable wavelength UV detector. The urine sample (200 microL) was saturated with 60 mg of sodium chloride and spiked with 20 microL of internal standard (O-methyl hippuric acid). Hydrochloric acid (6N HCl) was added for acidification followed by extraction with ethyl acetate. The extract (0.5 mL) was dried and reconstituted with the mobile phase. The mobile phase used was water-methanol (90:10) with 0.5% acetic acid. The filtrate (5 microL) was injected into the HPLC with a C18 column. The detection limits for MA and PGA were estimated to be 5 mg/L and 0.5 mg/L, respectively. The average recovery was 96% for MA and 84% for PGA. The between-days coefficients of variation for both metabolites were generally less than 11%. The average within-day variations were usually less than 5%. The method was verified with urine samples collected from workers exposed to styrene. Excellent correlations were observed between environmental styrene exposure and urinary MA (r = 0.92) and PGA (r = 0.85), determined by using the present method. The procedure is sensitive and reproducible, and can be applied to occupational health measurement of styrene exposure.
A semi automated procedure for the determination of 3-methoxy-4-hydroxy-mandelic acid (HMMA) in urine has been evaluated. This procedure offers advantages in simplicity, speed and precision over existing manual techniques which utilize spectrophotometric fluorimetric and gas liquid chromatographic methods. The urine is extracted with ethyl acetate from a highly acidic sample, purified by extraction into acetate buffer and the diazo colour reaction developed. All stages of the procedure are carried out using the Brown and semi-automatic extractor equipped with partition tube. The within and between assay coefficient of variation obtained on pooled freeze-dried urine samples was 6.7% and 7.7% respectively.
A sensitive and stereospecific GC method was developed for the analysis of R- and S-enantiomers of mandelic acid (MA) in urine, using a chiral CP Chirasil-Dex-CB column. The enantiomers of MA were derivatised with isopropanol into their corresponding isopropyl esters and determined either directly with flame ionisation detection (FID) or after subsequent derivatisation of a hydroxy group with pentafluoropropionic anhydride with electron-capture detection (ECD). Both derivatisation steps proceeded with negligible inversion of enantiomers (<1%). The limit of detection of the FID determination was 8 and 5 mg/l for R-MA and S-MA, respectively and of the ECD determination 1 mg/l for both enantiomers. Repeatability (within-day precision) and reproducibility (day-to-day precision) was for both enantiomers below 7.5% for the FID and below 5.8% for the ECD analysis. The method was applied to urine of volunteers exposed to 105 and 420 mg styrene/m3 air. In the urine of the exposed volunteers, the S-enantiomer showed higher excretion compared to that of the R-enantiomer, with marked interindividual differences in excretion of both enantiomers.
The use of a supercritical carbon dioxide reaction medium for the determination of the (R)- and (S)-enantiomers of mandelic acid (MA) is proposed. The process involves a previous derivatization step under supercritical conditions by which the carboxyl group is esterified with methanol, then followed by acylation of the hydroxyl group in methyl MA with pentafluoropropionic anhydride in the absence of a catalyst. These derivatization steps cause no enantiomeric inversion. The derivatized enantiomers are extracted and quantified by gas chromatography. A BETA DEX 225 capillary column allows the separation of (R)-MA and (S)-MA as pentafluoropropionyl methyl esters with good resolution and precision. The overall method was used to determine both enantiomers in urine samples.
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Presently marketed vaginal barrier methods are cytotoxic and damaging to the vaginal epithelium and natural vaginal flora when used frequently. Novel noncytotoxic agents are needed to protect men and women from sexually transmitted diseases. One novel candidate is a mandelic acid condensation polymer, designated SAMMA. The spectrum and mechanism of antiviral activity were explored using clinical isolates and laboratory-adapted strains of human immunodeficiency virus (HIV) and herpes simplex virus (HSV). SAMMA is highly effective against all CCR5 and CXCR4 isolates of HIV in primary human macrophages and peripheral blood mononuclear cells. SAMMA also inhibits infection of cervical epithelial cells by HSV. Moreover, it exhibits little or no cytotoxicity and has an excellent selectivity index. SAMMA, although not a sulfonated or sulfated polymer, blocks the binding of HIV and HSV to cells by targeting the envelope glycoproteins gp120 and gB-2, respectively, and also inhibits HSV entry postattachment. SAMMA is an excellent, structurally novel candidate microbicide that warrants further preclinical evaluation.
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