Concentrations of phenol, o-cresol, and 2,5-xylenol in the urine of workers employed in the distillation of the phenolic fraction of tar

Final Report on the Safety Assessment of Sodium p -Chloro- m -Cresol, p -Chloro- m -Cresol, Chlorothymol, Mixed Cresols, m -Cresol, o -Cresol, p -Cresol, Isopropyl Cresols, Thymol, o -Cymen-5-ol, and Carvacrol1

Sodium p -Chloro- m -Cresol, p -Chloro- m -Cresol (PCMC), Mixed Cresols, m -Cresol, o -Cresol, p -Cresol, Isopropyl Cresols, Thymol, Chlorothymol, o -Cymen-5-ol, and Carvacrol are substituted phenols used as cosmetic biocides/preservatives and/or fragrance ingredients. Only PCMC, Thymol, and o -Cymen-5-ol are reported to be in current use, with the highest concentration of use at 0.5% for o -Cymen-5-ol in perfumes. The use of PCMC in cosmetics is restricted in Europe and Japan. Cresols can be absorbed through skin, the respiratory tract, and the digestive tract; metabolized by the liver; and excreted by the kidney as glucuronide and sulfate metabolites. Several of these cresols increase the dermal penetration of other agents, including azidothymidine. In acute oral toxicity studies, LD50 values were in the 200 to 5000 mg/kg day-1 range across several species. In short-term studies in rats and mice, an o -Cresol, m -Cresol, p -Cresol or m -Cresol/ p -Cresol mixture at 30,000 ppm in the diet produced increases in liver and kidney weights, deficits in liver function, bone marrow hypocellularity, irritation to the gastrointestinal tract and nasal epithelia, and atrophy of female reproductive organs. The no observed effect levels (NOEL) of o -Cresol was 240 mg/kg in mink and 778 mg/kg in ferrets in short-term feeding studies, with no significant dose-related toxicity (excluding body weight parameters). In mice, 0.5% p -Cresol, but neither m -Cresol nor o -Cresol, caused loss of pigmentation. Short-term and subchronic oral toxicity tests performed with various cresols using mice, rats, hamsters, and rabbits resulted in no observed adverse effect levels (NOAELs) for mice of 625 ppm and rats of 50 mg/kg day -1, although the NOEL was 2000 ppm ina chronic study using rats. In rabbits, 160 mg/kg PCMC was found to produce irritation and erythema, but no systemic effects. Hamsters dosed with 1.5% p -Cresol in diet for 20 weeks had a greater incidence of mild and moderate forestomach hyperplasia as compared to the control. Acute inhalation toxicity studies using rats yielded LC50 values ranging from > 20 mg/m3 for o -Cresol to > 583 mg/m3 for PCMC. No deaths were recorded in mice given o -Cresol at 50 mg/m3. Cats exposed (short-term) to 9 to 50 mg/m3 of o -Cresol developed inflammation and irritation of the upper respiratory tract, pulmonary edema, and hemorrhage and perivascular sclerosis in the lungs. Rats exposed (subchronic) to o -Cresol at 9 mg/m3 had changes in leukocytes, spinal cord smears, nervous activity, liver function, blood effects, clinical signs, and neurological effects. In guinea pigs, exposure to 9 mg/m3 produced changes in hemoglobin concentrations and electrocardiograms (EKGs). Rats exposed (subchronic) to 0.05 mg/m3 Mixed Cresols by inhalation exhibited central nervous system (CNS) excitation, denaturation of lung protein, and decreased weight gain. All cresols appear to be ocular irritants. Numerous sensitization studies have been reported and most positive reactions were seen with higher concentrations of Cresol ingredients. Developmental toxicity is seen in studies of m -Cresol, o -Cresol, and p -Cresol, but only at maternally toxic levels. In a reproductive toxicity study of a mixture of m -Cresol and p -Cresol using mice under a continuous breeding protocol, 1.0% caused minimal adult reproductive and significant postnatal toxicity in the presence of systemic maternal toxicity. The o -Cresol NOAEL was 0.2% for both reproductive and general toxicity in both generations. Cresol ingredients were generally nongenotoxic in bacterial, fruit fly, and mammalian cell assays. Thymol did not induce primary lung tumors in mice. No skin tumors were found in mice exposed dermally to m -Cresol, o -Cresol, or p -Cresol for 12 weeks. In the tryphan blue exclusion assay, antitumor effects were observed for Thymol and Carvacrol. Clinical patch testing with 2% PCMC may produce irritant reactions, particularly in people with multiple patch test reactions, that are misinterpreted as allergic responses. o -Cresol, p -Cresol, Thymol, Carvacrol, and o -Cymen-5-ol caused no dermal irritation at or above use concentrations. In two predictive patch tests, PCMC did not produce a sensitization reaction. Overall, these ingredients are not significant sensitizing or photosensitizing agents. The Cosmetic Ingredient Review (CIR) Expert Panel noted some of these ingredients may increase the penetration of other cosmetic ingredients and advised cosmetic formulators to take this into consideration. The CIR Expert Panel concluded that the toxic effects of these ingredients are observed at doses higher than would be available from cosmetics. A concentration limitation of 0.5% was chosen to ensure the absence of a chemical leukoderma effect. For p -Cresol and Mixed Cresols (which contain p -Cresol), the Panel considered that the available data are insufficient to support the safety of these two ingredients in cosmetics. Studies that would demonstrate no chemical leukoderma at concentrations of use of p -Cresol and Mixed Cresols, or would demonstrate a dose response from which a safe concentration could be derived, are needed.

Renal excretion of phenol from physicians after nail matrix phenolization: an observational prospective study

BACKGROUND

Animal studies have shown that many signs of acute poisoning result from phenol entry into the systemic circulation by absorption or ingestion. While no evidence of systemic complications in patients who have undergone phenol nail matrixectomies have been reported, the safety of phenol vapour inhalation by physicians performing this treatment has yet to be investigated.

OBJECTIVE

The goal of this study was to determine whether the levels of phenol to which physicians are exposed to during a phenol-based matrixectomy procedure are within the limits of safe exposure.

METHODS

A continuous prospective study was carried out to measure the urinary phenol concentrations from physicians after performing chemical matrixectomy for ingrown toenails.

RESULTS

The highest concentration of urinary phenol was measured at almost 10 mg/L within the first 2 h after exposure, and subsequently decreased approximately 1 mg/L every 2 h for the first 10 h post exposure. The levels dropped to 3 mg/L at 72 h post exposure.

CONCLUSIONS

The risk associated with phenol exposure while performing chemical phenol matrixectomy was well below the current safety limits when the physician is exposed to 90% phenol vapour for approximately 20 min. Thus, no further specific safety recommendations are required for physicians performing this procedure.

2-Methoxy-4-(2-phthalimidinyl)phenylsulfonyl chloride as a fluorescent labeling reagent for determination of phenols in high-performance liquid chromatography and application for determination of urinary phenol and p-cresol

Highly sensitive fluorescent labeling reagents, 2-(alkyloxy)-4-(2-phthalimidinyl)phenylsulfonyl chlorides (alkyloxy = methoxy, ethoxy, and propoxy; MPS-Cl, EPS-Cl, and PPS-Cl, respectively), for determination of phenols by high-performance liquid chromatography (HPLC) have been developed. These reagents react with phenols in basic medium to produce the corresponding fluorescent sulfonyl esters. The maximum fluorescence wavelengths of the derivatives were 308 nm for excitation and 410 nm for emission. The peaks due to phenol labeled with MPS-Cl, EPS-Cl, and PPS-Cl eluted at 6.3, 8.8, and 12.8 min, respectively, on a reversed-phase column with isocratic elution of methanol/water (2:1, v/v), and the detection limits (signal-to-noise = 3) of the derivatives were 10, 12, and 17 fmol per injection, respectively. Among these reagents, MPS-Cl was advantageous because its derivatives had shorter retention times and higher sensitivities in HPLC. The efficiency of converting phenol to the fluorescent derivative by MPS-Cl was about 100%. When MPS-Cl was applied to the determination of urinary phenol and p-cresol by HPLC using p-ethylphenol as an internal standard, the derivatives were separated at retention times of 6.3, 8.7, and 12.3 min, respectively, under the HPLC conditions described above. The concentrations of phenol and p-cresol in normal human urine were 11.9-293.5 and 8.2-346.1 nmol/mg creatinine, respectively.

Quantitation of o-, m- and p-cresol and deuterated analogs in human urine by gas chromatography with electron capture detection

A gas chromatographic method for the analysis of cresol metabolites of toluene and [2H8]toluene in urine was developed. Cresol glucuronides and sulfates in urine were hydrolyzed with beta-glucuronidase and arylsulfatase. Following extraction with tert.-butyl methyl ether and solvent exchange into benzene, the cresols were derivatized with heptafluorobutyric anhydride to form the heptafluorobutyrate esters. The derivatives were analyzed by gas chromatography with electron capture detection. Chromatographic resolution was achieved between all cresol isomers and their 2H7 analogs. Calibration ranged from 0.001 to 500 microg/ml. Recoveries were 55-97% and showed no trend with respect to analyte concentration. Within-day precision of analyses of benchmark urine samples had a coefficient of variation of less than 4%. The assay sensitivity was limited by chromatographic background but was sufficient for quantification of the unlabeled cresols in urine from men with only environmental exposure to toluene. Average levels in urine samples from 45 men were 0.023, 0.054 and 37 microg/ml for o-, m- and p-cresol, respectively.

Simultaneous determination of phenol, cresol, xylenol isomers and naphthols in urine by capillary gas chromatography

An attempt was made to establish a method for the simultaneous determination of urinary concentrations of phenol, o-, p- and m-cresols, 1- and 2-naphthol and xylenol isomers by capillary gas chromatography. Urine samples were extracted after acid hydrolysis of glucuronides and sulfates by solid-phase extraction. The ten substances were separated gas chromatographically using a capillary column (Ultra 2) of cross-linked 5% phenylmethyl silicone. Calibration graphs were linear for 5-100 micrograms/ml of all the phenols determined. The corresponding detection limits for phenolic compounds varied from 0.1 to 0.2 microgram/ml. The relative standard deviations for samples in urine were in the range 2.6 - 16.6% and the accuracy was in the range 1.4-25%. Recoveries were generally over 80%.