Estimated daily intake of plasticizers in 1-week duplicate diet samples following regulation of DEHP-containing PVC gloves in Japan

Duplicate hospital diet samples obtained over 1 week in 2001 were analysed to estimate the daily intake of plasticizers and the results were compared with those obtained in 1999. The plasticizers quantified in this study were: dibutyl phthalate, butylbenzyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), di(2-ethylhexyl) adipate (DEHA), diisononyl adipate (DINA) and O-acetyl tributyl citrate (ATBC). Dipropyl, dipentyl, dihexyl and dicyclohexyl phthalate were also analysed but not detected. The analytical procedure for this follow-up study was essentially the same as in the previous one. Detection limits were 0.1-15.6 ng g(-1) for each plasticizer. One-week duplicate diet samples provided by three hospitals in three remote prefectures of Japan were analysed as individual meals. DEHP was detected at 6-675 ng g(-1) in 62 of 63 meals, significantly lower levels compared with those detected in 1999. Levels of DEHA and DINP also decreased. The mean intake of plasticizers estimated from all samples was 160 microg DEHP day(-1), 12.5 microg DEHA day(-1), 4.7 microg DINP day(-1) and 3.4 microg BBP day(-1). Levels of DINA were relatively high in meals from one hospital: in those meals, the average daily intake was 1338 microg day(-1). Those of ATBC were also higher in meals from another hospital: the average daily intake was 1228 microg day(-1). The sources of DINA and ATBC can be cling-film or sausage packaging.

[Clean-up procedure with ion-exchange mini column in the analysis of flusulfamide in agricultural products by HPLC]

A clean-up procedure with an ion-exchange column in the analysis of flusulfamide by HPLC was examined. Pesticide in the sample was extracted with methanol following liquid-liquid partition with ethyl acetate. The ethyl acetate fraction was cleaned up with silica gel column chromatography. The eluate from the silica gel column was further cleaned up with SAX + PSA mini column, then determined by HPLC. Carotenoids and interfering peaks were removed by washing the combined mini columns with 10 mL of 20% acetone-containing n-hexane and 5 mL of acetone, and flusulfamide was eluted with 35 mL of acetone.

Determination of clethodim and its oxidation metabolites in crops by liquid chromatography with confirmation by LC/MS

A method was developed for determination of the herbicide clethodim (C0) and its oxidation metabolites clethodim sulfoxide (C1) and clethodim sulfone (C2) in agricultural products. Upon extraction, both C0 and C1 were oxidized to C2 by m-chloroperoxybenzoic acid, and C2 was determined by liquid chromatography (LC). The C2 peak was confirmed by liquid chromatography/mass spectrometry (LC/MS) with electrospray ionization (ESI). Recoveries of C0 from radish, tomato, onion, sweet potato, kidney bean, carrot, cabbage, and lettuce ranged from 91 to 118% following fortification at 0.05-1.0 ppm. The detection limit of C2 in crops was 0.01 ppm (S/N > 3). The fortified samples of onion, sweet potato, kidney bean, and carrot were confirmed by LC/MS (ESI), and the peak of C2 was detected.

Di(2-ethylhexyl) phthalate contamination of retail packed lunches caused by PVC gloves used in the preparation of foods

Plasticizer contamination of foods sold in retail packed lunches and set lunches in restaurants was determined by GC/MS. The phthalate esters were as follows: diethyl, dipropyl, dibutyl, dipentyl, dihexyl, butylbenzyl, dicyclohexyl, di(2-ethylhexyl), dioctyl, diisooctyl (mixture of isomers) and diisononyl (mixture). Di(2-ethylhexyl) adipate was also determined. Sixteen packed lunches and ten set lunches were analysed, and in all samples the concentration of di(2-ethylhexyl) phthalate (DEHP) was the highest, at 0.80-11.8 mg/kg in packed lunches and 0.012-0.30 mg/kg in set lunches. The DEHP content of five packed lunches exceeded 1.85 mg, which is the EU tolerable daily intake (TDI) for a person of 50 kg body weight. Foodstuffs that were components of the packed lunches were taken from the factory at each step of preparation and phthalates were determined. For example, chicken contained 0.08 mg/kg DEHP when uncooked, 13.1 mg/kg after frying and 16.9 mg/kg after packing. Disposable PVC gloves used in the preparation of foods were apparently the source of high DEHP concentrations. The gloves used during cooking or packaging were sprayed with 68% (w/w) ethanol to sterilize them. PVC gloves from the factory contained 22 or 41% by weight of DEHP. To confirm the link with the contamination problem, samples of boiled rice, croquette and boiled dry radish were handled in the laboratory with PVC gloves containing 30% (w/w) DEHP. DEHP migration levels of 0.05 mg/kg in rice or 0.33 mg/kg in croquette, and 11.1 mg/kg in radish were found. The alcohol sprayed onto the gloves increased the migration of DEHP to 2.03 mg/kg in rice, 2.45 mg, kg in croquette, and 18.4 mg/kg in radish.

Simultaneous determination of residues of emamectin and its metabolites, and milbemectin, ivermectin, and abamectin in crops by liquid chromatography with fluorescence detection

A liquid chromatographic (LC) method was developed for the determination of emamectin and its metabolites (8,9-Z-isomer, N-demethylated, N-formylated, and N-methylformylated emamectin) in various crops. The analytes were extracted with acetone, cleaned up on cartridge columns (C18 and NH2), derivatized with trifluoroacetic anhydride and 1-methylimidazole, and determined by LC with fluorescence detection. Because radish inhibited the formation of the fluorescent derivatives, an additional Bond Elut PRS cartridge was used in the cleanup of Japanese radish samples. During sample preparation, N-formylated emamectin partially degraded to emamectin B1b and emamectin B1a, and the 8,9-Z-isomer partially degraded to N-demethylated emamectin. Therefore, emamectin and its metabolites were determined as total emamectin, i.e., their sum was estimated as emamectin benzoate. Their recoveries from most crops were approximately 80-110% with the developed method. The detection limits for the analytes in vegetables were 0.1-0.3 parts per trillion (ppt). The results for these compounds were confirmed by LC/mass spectrometry (LC/MS; electrospray ionization mode). Because the fluorescent derivative of emamectin was undetectable by LC/MS, the results for the analyte were confirmed by using a sample solution without derivatization. Limits of detection by LC/MS were similar to the fluorescence detection limits, 0.1-0.3 ppt in vegetables. In addition to the emamectins, milbemectin, ivermectin, and abamectin were also determined by the developed method.

Eleven phthalate esters and di(2-ethylhexyl) adipate in oneweek duplicate diet samples obtained from hospitals and their estimated daily intake

Plasticizers in duplicate diet samples obtained over 1 week were analysed in order to estimate daily intake. The phthalate esters were as follows: diethyl, dipropyl, dibutyl, dipentyl, dihexyl, butylbenzyl, dicyclohexyl, di(2-ethylhexyl), dioctyl, diisooctyl (mixture of isomers) and diisononyl (mixture). Di(2-ethylhexyl) adipate was also determined. Homogenized samples of composite meals were extracted with acetonitrile, lipids were removed by extraction into n-hexane and the acetonitrile layer was cleaned using Florisil and Bondesil PSA dual layer column. Phthalates were determined by GC/MS (SIM). Phthalate recovery from the fortified food mixture by this method was 62.5-140.8%. Quality assurance as assessed by three laboratories indicated coefficient of variance in the levels of detected phthalates in same lot samples as below 10%. Detection limits were 0.1-23 ng/g for each phthalate. One-week duplicate diet samples provided by three hospitals in three remote prefectures of Japan were analysed as individual meals. In all 63 samples, DEHP was present at the highest level among all phthalates in the range 10-4400 ng/g. The intake of plasticizers estimated from all samples was 519 microg DEHP/day, 86 microg DEHA/day, 65 microg DINP/day, and 4.7 microg BBP/day. Calculated DEHP in 2-day samples out of 21 days exceeded EU TDI for a person of 50 kg body weight (1850 microg per day). Disposable PVC gloves used during the preparation of meals were suspected as the source of the high DEHP content. One-day intake of the other phthalates and DEHA was below 7% of TDI in all cases. High concentrations of DEHP (5990 ng/g) was found in baby food used in quality assurance work. The source of contamination was the PVC-tube used during production and was effectively reduced by replacing the tube by one made of stainless steel.

[Contents of eleven phthalates and di(2-ethylhexyl) adipate in retail packed lunches after prohibition of DEHP-containing PVC gloves for cooking purposes]

Ten samples of retail packed lunches purchased from convenience stores were determined for 11 phthalates and di(2-ethylhexyl) adipate (DEHA) in August 2000, 2 months after the prohibition of DEHP-containing PVC gloves in Japan. Each homogenized sample was extracted with acetonitrile, partitioned with n-hexane, and cleaned up using Florisil and PSA columns. Phthalates in the extract were determined by GC/MS (SIM). The limits of detection were 14.9 ng/g for di(2-ethylhexyl) phthalate (DEHP) and 18.6 ng/g for dibutyl phthalate (DBP). Levels of phthalates in packed lunch samples were 45 to 517 ng DEHP/g (198 ng/g, average), ND to 90 ng DEHA/g, and ND to 10.0 ng BBP/g. Diisononyl phthalate (DINP) was detected in one sample at 76 ng/g. Average DEHP level in ten samples was 4% of that in 1999. The contents of other phthalates were also reduced. DBP was not detected in any sample. Recovery of deuterated isomers added as surrogates was 27.9% for DNP-d4, and 40.6 to 101.5% for the other phthalates.

Liquid chromatographic determination of emamectin, milbemectin, ivermectin and abamectin in crops and confirmation by liquid chromatography-mass spectrometry

Emamectin, milbemectin, ivermectin and abamectin are similar macrocyclic lactone chemicals used as an acaricides or parasiticides. We developed a simultaneous analytical method for determining the residual amounts of these compounds and emamectin metabolites in crops. A sample extracted with acetone was cleaned up with Bond Elut C18 and NH2. The sample was then fluorescence-derivatized with trifluoroacetic anhydride and 1-methylimidazole in acetonitrile. The analyte was measured by HPLC with fluorescence detection using an octadecylsilyl column with 3 microm particle size and gradient elution. In most crops, their recoveries by the developed method were ca. 80-110%. The detection limits of the analytes in vegetables were 0.1-0.3 ppt. Using the developed method, we surveyed the residues of these compounds in 20 commercial crops in Osaka, Japan. The result of the surveillance was that emamectin benzoate of 0.2-6.7 ppb was detected in nine cases and milbemectin of 16.7-279.3 ppb was detected in four cases. The detected samples were confirmed by LC-electrospray ionization (ESI) MS. The limit of detection by LC-ESI-MS was similar to the fluorescence detection level of 0.1-0.3 ppt in vegetables except for milbemectin.

Degradation of malathion and phenthoate by glutathione reductase in wheat germ

Residual malathion in wheat was estimated at a lower value when analysis was performed by extraction with acetone after addition of water to swell the wheat, according to the Japanese Bulletin Method. The supernatant of the wheat homogenate showed degradation not only of malathion but also of phenthoate. Malathion and phenthoate were not degraded by the boiled supernatant of the wheat homogenate. It was presumed for this reason that glutathione reductase (GR; EC 1.6. 4.2) in the wheat degraded malathion. The following results were obtained: (1) GR originating in wheat could degrade malathion and phenthoate. (2) The degradation of malathion by the GR was inhibited by excessive GSSG. (3) There was a high correlation between GR activity and malathion degradation activity of the supernatant of wheat homogenates. It is likely that GR acted on the specific structure of malathion and phenthoate, the S=P-S bond, and the blanch structure bonding with the sulfur atom. Following the above, extraction with acetone after addition of water (the Japanese Bulletin Method) should be replaced by extraction with pure organic solvent and without addition of water for swelling.

[Estimated production by the official inspection of coal-tar dyes (including dye aluminum lakes) in 1997]

The number of official inspection of coal-tar dyes and their lakes from April in 1997 till March in 1998 were 571 in total. The quantity which passed inspection amounted to 160.3 ton in Japan. The production of color in each month was summarised in Table 1, and by each producing company in Table 2. The food coal-tar dye produced in the largest quantity was Food Yellow No.4, occupying 39.8% in this period.

[Determination of tocopherols in oils of mixed tocopherol as food additive using reverse-phase high-performance liquid chromatography]

Simultaneous determination of four tocopherols was developed using reverse-phase high-performance chromatography with a mixture of methanol and water (88:12) as a mobile phase. The alpha-, beta-, gamma- and delta-tocopherols in oils of mixed tocopherol as food additive were determined. It is clarified that the proposed method is useful for the quality control of food additive.

[Estimated production by the official inspection of coal-tar dyes (including dye aluminum lakes) in 1996]

The number of official inspection of coal-tar dyes and their lakes from April in 1996 till March in 1997 were 581 in total. The quantity which passed inspection amounted to 164.5 ton in Japan. The production of color in each month was summarised in Table1, and by each producing company in Table2. The food coal-tar dye produced in the largest quantity was Food Yellow No. 4, occupying 43.4% in this period.

[Determination and survey of starting materials, intermediates, and subsidiary colors in food color of azo dye by high performance liquid chromatography]

A method for determination of starting materials, intermediates and subsidiary colors in food color of azo dye was developed by use of HPLC. The following conditions were used for analysis: column, L-column ODS (4.6 mm phi x 250 mmL); mobile phase, 0.02 M ammonium acetate (A), acetonitrile (B); concentration gradient, perform the linear concentration gradient from A:B (100:0) to (60:40) for 40 min; detection, starting materials and intermediates at 239 nm, and subsidiary colors at 510 nm. Standard material, domestic product and imported product were analyzed by the present HPLC method and impurities were measured. Recoveries of each impurity from azo dye averaged 99.1-103.5%. The detection limit was 0.05 microgram/g for each impurity.

[Studies on "Fast Green FCF Standard" for the dye standard on the National Institute of Health Sciences]

The raw material for Fast Green FCF was tested for preparation of the "Fast Green FCF Standard (C.I. 42053)". Analytical data obtained were as follows: paper chromatography, only one spot is observed; arsenic content, 0.38 microgram/g; chloride content, 0.11%; sulfate content, 3.30%; heavy metals, lead, 8.0 micrograms/g, manganese, 28.1 micrograms/g, and chromium, 1.6 micrograms/g; infrared spectra, 1575 cm-1, 1169 cm-1, and 1033 cm-1; loss on drying, 2.39%; assay, 93.0% by the titanium trichloride titration. Based on the above results, the raw material was authorized as the Dye Standard of National Institute of Health Sciences.

[Estimated production by the official inspection of coal-tar dyes (including dye aluminum lakes) in 1995]

The number of official inspection of coal-tar dyes and their lakes from April in 1995 till March in 1996 were 580 in total. The quantity which passed inspection amounted to 166.4 ton in Japan. The production of color in each month was summarised in Table 1, and by each producing company in Table 2. The food coal-tar dye produced in the largest quantity was Food Yellow No.4, occupying 43.9% in this period.

[Evaluation of anticoagulant activity for low molecular-weight heparin by chromogenic substrate. Measurement of factor Xa and thrombin activities]

We described an amidolytic method for determining the anticoagulant activity of commercially available low molecular-weight heparin (LMWH) with the use of factor Xa (FXa) and thrombin (FIIa), and a chromogenic peptidyl substrate, S-2222 or S-2238. The procedures were based on the photometric determination of the inactivation of FXa and FIIa after incubation with LMWH in the presence of antithrombin III (AT III). At first, the optimal conditions of FXa and FIIa activities with respect to pH, temperature, and the amounts of AT III and LMWH-International Standards (LMWH-IS) were determined. And then, the anticoagulant activities of various LMWHs were determined under the established conditions. In the comparative study with LMWHs, significant differences were found in anti FXa and anti FIIa activities, and their ratios. The anti FIIa activity was reconfirmed to decrease with decreasing molecular weight of LMWHs. On the other hand, the anti Xa activity was, however, less dependent on the molecular weight of LMWHs.

[Official inspection estimated production of coal-tar dyes (including dye aluminum lakes) in 1993-1994]

The number of official inspections of coal-tar dyes and their aluminum lakes from April 1993 till March 1994 were 734 in total, with the quantity which passed inspection amounting to 213 tons in Japan. Data for production by color for each month are summarised in Table 1, and by each producing company in Table 2. The food coal-tar dye produced in the largest quantity was Food Yellow No. 4, occupying a 42.9% proportion of the total during this period.

[The Dexamethasone Reference Standard (Control 931) of the National Institute of Health Sciences]

Raw dexamethasone material was tested for preparation of the "Dexamethasone Reference Standard (Control 931)". Analytical data obtained were as follows: melting point, 245.1 degrees C (decomposition); infrared spectrum, the same as that of the JP Dexamethasone Reference Standard; optical rotation, -alpha-20D = + 76.75 degrees; thin-layer chromatography, two impurities were detected; high-performance liquid chromatography (HPLC), one impurity was detected; loss on drying, 0.14%; assay result, 99.4% by HPLC. Based on the above findings, the raw material was authorized as the JP Dexamethasone Reference Standard (Control 931).

Determination of the molecular-weight distribution of low-molecular-weight heparins using high-performance gel permeation chromatography

The molecular-weight distribution of commercially available low-molecular-weight heparins (LMWHs) was estimated by high-performance gel permeation chromatography (HPGPC) using a LMWH molecular-weight calibrant, supplied by the National Institute for Biological Standards and Control for the calibration of columns. This calibrant is a mixture of many polysaccharides with a disaccharide unit prepared by a random depolymerization of unfractionated heparin, and the ends of the fragments have a UV absorption. The ratio of the refractive index to the UV absorption is a relative measure of molecular weight. Various molecular-weight parameters such as weight-, number- or z-average molecular-weights, polydispersity and relative distributions of high, middle and low molecular-weight components were estimated, indicating that LMWHs have a wide variation in molecular-weight distribution. This variation was ascribed to the difference in preparation methods from unfractionated heparins.

Molecular mass determination of low-molecular-mass heparins. Application of wide collection angle measurements of light scattering using a high-performance gel permeation chromatographic system equipped with a low-angle laser light-scattering photometer

A high-performance gel permeation chromatographic system with on-line low-angle laser light-scattering detection (HPGPC-LALLS) was used to determine molecular masses of low-molecular-mass heparins (LMMHs). Measurements at wide and narrow collection angles were compared and the application of the HPGPC-LALLS method to small molecules, with molecular masses in the range 1000-10,000, was assessed. The molecular mass averages of fractionated heparins and commercially available LMMHs were also determined by ordinary HPGPC analysis using an LMMH molecular-mass calibrant, supplied by the National Institute for Biological Standards and Control for the calibration of columns. The LALLS intensity at the routinely used narrow collection angle (theta col = 1 degree) about doubled at the wide collection angle (theta col = 2 degrees) and the signal-to-noise ratio was improved. The present study thus indicates that wide collection angle measurement of light scattering allows the application of the HPGPC-LALLS method to very small biopolymers of molecular mass < 10,000.

[Folic Acid Reference Standard (Control 921) of National Institute of Health Sciences]

Folic acid was tested for the preparation of "Folic Acid Reference Standard (Control 921)". The quality of the raw material was examined and compared with the previous Folic Acid Reference Standard (Control 862). Analytical data obtained were as follows: water content, 7.52%; free amines, 0.1%; infrared spectrum, the same as that of the JP Reference Standard; thin-layer chromatography, three impurities were detected; high-performance liquid chromatography (HPLC), two impurities were detected; assay, 101.2% by spectrophotometry at 550 nm and 100.4% by HPLC. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 921).

[Cortisone Acetate Reference Standard (Control 921) of National Institute of Health Sciences]

The raw material of cortisone acetate was tested for the preparation of "Cortisone Acetate Reference Standard (Control 921)". The quality of the raw material was examined and compared with the previous Cortisone Acetate Reference Standard (Control 743). Analytical data obtained were as follows: loss on drying, 0.06%; melting point, 245.9 degrees C (decomposition); optical rotation, [alpha]20D = +215.5 degrees; UV spectrum, lambda max = 239 nm and specific absorbance E 1%1 cm (239 nm) = 393; infrared spectrum, the same as that of the previous Reference Standard (Control 743); thin-layer chromatography, no impurities were detected up to 100 micrograms; high-performance liquid chromatography (HPLC), three impurities were detected; assay, 100.5% by HPLC. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 921).

[Pyridoxine hydrochloride reference standard (Control 911) of the National Institute of Hygienic Sciences]

The raw material of pyridoxine hydrochloride was examined for preparation of the "Pyridoxine Hydrochloride Reference Standard". Analytical data obtained were as follows: loss on drying, 0.00%; pH, 2.87; melting point, 204.6 degrees C (decomposition); infrared spectrum, same as Pyridoxine Hydrochloride Reference Standard (Control 879); thin-layer chromatography, nonimpurities were detected; assay, 100.0% by non-aqueous titration and 100.0% by UV spectrophotometry. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Standard (Control 911).

[Prednisolone reference standard (Control 911) of the National Institute of Hygienic Sciences]

Prednisolone was tested for preparation of the "Prednisolone Reference Standard (Control 911)". The quality of raw material was examined and compared with the previous Reference Standard (Control 872). Analytical data obtained were as follows: loss on drying, 0.10%; melting point, 233.2 degrees C (decomposition); optical rotation, [alpha]20D+98.77 degrees; UV spectrum, lambda max = 243nm; absorptivity, E1%1cm (243nm) = 413.5; IR spectrum, 1711, 1612, 1110, 888cm-1; one impurity was detected by thin-layer chromatography and high-performance liquid chromatography (HPLC), respectively; assay, 100.1% by HPLC. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Standard (Control 911).

[Tocopherol reference standard (Control 911) of the National Institute of Hygienic Sciences]

The raw material for tocopherol was tested for preparation of the "Tocopherol Reference Standard (Control 911)". Analytical data obtained were as follows: infrared spectrum, same as Tocopherol Reference Standard (Control 881); absorptivity, E1%1cm (292nm) = 75.5; thin-layer chromatography, no impurities were detected up to 50.0 micrograms; high performance liquid chromatography (HPLC), four impurities were detected; assay, 100.7% by HPLC. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Standard (Control 911).

[d-Camphor reference standard (Control 911) and dl-Camphor Reference Standard (Control 911) of the National Institute of Hygienic Sciences]

The raw materials of d-camphor and dl-camphor were examined for preparation of the "d-Camphor Reference Standard" and "dl-Camphor Reference Standard". Analytical data obtained were as follows: ultraviolet spectrum, lambda max = 290nm; infrared spectrum, 2958, 1742, 1045cm-1; optical rotation, [alpha]D20 = +42.7 degrees (d-camphor), [alpha]D20 = -0.3 degrees (dl-camphor); melting point, 180 degrees C (d-camphor), 179 degrees C (dl-camphor); gas-chromatography (GC), one impurity was detected in d-camphor and three impurities in dl-camphor; assay, 99.5% (d-camphor), 99.5% (dl-camphor) by GC. Based on the above results, these raw materials were authorized as the Japanese Pharmacopoeia Standard (Control 911).

[Tocopherol acetate reference standard (Control 911) of the National Institute of Hygienic Sciences]

The raw material for tocopherol acetate was tested for preparation of the "Tocopherol Acetate Reference Standard (Control 911)". Analytical data obtained were as follows: infrared spectrum, same as Tocopherol Acetate Reference Standard (Control 881); absorptivity, E1cm1% (284nm) = 43.5; thin-layer chromatography, no impurities were detected up to 50.0 micrograms; high performance liquid chromatography (HPLC), two impurities were detected; assay, 100.3% by HPLC. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Standard (Control 911).

[The effect of copper on o- and m-tyrosine content in the serum of guinea pigs]

The effect of copper on the concentrations of o- and m-tyrosines in the serum of guinea pigs was studied in vivo. When guinea pigs were fed the normal diet and 0.1% CuSO4 solution as a drinking water for 13 d, the concentrations of o- and m-tyrosines in the serum increased more significantly than that of guinea pigs fed normal diet and water without copper. Phenylalanine hydroxylase in the liver and kidney, and tyrosine hydroxylase in the brain and adrenal were not activated by the administration of copper to guinea pigs. The administration of copper caused an abnormal accumulation of copper in the liver, but not in the kidney, adrenal and brain, and significantly depressed the ascorbic acid content in various organs including the liver, kidney, brain and adrenal. The results obtained suggest that o- and m-tyrosines may be also formed nonenzymatically in vivo, in addition to the formation by the participation of enzymes such as phenylalanine and tyrosine hydroxylases.

[Prednisolone Acetate Reference Standard (Control 901) of the National Institute of Hygienic Sciences]

Prednisolone Acetate Reference Standard (Control 901) for the Japanese Pharmacopoeia (JP RS) was prepared. The following analytical data were obtained: melting point 236 degrees C (decomposition); IR spectrum was same as that of JP RS of prednisolone acetate; absorptivity at 243 nm E1%lcm = 379; optical rotation [alpha]20D = +113.0 degrees; no impurity was detected by TLC, but a small amount of two impurities was found by HPLC analysis; assay by HPLC against the JP RS 100.2%. Based on the above results, this raw material was authorized as the Reference Standard of the National Institute of Hygienic Sciences.

[Tolnaftate Reference Standard (Control 901) of National Institute of Hygienic Sciences]

The raw material of tolnaftate was examined for the preparation of the "Tolnaftate Reference Standard". Analytical data obtained were as follows: ultraviolet spectrum, lambda max = 257 nm; absorbance, E1cm1% (257 nm) = 723; infrared spectrum, same as that of USP Reference Standard of Tolnaftate; melting point, 112.1 degrees C; thin-layer chromatography, no impurities were detected until 500 micrograms; high-performance liquid chromatography, no impurities were detected; loss on drying, 0%; water, 0.01%; assay, 100.4% by absorbance method and 100.1% by the HPLC method in terms of the USP Reference Standard. Based on the above results, this raw material was authorized to be the Reference Standard of the National Institute of Hygienic Sciences.

[Retinol Acetate Reference Standard for Thin-layer Chromatography (Control 901) and Retinol Palmitate Reference Standard for Thin-layer Chromatography (Control 901) of National Institute of Hygienic Sciences]

The raw materials of retinol acetate and retinol palmitate were examined for the preparation of the "Retinol Acetate Reference Standard for Thin-layer Chromatography" and "Retinol Palmitate Reference Standard for Thin-layer Chromatography", respectively. Analytical data obtained were as follows: thin-layer chromatography, no impurities were detected in retinol acetate and one impurities was detected in retinol palmitate; The Rf values of retinol acetate and retinol palmitate were consistent with those of Reference Standards (Control 713), respectively; ultraviolet spectrum, lambda max = 326 approximately 327 nm; relative extinction, within the range reported in JPXI; weight variation of capsules, retinol acetate 224.0 +/- 15.5 mg (RSD 6.9%), retinol palmitate 222.0 +/- 13.8 mg (RSD 6.2%); assay, retinol acetate 57000 I.U./g, retinol palmitate 57000 I.U./g. Based on the above results, these raw materials were authorized to be the Reference Standards of the National Institute of Hygienic Sciences.

[Indocyanine Green Reference Standard (Control 901) of National Institute of Hygienic Sciences]

The raw material of indocyanine green was examined for the preparation of the "Indocyanine green Reference Standard (Control 901)". Analytical data obtained were as follows: ultraviolet and visible spectrum, lambda max = 785, 394, 216 nm; absorbance, E1cm(1%) (785 nm) = 3239; infrared spectrum, same as Indocyanine Green USP Reference Standard; sodium iodide, 4.1%; thin-layer chromatography, no impurities were detected until 100 micrograms; high-performance liquid chromatography, 4 impurities were detected; loss on drying, 1.8%; assay, 103.4% against USP Reference Standard. Based on the above results, this raw material was authorized to be the Reference Standard of the National Institute of Hygienic Sciences.

[Methylergometrine Maleate Reference Standard (Control 891) of National Institute of Hygienic Sciences]

The raw material of methylergometrine maleate was examined for the preparation of the "Methylergometrine Maleate Reference Standard". Analytical data obtained were as follows: melting point, 181.7 degrees C; ultraviolet spectrum, lambda max = 313 nm; absorbance, E1%1cm (313 nm) = 181.3; infrared spectrum, 3406, 2962, 2928, 1645, 1574 cm-1; thin-layer chromatography, 6 impurities were detected; high-performance liquid chromatography, no impurities were detected; loss on drying, 0.02%; optical rotation, [alpha]20D = + 44.04 degrees; assay, 99.5% against Ergometrine Maleate Reference Standard (Control 755). Based on the above results, this raw material was authorized to be the Reference Standard of the National Institute of Hygienic Sciences.

[Cyclandelate Reference Standard (Control 901) of National Institute of Hygienic Sciences]

The raw material of cyclandelate was examined for preparation of the "Cyclandelate Reference Standard". Analytical data obtained were as follows: melting point, 60 degrees C; ultraviolet spectrum, lambda max = 252, 258 and 264 nm E1%1cm = 6.1 (252 nm), 7.5 (258 nm), 5.9 (264 nm); infrared spectrum, 3454, 2948, 1730, 1453, 1202, 737, 695 cm-1; thin-layer chromatography, no impurities were detected until 1000 micrograms; high-performance liquid chromatography (HPLC), one impurity was detected, loss on drying, 0.00%. Based on the above results, this raw material was authorized to be the Reference Standard of the National Institute of Hygienic Sciences.

[Potassium Sucrose Octa Sulfate Reference Standard (Control 901) of National Institute of Hygienic Sciences]

The raw material of potassium sucrose octa sulfate was examined for the preparation of the "Potassium sucrose octa sulfate Reference Standard (Control 901)". Analytical data obtained were as follows: infrared spectrum, 3494, 1642, 1247, 1002, 795, 584 cm-1; high-performance liquid chromatography, 3 impurities were detected; water, 6.2%; assay of sucrose octa sulfate, 99.1%. Based on the above results, this raw material was authorized to be the Reference Standard of the National Institute of Hygienic Sciences.

[Ergocalciferol Reference Standard (Control 901) of the National Institute of Hygienic Sciences]

Ergocalciferol Reference Standard for the Japanese Pharmacopoeia (JP RS) was prepared. The following analytical data were obtained: melting point 118.4 degrees C; UV and IR spectra were in agreement with both of the previous JP RS and USP RS of ergocalciferol; absorptivity at 265nm E1%lcm = 467; optical rotation [alpha]20D = 103 degrees; no impurities were detected by TLC and HPLC analyses; assay 100.1% by HPLC against the USP RS. Based on the above results, the raw material was authorized as the Reference Standard of the National Institute of Hygienic Sciences.

[Diclofenamide Reference Standard (Control 891) of National Institute of Hygienic Sciences]

Quality of the raw material of diclofenamide was evaluated for preparation of "Diclofenamide Reference Standard". Analytical results for the sample were as follows: melting point 240 degrees C (decomposition); UV spectrum indicates absorption maxima at 286 and 295 nm and the absorption ratio A286/A295 1.04; IR spectrum is same as that of the USP Reference Standard; no impurity was found by TLC, but a trace of one was found by HPLC analysis; the purity is assumed to be 99.95% by HPLC analysis; loss on drying 0.1%; assay by HPLC against USP Reference Standard 100.2%. Based on the results, the present raw material was authorized to be the Reference Standard of the National Institute of Hygienic Sciences.

[Methoxalene Reference Standard (Control 901) of National Institute of Hygienic Sciences]

The raw material of methoxalene was examined for the preparation of the "Methoxalene Reference Standard". Analytical data obtained were as follows: ultraviolet spectrum, lambda max = 300, 249 and 218 nm; absorbance, E1cm(1%) (300 nm) = 559; infrared spectrum, same as that of USP Reference Standard of Methoxalene; melting point, 148 degrees C; thin-layer chromatography, no impurities were detected until 50 micrograms; high-performance liquid chromatography (HPLC), no impurities were detected, water, 0.04%; assay, 99.9% by absorbance method and 100.4% by the HPLC method in terms of the USP Reference Standard. Based on the above results, this raw material was authorized to be the Reference Standard of the National Institute of Hygienic Sciences.

[d-Camphor Reference Standard (Control 901) and dl-Camphor Reference Standard (Control 901) of National Institute of Hygienic Sciences]

The raw materials of d-camphor and dl-camphor were examined for the preparation of the "d-Camphor Reference Standard" and "dl-Camphor Reference Standard". Analytical data obtained were as follows: ultraviolet spectrum, lambda max = 257 nm; absorbance, E1%1cm(257 nm) = 723; infrared spectrum, 2956, 1742, 1045 cm-1; optical rotation, [alpha]20D = +42.9 degrees (d-camphor), [alpha]20D = -0.00 degrees (dl-camphor); melting point, 180 degrees C (d-camphor), 179 degrees C (dl-camphor); gas-chromatography, one impurity was detected in d-camphor and four impurities were detected in dl-camphor. Based on the above results, these raw materials were authorized to be the Reference Standards of the National Institute of Hygienic Sciences.

[Cholecalciferol Reference Standard (Control 901) of the National Institute of Hygienic Sciences]

Cholecalciferol Reference Standard for the Japanese Pharmacopoeia (JP RS) was prepared. The following analytical data were obtained: melting point 85.8 degrees C; UV and IR spectra were in agreement with both of the previous JP RS and USP RS of Cholecalciferol; absorptivity at 265 nm E1%lcm = 476; optical rotation [alpha]20D = + 110.1 degrees; no impurities were detected by TLC and HPLC analyses; assay 100.1% by HPLC against the USP RS. Based on the above results, the raw material was authorized as the Reference Standard of the National Institute of Hygienic Sciences.

[Riboflavin Reference Standard (Control 891) of National Institute of Hygienic Sciences]

The raw material of riboflavin was examined for the preparation of the "Riboflavin Reference Standard (Control 891)". Analytical data obtained were as follows: melting point, 238.2 degrees C (decomposition); absorbance, E1%1cm = 859 (267 nm), 277 (372 nm), 327 (445 nm); infrared spectrum, same as Riboflavin Reference Standard (Control 872); thin-layer chromatography, 5 impurities were detected; high-performance liquid chromatography, 11 impurities were detected; loss on drying, 0.25%; optical rotation, [alpha]20D = -133.6 degrees; solubility, less than 16 min; assay, 100.1% against Riboflavin Reference Standard (Control 872). Based on the above results, this raw material was authorized to be the Reference Standard of the National Institute of Hygienic Sciences.

Accelerating effect of glutathione on hydroxylation of phenylalanine by stimulated polymorphonuclear leukocytes

Sulfhydryl compounds significantly accelerated the hydroxylation of phenylalanine by stimulated polymorphonuclear leukocytes. The reduced form of glutathione (G-SH) was most effective. The hydroxylation reaction in the presence of G-SH was largely prevented by superoxide dismutase and hydroxyl radical scavengers. The results suggest that a much faster production of hydroxyl radical may occur in a reaction mixture containing both G-SH and stimulated polymorphonuclear leukocytes than in that containing stimulated polymorphonuclear leukocytes alone.

Tyrosine formation from phenylalanine by ultraviolet irradiation

When phenylalanine was irradiated at ultraviolet (UV) light, p-tyrosine, m-tyrosine and o-tyrosine were identified as hydroxylated products. From p-tyrosine and m-tyrosine, the formation of L-3,4-dihydroxyphenylalanine (DOPA) was observed. The hydroxylation of phenylalanine was prevented by radical scavengers, e.g., catalase, superoxide dismutase, sodium thiocyanate, mannitol, potassium iodide and thiourea. Replacement of air with nitrogen gas prevented the hydroxylation, but did not depress it completely. The addition of H2O2 increased significantly the hydroxylation of phenylalanine. These results suggest that the hydroxylation of phenylalanine by UV irradiation may be caused by .OH formed during the decomposition of H2O.