Eiichi Mikami

Aichi Prefectural Institute of Public Health, Nagoya, Aichi, Japan

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Publications (12)10.51 Total impact

  • Tsutomu Ohno, Eiichi Mikami, Hisao Oka
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    ABSTRACT: We performed identification tests of the main components (ginsenoside-Rg1, gentiopicroside, puerarin, geniposide, schizandrin, and [6]-gingerol) of the following crude drugs from the Japanese Pharmacopoeia, 14th edition (JP14): ginseng, red ginseng, gentian, Japanese gentian, pueraria root, gardenia fruit, schisandra fruit, and ginger). The identification was carried out with reversed-phase thin-layer chromatography using water, acetonitrile, methanol, 2-butanone, and n-hexane as developing solvents. A single spot could be separated from other components (Rf value: 0.44–0.59). In addition, spectral information could be simultaneously obtained by scanning densitometry. Thus, the main components of crude drugs in the JP14 could be identified by this method simply, rapidly, and accurately.
    Journal of Natural Medicines 01/2006; 60(2):141-145. · 1.52 Impact Factor
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    Journal of Health Science - J HEALTH SCI. 01/2006; 52(1):78-81.
  • Journal of Health Science - J HEALTH SCI. 01/2005; 51(3):278-283.
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    ABSTRACT: 3,5-diiodo-L-tyrosine, C 15 H 11 I 4 NO 4 , mol.wt. 776.87] is one of the thyroid hormones prescribed for the symptoms of hypothyroidism. It is also possible that mild thyroid hormones excess over many years may increase the risk for a serious heart rhythm problem and fractures caused by excessive calcium loss from bones. In general, LC/MS is used for the assay of T4 in supplements with enzymatic hydrolysis and extraction procedure. 5) This assay method is time-consuming and requires proficient techniques. Enzyme-linked immunosorbent assay (ELISA) has become an increasingly important alternative de-tection method for the determination of pesticides, 6) toxins 7) and forensic drugs 8) as a screening tool. ELISA for the detection of T4 in serum have been developed as a specific and rapid method, and a com-mercial test kit based on ELISA for clinical diagno-sis of various thyroid disorders is available on the market. The present study examined an ELISA pro-cedure for the detection of T4 in supplements made from Chinese herbal preparations advertised as weight reducers. MATERIALS AND METHODS Materials —–— Five samples were offered by con-sumers with thyroid gland disease and liver trouble. Eight samples were collected from Aichi prefecture (Japan) by drug inspectors in 2002. All samples were claimed to be extracts of animal organs and tradi-tional Chinese herbs, for use as weight reducers. Reagents and Instrumentation —–— Dried thy-roid of Japanese Pharmacopoeia quality was pur-chased from Teikoku Hormone Mfg. (Tokyo, Japan) and 0.01 mol/l phosphate buffered saline (PBS, for tissue washing) and protease (for biochemistry) were purchased from Wako Pure Chemical Industries (Osaka, Japan). Reducing buffer solution was pre-pared as a solution in 0.11 mol/l sodium chloride Thyroxine (T4), one of the thyroid hormones, in adulterated dietary supplements was analyzed using two different methods; enzyme-linked immunosorbent assay (ELISA) and LC/MS. To release T4 from thyro-globulin, samples were first hydrolyzed with pro-teolytic enzyme, and then the supernatant was diluted and directly analyzed using a commercial free T4 ELISA kit for diagnostic discrimination. In contrast, T4 was extracted with ethyl acetate from the superna-tant, and then ethyl acetate layer was evaporated. The residue was dissolved in the mobile phase and analyzed by LC/MS with electrospray ionization (ESI) interface under positive ion mode. These methods were applied to the analyses of 13 dietary supplements advertised as weight reducers. T4 was detected in four of the samples and the analytical results by ELISA agreed well with those obtained by LC/MS. The ELISA tech-nology described here is available for the screening of T4 in adulterated supplements.
    Journal of Health Science. 01/2003; 49:305-843.
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    ABSTRACT: A simple and rapid analytical method of oil-soluble coal tar dyes in cosmetics was established using re-versed-phase TLC/scanning densitometry. Eleven kinds of oil-soluble coal tar dyes were able to be sepa-rated completely on reversed-phase TLC plates by the complementary use of 2 solvent systems. The solvent systems were A; n-hexane/2-butanone solution (5 : 1, v/v), solvent system B; acetonitrile/methanol solution (5 : 1, v/v). Then we measured visible absorption spec-tra of spots developed on the reversed-phase TLC plates by scanning densitometer to identify these coal tar dyes. The proposed method was successfully ap-plied to the identification of oil-soluble coal tar dyes in commercial cosmetics.
    Journal of Health Science. 01/2003; 49:401-404.
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    ABSTRACT: An easily available, simultaneous identification/determination procedure for phentolamine (PHE) and sildenafil (SIL) in adulterated dietary supplements was established by using a combination of three different analytical methods; thin-layer chromatography (TLC), liquid chromatography-mass spectrometry (LC/MS) and a high-performance liquid chromatography (HPLC)/photo-diode-array. The sample solution for TLC was applied to silica gel 60 F(254) plates with chloroform/ammonia solution (28)/methanol (70:5:3, lower layer) and chloroform/diethylamine/methanol (15:3:2) as the developing solvent. Spots were located under UV radiation at 254 nm. Mass spectra of PHE and SIL by LC/MS were investigated with electrospray ionization (ESI) interface, under both positive and negative ion mode. The HPLC analysis was performed on a column of Wakosil 5C18 (4.6 mm x 150 mm, 5 microm) with water/methanol/acetonitrile/triethylamine (580:250:170:1) adjusted with phosphoric acid to pH 3.0 as the mobile phase, and the effluent was monitored with a photo-diode-array detector. Quantitative HPLC analysis of PHE and SIL were detected at 280 nm. When this procedure was applied to commercial soft drinks, PHE and SIL were identified and determined at a concentration of 17 mg PHE and 44 mg SIL per bottle, respectively. The procedure described here is available for the screening of PHE and SIL in adulterated supplements.
    Forensic Science International 01/2003; 130(2-3):140-6. · 2.31 Impact Factor
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    ABSTRACT: A high-performance liquid chromatographic (HPLC) method for the simultaneous analysis of triamterene, trichlormethiazide, furosemide and spironolactone is presented for application in the examination of health food supplements advertising weight reduction and in the analysis of pharmaceuticals. The HPLC assay was performed under gradient conditions using a Wakosil ODS 5C18 column (5 microns, 150 x 4.6 mm i.d.). The mobile phase consisted of a gradient program with a mixture of water and acetonitrile containing 0.1% triethylamine adjusted with phosphoric acid to pH 3.0: from 0 to 6 min, 15% acetonitrile; from 6 to 20 min, linear gradient from 15 to 50% acetonitrile; and from 20 to 40 min, 50% acetonitrile. The column effluent was monitored from 0 to 20 min at 260 nm and from 20 to 40 min at 235 nm. The calibration curves of the four drugs showed good linearity and the correlation coefficients were better than 0.999 in all cases. The lower limits of detection were approximately 40 ng for each drug. Commercially available health food supplements and pharmaceuticals were analyzed after extraction with a mixture of methanol and acetic acid (99:1). The procedure described here is suitable for the screening of four diuretic drugs in adulterated supplements and for the quality control of pharmaceuticals with minimal sample preparation.
    Journal of the Food Hygienic Society of Japan (Shokuhin Eiseigaku Zasshi) 05/2002; 43(2):95-8. · 0.33 Impact Factor
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    ABSTRACT: A high-performance liquid chromatographic (HPLC) method for simultaneous determination of dehydroacetic acid (DHA), benzoic acid (BA), sorbic acid (SOA) and salicylic acid (SA) was developed for application to cosmetic products. Isocratic reversed-phase HPLC was employed for quantitative analysis using tetra-n-butylammonium (TBA) hydroxide as an ion-pair reagent. Cosmetic samples were purified by solid-phase extraction using Bond-Elut SI cartridges. Four acidic preservatives were eluted with methanol from cartridges. The HPLC assay was carried out using TSK gel ODS-80TM column (5 microm, 150 x 4.6 mm I.D.). The mobile phase consisted of a mixture of water and methanol (65:35, v/v) containing 2.5 mM TBA hydroxide adjusted with phosphoric acid to pH 7.0. The calibration curves of these preservatives showed good linearity with UV detection (235 nm). The correlation coefficients were better than 0.999 in all cases. The lower limits of detection (defined as a signal-to-noise ratio of about 3) were approximately 2.5 ng for DHA, 4.0 ng for BA, 2.0 ng for SOA and 5.5 ng for SA. The procedure described here is simple, selective and is suitable for quality control of finished cosmetic products.
    Journal of Pharmaceutical and Biomedical Analysis 05/2002; 28(2):261-7. · 2.95 Impact Factor
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    ABSTRACT: A high-performance liquid chromatographic (HPLC) method for simultaneous determination of naproxen (NAP), nabumetone (NAB) and its major metabolite, 6-methoxy-2-naphthylacetic acid (6-MNA), was developed for the application to pharmaceuticals and human urine. Isocratic reversed-phase HPLC was employed for quantitative analysis using triethylamine and 1-heptanesulfonic acid sodium salt (HSA) as ion-pair reagents. Urine samples were purified by solid-phase extraction using Bond-Elut Certify II cartridges containing reversed-phase and anion exchange functionalities. The HPLC assay was carried out using a Wakosil ODS 5C18 column (5 microm, 150 x 4.6 mm, i.d.). The mobile phase consisted of 0.5 g of HSA dissolved in 1,000 ml of a mixture of acetonitrile, water and triethylamine (500:500:1, v/v) adjusted with phosphoric acid to pH 3. The calibration curves of NAP and NAB showed good linearity in the concentration range 32-160 microg/ml with UV detection (270 nm) for pharmaceuticals. In the low concentration ranges (8-96 ng of NAP per ml, 24-288 ng of NAB per ml and 5.6-67.2 ng of 6-MNA per ml), the calibration curves were also obtained with fluorimetric detection (excitation 280 nm, emission 350 nm) for biological fluids. The correlation coefficients were better than 0.999 in all cases. The lower limits of detection (defined as a signal-to-noise ratio of about 3) were approximately 0.3 ng for NAP, 1.5 ng for NAB and 0.2 ng for 6-MNA. The procedure described here is rapid, simple, selective, and is suitable for routine analysis of pharmaceuticals and pharmacokinetic studies in human urine samples.
    Journal of Pharmaceutical and Biomedical Analysis 11/2000; 23(5):917-25. · 2.95 Impact Factor
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    ABSTRACT: A high-performance liquid chromatographic (HPLC) method for simultaneous determination of mefenamic acid (MFA), flufenamic acid (FFA) and tolfenamic acid (TFA) is presented for application to pharmaceuticals and human urine. Isocratic reversed-phase HPLC was employed for quantitative analysis using tetra-pentylammonium bromide (TPAB) as an ion-pair reagent. Urine samples were purified by solid-phase extraction using a silica-based strong anion-exchanger, Bond-Elut SAX cartridge. The HPLC assay was carried out using a Wakosil ODS 5C18 column (5 microm, 150x4.6 mm I.D.). The mobile phase consisted of 1.9 g of TPAB dissolved in 1:1 of a mixture of acetic acid-sodium acetate buffer solution, pH 5.0, and acetonitrile (11:9, v/v). The calibration curves of MFA, FFA and TFA showed good linearity in the concentration range of 33-167 microg/ml with a wavelength of 280 nm for pharmaceuticals, and in the low concentration range (1.7-30.1 microg/ml) with a wavelength of 230 nm for biological fluids. The correlation coefficients were better than 0.9999 in all cases. The lower limits of detection (defined as a signal-to-noise ratio of about 3) were approximately 2 ng for MFA, 3.5 ng for FFA and 2.5 ng for TFA. The procedure described here is rapid, simple, selective and is suitable for routine analysis of pharmaceuticals and pharmacokinetic studies in human urine samples.
    Journal of chromatography. B, Biomedical sciences and applications 08/2000; 744(1):81-9.
  • Yakugaku zasshi journal of the Pharmaceutical Society of Japan 11/1985; 105(10):996-1000. · 0.46 Impact Factor
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    ABSTRACT: A new method has been proposed for detection of lac color in food. Lac color is a natural color additive derived from a secretion of the insect Coccus Laccae (Laccifer lacca Kerr). It is extracted from food with methanolic oxalic acid and eluted from a column of Amberlite XAD-2 with the same solvent. The fraction containing the lac color is treated with diazomethane to produce 2 reddish-orange markers. The marker species in the reaction mixture are detected by both thin-layer chromatography and reverse-phase liquid chromatography.
    Journal - Association of Official Analytical Chemists 72(1):48-51.