Derivados de Purinas e Pirimidinas

<p>Applications N-Acetyl Memantine is an intermediate used for preparation of Memantine (M218000).<br>References Gerzon, K., et al.: J. Med. Chem., 6, 760 (1963), Reddy, J., et al.: Org. Process Res. Dev., 11, 268 (2007),<br></p>

<p>Applications Ethyl 2-(4-Hydroxyphenyl)-4-methylthiazole-5-carboxylate is used in the synthesis of the major metabolites of Febuxostat (F229000), a xanthine oxidase/xanthine dehydrogenase inhibitor. Used for treatment of hyperuricemia and chronic gout. 40-120 mg/day febuxostat was proven effective in lowering serum urate levels when administered to manage hyperuricemia in patients with gout.<br>References Li, X., et. al.: Lett. Org. Chem., 12, 217 (2015); Vallu, V., et. al.: Anal. Chem. Indian J., 14, 339 (2014); Osada, Y., et al.: Eur. J. Pharmacol., 241, 183 (1993); Okamoto, K., et al.: J. Biol. Chem., 278, 1848 (2003); Mayer, M.D., et al.: Am. J. Therap., 12, 22 (2005); Tomlinson, B., et al.: Curr. Opin. Invest. Drugs, 6, 1168 (2005)<br></p>

<p>Applications A xanthine derivative with bronchodilator activity. Typically combined as salt component with other medications such as Ambroxol to treat bronchial and pulmonary diseases.<br>References Kim, S., et al.: J. Med. Chem., 45, 2131 (2002), Bruno-Blanch, L., et al.: Bioorg. Med. Chem. Lett., 13, 2749 (2003), Foppoli, A., et al.: J. Pharm. Sci., 96, 1139(2007),<br></p>

<p>Applications A fluorescent analog of Nicotinamide Adenine Dinucleotide as a coenzyme for glutamate dehydrogenase.<br>References Gafni, A., et al.: Biochemistry, 20, 6041 (1981), Creedon, K., et al.: J. Biol. Chem., 269, 16364 (1994), Seley, K., et al.: Bioorg. Med. Chem., 6, 797 (1998),<br></p>

<p>Applications Lablled Caffeine (C080100). Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug and a reversible acetylcholinesterase inhibitor. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants. In humans, caffeine acts as a central nervous system stimulant, temporarily warding off drowsiness and restoring alertness. Caffeine is a cardiac and respiratory stimulant; diuretic. Caffeine is toxic at sufficiently high doses.<br> Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package<br>References Zubair, U.M., et al.: Anal. Profiles Drug Subs., 15, 71 (1986); Cherrah, Y., et al.: Biochem. Pharmacol., 37, 1311 (1988);<br></p>

<p>Applications S(+)-N-(2-(2-Thienyl)ethyl)-2-chlorophenyl Glycine Methyl Ester Hydrochloride is an impurity from Clopidogrel (C587250) which acts as an anti-platelet agent.<br>References Zhu, Y. et al.: ACS. Med. Chem. Lett., 4, 349 (2013); Feuerstein, G., et al.: Exp. Opin. Invest. Drugs, 4, 425 (1995)<br></p>

<p>Applications Impurity of Allopurinol (A547300), an xanthine oxidase inhibitor used in treatment of hyperuricemia and chronic gout. Antiurolithic.<br>References Benezra, S.A., et al.: Anal. Profiles Drug Subs., 7, 1, (1978), Dalbeth, N., et al.: Rheumatology, 44, 1090 (2005), Dinarello, C., et al.: J. Exp. Med., 201, 1355 (2005),<br></p>

<p>Applications 8-Descarboxamido-8-cyano Temozolomide is a useful synthetic intermediate in the synthesis of Temozolomide (T017775); an imidazotetrazine alkylating agent and antineoplastic.<br>References Newlands, E.S., et al.: Cancer Treat. Rev., 23, 35 (1997); Kim, C., et al.: J. Biol. Chem., 274, 1233 (1999); Hait, W., et al.: Cancer Res., 69, 1263 (2009); Wang, Y., et al.: J. Org. Chem., 62, 7288 (1997)<br></p>

<p>Applications A metabolite of Theophylline.<br>References Chen, Y., et al.: Clin. Exper. Pharmacol. Physiol., 36, 828 (2009), Yu, C., et al.: J. Bacteriol., 191, 4624 (2009), Jetter, A., et al.: Eur. J. Clin. Pharmacol., 65, 411 (2009),<br></p>

<p>Impurity Memantine Related Compound A (1,3-Dimethyladamantane)<br>Applications 1,3-Dimethyladamantane is a dimethylated adamantane derivative. Memantine impurity A. Memantine Related Compound A (1,3-Dimethyladamantane).<br> Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package<br></p>

<p>Applications Ethyl 2-Chloracetoacetate is used in the preparation of oxazoles and thiazoles as agonists for peroxisome proliferator-activated receptor δ. It is also used to synthesize dimethylimidazothiadiazolecarbohydrazides with anticancer activities.<br> Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package<br>References Sznaidman, M., et al.: Bioorg. Med. chem. Lett., 13, 1517 (2003); Terzioglu, N., et al.: Eur. J. Med. Chem., 38, 781 (2003)<br></p>

<p>Stability Moisture Sensitive<br>Applications Used in conjunction with Isothiocyanate to conduct partial Edman Degradation on biologically active peptides.<br> Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package<br>References Heidenreich, O., et al.: J. Biol. Chem., 269, 2131 (1994), Kothe, U., et al.: Anal. Biochem., 356, 148 (2006), Thakkar, A., et al.: Anal. Chem., 78, 5935 (2006),<br></p>

<p>Applications 3-Chlorodiphenylamine (cas# 101-17-7) is a compound useful in organic synthesis.<br></p>

<p>Applications Metabolite of Caffeine (C080100).<br>References Grant, D.M., et al.: Clin. Pharm. and Ther., 33, 591 (1983),<br></p>

<p>Stability Hygroscopic<br>Applications A metabolite of DAMPA.<br>References Bleyer, W., et al.: Cancer, 41, 36 ( 1978), Abelson, H., et al.: J. Clin. Oncol., 1, 208 (1983), Fabre, G., et al.: Biochem. Pharmacol., 35, 1325 (1986), Widemann, B., et al.: Clin. Chem., 45, 223 (1999),<br></p>

<p>Impurity Zolmitriptan USP Related Compound H<br>Applications 4-Dimethylaminobutyraldehyde Diethyl Acetal (Zolmitriptan USP Related Compound H) is used in the preparation of N,N-Dimethyltryptamines, 5-HT1D receptor agonists, for medicinal treatments such as antimigraine drugs.<br>References Chen, C. et al.: J. Org. Chem., 59, 3738 (1994);<br></p>

<p>Applications An immunosuppressive drug used to treat leukemia. It is also used for pediatric non-Hodgkin’s lymphoma, polycythemia vera, and psoriatic arthritis.<br> Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package<br>References Zeng, H., et al.: Biochem. Pharmacol., 68, 911 (2004),<br></p>

<p>Stability Hygroscopic<br>Applications 2-Amino-6-mercaptopurine-9-D-riboside Hydrate (cas# 345909-25-3) is a compound useful in organic synthesis.<br></p>

<p>Impurity Allopurinol EP Impurity E / Allopurinol USP Related Compound E<br>Applications 3-(Formylamino)-1H-pyrazole-4-carboxylic Acid Ethyl Ester (Allopurinol EP Impurity E) is an impurity of Allopurinol (A547300), a pyrazole derivative that has been shown to induce neoplasm immunogenicity.<br>References Nicolin, A. et al.: Cancer, Chemother. Rep., 57, 3 (1973); Bonmassar, E. et al.: Cancer Res., 35, 1957 (1975)<br></p>

<p>Impurity Tenofovir Disoproxil USP Related Compound A<br>Applications The S-enantiomeric impurity of the antiviral Tenofovir Disoproxil Fumarate (T018505(P)), which is an acyclic phosphonate nucleotide analogue; reverse transcriptase inhibitor and used as an anti-HIV agent.Tenofovir Disoproxil USP Related Compound A.<br>References Shaw, J. P., et al.: Pharm. Res., 14, 1824 (1997), Wyles, D., et al.: Clin Infect. Dis., 40, 174 (2005), Peng, J., et al.: J. Clin. Pharmacol., 46, 265 (2006), Seminari, E., et al.: J. Antimicrob. Chemother., 60, 831 (2007)<br></p>

<p>Stability Hygroscopic<br>Applications A Folic acid antagonist. Used as a antineoplastic and antirheumatic.<br> Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package<br>References Freeman, M.V., J. Pharmacol. Exp. Ther., 122, 154 (1958), Weinblass, M.E., et al.: N. Engl. J. Med., 312, 818 (1985),<br></p>

<p>Applications Pemetrexed Sodium Methyl Ester is an impurity of Pemetrexed(P219550). Pemetrexed Disodium Heptahydrate is an chemotherapy drug for the treatment of pleural mesothelioma and non-small cell lung cancer. Pemetrexed Disodium Heptahydrate exhibit inhibitory activities towards thymidylate synthase as well as other folate dependent enzymes.<br>References Vogelzang, N.J., et al.: J. Clin. Oncol., 21,2636 (2003); Paz-Ares, L., et al.: Lancet. Oncol., 13, 247 (2012);<br></p>

<p>Stability Very Hygroscopic<br>Applications Tri-POC Tenofovir Dimer is a dimer of Tenofovir Disoproxil (T018505), an acyclic phosphonate nucleotide analogue; reverse transcriptase inhibitor. Used as an anti-HIV agent. Antiviral. It is also used in the preparation of phosphocitrate for the treatment of rheumatoid and osteoarthritis in the elderly.<br>References Turhanen, P. et al.: J. Org. Chem., 72, 1468 (2007);<br></p>

<p>Applications A acyclic phosphonate nucleotide.<br></p>

<p>Applications Zeatin belongs to the family of plant-growth hormones called cytokinins and it can be used for agricultural use as agrochemicals for increasing crop yields and regulate various aspects of plant growth and development.<br>References Koprna, R., et al.: Bioorgan. Med. Chem., 24, 484-492 (2016)<br></p>

<p>Impurity Tenofovir Disoproxil USP Related Compound B<br>Applications 9-Propenyladenine (Tenofovir Disoproxil USP Related Compound B) is an N-substituted purine and an impurity of Tenofovir (T018500). Tenofovir Disoproxil Related Compound B ((E)-9-(Prop-1-enyl)-9H-purin-6-amine).<br>References Montgomery, J.A. et al.: J. Org. Chem., 30, 3235 (1965);<br></p>

<p>Applications Isotope Labelled 5,6-Dihydro Uracil is a degradation product of DNA and was used in mass spectrometric studies of cellular DNA damage.<br>References Nelson, V.C., et al.: J. Label. Com. Radiopharma., 38, 713 (1996)<br></p>

<p>Impurity Sumatriptan EP Impurity A<br>Stability Light Sensitive<br>Applications 2-[[3-[2-(dimethylamino)ethyl]-1H-indol-5-yl]methyl] Sumatriptan Succinate (Sumatriptan EP Impurity A) is an impurity of Sumatriptan (S810000), a serotonin 5HT-1-receptor agonist.<br>References Skwierawska, A.. et al.: Poish. J. Chem., 77, 329 (2003);<br></p>

<p>Applications Methotrexate-d3 Diglutamate is the isotope labelled analog of Methotrexate Diglutamate (M260720); a metabolite of Methotrexate (M260675) which is a folic acid antagonist, antineoplastic, and antirheumatic.<br>References Freeman, M.V., J. Pharmacol. Exp. Ther., 122, 154 (1958); Weinblass, M.E., et al.: N. Engl. J. Med., 312, 818 (1985)<br></p>

<p>Impurity Temozolomide USP Related Compound A<br>Applications Temozolomide USP Related Compound A<br></p>

<p>Applications 2-[3-(Aminocarbonyl)-4-(2-methylpropoxy)phenyl]-4-methyl-5-thiazolecarboxylic acid is an impurity of Febuxostat (F229000), an xanthine oxidase/xanthine dehydrogenase inhibitor used for the treatment of hyperuricemia and chronic gout.<br>References Kadivar, M.H., et al.: J. Pharma. Biomed. Anal., 56, 749 (2011);<br></p>

<p>Applications Caffeine-d3 (7-methyl-d3) (CAS# 26351-04-2) is a useful isotopically labeled research compound.<br></p>

<p>Stability Hygroscopic<br>Applications Tetrahydrobiopterin is a naturally occurring essential cofactor of the three aromatic amino acid hydroxylase enzymes, used in the degradation of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotonin, melatonin, dopamine, norepinephrine , epinephrine, and is a cofactor for the production of nitric oxide by the nitric oxide synthases. Chemically, its structure is that of a reduced pteridine derivative.<br>References Levy, Harvey L., et al.: Lancet,  370, 504 (2007); Isojima, Yasushi., et al.: Proc Natl Acad Sci USA .,106, 15744 (2009); Burton, B. K., et al.: J. Inherit. Metab. Dis., 30, 700 (2007)<br></p>

<p>Applications L-Monapterin is the major pterin compound extracted from Escherichia coli (E.coli) and is used in its detection and identification.<br>References Sugimoto, T. et al.: Hetero., 54, 283 (2001); Ikawa, M. et al.: Phytochem., 38, 1229 (1995);<br></p>

<p>Applications 6-Methylpurine (cas# 2004-03-7) is a compound useful in organic synthesis.<br> Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package<br></p>

<p>Stability Hygroscopic<br>Applications A serotonin 5HT1-receptor agonist. Antimigraine.<br>References Humphrey, P.P.A., et al.: Br. J. Pharmacol., 94, 1123 (1988),<br></p>

<p>Stability Stable at RT<br>Applications An intermediate used for the sythesis of xanthine derivatives.<br>References Daly, J.W., et al.: J. Med. Chem., 28, 487 (1985), Erickson, R.H., et al.: J. Med. Chem., 34, 3405 (1991),<br></p>

<p>Applications Nonionic radiocontrast medium. Diagnostic aid (radiopaque medium).<br>References Drayer, B., et al.: Am. J. Neuroradiol., 3, 59 (1982), Molyneux, A.J., et al.: Br. J. Radiol., 55, 117 (1982), Sovak, M., et al.: Radiology, 142, 115 (1982), Felder, E., et al.: Anal. Profiles Drug Subs., 17, 115 (1988),<br></p>

<p>Applications Nicotinic Acid-13C6 is labelled Nicotinic acid. It is a precursor of the coenzymes NAD and NADP. Widely distributed in nature; appreciable amounts are found in liver , fish, yeast and cereal grains. Dietary deficiency is associated with pellagra. The term “niacin” has also been applied to nicotinamide or to other derivatives exhibiting the biological activity of nicotinic acid. Vitamin (enzyme cofactor).<br>References Darby, W.J., et al.: Nutr. Rev., 33, 289 (1975), Black, A., et al.: Eur. J. Clin. Nutr., 54, 395 (2000), Cole, T., et al.: Br. Med. J., 320, 1240 (2000), Forshee, R., et al.: J. Nutr., 134, 2733 (2004),<br></p>

<p>Applications L-Phenyl-d5-alanine-2,3,3-d3 is an isotope labelled compound of L-Phenylalanine (P319415). L-Phenylalanine (Aspartame EP Impurity C) is an essential amino acid. L-Phenylalanine is biologically converted into L-tyrosine, another one of the DNA-encoded amino acids, which in turn is converted to L-DOPA and further converted into dopamine, norepinephrine, and epinephrine. L-Phenylalanine is produced for medical, feed, and nutritional applications such as in the preparation of Aspartame. Neuroprotective product.<br>References Hollunger, G. et al.: Acta Pharmacol. Toxicol., 34, 391 (1974); Bagchi, S.P. et al.: Biochem. Pharmacol., 26, 900 (1977)<br></p>

<p>Applications 4-Amino-1,3-dimethyl-5-nitrosouracil is a useful building block for organic synthesis.<br></p>

<p>Applications Caffeine-13C is carbon-13 labeled Caffeine (C080100). Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug and a reversible acetylcholinesterase inhibitor. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants. In humans, caffeine acts as a central nervous system stimulant, temporarily warding off drowsiness and restoring alertness. Caffeine is a cardiac and respiratory stimulant; diuretic. Caffeine is toxic at sufficiently high doses.A study at Johns Hopkins University indicates that caffeine can improve pattern separation memory.<br> Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package<br>References Zubair, U.M., et al.: Anal. Profiles Drug Subs., 15, 71 (1986); Cherrah, Y., et al.: Biochem. Pharmacol., 37, 1311 (1988);  Chem. and Eng. News p.34, Jan. 20, (2014)<br></p>

<p>Applications 9-(2-Propenyl)adenine is an N-substituted purine used in the preparation of mesityl dihydroisoxazolyl homo-N-nucleosides.<br>References Thalassitis, A. et al.: Bioorg. Med. Chem. Lett., 19, 6433 (2009); Chiacchio, U. et al.: Tetrahedron, 60, 441 (2004)<br></p>

<p>Applications Used in the biological study of differentiation induced by nicotinic acid, nicotinamide and isonicotinic acid in human leukemia cell lines.<br>References Zeilinger, S., et al.: J. Biol. Chem., 271, 25624 (1996), Panagiotou, G., et al.: J. Biotechnol., 118, 304 (2005),<br></p>

<p>Applications Acyclic phosphonate nucleotide analogue; reverse transcriptase inhibitor. Used as an anti-HIV agent. Antiviral.<br>References Shaw, J.-P., et al.: Pharm. Res., 14, 1824 (1997), Wyles, D., et al.: Clin Infect. Dis., 40, 174 (2005), Peng, J., et al.: J. Clin. Pharmacol., 46, 265 (2006), Seminari, E., et al.: J. Antimicrob. Chemother., 60, 831 (2007),<br></p>

<p>Applications L-Aspartyl-L-phenylalanine is an impurity of Thiamine (T344185). Thiamine Impurity B.<br>References Aluwihare, L., et al.: Science, 308, 1007 (2005), Koch, B., et al.: Anal. Chem., 79, 1758 (2007), Reemtsma, T., et al.: Environ. Sci. Technol., 42, 1430 (2008),<br></p>

<p>Stability Hygroscopic<br>Applications A labelled specific serotonin (5-HT3) receptor antagonist. Antiemetic.<br> Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package<br>References Kris, M.G., et al.: J. Clin. Oncol., 6, 659 (1988), Faris, P..L., et al.: Lances, 355, 792 (2000),<br></p>

<p>Applications Tenofovir Alafenamide Fumarate is a prodrug of Tenofovir (T018500), which is a reverse transcriptase inhibitor used to treat HIV and Hepatitis B. Antiviral.<br>References Shaw, J.-P., et al.: Pharm. Res., 14, 1824 (1997), Wyles, D., et al.: Clin Infect. Dis., 40, 174 (2005), Peng, J., et al.: J. Clin. Pharmacol., 46, 265 (2006), Seminari, E., et al.: J. Antimicrob. Chemother., 60, 831 (2007),<br></p>

<p>Applications Allopurinol-13C,15N2, is the labeled analogue of Allopurinol (A547300), acting as an Xanthine oxidase inhibitor, and used in treatment of hyperuricemia and chronic gout.<br> Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package<br>References Benezra, S.A., et al.: Anal. Profiles Drug Subs., 7, 1, (1978), Dalbeth, N., et al.: Rheumatology, 44, 1090 (2005), Dinarello, C., et al.: J. Exp. Med., 201, 1355 (2005),<br></p>

<p>Applications Methotrexate Dimethylamide is an impurity of Methotrexate (M260675) which is a folic acid antagonist. Used as a antineoplastic and antirheumatic.<br>References Freeman, M.V., J. Pharmacol. Exp. Ther., 122, 154 (1958), Weinblass, M.E., et al.: N. Engl. J. Med., 312, 818 (1985),<br></p>

<p>Applications Febuxostat-d7, is the labeled analogue of Febuxostat-d7 (F229000), a Xanthine oxidase/xanthine dehydrogenase inhibitor. Used for treatment of hyperuricemia and chronic gout.<br>References Osada, Y., et al.: Eur. J. Pharmacol., 241, 183 (1993), Okamoto, K., et al.: J. Biol. Chem., 278, 1848 (2003), Mayer, M.D., et al.: Am. J. Therap., 12, 22 (2005), Tomlinson, B., et al.: Curr. Opin. Invest. Drugs, 6, 1168 (2005),<br></p>

<p>Applications Metabolite of Theophylline and Caffeine.<br>References Yu, Ch. et al.: J. Bacteriol. 191, 4624 (2009); Geraets, L. et al.: Biochem. Pharmacol. 72, 902 (2006).<br></p>

<p>Applications 2-(3-Cyano-4-hydroxyphenyl)-4-methyl-1,3-thiazole-5-carboxylic Acid Ethyl Ester, can be used for the synthesis of Febuxostat (F229000), an antipodagrics.<br>References Zheng, F., et al.: Zhongguo Yiyao Gongye Zazhi, 40, 726 (2009);<br></p>

<p>Applications An alkyladamantane derivative that are biotransformed via strains of Pseudomonas. It is used to study alkyladamantane adsorption on graphitized thermal carbon black.<br>References Yashkin, S.N. et al.: Rus. Che,. Bull., 57, 2472 (2008); Slepen’kin, A. et al.: Nefeckhim., 33, 406 (1993);<br></p>

<p>Applications Intermediate in the production of Thyroxine<br></p>

<p>Applications 4-(3-Bromo-4-oxobutyl)benzoic Acid Methyl Ester is used as a reagent in the synthesis of furoxanoxyalkyl esters of pemetrexed as antifolates and nitric oxide donors for use as anticancer agents and their activities against four human cancer cell lines.<br>References Min, T., et al.: Med. Chem. Res., 18, 495 (2009); Barnett, C.J., et al.: Org. Process Res. Dev., 3, 184 (1999)<br></p>

<p>Impurity Methotrexate EP Impurity B<br>Applications Aminopterin (Methotrexate EP Impurity B) is a folic acid antagonist. Its actively transported into cells by thefolate transporter. In the cell, its converted to a high molecular weight polyglutamate metabolite by folylpolyglutamate synthase, that, in turn, binds to dihydrofolate reductase and inhibits its activity.<br> Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package<br>References Matherly, L.H., et al.: Cancer Res., 45, 1073 (1985), Rumberger, B.G., et al.: Cancer Res., 50, 4639 (1990), Roy, K., et al.: J. Biol. Chem., 273, 2526 (1998),<br></p>

<p>Applications Succinimide is a reagent that is used in the synthesis of Lumiflavin (L473900), which is a toxic photolysis product of vitamin B2 (R415000).<br>References Zhao, X. et al.: Chemosphere, 63, 1116 (2006); Litke, S.V. et al.: Khim. Fiz., 10, 48 (1991); Ye, W. et al.: Guang. Yaox. Xueb., 12, 175 (1996);<br></p>

<p>Applications Labelled Urea. Physiological regulator of nitrogen excretion in mammals; synthesized in the liver as an end-product of protein catabolism and excreted in urine. Also occurs normally in skin. Emollient; diuretic.<br>References Demetriou, A., et al.: Science, 233, 1190 (1986), Aebischer, P., et al.: Nat. Med., 2, 696 (1996), Prakash, S., et al.: Biotechnol. Bioeng., 46, 621 (1995),<br></p>

<p>Applications Perfume composition.<br> Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package<br>References Hansen, B., et al.: Environ. Toxicol. Chem., 18, 772 (1999),<br></p>