{"id":32256,"date":"2025-11-17T15:07:14","date_gmt":"2025-11-17T08:07:14","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=32256"},"modified":"2025-11-17T15:07:14","modified_gmt":"2025-11-17T08:07:14","slug":"tryptophan","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/tryptophan\/","title":{"rendered":"Tryptophan"},"content":{"rendered":"

Edition: BP 2025 (Ph. Eur. 11.6 update)<\/p>\n

(Ph. Eur. monograph 1272)<\/p>\n

C\u2081\u2081H\u2081\u2082N\u2082O\u2082\u2003 204.2\u2003 CAS: 73-22-3<\/p>\n

DEFINITION<\/h2>\n

(2S)-2-Amino-3-(1H-indol-3-yl)propanoic acid.
\nProduct of fermentation or of protein hydrolysis.<\/p>\n

Content: 98.5% to 101.0% (dried substance).<\/p>\n

CHARACTERS<\/h2>\n

Appearance
\nWhite or almost white, crystalline or amorphous powder.<\/p>\n

Solubility
\nSparingly soluble in water, slightly soluble in ethanol (96%).
\nIt dissolves in dilute solutions of mineral acids and alkali hydroxides.<\/p>\n

IDENTIFICATION<\/h2>\n

First identification: A, B.
\nSecond identification: A, C, D.<\/p>\n

A. Specific optical rotation (see Tests).
\nB. Infrared absorption spectrophotometry (2.2.24).
\nC. Thin-layer chromatography (2.2.27).<\/p>\n

Solvent mixture: glacial acetic acid, water (50:50 V\/V).<\/p>\n

Test solution: Dissolve 10 mg of the substance to be examined in the solvent mixture and dilute to 50 mL.
\nReference solution: Dissolve 10 mg of tryptophan CRS in the same solvent mixture and dilute to 50 mL.<\/p>\n

Plate: TLC silica gel plate.
\nMobile phase: glacial acetic acid, water, butanol (20:20:60 V\/V\/V).
\nApplication: 5 \u00b5L.
\nDevelopment: Over 2\/3 of the plate.
\nDrying: In air.
\nDetection: Spray with ninhydrin solution and heat at 105 \u00b0C for 15 min.<\/p>\n

Results:
\nPrincipal spot of test solution similar in position, colour, size to reference.<\/p>\n

D. Dissolve about 20 mg in 10 mL of water.
\nAdd 5 mL dimethylaminobenzaldehyde solution and 2 mL hydrochloric acid.
\nHeat on water-bath \u2192 purple-blue colour.<\/p>\n

TESTS<\/p>\n

Appearance of solution<\/p>\n

Clear and not more intensely coloured than reference solution BY6.
\nDissolve 0.1 g in 1 M HCl and dilute to 10 mL.<\/p>\n

Specific optical rotation (2.2.7)<\/p>\n

\u201333.0 to \u201330.0 (dried substance).
\nDissolve 0.25 g in water, heat if necessary, dilute to 25 mL.<\/p>\n

Ninhydrin-positive substances<\/p>\n

Amino acid analysis (2.2.56), Method 1.<\/p>\n

Solution A: dilute HCl or suitable buffer.
\nTest solution: Dissolve 30 mg in solution A \u2192 50 mL.
\nReference solutions: (a), (b), (c) prepared exactly as trong file.<\/p>\n

Blank: Solution A.<\/p>\n

Inject test, blank, references into amino acid analyser.<\/p>\n

System suitability (Reference solution d):
\n\u2014 resolution \u2265 1.5 between isoleucine and leucine.<\/p>\n

Limits:
\n\u2014 any impurity \u2264 0.2%
\n\u2014 total \u2264 0.5%
\n\u2014 reporting threshold: 0.05%<\/p>\n

The thresholds under \u201cSubstances for pharmaceutical use (2034)\u201d do not apply.<\/p>\n

Impurity A and other related substances<\/p>\n

Liquid chromatography (2.2.29).
\nPrepare solutions immediately before use.<\/p>\n

Buffer pH 2.3: sodium dihydrogen phosphate + phosphoric acid, adjust pH.<\/p>\n

Solvent mixture: acetonitrile : water (10:90).<\/p>\n

Standard solution: N-acetyltryptophan 10 mg \u2192 100 mL \u2192 diluted.<\/p>\n

Test solution (a): 0.10 g substance \u2192 10 mL solvent mixture.
\nTest solution (b): same but dissolved in standard solution.<\/p>\n

Reference solutions: prepared with impurity A.<\/p>\n

Column: 250 mm \u00d7 4.6 mm; 5 \u00b5m ODS silica; 40 \u00b0C.<\/p>\n

Mobile phase gradient:<\/p>\n\n\n\n\n\n\n\n
Time (min)<\/th>\nMobile phase A (%)<\/th>\nMobile phase B (%)<\/th>\n<\/tr>\n<\/thead>\n
0\u201310<\/td>\n100<\/td>\n0<\/td>\n<\/tr>\n
10\u201345<\/td>\n100 \u2192 0<\/td>\n0 \u2192 100<\/td>\n<\/tr>\n
45\u201365<\/td>\n0<\/td>\n100<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Flow: 0.7 mL\/min
\nDetection: 220 nm
\nInjection: 20 \u00b5L<\/p>\n

Retention times:
\nTryptophan \u2248 8 min
\nN-acetyltryptophan \u2248 29 min
\nImpurity A \u2248 34 min<\/p>\n

System suitability:
\n\u2014 resolution \u2265 8.0 (N-acetyltryptophan vs impurity A)
\n\u2014 S\/N \u2265 15 (reference solution c)
\n\u2014 symmetry factor \u2264 3.5
\n\u2014 In test solution (a): no peak at retention time of N-acetyltryptophan.<\/p>\n

Limits (Test solution b):
\n\u2014 impurity A \u2264 0.5 \u00d7 area of reference (c) (10 ppm)
\n\u2014 impurities RT < tryptophan \u2264 0.6 \u00d7 area of N-acetyltryptophan (100 ppm)
\n\u2014 impurities RT > tryptophan to 1.8 \u00d7 RT N-acetyltryptophan \u2264 1.9 \u00d7 area (300 ppm)
\n\u2014 disregard limit: 0.02 \u00d7 N-acetyltryptophan peak area.<\/p>\n

Chlorides (2.4.4)<\/p>\n

\u2264 200 ppm.
\nDissolve 0.25 g in dilute nitric acid \u2192 dilute to 15 mL.<\/p>\n

Sulfates (2.4.13)<\/p>\n

\u2264 300 ppm.
\nDissolve 0.5 g in dilute HCl + distilled water \u2192 dilute to 15 mL.<\/p>\n

Ammonium<\/p>\n

Amino acid analysis with modifications.
\nLimit:
\n\u2014 ammonium at 570 nm \u2264 area of reference (c), accounting for blank.<\/p>\n

Iron (2.4.9)<\/p>\n

\u2264 20 ppm.
\nDissolve 0.50 g in dilute HCl \u2192 extract with methyl isobutyl ketone.
\nCheck aqueous layer.<\/p>\n

Loss on drying (2.2.32)<\/p>\n

\u2264 0.5%, drying at 105 \u00b0C.<\/p>\n

Sulfated ash (2.4.14)<\/p>\n

\u2264 0.1% on 1 g.<\/p>\n

ASSAY<\/h2>\n

Dissolve 0.150 g in anhydrous formic acid \u2192 add 50 mL anhydrous acetic acid.
\nTitrate with 0.1 M perchloric acid (potentiometric).
\nBlank correction.
\n1 mL 0.1 M HClO\u2084 = 20.42 mg C\u2081\u2081H\u2081\u2082N\u2082O\u2082.<\/p>\n

STORAGE<\/h2>\n

Protect from light.<\/p>\n

IMPURITIES<\/h2>\n

Specified impurities A.<\/p>\n

Other detectable impurities (the following substances would, if present at a sufficient level, be detected by one or ander of the tests in the monograph. They are limited by the general acceptance criterion for other\/unspecified impurities. It is therefore not necessary to identify these impurities for demonstration of compliance. See also 5.10. Control of impurities in substances for pharmaceutical use) B, C, D, E, F, G, H, I, J, K, L.<\/p>\n

 <\/p>\n

\"\"
A.\u20033,3\u2032-[ethane-1,1-diylbis(1H-indol-1,3-diyl)]bis[(2S)-2-aminopropanoic acid] (ethane-1,1-diylbistryptophan),<\/figcaption><\/figure>\n
\"\"
B.\u2003(2S)-2-amino-3-[(3RS)-3-hydroxy-2-oxo-2,3-dihydro-1H-indol-3-yl]propanoic acid (dioxyindolylalanine),<\/figcaption><\/figure>\n
\"\"
C.\u2003(2S)-2-amino-4-(2-aminophenyl)-4-oxobutanoic acid (kynurenine),<\/figcaption><\/figure>\n

 <\/p>\n

\"\"
D.\u2003(2S)-2-amino-3-(5-hydroxy-1H-indol-3-yl)propanoic acid (5-hydroxytryptophan),<\/figcaption><\/figure>\n

 <\/p>\n

\"\"
E.\u2003(2S)-2-amino-4-[2-(formylamino)phenyl]-4-oxobutanoic acid (N-formylkynurenine),<\/figcaption><\/figure>\n
\"\"
F.\u2003(2S)-2-amino-3-(phenylamino)propanoic acid (3-phenylaminoalanine),<\/figcaption><\/figure>\n

 <\/p>\n

\"\"
G.\u2003(2S)-2-amino-3-(2-hydroxy-1H-indol-3-yl)propanoic acid (2-hydroxytryptophan),<\/figcaption><\/figure>\n

 <\/p>\n

\"\"
H.\u2003(3RS)-1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indole-3-carboxylic acid,<\/figcaption><\/figure>\n
\"\"
I.\u20031-methyl-1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indole-3-carboxylic acid,<\/figcaption><\/figure>\n
\"\"
J.\u2003(2S)-2-amino-3-[2-[2,3-dihydroxy-1-(1H-indol-3-yl)propyl]-1H-indol-3-yl]propanoic acid,<\/figcaption><\/figure>\n
\"\"
K.\u2003(2S)-2-amino-3-[2-(1H-indol-3-ylmethyl)-1H-indol-3-yl]propanoic acid,<\/figcaption><\/figure>\n
\"\"
L.\u20031-(1H-indol-3-ylmethyl)-1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indole-3-carboxylic acid.<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"

Edition: BP 2025 (Ph. Eur. 11.6 update) (Ph. Eur. monograph 1272) C\u2081\u2081H\u2081\u2082N\u2082O\u2082\u2003 204.2\u2003 CAS: 73-22-3 DEFINITION (2S)-2-Amino-3-(1H-indol-3-yl)propanoic acid. Product of fermentation or of protein hydrolysis. Content: 98.5% to 101.0% (dried substance). CHARACTERS Appearance White or almost white, crystalline or amorphous powder. Solubility Sparingly soluble in water, slightly soluble in ethanol (96%). It dissolves in dilute…<\/p>\n","protected":false},"author":5,"featured_media":32257,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-32256","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-medicinal-substances"],"acf":[],"_links":{"self":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/32256","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/comments?post=32256"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/32256\/revisions"}],"predecessor-version":[{"id":32272,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/32256\/revisions\/32272"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/32257"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=32256"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=32256"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=32256"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}