{"id":13897,"date":"2025-10-14T14:03:39","date_gmt":"2025-10-14T07:03:39","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=13897"},"modified":"2025-10-14T14:03:39","modified_gmt":"2025-10-14T07:03:39","slug":"galactose","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/galactose\/","title":{"rendered":"Galactose"},"content":{"rendered":"

(Ph. Eur. monograph 1215)<\/p>\n

C_{6<\/sub>H_{12<\/sub>O_{6\u00a0<\/sub> \u00a0 \u00a0 \u00a0180.2\u00a0 \u00a0 \u00a0 \u00a059-23-4<\/p>\n}}}

DEFINITION<\/h2>\n
D-Galactopyranose.<\/p>\n

Content<\/h3>\n
97.0 per cent to 102.0 per cent (anhydrous substance).<\/p>\n

CHARACTERS<\/h2>\n

Appearance<\/h3>\n
White or almost white, crystalline or finely granulated powder.<\/p>\n

Solubility<\/h3>\n
Freely soluble or soluble in water, very slightly soluble in ethanol (96 per cent).<\/p>\n

IDENTIFICATION<\/h2>\n
First identification: A.<\/p>\n
Second identification: B, C.<\/p>\n
A. Infrared absorption spectrophotometry (2.2.24).<\/p>\n
Comparison: galactose CRS.<\/p>\n
B. Thin-layer chromatography (2.2.27).<\/p>\n
Test solution: Dissolve 10 mg of the substance to be examined in a mixture of 2 volumes of water R and 3 volumes of methanol R and dilute to 20 mL with the same mixture of solvents.<\/p>\n
Reference solution (a): Dissolve 10 mg of galactose CRS in a mixture of 2 volumes of water R and 3 volumes of methanol R and dilute to 20 mL with the same mixture of solvents.<\/p>\n
Reference solution (b): Dissolve 10 mg each of galactose R, glucose R and lactose monohydrate R (impurity A) in a mixture of 2 volumes of water R and 3 volumes of methanol R and dilute to 20 mL with the same mixture of solvents.<\/p>\n
Plate: TLC silica gel plate R.<\/p>\n
Mobile phase: water R, propanol R (15:85 V\/V).<\/p>\n
Application: 2 \u03bcL; thoroughly dry the points of application.<\/p>\n
Development: In an unsaturated tank over 3\/4 of the plate.<\/p>\n
Drying: In a current of warm air.<\/p>\n
Detection: Spray with a solution of 0.5 g of thymol R in a mixture of 5 mL of sulfuric acid R and 95 mL of ethanol (96 per cent) R. Heat in an oven at 130 \u00b0C for 10 min.<\/p>\n
System suitability: Reference solution (b):<\/p>\n
\u2014 the chromatogram shows 3 clearly separated spots.<\/p>\n
Results: The principal spot in the chromatogram obtained with the test solution is similar in position, colour and size to the principal spot in the chromatogram obtained with reference solution (a).<\/p>\n
C. Dissolve 0.1 g in 10 mL of water R. Add 3 mL of cupri-tartaric solution R and heat. An orange or red precipitate is formed.<\/p>\n

TESTS<\/h2>\n

Solution S<\/h3>\n
Dissolve, with heating in a water-bath at 50 \u00b0C, 10.0 g in carbon dioxide-free water R prepared from distilled water R and dilute to 50 mL with the same solvent.<\/p>\n

Appearance of solution<\/h3>\n
Solution S is clear (2.2.1) and not more intensely coloured than reference solution B_{8<\/sub> (2.2.2, Method II).<\/p>\n}

Acidity or alkalinity<\/h3>\n
To 30 mL of solution S add 0.3 mL of phenolphthalein solution R. The solution is colourless. Not more than 1.5 mL of 0.01 M sodium hydroxide is required to change the colour of the indicator to pink.<\/p>\n

Proteins<\/h3>\n
Maximum 0.1 mg\/mL.<\/p>\n
Dissolve 1.000 g of the substance to be examined in water R and dilute to 10.0 mL with the same solvent. Measure the absorbance (2.2.25) of the solution at 260 nm and at 280 nm and calculate the protein content, in milligrams per millilitre, using the following expression:<\/p>\n
(A_{280<\/sub> \u00d7 1.45) \u2212 (A_{260<\/sub> \u00d7 0.74)<\/p>\n}}
A_{280<\/sub> = absorbance at 280 nm;<\/p>\n}
A_{260<\/sub> = absorbance at 260 nm.<\/p>\n}

Related substances<\/h3>\n
Liquid chromatography (2.2.29).<\/p>\n
Test solution (a): Dissolve 0.250 g of the substance to be examined in water R and dilute to 10.0 mL with the same solvent.<\/p>\n
Test solution (b): Dilute 1.0 mL of test solution (a) to 50.0 mL with water R.<\/p>\n
Reference solution (a): Dilute 1.0 mL of test solution (a) to 100.0 mL with water R.<\/p>\n
Reference solution (b): Dissolve 3 mg each of 1,6-galactosylgalactose R (impurity B), galacturonic acid R (impurity C) and lactose monohydrate R (impurity A) in water R and dilute to 10 mL with the same solvent. To 100 \u03bcL of the solution add 900 \u03bcL of test solution (a).<\/p>\n
Reference solution (c): Dissolve 25.0 mg of galactose CRS in water R and dilute to 50.0 mL with the same solvent.<\/p>\n
Column 2 columns to be connected in series:<\/p>\n
\u2014 size: l = 0.30 m, \u00d8 = 6.5 mm;<\/p>\n
\u2014 stationary phase: strong cation-exchange resin (calcium form) R (10 \u03bcm);<\/p>\n
\u2014 temperature: 75 \u00b0C.<\/p>\n
Mobile phase: Dissolve 50 mg of sodium calcium edetate R in 900 mL of water for chromatography R, add 1.0 mL of sulfuric acid R and dilute to 1000 mL with water for chromatography R.<\/p>\n
Flow rate: 0.4 mL\/min.<\/p>\n
Detection: Differential refractometer maintained at a constant temperature (about 40 \u00b0C).<\/p>\n
Injection: 10 \u03bcL of test solution (a) and reference solutions (a) and (b).<\/p>\n
Run time: Twice the retention time of galactose.<\/p>\n
Identification of impurities: Use the chromatogram obtained with reference solution (b) to identify the peaks due to impurities A + B and C.<\/p>\n
Relative retention: With reference to galactose (retention time = about 24 min): impurities A and B = about 0.8; impurity C = about 0.9.<\/p>\n
System suitability: Reference solution (b):<\/p>\n
\u2014 resolution: minimum 2.0 between the peaks due to impurity C and galactose.<\/p>\n
Calculation of percentage contents:<\/p>\n
\u2014 for each impurity, use the concentration of galactose in reference solution (a).<\/p>\n
Limits:<\/p>\n
\u2014 sum of impurities A and B: maximum 1.0 per cent;<\/p>\n
\u2014 unspecified impurities: for each impurity, maximum 0.3 per cent;<\/p>\n
\u2014 total: maximum 2.0 per cent;<\/p>\n
\u2014 reporting threshold: 0.2 per cent.<\/p>\n

Water (2.5.12)<\/h4>\n
Maximum 1.0 per cent, determined on 1.00 g.<\/p>\n

Sulfated ash<\/h4>\n
Maximum 0.1 per cent.<\/p>\n
To 5 mL of solution S add 2 mL of sulfuric acid R, evaporate to dryness on a water-bath and ignite to constant mass. The residue weighs a maximum of 1 mg.<\/p>\n

Microbial contamination<\/h3>\n
TAMC: acceptance criterion 10 CFU\/g (2.6.12).<\/p>\n

ASSAY<\/h2>\n
Liquid chromatography (2.2.29) as described in the test for related substances with the following modification.<\/p>\n
Injection: 10 \u03bcL of test solution (b) and reference solution (c).<\/p>\n
Calculate the percentage content of C_{6<\/sub>H_{12<\/sub>O_{6<\/sub> taking into account the assigned content of galactose CRS.<\/p>\n}}}

IMPURITIES<\/h2>\n
Specified impurities A, B.<\/p>\n
Other detectable impurities (the following substances would, if present at a sufficient level, be detected by one or other 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) C, D, E.<\/p>\n
$\"Galactose\"$ <\/p>\n
A. 4-O-\u03b2-D-galactopyranosyl-D-glucopyranose (lactose),<\/p>\n
$\"Galactose\"$ <\/p>\n
B. 6-O-\u03b2-D-galactopyranosyl-D-galactopyranose (1,6-galactosylgalactose),<\/p>\n
$\"Galactose\"$ <\/p>\n
C. D-galactopyranuronic acid (galacturonic acid),<\/p>\n
$\"Galactose\"$ <\/p>\n
D. D-tagatose,<\/p>\n
$\"Galactose\"$ <\/p>\n
E. galactitol (dulcitol).<\/p>\n","protected":false},"excerpt":{"rendered":"
(Ph. Eur. monograph 1215) C6H12O6\u00a0 \u00a0 \u00a0 \u00a0180.2\u00a0 \u00a0 \u00a0 \u00a059-23-4 DEFINITION D-Galactopyranose. Content 97.0 per cent to 102.0 per cent (anhydrous substance). CHARACTERS Appearance White or almost white, crystalline or finely granulated powder. Solubility Freely soluble or soluble in water, very slightly soluble in ethanol (96 per cent). IDENTIFICATION First identification: A. Second identification:…<\/p>\n","protected":false},"author":2,"featured_media":13915,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-13897","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\/13897","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\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/comments?post=13897"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/13897\/revisions"}],"predecessor-version":[{"id":13919,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/13897\/revisions\/13919"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/13915"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=13897"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=13897"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=13897"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

DEFINITION<\/h2>\nD-Galactopyranose.<\/p>\n

Content<\/h3>\n97.0 per cent to 102.0 per cent (anhydrous substance).<\/p>\n

CHARACTERS<\/h2>\n

Appearance<\/h3>\nWhite or almost white, crystalline or finely granulated powder.<\/p>\n

Solubility<\/h3>\nFreely soluble or soluble in water, very slightly soluble in ethanol (96 per cent).<\/p>\n

TESTS<\/h2>\n

Solution S<\/h3>\nDissolve, with heating in a water-bath at 50 \u00b0C, 10.0 g in carbon dioxide-free water R prepared from distilled water R and dilute to 50 mL with the same solvent.<\/p>\n

Appearance of solution<\/h3>\nSolution S is clear (2.2.1) and not more intensely coloured than reference solution B8<\/sub> (2.2.2, Method II).<\/p>\n

Acidity or alkalinity<\/h3>\nTo 30 mL of solution S add 0.3 mL of phenolphthalein solution R. The solution is colourless. Not more than 1.5 mL of 0.01 M sodium hydroxide is required to change the colour of the indicator to pink.<\/p>\n

Water (2.5.12)<\/h4>\nMaximum 1.0 per cent, determined on 1.00 g.<\/p>\n

Sulfated ash<\/h4>\nMaximum 0.1 per cent.<\/p>\nTo 5 mL of solution S add 2 mL of sulfuric acid R, evaporate to dryness on a water-bath and ignite to constant mass. The residue weighs a maximum of 1 mg.<\/p>\n

Microbial contamination<\/h3>\nTAMC: acceptance criterion 10 CFU\/g (2.6.12).<\/p>\n