{"id":28651,"date":"2025-11-08T17:02:09","date_gmt":"2025-11-08T10:02:09","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=28651"},"modified":"2025-11-08T17:02:09","modified_gmt":"2025-11-08T10:02:09","slug":"propylthiouracil","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/propylthiouracil\/","title":{"rendered":"Propylthiouracil"},"content":{"rendered":"

(Ph. Eur. monograph 0525)<\/p>\n

C_{7<\/sub>H_{10<\/sub>N_{2<\/sub>OS\u00a0 \u00a0 \u00a0 \u00a0170.2\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a051-52-5<\/p>\n}}}

Action and use<\/strong><\/p>\n

Thiourea antithyroid drug.<\/p>\n

Preparation<\/strong><\/p>\n

Propylthiouracil Tablets<\/p>\n

DEFINITION<\/h2>\n
6-Propyl-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one.<\/p>\n
Content<\/h3>\n
98.0 per cent to 101.0 per cent (dried substance).<\/p>\n
CHARACTERS<\/h2>\n
Appearance<\/h3>\n
White or almost white, crystalline powder or crystals.<\/p>\n
Solubility<\/h3>\n
Very slightly soluble in water, sparingly soluble in ethanol (96 per cent). It dissolves in solutions of alkali hydroxides.<\/p>\n
IDENTIFICATION<\/h2>\n
First identification: B.<\/p>\n
Second identification: A, C.<\/p>\n
A. Melting point (2.2.14): 217 \u00b0C to 221 \u00b0C.<\/p>\n
B. Infrared absorption spectrophotometry (2.2.24).<\/p>\n
Comparison: propylthiouracil CRS.<\/p>\n
C. To about 20 mg add 8 mL of bromine water R and shake for a few minutes. Boil until the mixture is decolourised, allow to cool and filter. To the filtrate add 2 mL of barium chloride solution R1. A white precipitate is formed whose colour does not become violet on the addition of 5 mL of dilute sodium hydroxide solution R.<\/p>\n
TESTS<\/h2>\n
Impurity A<\/h3>\n
Liquid chromatography (2.2.29).<\/p>\n
Solvent mixtureL water R, acetonitrile R (30:70 V\/V).<\/p>\n
Test solution: Dissolve 50.0 mg of the substance to be examined in the solvent mixture and dilute to 50.0 mL with the solvent mixture.<\/p>\n
Reference solution: Dissolve 2.5 mg of propylthiouracil impurity A CRS in 70 mL of the solvent mixture and dilute to 100.0 mL with the solvent mixture. Dilute 1.0 mL of the solution to 50.0 mL with the solvent mixture.<\/p>\n
Column:<\/p>\n
\u2014 size: l = 0.25 m, \u00d8 = 4.6 mm;<\/p>\n
\u2014 stationary phase: silica gel for chromatography, alkyl-bonded for use with highly aqueous mobile phases R (5 \u03bcm);<\/p>\n
\u2014 temperature: 25 \u00b0C.<\/p>\n
Mobile phase:<\/p>\n
\u2014 mobile phase A: to 1000 mL of water for chromatography R, add 1 mL of phosphoric acid R and mix. Mix 900 mL of this solution and 100 mL of acetonitrile for chromatography R<\/p>\n
\u2014 mobile phase B: acetonitrile for chromatography R;<\/p>\n\n\n\n\n\n\n
Time<\/strong>
\n(min)<\/strong><\/td>\n Mobile phase A<\/strong>
\n(per cent V\/V)<\/strong><\/td>\n Mobile phase B<\/strong>
\n(per cent V\/V)<\/strong><\/td>\n<\/tr>\n
0 – 5<\/td>\n 100<\/td>\n 0<\/td>\n<\/tr>\n
5 – 15<\/td>\n 100 \u2192 70<\/td>\n 0 \u2192 30<\/td>\n<\/tr>\n
15 – 25<\/td>\n 70<\/td>\n 30<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
Flow rate: 0.6 mL\/min.<\/p>\n
Detection: Spectrophotometer at 235 nm.\u01b0<\/p>\n
Injection: 20 \u03bcL.<\/p>\n
Run time: 1.5 times the retention time of propylthiouracil.<\/p>\n
Identification of impurities: Use the chromatogram obtained with the reference solution to identify the peak due to impurity A.<\/p>\n
Relative retention: With reference to propylthiouracil (retention time = about 16 min): impurity A = about 0.27.<\/p>\n
Calculation of percentage content:<\/p>\n
\u2014 for impurity A, use the concentration of impurity A in the reference solution.<\/p>\n
Limit:<\/p>\n
\u2014 impurity A: maximum 0.05 per cent.<\/p>\n
Related substances<\/h3>\n
Liquid chromatography (2.2.29).<\/p>\n
Test solution: Dissolve 25.0 mg of the substance to be examined in 20 mL of methanol R, sonicate to dissolve and dilute to 100.0 mL with methanol R.<\/p>\n
Reference solution (a): Dilute 1.0 mL of the test solution to 10.0 mL with methanol R. Dilute 1.0 mL of the solution to 100.0 mL with methanol R.<\/p>\n
Reference solution (b): Dissolve 25 mg of the substance to be examined and 25 mg of methylthiouracil R (impurity B) in 50 mL of methanol R and dilute to 100 mL with the same solvent. Dilute 0.5 mL of the solution to 50 mL with methanol R.<\/p>\n
Column:<\/p>\n
\u2014 size: l = 0.25 m, \u00d8 = 4.6 mm;<\/p>\n
\u2014 stationary phase: base-deactivated end-capped octadecylsilyl silica gel for chromatography R (5 \u03bcm);<\/p>\n
\u2014 temperature: 30 \u00b0C.<\/p>\n
Mobile phase: To 1000 mL of water for chromatography R, add 1 mL of phosphoric acid R and mix. Mix 900 mL of this solution and 100 mL of acetonitrile R.<\/p>\n
Flow rate: 1.0 mL\/min.<\/p>\n
Detection: Spectrophotometer at 275 nm.<\/p>\n
Injection: 10 \u03bcL.<\/p>\n
Run time: 1.5 times the retention time of propylthiouracil.<\/p>\n
Identification of impurities: Use the chromatogram obtained with reference solution (b) to identify the peak due to impurity B.<\/p>\n
Relative retention: With reference to propylthiouracil (retention time = about 19 min): impurity B = about 0.3.<\/p>\n
System suitability: Reference solution (b):<\/p>\n
\u2014 resolution: minimum 20 between the peaks due to impurity B and propylthiouracil.<\/p>\n
Calculation of percentage contents:<\/p>\n
\u2014 for each impurity, use the concentration of propylthiouracil in reference solution (a).<\/p>\n
Limits:<\/p>\n
\u2014 unspecified impurities: for each impurity, maximum 0.10 per cent;<\/p>\n
\u2014 total: maximum 0.2 per cent;<\/p>\n
\u2014 reporting threshold: maximum 0.05 per cent.<\/p>\n
Loss on drying (2.2.32)<\/h4>\n
Maximum 0.5 per cent, determined on 1.000 g by drying in an oven at 105 \u00b0C.<\/p>\n
Sulfated ash (2.4.14)<\/h4>\n
Maximum 0.1 per cent, determined on 1.0 g.<\/p>\n
ASSAY<\/h2>\n
To 0.300 g add 30 mL of water R and 30.0 mL of 0.1 M sodium hydroxide. Boil and shake until dissolution is complete. Add 50 mL of 0.1 M silver nitrate while stirring, boil gently for 5 min and cool. Titrate with 0.1 M sodium hydroxide, determining the end-point potentiometrically (2.2.20). The volume of 0.1 M sodium hydroxide used is equal to the sum of the volume added initially and the volume used in the final titration.<\/p>\n
1 mL of 0.1 M sodium hydroxide is equivalent to 8.511 mg of C_{7<\/sub>H_{10<\/sub>N_{2<\/sub>OS.<\/p>\n}}}
STORAGE<\/h2>\n
Protected 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 other of the tests in the monograph. They are limited by the general acceptance criterion for other\/unspecified impurities and\/or by the general monograph Substances for pharmaceutical use (2034). 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.<\/p>\n
$\"Propylthiouracil\"$ <\/p>\n
A. thiourea,<\/p>\n
$\"Propylthiouracil\"$ <\/p>\n
B. 6-methyl-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one (methylthiouracil).<\/p>\n","protected":false},"excerpt":{"rendered":"
(Ph. Eur. monograph 0525) C7H10N2OS\u00a0 \u00a0 \u00a0 \u00a0170.2\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a051-52-5 Action and use Thiourea antithyroid drug. Preparation Propylthiouracil Tablets DEFINITION 6-Propyl-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one. Content 98.0 per cent to 101.0 per cent (dried substance). CHARACTERS Appearance White or almost white, crystalline powder or crystals. Solubility Very slightly soluble in water, sparingly soluble in ethanol (96…<\/p>\n","protected":false},"author":2,"featured_media":28686,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-28651","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\/28651","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=28651"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/28651\/revisions"}],"predecessor-version":[{"id":28702,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/28651\/revisions\/28702"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/28686"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=28651"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=28651"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=28651"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

Time<\/strong> \n(min)<\/strong><\/td>\n	Mobile phase A<\/strong> \n(per cent V\/V)<\/strong><\/td>\n	Mobile phase B<\/strong> \n(per cent V\/V)<\/strong><\/td>\n<\/tr>\n
0 – 5<\/td>\n	100<\/td>\n	0<\/td>\n<\/tr>\n
5 – 15<\/td>\n	100 \u2192 70<\/td>\n	0 \u2192 30<\/td>\n<\/tr>\n
15 – 25<\/td>\n	70<\/td>\n	30<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Flow rate: 0.6 mL\/min.<\/p>\n Detection: Spectrophotometer at 235 nm.\u01b0<\/p>\n Injection: 20 \u03bcL.<\/p>\n Run time: 1.5 times the retention time of propylthiouracil.<\/p>\n Identification of impurities: Use the chromatogram obtained with the reference solution to identify the peak due to impurity A.<\/p>\n Relative retention: With reference to propylthiouracil (retention time = about 16 min): impurity A = about 0.27.<\/p>\n Calculation of percentage content:<\/p>\n \u2014 for impurity A, use the concentration of impurity A in the reference solution.<\/p>\n Limit:<\/p>\n \u2014 impurity A: maximum 0.05 per cent.<\/p>\n Related substances<\/h3>\n Liquid chromatography (2.2.29).<\/p>\n Test solution: Dissolve 25.0 mg of the substance to be examined in 20 mL of methanol R, sonicate to dissolve and dilute to 100.0 mL with methanol R.<\/p>\n Reference solution (a): Dilute 1.0 mL of the test solution to 10.0 mL with methanol R. Dilute 1.0 mL of the solution to 100.0 mL with methanol R.<\/p>\n Reference solution (b): Dissolve 25 mg of the substance to be examined and 25 mg of methylthiouracil R (impurity B) in 50 mL of methanol R and dilute to 100 mL with the same solvent. Dilute 0.5 mL of the solution to 50 mL with methanol R.<\/p>\n Column:<\/p>\n \u2014 size: l = 0.25 m, \u00d8 = 4.6 mm;<\/p>\n \u2014 stationary phase: base-deactivated end-capped octadecylsilyl silica gel for chromatography R (5 \u03bcm);<\/p>\n \u2014 temperature: 30 \u00b0C.<\/p>\n Mobile phase: To 1000 mL of water for chromatography R, add 1 mL of phosphoric acid R and mix. Mix 900 mL of this solution and 100 mL of acetonitrile R.<\/p>\n Flow rate: 1.0 mL\/min.<\/p>\n Detection: Spectrophotometer at 275 nm.<\/p>\n Injection: 10 \u03bcL.<\/p>\n Run time: 1.5 times the retention time of propylthiouracil.<\/p>\n Identification of impurities: Use the chromatogram obtained with reference solution (b) to identify the peak due to impurity B.<\/p>\n Relative retention: With reference to propylthiouracil (retention time = about 19 min): impurity B = about 0.3.<\/p>\n System suitability: Reference solution (b):<\/p>\n \u2014 resolution: minimum 20 between the peaks due to impurity B and propylthiouracil.<\/p>\n Calculation of percentage contents:<\/p>\n \u2014 for each impurity, use the concentration of propylthiouracil in reference solution (a).<\/p>\n Limits:<\/p>\n \u2014 unspecified impurities: for each impurity, maximum 0.10 per cent;<\/p>\n \u2014 total: maximum 0.2 per cent;<\/p>\n \u2014 reporting threshold: maximum 0.05 per cent.<\/p>\n Loss on drying (2.2.32)<\/h4>\n Maximum 0.5 per cent, determined on 1.000 g by drying in an oven at 105 \u00b0C.<\/p>\n Sulfated ash (2.4.14)<\/h4>\n Maximum 0.1 per cent, determined on 1.0 g.<\/p>\n ASSAY<\/h2>\n To 0.300 g add 30 mL of water R and 30.0 mL of 0.1 M sodium hydroxide. Boil and shake until dissolution is complete. Add 50 mL of 0.1 M silver nitrate while stirring, boil gently for 5 min and cool. Titrate with 0.1 M sodium hydroxide, determining the end-point potentiometrically (2.2.20). The volume of 0.1 M sodium hydroxide used is equal to the sum of the volume added initially and the volume used in the final titration.<\/p>\n 1 mL of 0.1 M sodium hydroxide is equivalent to 8.511 mg of C_{7<\/sub>H_{10<\/sub>N_{2<\/sub>OS.<\/p>\n}}} STORAGE<\/h2>\n Protected 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 other of the tests in the monograph. They are limited by the general acceptance criterion for other\/unspecified impurities and\/or by the general monograph Substances for pharmaceutical use (2034). 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.<\/p>\n $\"Propylthiouracil\"$ <\/p>\n A. thiourea,<\/p>\n $\"Propylthiouracil\"$ <\/p>\n B. 6-methyl-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one (methylthiouracil).<\/p>\n","protected":false},"excerpt":{"rendered":" (Ph. Eur. monograph 0525) C7H10N2OS\u00a0 \u00a0 \u00a0 \u00a0170.2\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a051-52-5 Action and use Thiourea antithyroid drug. Preparation Propylthiouracil Tablets DEFINITION 6-Propyl-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one. Content 98.0 per cent to 101.0 per cent (dried substance). CHARACTERS Appearance White or almost white, crystalline powder or crystals. Solubility Very slightly soluble in water, sparingly soluble in ethanol (96…<\/p>\n","protected":false},"author":2,"featured_media":28686,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-28651","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\/28651","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=28651"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/28651\/revisions"}],"predecessor-version":[{"id":28702,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/28651\/revisions\/28702"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/28686"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=28651"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=28651"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=28651"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

Content<\/h3>\n98.0 per cent to 101.0 per cent (dried substance).<\/p>\n

CHARACTERS<\/h2>\n

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

Solubility<\/h3>\nVery slightly soluble in water, sparingly soluble in ethanol (96 per cent). It dissolves in solutions of alkali hydroxides.<\/p>\n

TESTS<\/h2>\n

Loss on drying (2.2.32)<\/h4>\nMaximum 0.5 per cent, determined on 1.000 g by drying in an oven at 105 \u00b0C.<\/p>\n

Sulfated ash (2.4.14)<\/h4>\nMaximum 0.1 per cent, determined on 1.0 g.<\/p>\n

STORAGE<\/h2>\nProtected from light.<\/p>\n

Content<\/h3>\n
98.0 per cent to 101.0 per cent (dried substance).<\/p>\n

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

Solubility<\/h3>\n
Very slightly soluble in water, sparingly soluble in ethanol (96 per cent). It dissolves in solutions of alkali hydroxides.<\/p>\n

Loss on drying (2.2.32)<\/h4>\n
Maximum 0.5 per cent, determined on 1.000 g by drying in an oven at 105 \u00b0C.<\/p>\n

Sulfated ash (2.4.14)<\/h4>\n
Maximum 0.1 per cent, determined on 1.0 g.<\/p>\n

STORAGE<\/h2>\n
Protected from light.<\/p>\n