Action and use<\/strong><\/p>\n Dopa decarboxylase inhibitor.<\/p>\n Preparations<\/strong><\/p>\n Co-beneldopa Capsules<\/p>\n Co-beneldopa Dispersible Tablets<\/p>\n Co-beneldopa Prolonged-release Capsules<\/p>\n (2RS)-2-Amino-3-hydroxy-N\u2032-[(2,3,4-trihydroxyphenyl)methyl]propanehydrazide hydrochloride.<\/p>\n 98.5 per cent to 101.0 per cent (anhydrous substance).<\/p>\n White or yellowish-white or orange-white, crystalline powder.<\/p>\n Freely soluble in water, very slightly soluble in anhydrous ethanol, practically insoluble in acetone.<\/p>\n It shows polymorphism (5.9).<\/p>\n A. Infrared absorption spectrophotometry (2.2.24).<\/p>\n Comparison: benserazide hydrochloride CRS.<\/p>\n If the spectra obtained show differences, dissolve the substance to be examined and the reference substance separately in hot methanol R, evaporate to dryness and record new spectra using the residues.<\/p>\n B. Dissolve 16 mg in 2 mL of methanol R. The solution gives reaction (a) of chlorides (2.3.1).<\/p>\n Dissolve 1.0 g in carbon dioxide-free water R and dilute to 100 mL with the same solvent.<\/p>\n Solution S is clear (2.2.1) and not more intensely coloured than reference solution BY6 (2.2.2, Method II).<\/p>\n 4.0 to 5.0 for solution S.<\/p>\n Liquid chromatography (2.2.29). All solutions must be injected immediately or stored at 4 \u00b0C.<\/p>\n Test solution: Dissolve 0.100 g of the substance to be examined in methanol R and dilute to 50.0 mL with the same solvent.<\/p>\n Reference solution (a): Dilute 1.0 mL of the test solution to 100.0 mL with methanol R. Dilute 1.0 mL of this solution to 10.0 mL with methanol R.<\/p>\n Reference solution (b): Dissolve 5.0 mg of benserazide impurity A CRS and 5.0 mg of benserazide impurity C CRS in methanol R and dilute to 50.0 mL with the same solvent. Dilute 1.0 mL of the solution to 10.0 mL with methanol R.<\/p>\n Reference solution (c): Dissolve 5 mg of benserazide for peak identification A CRS (containing impurity B) in 5 mL of reference solution (b).<\/p>\n Column:<\/p>\n \u2014 size: l = 0.25 m, \u00d8 = 4 mm;<\/p>\n \u2014 stationary phase: octylsilyl silica gel for chromatography R (5 \u03bcm);<\/p>\n \u2014 temperature: 30 \u00b0C.<\/p>\n Mobile phase:<\/p>\n \u2014 mobile phase A: dissolve 2.2 g of sodium heptanesulfonate monohydrate R and 6.8 g of potassium dihydrogen phosphate R in 900 mL of water for chromatography R, add 50 mL of methanol R2 and adjust to pH 3.5 with phosphoric acid R;<\/p>\n \u2014 mobile phase B: dissolve 2.2 g of sodium heptanesulfonate monohydrate R and 6.8 g of potassium dihydrogen phosphate R in 500 mL of water for chromatography R, adjust to pH 3.5 with phosphoric acid R and add 500 mL of methanol R2;<\/p>\n (min)<\/strong><\/td>\n (per cent V\/V)<\/strong><\/td>\n (per cent V\/V)<\/strong><\/td>\n<\/tr>\n Flow rate: 1.3 mL\/min.<\/p>\n Detection: Spectrophotometer at 210 nm.<\/p>\n Injection: 5 \u03bcL.<\/p>\n Identification of impurities: Use the chromatogram obtained with reference solution (b) to identify the peaks due to impurities A and C; use the chromatogram supplied with benserazide for peak identification A CRS and the chromatogram obtained with reference solution (c) to identify the peak due to impurity B; doubling of the peak due to impurity C, related to separation of the (EZ)-isomers, may be observed.<\/p>\n Relative retention: With reference to benserazide (retention time = about 9 min): impurity A = about 0.6; impurity C = about 1.2; impurity B = about 1.5.<\/p>\n System suitability: Reference solution (c):<\/p>\n \u2014 resolution: minimum 5.0 between the peaks due to benserazide and impurity C; use the 1 peak of impurity C if 2 peaks occur.<\/p>\n Limits:<\/p>\n \u2014 correction factor: for the calculation of content, multiply the peak area of impurity B by 0.7;<\/p>\n \u2014 impurity A: not more than the area of the corresponding peak in the chromatogram obtained with reference solution (b) (0.5 per cent);<\/p>\n \u2014 impurity B: not more than 5 times the area of the principal peak in the chromatogram obtained with reference solution (a) (0.5 per cent);<\/p>\n \u2014 impurity C: not more than the area of the corresponding peak or pair of peaks in the chromatogram obtained with reference solution (b) (0.5 per cent);<\/p>\n \u2014 unspecified impurities: for each impurity, not more than the area of the principal peak in the chromatogram obtained with reference solution (a) (0.10 per cent);<\/p>\n \u2014 sum of impurities other than A: not more than 10 times the area of the principal peak in the chromatogram obtained with reference solution (a) (1.0 per cent);<\/p>\n \u2014 disregard limit: 0.5 times the area of the principal peak in the chromatogram obtained with reference solution (a) (0.05 per cent).<\/p>\n Maximum 1.0 per cent, determined on 0.500 g. Use as the solvent a solution containing 30 mL of formamide R, 30 mL of methanol R and 7.0 g of salicylic acid R (the salicylic acid R must be added to the solvent mixture in the titration vessel).<\/p>\n Maximum 0.1 per cent, determined on 1.0 g.<\/p>\n In order to avoid overheating during the titration, mix thoroughly throughout and stop the titration immediately after the end-point has been reached.<\/p>\n Dissolve 0.250 g in 5 mL of anhydrous formic acid R. Add 70 mL of anhydrous acetic acid R. Titrate immediately with 0.1 M perchloric acid, determining the end-point potentiometrically (2.2.20).<\/p>\n 1 mL of 0.1 M perchloric acid is equivalent to 29.37 mg of C10<\/sub>H16<\/sub>ClN3<\/sub>O5<\/sub>.<\/p>\n Protected from light.<\/p>\n Specified impurities A, B, C.<\/p>\n A. (2RS)-2-amino-3-hydroxypropanehydrazide,<\/p>\n B. (2RS)-2-amino-3-hydroxy-N\u2032,N\u2032-bis[(2,3,4-trihydroxyphenyl)methyl]propanehydrazide,<\/p>\n C. (2RS)-2-amino-3-hydroxy-N\u2032-[(EZ)-(2,3,4-trihydroxyphenyl)methylidene]propanehydrazide.<\/p>\n","protected":false},"excerpt":{"rendered":" (Ph. Eur. monograph 1173) C10H16ClN3O5\u00a0 \u00a0293.7\u00a0 \u00a014919-77-8 Action and use Dopa decarboxylase inhibitor. Preparations Co-beneldopa Capsules Co-beneldopa Dispersible Tablets Co-beneldopa Prolonged-release Capsules DEFINITION (2RS)-2-Amino-3-hydroxy-N\u2032-[(2,3,4-trihydroxyphenyl)methyl]propanehydrazide hydrochloride. Content 98.5 per cent to 101.0 per cent (anhydrous substance). CHARACTERS Appearance White or yellowish-white or orange-white, crystalline powder. Solubility Freely soluble in water, very slightly soluble in anhydrous ethanol,…<\/p>\n","protected":false},"author":4,"featured_media":3664,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-3644","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\/3644","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\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/comments?post=3644"}],"version-history":[{"count":6,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/3644\/revisions"}],"predecessor-version":[{"id":9021,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/3644\/revisions\/9021"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/3664"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=3644"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=3644"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=3644"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}DEFINITION<\/h2>\n
Content<\/h3>\n
CHARACTERS<\/h2>\n
Appearance<\/h3>\n
Solubility<\/h3>\n
IDENTIFICATION<\/h2>\n
TESTS<\/h2>\n
Solution S<\/h3>\n
Appearance of solution<\/h3>\n
pH (2.2.3)<\/h3>\n
Related substances<\/h3>\n
\n\n
\n Time<\/strong><\/p>\n Mobile phase A<\/strong><\/p>\n Mobile phase B <\/strong><\/p>\n \n 0 – 15<\/td>\n 100 \u2192 0<\/td>\n 0 \u2192 100<\/td>\n<\/tr>\n \n 15 – 25<\/td>\n 0<\/td>\n 100<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Water (2.5.12)<\/h3>\n
Sulfated ash (2.4.14)<\/h3>\n
ASSAY<\/h2>\n
STORAGE<\/h2>\n
IMPURITIES<\/h2>\n
![\"Benserazide](\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/09\/1-187-300x163.jpg\")
<\/p>\n![\"Benserazide](\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/09\/2-230-300x163.jpg\")
<\/p>\n![\"Benserazide](\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/09\/3-236-300x163.jpg\")
<\/p>\n