{"id":14733,"date":"2025-10-15T16:37:18","date_gmt":"2025-10-15T09:37:18","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=14733"},"modified":"2025-10-15T16:37:18","modified_gmt":"2025-10-15T09:37:18","slug":"finasteride-2","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/finasteride-2\/","title":{"rendered":"Finasteride"},"content":{"rendered":"<p><em>(Ph. Eur. monograph 1615)<\/em><\/p>\n<p>C<sub>23<\/sub>H<sub>36<\/sub>N<sub>2<\/sub>O<sub>2<\/sub> 372.6 98319-26-7<\/p>\n<p><strong>Action and use<\/strong><\/p>\n<p>5-Alpha reductase inhibitor; treatment of benign prostatic hyperplasia.<\/p>\n<p><strong>Preparation<\/strong><\/p>\n<p>Finasteride Tablets<\/p>\n<h2>DEFINITION<\/h2>\n<p>N-(1,1-Dimethylethyl)-3-oxo-4-aza-5\u03b1-androst-1-ene-17\u03b2-carboxamide.<\/p>\n<h3>Content<\/h3>\n<p>98.0 per cent to 102.0 per cent (dried substance).<\/p>\n<h2>CHARACTERS<\/h2>\n<h3>Appearance<\/h3>\n<p>White or almost white, crystalline powder.<\/p>\n<h3>Solubility<\/h3>\n<p>Practically insoluble in water, freely soluble in anhydrous ethanol and in methylene chloride.<\/p>\n<p>It shows polymorphism (5.9).<\/p>\n<h2>IDENTIFICATION<\/h2>\n<p>Infrared absorption spectrophotometry (2.2.24).<\/p>\n<p>Comparison: finasteride CRS.<\/p>\n<p>If the spectra obtained in the solid state show differences, dissolve the substance to be examined and the reference substance separately in methanol R, evaporate to dryness and record new spectra using the residues.<\/p>\n<h2>TESTS<\/h2>\n<h3>Specific optical rotation (2.2.7)<\/h3>\n<p>+ 12.0 to + 14.0 (dried substance).<\/p>\n<p>Dissolve 0.250 g in methanol R and dilute to 25.0 mL with the same solvent.<\/p>\n<h3>Related substances<\/h3>\n<p>Liquid chromatography (2.2.29).<\/p>\n<p>Solvent mixture acetonitrile R1, water for chromatography R (50:50 V\/V).<\/p>\n<p>Test solution (a): Dissolve 25.0 mg of the substance to be examined in the solvent mixture and dilute to 50.0 mL with the solvent mixture.<\/p>\n<p>Test solution (b): Dissolve 100.0 mg of the substance to be examined in the solvent mixture and dilute to 10.0 mL with the solvent mixture.<\/p>\n<p>Reference solution (a): Dissolve 25.0 mg of finasteride CRS in the solvent mixture and dilute to 50.0 mL with the solvent mixture.<\/p>\n<p>Reference solution (b): Dissolve 10 mg of finasteride for peak identification CRS (containing impurities A and C) in 1.0 mL of the solvent mixture.<\/p>\n<p>Reference solution (c): Dilute 1.0 mL of test solution (b) to 100.0 mL with the solvent mixture. Dilute 1.0 mL of this solution to 10.0 mL with the solvent mixture.<\/p>\n<p>Column:<\/p>\n<p>\u2014 size: l = 0.25 m, \u00d8 = 4.0 mm;<\/p>\n<p>\u2014 stationary phase: base-deactivated end-capped octadecylsilyl silica gel for chromatography R (5 \u03bcm);<\/p>\n<p>\u2014 temperature: 60 \u00b0C.<\/p>\n<p>Mobile phase: acetonitrile R1, tetrahydrofuran R, water for chromatography R (10:10:80 V\/V\/V).<\/p>\n<p>Flow rate: 1.5 mL\/min.<\/p>\n<p>Detection: Spectrophotometer at 210 nm.<\/p>\n<p>Injection: 15 \u03bcL of test solution (b) and reference solutions (b) and (c).<\/p>\n<p>Run time: Twice the retention time of finasteride.<\/p>\n<p>Identification of impurities Use the chromatogram supplied with finasteride for peak identification CRS and the chromatogram obtained with reference solution (b) to identify the peaks due to impurities A and C.<\/p>\n<p>Relative retention: With reference to finasteride (retention time = about 28 min): impurity A = about 0.9; impurity C = about 1.3.<\/p>\n<p>System suitability:<\/p>\n<p>\u2014 signal-to-noise ratio: minimum 40 for the principal peak in the chromatogram obtained with reference solution (c);<\/p>\n<p>\u2014 peak-to-valley ratio: minimum 5, where Hp = height above the baseline of the peak due to impurity A and Hv = height above the baseline of the lowest point of the curve separating this peak from the peak due to finasteride in the chromatogram obtained with reference solution (b).<\/p>\n<p>Calculation of percentage contents:<\/p>\n<p>\u2014 correction factor: multiply the peak area of impurity A by 2.4;<\/p>\n<p>\u2014 for each impurity, use the concentration of finasteride in reference solution (c).<\/p>\n<p>Limits:<\/p>\n<p>\u2014 impurities A, C: for each impurity, maximum 0.3 per cent;<\/p>\n<p>\u2014 unspecified impurities: for each impurity, maximum 0.10 per cent;<\/p>\n<p>\u2014 total: maximum 0.5 per cent;<\/p>\n<p>\u2014 reporting threshold: 0.05 per cent.<\/p>\n<h3>Loss on drying (2.2.32)<\/h3>\n<p>Maximum 0.5 per cent, determined on 1.000 g by drying in an oven at 105 \u00b0C.<\/p>\n<h2>ASSAY<\/h2>\n<p>Liquid chromatography (2.2.29) as described in the test for related substances with the following modification.<\/p>\n<p>Injection: Test solution (a) and reference solution (a).<\/p>\n<p>Calculate the percentage content of C<sub>23<\/sub>H<sub>36<\/sub>N<sub>2<\/sub>O<sub>2<\/sub> taking into account the assigned content of finasteride CRS.STORAGE<\/p>\n<p>Protected from light.<\/p>\n<h2>IMPURITIES<\/h2>\n<p>Specified impurities A, C.<\/p>\n<p>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<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-14762\" src=\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/2-204-300x163.jpg\" alt=\"Finasteride \" width=\"300\" height=\"163\" srcset=\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/2-204-300x163.jpg 300w, https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/2-204-1024x555.jpg 1024w, https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/2-204-768x416.jpg 768w, https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/2-204.jpg 1200w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/p>\n<p>A. N-(1,1-dimethylethyl)-3-oxo-4-aza-5\u03b1-androstane-17\u03b2-carboxamide (dihydrofinasteride),<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-14763\" src=\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/3-191-300x163.jpg\" alt=\"Finasteride \" width=\"300\" height=\"163\" srcset=\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/3-191-300x163.jpg 300w, https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/3-191-1024x555.jpg 1024w, https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/3-191-768x416.jpg 768w, https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/3-191.jpg 1200w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/p>\n<p>B. methyl 3-oxo-4-aza-5\u03b1-androst-1-ene-17\u03b2-carboxylate,<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-14764\" src=\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/4-173-300x163.jpg\" alt=\"Finasteride \" width=\"300\" height=\"163\" srcset=\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/4-173-300x163.jpg 300w, https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/4-173-1024x555.jpg 1024w, https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/4-173-768x416.jpg 768w, https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/10\/4-173.jpg 1200w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/p>\n<p>C. N-(1,1-dimethylethyl)-3-oxo-4-azaandrosta-1,5-diene-17\u03b2-carboxamide<\/p>\n","protected":false},"excerpt":{"rendered":"<p>(Ph. Eur. monograph 1615) C23H36N2O2 372.6 98319-26-7 Action and use 5-Alpha reductase inhibitor; treatment of benign prostatic hyperplasia. Preparation Finasteride Tablets DEFINITION N-(1,1-Dimethylethyl)-3-oxo-4-aza-5\u03b1-androst-1-ene-17\u03b2-carboxamide. Content 98.0 per cent to 102.0 per cent (dried substance). CHARACTERS Appearance White or almost white, crystalline powder. Solubility Practically insoluble in water, freely soluble in anhydrous ethanol and in methylene chloride&#8230;.<\/p>\n","protected":false},"author":4,"featured_media":14761,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-14733","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\/14733","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=14733"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/14733\/revisions"}],"predecessor-version":[{"id":14772,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/14733\/revisions\/14772"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/14761"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=14733"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=14733"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=14733"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}