Edition: BP 2025 (Ph. Eur. 11.6 update)<\/p>\n
Action and use<\/strong><\/p>\n Alpha-adrenoceptor agonist. Ph Eur<\/p>\n 2-(Naphthalen-1-ylmethyl)-4,5-dihydro-1H-imidazole nitrate.<\/p>\n Content<\/strong><\/p>\n 99.0 per cent to 101.0 per cent (dried substance).<\/p>\n White or almost white, crystalline powder.<\/p>\n Sparingly soluble in water, soluble in ethanol (96 per cent).<\/p>\n First identification: C.<\/em><\/p>\n Second identification: A, B, D.<\/em><\/p>\n A. Melting point (2.2.14): 167 \u00b0C to 170 \u00b0C.<\/p>\n B. Ultraviolet and visible absorption spectrophotometry (2.2.25).<\/p>\n Test solution\u00a0 Dissolve 50.0 mg in 0.01 M hydrochloric acid and dilute to 250.0 mL with the same acid. Dilute 25.0 mL of the solution to 100.0 mL with 0.01 M hydrochloric acid.<\/p>\n Spectral range\u00a0 230-350 nm.<\/p>\n Absorption maximum\u00a0 At 270 nm, 280 nm, 287 nm and 291 nm.<\/p>\n Absorbance ratio:<\/p>\n \u2014 A270\/A280 = 0.82 to 0.86,<\/p>\n \u2014 A291\/A280 = 0.65 to 0.69.<\/p>\n C. Infrared absorption spectrophotometry (2.2.24).<\/p>\n Comparison\u00a0 naphazoline nitrate CRS.<\/em><\/p>\n D. Dissolve 45 mg of the substance to be examined in 2 mL of water R. Add 1 mL of sulfuric acid R. Shake carefully and allow to cool. Add 1 mL of ferrous sulfate solution R2 dropwise along the walls of the container. At the junction of the 2 liquids, a brown colour develops.<\/p>\n Dissolve 0.5 g in carbon dioxide-free water R, warming gently, and dilute to 50 mL with the same solvent.<\/p>\n Solution S is clear (2.2.1) and colourless (2.2.2, Method II).<\/p>\n pH (2.2.3)<\/strong><\/p>\n 5.0 to 6.5 for solution S.<\/p>\n Liquid chromatography (2.2.29).<\/p>\n Test solution\u00a0 Dissolve 50.0 mg of the substance to be examined in the mobile phase and dilute to 100.0 mL with the mobile phase.<\/p>\n Reference solution (a)\u00a0 Dissolve 5 mg of 1-naphthylacetic acid R in the mobile phase, add 5 mL of the test solution and dilute to 100 mL with the mobile phase.<\/p>\n Reference solution (b)\u00a0 Dissolve 5.0 mg of naphazoline impurity A CRS in the mobile phase and dilute to 100.0 mL with the same solvent. Dilute 5.0 mL of this solution to 100.0 mL with the mobile phase.<\/p>\n Reference solution (c)\u00a0 Dilute 2.0 mL of the test solution to 10.0 mL with the mobile phase. Dilute 1.0 mL of this solution to 100.0 mL with the mobile phase.<\/p>\n Column:<\/p>\n \u2014 size: l = 0.25 m, \u00d8 = 4.0 mm,<\/p>\n \u2014 stationary phase: base-deactivated end-capped octylsilyl silica gel for chromatography R (4 \u00b5m) with a pore size of 6 nm.<\/p>\n Mobile phase\u00a0 Dissolve 1.1 g of sodium octanesulfonate R in a mixture of 5 mL of glacial acetic acid R, 300 mL of acetonitrile R and 700 mL of water R.<\/p>\n Flow rate\u00a0 1 mL\/min.<\/p>\n Detection\u00a0 Spectrophotometer at 280 nm.<\/p>\n Injection\u00a0 20 \u00b5L.<\/p>\n Run time\u00a0 3 times the retention time of naphazoline.<\/p>\n Relative retention\u00a0 With reference to naphazoline (retention time = about 14 min): impurity A = about 0.76; impurity D = about 1.24; impurity B = about 1.27; impurity C = about 2.8.<\/p>\n System suitability\u00a0 Reference solution (a):<\/p>\n \u2014 resolution: minimum 5.0 between the peaks due to naphazoline and impurity B.<\/p>\n Limits:<\/p>\n \u2014 impurity A: not more than the area of the principal peak in the chromatogram obtained with reference solution (b) (0.5 per cent),<\/p>\n \u2014 unspecified impurities: for each impurity, not more than 0.5 times the area of the principal peak in the chromatogram obtained with reference solution (c) (0.10 per cent),<\/p>\n \u2014 total: not more than 5 times the area of the principal peak in the chromatogram obtained with reference solution (c) (1.0 per cent),<\/p>\n \u2014 disregard limit: 0.25 times the area of the principal peak in the chromatogram obtained with reference solution (c) (0.05 per cent); disregard the peak due to the nitrate ion.<\/p>\n Chlorides (2.4.4)<\/strong><\/p>\n Maximum 330 ppm, determined on solution S.<\/p>\n Loss on drying (2.2.32)<\/strong><\/p>\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)<\/strong><\/p>\n Maximum 0.1 per cent, determined on 1.0 g.<\/p>\n Dissolve 0.200 g in 30 mL of anhydrous acetic acid R. Titrate with 0.1 M perchloric acid, determining the end-point potentiometrically (2.2.20). Protected from light.<\/p>\n Specified impurities\u00a0 A.<\/em><\/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.<\/em><\/p>\n Control of impurities in substances for pharmaceutical use)\u00a0 B, C, D.<\/em><\/p>\n A. N-(2-aminoethyl)-2-(naphthalen-1-yl)acetamide (naphthylacetylethylenediamine),<\/p>\n B. (naphthalen-1-yl)acetic acid (1-naphthylacetic acid),<\/p>\n C. (naphthalen-1-yl)acetonitrile (1-naphthylacetonitrile),<\/p>\n D. 2-(naphthalen-2-ylmethyl)-4,5-dihydro-1H-imidazole (\u03b2-naphazoline).<\/p>\n","protected":false},"excerpt":{"rendered":" Edition: BP 2025 (Ph. Eur. 11.6 update) Action and use Alpha-adrenoceptor agonist. Ph Eur DEFINITION 2-(Naphthalen-1-ylmethyl)-4,5-dihydro-1H-imidazole nitrate. Content 99.0 per cent to 101.0 per cent (dried substance). CHARACTERS Appearance White or almost white, crystalline powder. Solubility Sparingly soluble in water, soluble in ethanol (96 per cent). IDENTIFICATION First identification: C. Second identification: A, B, D….<\/p>\n","protected":false},"author":5,"featured_media":25738,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-25737","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\/25737","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=25737"}],"version-history":[{"count":3,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/25737\/revisions"}],"predecessor-version":[{"id":25759,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/25737\/revisions\/25759"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/25738"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=25737"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=25737"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=25737"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}DEFINITION<\/h2>\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
Related substances<\/h3>\n
ASSAY<\/h2>\n
\n1 mL of 0.1 M perchloric acid is equivalent to 27.33 mg of C14H15N3O3.<\/p>\nSTORAGE<\/h2>\n
IMPURITIES<\/h2>\n