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 hydrochloride.<\/p>\n Content<\/p>\n 99.0 per cent to 101.0 per cent (dried substance).<\/p>\n White or almost white, crystalline powder.<\/p>\n Freely soluble in water, soluble in ethanol (96 per cent).<\/p>\n About 259 \u00b0C, with decomposition.<\/p>\n First identification: B. <\/em><\/p>\n Second identification: A, C.<\/em><\/p>\n A. 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. Examined between 230 nm and 350 nm (2.2.25), the solution shows 4 absorption maxima, at 270 nm, 280 nm, 287 nm and 291 nm. The ratios of the absorbances measured at the maxima at 270 nm, 287 nm and 291 nm to that measured at the maximum at 280 nm are 0.82 to 0.86, 0.67 to 0.70 and 0.65 to 0.69, respectively.<\/p>\n B. Infrared absorption spectrophotometry (2.2.24).<\/p>\n Comparison\u00a0 naphazoline hydrochloride CRS.<\/em><\/p>\n C. It gives reaction (a) of chlorides (2.3.1).<\/p>\n Dissolve 0.5 g in carbon dioxide-free water R 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 To 20 mL of solution S add 0.2 mL of 0.01 M sodium hydroxide and 0.1 mL of methyl red solution R. The solution is yellow. Not more than 0.6 mL of 0.01 M hydrochloric acid is required to change the colour of the solution to red.<\/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 mobile phase. Dilute 1.0 mL of this solution to 100.0 mL with the mobile phase.<\/p>\n Reference solution (c)\u00a0 Dilute 1.0 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 Retention time\u00a0 Naphazoline = about 14 min.<\/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) (0.1 per cent);<\/p>\n \u2014 unspecified impurities: not more than 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) (0.5 per cent);<\/p>\n \u2014 disregard limit: 0.5 times the area of the principal peak in the chromatogram obtained with reference solution (c) (0.05 per cent).<\/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 a mixture of 5.0 mL of 0.01 M hydrochloric acid and 50 mL of ethanol (96 per cent) R. Carry out a potentiometric titration (2.2.20), using 0.1 M sodium hydroxide. Read the volume added between the 2 points of inflexion.<\/p>\n 1 mL of 0.1 M sodium hydroxide is equivalent to 24.67 mg of C14<\/sub>H15<\/sub>ClN2<\/sub>.<\/p>\n Protected from light.<\/p>\n Specified impurities\u00a0 A.<\/em><\/p>\n Other detectable impurities: 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 Ph Eur<\/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 hydrochloride. Content 99.0 per cent to 101.0 per cent (dried substance). CHARACTERS Appearance White or almost white, crystalline powder. Solubility Freely soluble in water, soluble in ethanol (96 per cent). mp About 259 \u00b0C, with decomposition. IDENTIFICATION First identification:…<\/p>\n","protected":false},"author":5,"featured_media":25733,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-25732","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\/25732","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=25732"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/25732\/revisions"}],"predecessor-version":[{"id":25736,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/25732\/revisions\/25736"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/25733"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=25732"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=25732"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=25732"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}DEFINITION<\/h2>\n
CHARACTERS<\/h2>\n
Appearance<\/h3>\n
Solubility<\/h3>\n
mp<\/h3>\n
IDENTIFICATION<\/h2>\n
TESTS<\/h2>\n
Solution S<\/h3>\n
Appearance of solution<\/h3>\n
Acidity or alkalinity<\/h3>\n
Related substances<\/h3>\n
ASSAY<\/h2>\n
STORAGE<\/h2>\n
IMPURITIES<\/h2>\n
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