{"id":25284,"date":"2025-11-04T11:04:12","date_gmt":"2025-11-04T04:04:12","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=25284"},"modified":"2025-11-04T11:04:12","modified_gmt":"2025-11-04T04:04:12","slug":"norfloxacin","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/norfloxacin\/","title":{"rendered":"Norfloxacin"},"content":{"rendered":"

(Ph. Eur. monograph 1248)<\/em><\/p>\n

C16<\/sub>H18<\/sub>FN3<\/sub>O3<\/sub> 319.3 70458-96-7<\/p>\n

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

Fluoroquinolone antibacterial.<\/p>\n

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

Norfloxacin Tablets<\/p>\n

DEFINITION<\/h2>\n

1-Ethyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid.<\/p>\n

Content<\/h3>\n

99.0 per cent to 101.0 per cent (anhydrous substance).<\/p>\n

CHARACTERS<\/h2>\n

Appearance<\/h3>\n

White or pale yellow, hygroscopic, photosensitive, crystalline powder.<\/p>\n

Solubility<\/h3>\n

Very slightly soluble in water, slightly soluble in acetone and in ethanol (96 per cent).<\/p>\n

It shows polymorphism (5.9).<\/p>\n

IDENTIFICATION<\/h2>\n

Infrared absorption spectrophotometry (2.2.24).<\/p>\n

Comparison: norfloxacin CRS.<\/p>\n

If the spectra obtained in the solid state show differences, dissolve the substance to be examined and the reference substance separately in methylene chloride R, evaporate to dryness in a water-bath at 45 \u00b0C, dry
\nin an oven at 105 \u00b0C for about 1 h and record new spectra using the residues.<\/p>\n

TESTS<\/h2>\n

Appearance of solution<\/h3>\n

Dissolve 0.5 g in a previously filtered 4 g\/L solution of sodium hydroxide R in methanol R and dilute to 50 mL with the same solution. The solution is not more opalescent than reference suspension II (2.2.1) and not
\nmore intensely coloured than reference solution B7 (2.2.2, Method II).<\/p>\n

Related substances<\/h3>\n

Liquid chromatography (2.2.29).<\/p>\n

Solvent mixture acetonitrile R, water R adjusted to pH 2.0 with phosphoric acid R (5:95 V\/V).<\/p>\n

Test solution: Dissolve 20.0 mg of the substance to be examined in 25 mL of the solvent mixture using sonication, and dilute to 50.0 mL with the solvent mixture.<\/p>\n

Reference solution (a): Dilute 1.0 mL of the test solution 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

Reference solution (b): Dissolve 4 mg of norfloxacin for system suitability CRS (containing impurities A, E and H) in 5 mL of the solvent mixture using sonication, and dilute to 10 mL with the solvent mixture.<\/p>\n

Reference solution (c): Dissolve 4 mg of norfloxacin for peak identification CRS (containing impurity K) in 5 mL of the solvent mixture using sonication, and dilute to 10 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: end-capped amidohexadecylsilyl silica gel for chromatography R (5 \u03bcm);<\/p>\n

\u2014 temperature: 60 \u00b0C.<\/p>\n

Mobile phase:<\/p>\n

\u2014 mobile phase A: water for chromatography R adjusted to pH 2.0 with phosphoric acid R;<\/p>\n

\u2014 mobile phase B: acetonitrile R;<\/p>\n\n\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>\n95<\/td>\n5<\/td>\n<\/tr>\n
5 – 7<\/td>\n95 \u2192 93<\/td>\n5 \u2192 7<\/td>\n<\/tr>\n
7 – 10<\/td>\n93 \u2192 87<\/td>\n7 \u2192 13<\/td>\n<\/tr>\n
10 – 15<\/td>\n87 \u2192 47<\/td>\n13 \u2192 53<\/td>\n<\/tr>\n
15 – 20<\/td>\n47 \u2192 10<\/td>\n53 \u2192 90<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Flow rate: 1.4 mL\/min.<\/p>\n

Detection: Spectrophotometer at 265 nm.<\/p>\n

Injection: 20 \u03bcL.<\/p>\n

Identification of impurities: Use the chromatogram supplied with norfloxacin for system suitability CRS and the chromatogram obtained with reference solution (b) to identify the peaks due to impurities A, E and H;
\nuse the chromatogram supplied with norfloxacin for peak identification CRS and the chromatogram obtained with reference solution (c) to identify the peak due to impurity K.<\/p>\n

Relative retention: With reference to norfloxacin (retention time = about 11 min): impurity K = about 0.6; impurity E = about 0.97; impurity A = about 1.5; impurity H = about 1.6.<\/p>\n

System suitability: Reference solution (b):<\/p>\n

\u2014 resolution: minimum 3.0 between the peaks due to impurities A and H;<\/p>\n

\u2014 peak-to-valley ratio: minimum 5.0, where Hp = height above the baseline of the peak due to impurity E and Hv = height above the baseline of the lowest point of the curve separating this peak from the peak due to norfloxacin.<\/p>\n

Limits:<\/p>\n

\u2014 impurities E, K: for each impurity, not more than 1.5 times the area of the principal peak in the chromatogram obtained with reference solution (a) (0.15 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 total: 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 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

Water (2.5.12)<\/h2>\n

Maximum 1.0 per cent, determined on 0.700 g. Use as the solvent a mixture of 10 mL of anhydrous methanol R and 20 mL of formamide R.<\/p>\n

Sulfated ash (2.4.14)<\/h3>\n

Maximum 0.1 per cent, determined on 1.0 g in a platinum crucible.<\/p>\n

ASSAY<\/h2>\n

Dissolve 0.240 g in 80 mL of anhydrous acetic acid R. Titrate with 0.1 M perchloric acid, determining the end-point potentiometrically (2.2.20). 1 mL of 0.1 M perchloric acid is equivalent to 31.93 mg of C16H18FN3O3.<\/p>\n

STORAGE<\/h2>\n

In an airtight container, protected from light.<\/p>\n

IMPURITIES<\/h2>\n

Specified impurities E, K.<\/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
\nother\/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) A, B, C, D, F, G, H, I, J.<\/p>\n

\"Norfloxacin<\/p>\n

A. 7-chloro-1-ethyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid,<\/p>\n

\"Norfloxacin<\/p>\n

B. 7-[(2-aminoethyl)amino]-1-ethyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid,<\/p>\n

\"Norfloxacin<\/p>\n

C. 1-ethyl-4-oxo-6,7-di(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid,<\/p>\n

\"Norfloxacin<\/p>\n

D. 1-ethyl-6-fluoro-7-(piperazin-1-yl)quinolin-4(1H)-one,<\/p>\n

\"Norfloxacin<\/p>\n

E. 7-chloro-1-ethyl-4-oxo-6-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid,<\/p>\n

\"Norfloxacin<\/p>\n

F. 6-chloro-1-ethyl-4-oxo-7-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid,<\/p>\n

\"Norfloxacin<\/p>\n

G. 1-ethyl-6-fluoro-7-(4-formylpiperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid,<\/p>\n

\"Norfloxacin<\/p>\n

H. 7-[4-(ethoxycarbonyl)piperazin-1-yl]-1-ethyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid,<\/p>\n

\"Norfloxacin<\/p>\n

I. 7-chloro-6-[4-(ethoxycarbonyl)piperazin-1-yl]-1-ethyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid,<\/p>\n

\"Norfloxacin<\/p>\n

J. 6,7-bis[4-(ethoxycarbonyl)piperazin-1-yl]-1-ethyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid,<\/p>\n

\"Norfloxacin<\/p>\n

K. 6-fluoro-1-methyl-4-oxo-7-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid.<\/p>\n","protected":false},"excerpt":{"rendered":"

(Ph. Eur. monograph 1248) C16H18FN3O3 319.3 70458-96-7 Action and use Fluoroquinolone antibacterial. Preparation Norfloxacin Tablets DEFINITION 1-Ethyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid. Content 99.0 per cent to 101.0 per cent (anhydrous substance). CHARACTERS Appearance White or pale yellow, hygroscopic, photosensitive, crystalline powder. Solubility Very slightly soluble in water, slightly soluble in acetone and in ethanol (96 per cent). It…<\/p>\n","protected":false},"author":4,"featured_media":25294,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-25284","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\/25284","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=25284"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/25284\/revisions"}],"predecessor-version":[{"id":25308,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/25284\/revisions\/25308"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/25294"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=25284"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=25284"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=25284"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}