{"id":23985,"date":"2025-11-01T15:42:13","date_gmt":"2025-11-01T08:42:13","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=23985"},"modified":"2025-11-01T17:33:21","modified_gmt":"2025-11-01T10:33:21","slug":"fipronil","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/fipronil\/","title":{"rendered":"Fipronil"},"content":{"rendered":"

Edition: BP 2025 (Ph. Eur. 11.6 update)<\/p>\n

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

Acaricide and insecticide (veterinary).<\/p>\n

Ph Eur<\/p>\n

\n

DEFINITION<\/h2>\n

5-Amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(RS)-(trifluoromethyl)sulfinyl]-1H-pyrazole-3-carbonitrile.<\/p>\n

Content<\/strong><\/p>\n

95.5 per cent to 102.0 per cent (dried substance).<\/p>\n

CHARACTERS<\/h2>\n

Appearance<\/h3>\n

White or almost white or yellowish powder.<\/p>\n

Solubility<\/h3>\n

Practically insoluble in water, soluble in anhydrous ethanol, practically insoluble in heptane. It shows polymorphism (5.9).<\/p>\n

IDENTIFICATION<\/h2>\n

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

Comparison\u00a0 fipronil CRS.<\/em><\/p>\n

If the spectra obtained in the solid state show differences, dissolve the substance to be examined and the reference substance separately in the minimum volume of methylene chloride R, evaporate to dryness and record new spectra using the residues.<\/p>\n

TESTS<\/h2>\n

Related substances<\/h3>\n

Liquid chromatography (2.2.29). Carry out the test protected from light. Solvent mixture\u00a0 methanol R, water R, acetonitrile R (30:30:40 V\/V\/V).<\/p>\n

Test solution (a)<\/em> Dissolve 35.0 mg of the substance to be examined in the solvent mixture and dilute to 50.0 mL with the solvent mixture.<\/p>\n

Test solution (b)\u00a0<\/em> Dilute 3.0 mL of test solution (a) to 20.0 mL with the solvent mixture.<\/p>\n

Reference solution (a)<\/em> Dissolve 1.5 mg of fipronil for system suitability CRS (containing impurities A and B) in the solvent mixture and dilute to 2.0 mL with the solvent mixture.<\/p>\n

Reference solution (b)<\/em> Dilute 1.0 mL of test solution (a) to 100.0 mL with the solvent mixture. Dilute 2.0 mL of this solution to 10.0 mL with the solvent mixture.<\/p>\n

Reference solution (c)<\/em> Dissolve 35.0 mg of fipronil CRS in the solvent mixture and dilute to 50.0 mL with the solvent mixture. Dilute 3.0 mL of the solution to 20.0 mL with the solvent mixture.<\/p>\n

Column:<\/em><\/p>\n

\u2014 size: l<\/em> = 0.15 m, \u00d8 = 4.6 mm;<\/p>\n

\u2014 stationary phase:<\/em> end-capped octadecylsilyl silica gel for chromatography R (1.8 \u00b5m).<\/p>\n

Mobile phase<\/em> tetrahydrofuran R, methanol R2, water for chromatography R, acetonitrile R1 (0.5:30:30:40 V\/V\/V\/V). Flow rate 1.0 mL\/min.<\/p>\n

Detection<\/em>\u00a0 Spectrophotometer at 210 nm.<\/p>\n

Injection<\/em>\u00a0 5 \u00b5L of test solution (a) and reference solutions (a) and (b).<\/p>\n

Run time<\/em>\u00a0 Twice the retention time of fipronil.<\/p>\n

Identification of impurities<\/em> Use the chromatogram supplied with fipronil for system suitability CRS and the chromatogram obtained with reference solution (a) to identify the peaks due to impurities A and B.<\/p>\n

Relative retention<\/em>\u00a0 With reference to fipronil (retention time = about 6 min): impurity A = about 1.3; impurity B = about 1.4.<\/p>\n

System suitability\u00a0<\/em> Reference solution (a):<\/p>\n

\u2014 resolution:<\/em> minimum 2.5 between the peaks due to impurities A and B.<\/p>\n

Calculation of percentage contents:<\/em><\/p>\n

\u2014 for each impurity, use the concentration of fipronil in reference solution (b).<\/p>\n

Limits:<\/em><\/p>\n

\u2014 impurity B:<\/em> maximum 3.5 per cent;<\/p>\n

\u2014 impurity A:<\/em> maximum 1.5 per cent;<\/p>\n

\u2014 unspecified impurities:<\/em> for each impurity, maximum 0.20 per cent;<\/p>\n

\u2014 total:<\/em> maximum 4.5 per cent;<\/p>\n

\u2014 reporting threshold:<\/em> 0.10 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 in a platinum crucible.<\/p>\n

ASSAY<\/h2>\n

Liquid chromatography (2.2.29) as described in the test for related substances with the following modification.<\/p>\n

Injection\u00a0<\/em> Test solution (b) and reference solution (c).<\/p>\n

Calculate the percentage content of C12<\/sub>H4<\/sub>Cl2<\/sub>F6<\/sub>N4<\/sub>OS taking into account the assigned content of fipronil CRS.<\/p>\n

IMPURITIES<\/h2>\n

Specified impurities\u00a0 A, B.<\/p>\n

\"Fipronil\"<\/p>\n

A. 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfanyl]-1H-pyrazole-3-carbonitrile,<\/p>\n

\"Fipronil\"<\/p>\n

B. 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfonyl]-1H-pyrazole-3-carbonitrile.<\/p>\n

\n

Ph Eur<\/p>\n","protected":false},"excerpt":{"rendered":"

Edition: BP 2025 (Ph. Eur. 11.6 update) Action and use Acaricide and insecticide (veterinary). Ph Eur DEFINITION 5-Amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(RS)-(trifluoromethyl)sulfinyl]-1H-pyrazole-3-carbonitrile. Content 95.5 per cent to 102.0 per cent (dried substance). CHARACTERS Appearance White or almost white or yellowish powder. Solubility Practically insoluble in water, soluble in anhydrous ethanol, practically insoluble in heptane. It shows polymorphism (5.9). IDENTIFICATION…<\/p>\n","protected":false},"author":5,"featured_media":23986,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[176],"tags":[],"class_list":["post-23985","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-british-pharmacopoeia-veterinary-2020"],"acf":[],"_links":{"self":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/23985","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=23985"}],"version-history":[{"count":3,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/23985\/revisions"}],"predecessor-version":[{"id":24247,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/23985\/revisions\/24247"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/23986"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=23985"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=23985"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=23985"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}