{"id":24662,"date":"2025-11-03T14:52:19","date_gmt":"2025-11-03T07:52:19","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=24662"},"modified":"2025-11-03T17:27:05","modified_gmt":"2025-11-03T10:27:05","slug":"oxfendazole","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/oxfendazole\/","title":{"rendered":"Oxfendazole"},"content":{"rendered":"

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

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

Antihelminthic.<\/p>\n

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

Oxfendazole Oral Suspension<\/p>\n

\n

Ph Eur<\/p>\n

DEFINITION<\/h2>\n

Methyl [5-(phenylsulfinyl)-1H-benzimidazol-2-yl]carbamate.<\/p>\n

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

97.5 per cent to 100.5 per cent (dried substance).<\/p>\n

CHARACTERS<\/h2>\n

Appearance<\/h3>\n

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

Solubility<\/h3>\n

Practically insoluble in water, slightly soluble in ethanol (96 per cent) and in methylene chloride. It shows polymorphism (5.9).<\/p>\n

IDENTIFICATION<\/h2>\n

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

Comparison\u00a0 oxfendazole 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 ethanol (96 per cent) 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).<\/p>\n

Test solution<\/em> Dissolve 25.0 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)<\/em>\u00a0 Dilute 1.0 mL of the test solution to 100.0 mL with the mobile phase.<\/p>\n

Reference solution (b)<\/em> In order to prepare impurity C in situ, add 0.25 mL of strong hydrogen peroxide solution R to 10 mL of the test solution, then dilute to 25 mL with the mobile phase.<\/p>\n

Reference solution (c)<\/em> Dissolve 5.0 mg of fenbendazole CRS (impurity A) in the mobile phase and dilute to 100.0 mL with the mobile phase. Dilute 1.0 mL of the solution to 20.0 mL with the mobile phase.<\/p>\n

Reference solution (d)<\/em> Dissolve 10.0 mg of oxfendazole impurity B CRS in the mobile phase and dilute to 100.0 mL with the mobile phase. Dilute 1.0 mL of the solution to 20.0 mL with the mobile phase.<\/p>\n

Reference solution (e)<\/em> Dissolve 5 mg of oxfendazole with impurity D CRS in the mobile phase and dilute to 20 mL with the mobile phase.<\/p>\n

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

\u2014 size: l<\/em> = 0.25 m, \u00d8 = 4.6 mm;<\/p>\n

\u2014 stationary phase:<\/em> end-capped octadecylsilyl silica gel for chromatography R (5 \u00b5m).<\/p>\n

Mobile phase<\/em>\u00a0 Mix 36 volumes of acetonitrile R and 64 volumes of a 2 g\/L solution of sodium pentanesulfonate R previously adjusted to pH 2.7 with a 2.8 per cent V\/V solution of sulfuric acid R. Flow rate 1 mL\/min.<\/p>\n

Detection<\/em>\u00a0 Spectrophotometer at 254 nm.<\/p>\n

Injection<\/em>\u00a0 20 \u00b5L.<\/p>\n

Run time<\/em>\u00a0 6 times the retention time of oxfendazole.<\/p>\n

Identification of impurities<\/em>\u00a0 Use the chromatogram obtained with reference solution (c) to identify the peak due to impurity A; use the chromatogram obtained with reference solution (d) to identify the peak due to impurity B; use the chromatogram obtained with reference solution (b) to identify the peak due to impurity C; use the chromatogram supplied with oxfendazole with impurity D CRS and the chromatogram obtained with reference solution (e) to identify the peak due to impurity D.<\/p>\n

Relative retention<\/em> With reference to oxfendazole (retention time = about 7 min): impurity C = about 0.4; impurity B = about 1.9; impurity D = about 2.7; impurity A = about 5.4.<\/p>\n

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

\u2014 resolution<\/em>: minimum 4.0 between the peaks due to impurity C and oxfendazole.<\/p>\n

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

\u2014 impurity B<\/em>: not more than the area of the corresponding peak in the chromatogram obtained with reference solution (d) (2.0 per cent);<\/p>\n

\u2014 impurity A:<\/em> not more than the area of the corresponding peak in the chromatogram obtained with reference solution (c) (1.0 per cent);<\/p>\n

\u2014 impurities C, D:<\/em> for each impurity, not more than the area of the principal peak in the chromatogram obtained with reference solution (a) (1.0 per cent);<\/p>\n

\u2014 unspecified impurities:<\/em> not more than 0.2 times the area of the principal peak in the chromatogram obtained with reference solution (a) (0.20 per cent);<\/p>\n

\u2014 total:<\/em> maximum 3.0 per cent;<\/p>\n

\u2014 disregard limit:<\/em> 0.1 times the area of the principal peak in the chromatogram obtained with reference solution (a) (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 vacuo at 105 \u00b0C for 2 h.<\/p>\n

Sulfated ash (2.4.14)<\/strong><\/p>\n

Maximum 0.2 per cent, determined on 1.0 g.<\/p>\n

ASSAY<\/h2>\n

Dissolve 0.250 g in 3 mL of anhydrous formic acid R. Add 40 mL of anhydrous acetic acid R. Titrate with 0.1 M perchloric acid, determining the end-point potentiometrically (2.2.20).<\/p>\n

1 mL of 0.1 M perchloric acid is equivalent to 31.53 mg of C15H13N3O3S.<\/p>\n

STORAGE<\/h2>\n

Protected from light.<\/p>\n

IMPURITIES<\/h2>\n

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

\"Oxfendazole\"<\/p>\n

A. methyl [5-(phenylsulfanyl)-1H-benzimidazol-2-yl]carbamate (fenbendazole),<\/p>\n

\"Oxfendazole\"<\/p>\n

B. methyl [5-(phenylsulfonyl)-1H-benzimidazol-2-yl]carbamate,<\/p>\n

\"Oxfendazole\"<\/p>\n

C. 5-(phenylsulfinyl)-1H-benzimidazol-2-amine,<\/p>\n

\"Oxfendazole\"<\/p>\n

D. N,N\u2032-bis[5-(phenylsulfinyl)-1H-benzimidazol-2-yl]urea.<\/p>\n","protected":false},"excerpt":{"rendered":"

Edition: BP 2025 (Ph. Eur. 11.6 update) Action and use Antihelminthic. Preparation Oxfendazole Oral Suspension Ph Eur DEFINITION Methyl [5-(phenylsulfinyl)-1H-benzimidazol-2-yl]carbamate. Content 97.5 per cent to 100.5 per cent (dried substance). CHARACTERS Appearance White or almost white powder. Solubility Practically insoluble in water, slightly soluble in ethanol (96 per cent) and in methylene chloride. It shows…<\/p>\n","protected":false},"author":5,"featured_media":24663,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[176],"tags":[],"class_list":["post-24662","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\/24662","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=24662"}],"version-history":[{"count":4,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/24662\/revisions"}],"predecessor-version":[{"id":25073,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/24662\/revisions\/25073"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/24663"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=24662"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=24662"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=24662"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}