{"id":14659,"date":"2025-10-15T15:22:17","date_gmt":"2025-10-15T08:22:17","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=14659"},"modified":"2025-10-15T17:24:36","modified_gmt":"2025-10-15T10:24:36","slug":"flubendazole","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/flubendazole\/","title":{"rendered":"Flubendazole"},"content":{"rendered":"

(Ph. Eur. monograph 1721)<\/p>\n

C_{16<\/sub>H_{12<\/sub>FN_{3<\/sub>O_{3<\/sub>\u00a0 \u00a0 313.3\u00a0 \u00a031430-15-6<\/p>\n}}}}

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

Benzimadazole antihelminthic.<\/p>\n

DEFINITION<\/h2>\n
Methyl [5-(4-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamate.<\/p>\n
Content<\/h3>\n
99.0 per cent to 101.0 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, in ethanol (96 per cent) and in methylene chloride.<\/p>\n
It shows polymorphism (5.9).<\/p>\n
IDENTIFICATION<\/h2>\n
Infrared absorption spectrophotometry (2.2.24), without recrystallisation.<\/p>\n
Comparison flubendazole CRS.<\/p>\n
TESTS<\/h2>\n
Related substances<\/h3>\n
Liquid chromatography (2.2.29).<\/p>\n
Test solution: Dissolve 0.100 g of the substance to be examined in dimethylformamide R and dilute to 100.0 mL with the same solvent.<\/p>\n
Reference solution (a): Dissolve 5 mg of flubendazole for system suitability CRS in dimethylformamide R and dilute to 5.0 mL with the same solvent.<\/p>\n
Reference solution (b): Dilute 1.0 mL of the test solution to 100.0 mL with dimethylformamide R. Dilute 5.0 mL of this solution to 20.0 mL with dimethylformamide R.<\/p>\n
Column:<\/p>\n
\u2014 size: l = 0.10 m, \u00d8 = 4.6 mm,<\/p>\n
\u2014 stationary phase: base-deactivated octadecylsilyl silica gel for chromatography R (3 \u03bcm),<\/p>\n
\u2014 temperature: 40 \u00b0C.<\/p>\n
Mobile phase:<\/p>\n
\u2014 mobile phase A: 7.5 g\/L solution of ammonium acetate R,<\/p>\n
\u2014 mobile phase B: acetonitrile R,<\/p>\n\n\n\n\n\n\n\n
Time
\n(min)<\/td>\n Mobile phase A
\n(per cent V\/V)<\/td>\n Mobile phase B
\n(per cent V\/V)<\/td>\n<\/tr>\n
0 – 15<\/td>\n \u00a090 \u2192 75<\/td>\n 10 \u2192 25<\/td>\n<\/tr>\n
15 – 30<\/td>\n \u00a075 \u2192 45<\/td>\n \u00a025 \u2192 55<\/td>\n<\/tr>\n
30 – 32<\/td>\n 45 \u2192 10<\/td>\n 55 \u2192 90<\/td>\n<\/tr>\n
32 – 37<\/td>\n 10<\/td>\n 90<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
Flow rate 1.2 mL\/min.<\/p>\n
Detection: Spectrophotometer at 250 nm.<\/p>\n
Injection 10 \u03bcL.<\/p>\n
System suitability Reference solution (a):<\/p>\n
\u2014 the chromatogram obtained is similar to the chromatogram supplied with flubendazole for system suitability CRS.<\/p>\n
Limits:<\/p>\n
\u2014 correction factors: for the calculation of contents, multiply the peak areas of the following impurities by the corresponding correction factor: impurity A = 1.4; impurity C = 1.3; impurity D = 1.3; impurity G = 1.4,<\/p>\n
\u2014 impurities A, B, C, D, E, G: for each impurity, not more than the area of the principal peak in the chromatogram obtained with reference solution (b) (0.25 per cent),<\/p>\n
\u2014 impurity F: not more than twice the area of the principal peak in the chromatogram obtained with reference solution (b) (0.5 per cent),<\/p>\n
\u2014 any other impurity with a relative retention between 1.2 and 1.3: not more than the area of the principal peak in the chromatogram obtained with reference solution (b) (0.25 per cent),<\/p>\n
\u2014 total: not more than 6 times the area of the principal peak in the chromatogram obtained with reference solution (b) (1.5 per cent),<\/p>\n
\u2014 disregard limit: 0.2 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.05 per cent).<\/p>\n
Loss on drying (2.2.32)<\/h4>\n
Maximum 0.5 per cent, determined on 1.000 g by drying in an oven at 105 \u00b0C, for 4 h.<\/p>\n
Sulfated ash (2.4.14)<\/h4>\n
Maximum 0.1 per cent, determined on 1.0 g.<\/p>\n
ASSAY<\/h2>\n
Dissolve 0.250 g in 3 mL of anhydrous formic acid R and add 50 mL of a mixture of 1 volume of anhydrous acetic acid R and 7 volumes of methyl ethyl ketone 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 31.33 mg of C_{16<\/sub>H_{12<\/sub>FN_{3<\/sub>O_{3<\/sub>.<\/p>\n}}}}
STORAGE<\/h2>\n
Protected from light.<\/p>\n
IMPURITIES<\/h2>\n
Specified impurities A, B, C, D, E, F, G.<\/p>\n
$\"Flubendazole-1\"$ <\/p>\n
A. methyl [5-[4-(formylamino)benzoyl]-1H-benzimidazol-2-yl]carbamate,<\/p>\n
$\"Flubendazole-2\"$ <\/p>\n
B. (2-amino-1H-benzimidazol-5-yl)(4-fluorophenyl)methanone,<\/p>\n
$\"Flubendazole-3\"$ <\/p>\n
C. (4-fluorophenyl)(2-hydroxy-1H-benzimidazol-5-yl)methanone,<\/p>\n
$\"Flubendazole-4\"$ <\/p>\n
D. (1H-benzimidazol-5-yl)(4-fluorophenyl)methanone,<\/p>\n
$\"Flubendazole-5\"$ <\/p>\n
E. methyl [5-(2-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamate,<\/p>\n
$\"Flubendazole-6\"$ <\/p>\n
F. methyl [5-(4-fluorobenzoyl)-1-methyl-1H-benzimidazol-2-yl]carbamate,<\/p>\n
$\"Flubendazole-7\"$ <\/p>\n
G. methyl [5-[4-(1-methylethoxy)benzoyl]-1H-benzimidazol-2-yl]carbamate.<\/p>\n","protected":false},"excerpt":{"rendered":"
(Ph. Eur. monograph 1721) C16H12FN3O3\u00a0 \u00a0 313.3\u00a0 \u00a031430-15-6 Action and use Benzimadazole antihelminthic. DEFINITION Methyl [5-(4-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamate. Content 99.0 per cent to 101.0 per cent (dried substance). CHARACTERS Appearance White or almost white powder. Solubility Practically insoluble in water, in ethanol (96 per cent) and in methylene chloride. It shows polymorphism (5.9). IDENTIFICATION Infrared absorption spectrophotometry…<\/p>\n","protected":false},"author":3,"featured_media":14669,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-14659","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\/14659","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\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/comments?post=14659"}],"version-history":[{"count":3,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/14659\/revisions"}],"predecessor-version":[{"id":14815,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/14659\/revisions\/14815"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/14669"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=14659"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=14659"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=14659"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

Time \n(min)<\/td>\n	Mobile phase A \n(per cent V\/V)<\/td>\n	Mobile phase B \n(per cent V\/V)<\/td>\n<\/tr>\n
0 – 15<\/td>\n	\u00a090 \u2192 75<\/td>\n	10 \u2192 25<\/td>\n<\/tr>\n
15 – 30<\/td>\n	\u00a075 \u2192 45<\/td>\n	\u00a025 \u2192 55<\/td>\n<\/tr>\n
30 – 32<\/td>\n	45 \u2192 10<\/td>\n	55 \u2192 90<\/td>\n<\/tr>\n
32 – 37<\/td>\n	10<\/td>\n	90<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Flow rate 1.2 mL\/min.<\/p>\n Detection: Spectrophotometer at 250 nm.<\/p>\n Injection 10 \u03bcL.<\/p>\n System suitability Reference solution (a):<\/p>\n \u2014 the chromatogram obtained is similar to the chromatogram supplied with flubendazole for system suitability CRS.<\/p>\n Limits:<\/p>\n \u2014 correction factors: for the calculation of contents, multiply the peak areas of the following impurities by the corresponding correction factor: impurity A = 1.4; impurity C = 1.3; impurity D = 1.3; impurity G = 1.4,<\/p>\n \u2014 impurities A, B, C, D, E, G: for each impurity, not more than the area of the principal peak in the chromatogram obtained with reference solution (b) (0.25 per cent),<\/p>\n \u2014 impurity F: not more than twice the area of the principal peak in the chromatogram obtained with reference solution (b) (0.5 per cent),<\/p>\n \u2014 any other impurity with a relative retention between 1.2 and 1.3: not more than the area of the principal peak in the chromatogram obtained with reference solution (b) (0.25 per cent),<\/p>\n \u2014 total: not more than 6 times the area of the principal peak in the chromatogram obtained with reference solution (b) (1.5 per cent),<\/p>\n \u2014 disregard limit: 0.2 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.05 per cent).<\/p>\n Loss on drying (2.2.32)<\/h4>\n Maximum 0.5 per cent, determined on 1.000 g by drying in an oven at 105 \u00b0C, for 4 h.<\/p>\n Sulfated ash (2.4.14)<\/h4>\n Maximum 0.1 per cent, determined on 1.0 g.<\/p>\n ASSAY<\/h2>\n Dissolve 0.250 g in 3 mL of anhydrous formic acid R and add 50 mL of a mixture of 1 volume of anhydrous acetic acid R and 7 volumes of methyl ethyl ketone 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 31.33 mg of C_{16<\/sub>H_{12<\/sub>FN_{3<\/sub>O_{3<\/sub>.<\/p>\n}}}} STORAGE<\/h2>\n Protected from light.<\/p>\n IMPURITIES<\/h2>\n Specified impurities A, B, C, D, E, F, G.<\/p>\n $\"Flubendazole-1\"$ <\/p>\n A. methyl [5-[4-(formylamino)benzoyl]-1H-benzimidazol-2-yl]carbamate,<\/p>\n $\"Flubendazole-2\"$ <\/p>\n B. (2-amino-1H-benzimidazol-5-yl)(4-fluorophenyl)methanone,<\/p>\n $\"Flubendazole-3\"$ <\/p>\n C. (4-fluorophenyl)(2-hydroxy-1H-benzimidazol-5-yl)methanone,<\/p>\n $\"Flubendazole-4\"$ <\/p>\n D. (1H-benzimidazol-5-yl)(4-fluorophenyl)methanone,<\/p>\n $\"Flubendazole-5\"$ <\/p>\n E. methyl [5-(2-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamate,<\/p>\n $\"Flubendazole-6\"$ <\/p>\n F. methyl [5-(4-fluorobenzoyl)-1-methyl-1H-benzimidazol-2-yl]carbamate,<\/p>\n $\"Flubendazole-7\"$ <\/p>\n G. methyl [5-[4-(1-methylethoxy)benzoyl]-1H-benzimidazol-2-yl]carbamate.<\/p>\n","protected":false},"excerpt":{"rendered":" (Ph. Eur. monograph 1721) C16H12FN3O3\u00a0 \u00a0 313.3\u00a0 \u00a031430-15-6 Action and use Benzimadazole antihelminthic. DEFINITION Methyl [5-(4-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamate. Content 99.0 per cent to 101.0 per cent (dried substance). CHARACTERS Appearance White or almost white powder. Solubility Practically insoluble in water, in ethanol (96 per cent) and in methylene chloride. It shows polymorphism (5.9). IDENTIFICATION Infrared absorption spectrophotometry…<\/p>\n","protected":false},"author":3,"featured_media":14669,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-14659","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\/14659","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\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/comments?post=14659"}],"version-history":[{"count":3,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/14659\/revisions"}],"predecessor-version":[{"id":14815,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/14659\/revisions\/14815"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/14669"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=14659"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=14659"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=14659"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

Content<\/h3>\n99.0 per cent to 101.0 per cent (dried substance).<\/p>\n

CHARACTERS<\/h2>\n

Appearance<\/h3>\nWhite or almost white powder.<\/p>\n

Solubility<\/h3>\nPractically insoluble in water, in ethanol (96 per cent) and in methylene chloride.<\/p>\nIt shows polymorphism (5.9).<\/p>\n

IDENTIFICATION<\/h2>\nInfrared absorption spectrophotometry (2.2.24), without recrystallisation.<\/p>\nComparison flubendazole CRS.<\/p>\n

TESTS<\/h2>\n

Loss on drying (2.2.32)<\/h4>\nMaximum 0.5 per cent, determined on 1.000 g by drying in an oven at 105 \u00b0C, for 4 h.<\/p>\n

Sulfated ash (2.4.14)<\/h4>\nMaximum 0.1 per cent, determined on 1.0 g.<\/p>\n

STORAGE<\/h2>\nProtected from light.<\/p>\n

Content<\/h3>\n
99.0 per cent to 101.0 per cent (dried substance).<\/p>\n

Appearance<\/h3>\n
White or almost white powder.<\/p>\n

Solubility<\/h3>\n
Practically insoluble in water, in ethanol (96 per cent) and in methylene chloride.<\/p>\n
It shows polymorphism (5.9).<\/p>\n

IDENTIFICATION<\/h2>\n
Infrared absorption spectrophotometry (2.2.24), without recrystallisation.<\/p>\n
Comparison flubendazole CRS.<\/p>\n

Loss on drying (2.2.32)<\/h4>\n
Maximum 0.5 per cent, determined on 1.000 g by drying in an oven at 105 \u00b0C, for 4 h.<\/p>\n

Sulfated ash (2.4.14)<\/h4>\n
Maximum 0.1 per cent, determined on 1.0 g.<\/p>\n

STORAGE<\/h2>\n
Protected from light.<\/p>\n