{"id":16482,"date":"2025-10-20T16:57:22","date_gmt":"2025-10-20T09:57:22","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=16482"},"modified":"2025-10-21T11:10:06","modified_gmt":"2025-10-21T04:10:06","slug":"levamisole-hydrochloride","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/levamisole-hydrochloride\/","title":{"rendered":"Levamisole Hydrochloride"},"content":{"rendered":"

(Ph. Eur. monograph 0726)<\/p>\n

C_{11<\/sub>H_{13<\/sub>ClN_{2<\/sub>S\u00a0 \u00a0 \u00a0 \u00a0240.8\u00a0 \u00a0 \u00a0 \u00a016595-80-5<\/p>\n}}}

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

Immunostimulant; antihelminthic.<\/p>\n

DEFINITION<\/h2>\n
(6S)-6-Phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole hydrochloride.<\/p>\n
Content<\/h3>\n
98.5 per cent to 101.0 per cent (dried substance).<\/p>\n
CHARACTERS<\/h2>\n
Appearance<\/h3>\n
White or almost white, crystalline powder.<\/p>\n
Solubility<\/h3>\n
Freely soluble in water, soluble in ethanol (96 per cent), slightly soluble in methylene chloride.<\/p>\n
IDENTIFICATION<\/h3>\n
A. Specific optical rotation (see Tests).<\/p>\n
B. Infrared absorption spectrophotometry (2.2.24).<\/p>\n
Comparison: levamisole hydrochloride CRS.<\/p>\n
C. It gives reaction (a) of chlorides (2.3.1).<\/p>\n
TESTS<\/h2>\n
Solution S<\/h3>\n
Dissolve 2.50 g in carbon dioxide-free water R and dilute to 50.0 mL with the same solvent.<\/p>\n
Appearance of solution<\/h3>\n
Solution S is clear (2.2.1) and not more intensely coloured than reference solution Y_{7<\/sub> (2.2.2, Method II).<\/p>\n}
pH (2.2.3)<\/h4>\n
3.0 to 4.5 for solution S.<\/p>\n
Specific optical rotation (2.2.7)<\/h4>\n
-128 to -121 (dried substance), determined on solution S.<\/p>\n
Related substances<\/h3>\n
Liquid chromatography (2.2.29). Prepare the solutions immediately before use, protect from light and keep below 25 \u00b0C.<\/p>\n
Test solution: Dissolve 0.100 g of the substance to be examined in methanol R, add 1.0 mL of concentrated ammonia R and dilute to 10.0 mL with methanol R.<\/p>\n
Reference solution (a): Dissolve 10 mg of levamisole hydrochloride for system suitability CRS (containing impurities A, B, C, D and E) in methanol R, add 0.1 mL of concentrated ammonia R and dilute to 1.0 mL with methanol R.<\/p>\n
Reference solution (b): Dilute 1.0 mL of the test solution to 100.0 mL with methanol R. Dilute 5.0 mL of this solution to 25.0 mL with methanol 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
Mobile phase:<\/p>\n
\u2014 mobile phase A: dissolve 0.5 g of ammonium dihydrogen phosphate R in 90 mL of water R, adjust to pH 6.5 with a 40 g\/L solution of sodium hydroxide R and dilute to 100 mL with water R;<\/p>\n
\u2014 mobile phase B: acetonitrile R;<\/p>\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 – 8<\/td>\n 90 \u2192 30<\/td>\n 10 \u2192 70<\/td>\n<\/tr>\n
8 – 10<\/td>\n 30<\/td>\n 70<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
Flow rate: 1.5 mL\/min.<\/p>\n
Detection: Spectrophotometer at 215 nm.<\/p>\n
Equilibration: At least 4 min with the mobile phase at the initial composition.<\/p>\n
Injection: 10 \u03bcL.<\/p>\n
Identification of impurities: Use the chromatogram supplied with levamisole hydrochloride for system suitability CRS and the chromatogram obtained with reference solution (a) to identify the peaks due to impurities A, B, C, D and E.<\/p>\n
Relative retention: With reference to levamisole (retention time = about 3 min): impurity A = about 0.9; impurity B = about 1.4; impurity C = about 1.5; impurity D = about 1.6; impurity E = about 2.0.<\/p>\n
System suitability:<\/p>\n
\u2014 the chromatogram obtained with reference solution (a) is similar to the chromatogram supplied with levamisole hydrochloride for system suitability CRS;<\/p>\n
\u2014 symmetry factor: maximum 3.5 for the principal peak in the chromatogram obtained with reference solution (b).<\/p>\n
Limits:<\/p>\n
\u2014 correction factors: for the calculation of content, multiply the peak areas of the following impurities by the corresponding correction factor: impurity A = 2.0; impurity B = 1.7; impurity C = 2.9; impurity D = 1.3; impurity E = 2.7;<\/p>\n
\u2014 impurities A, B, C, D, E: for each impurity, not more than the area of the principal peak in the chromatogram obtained with reference solution (b) (0.2 per cent);<\/p>\n
\u2014 unspecified impurities: for each impurity, not more than 0.5 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.10 per cent);<\/p>\n
\u2014 total: not more than 1.5 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.3 per cent);<\/p>\n
\u2014 disregard limit: 0.25 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 0.200 g in 30 mL of ethanol (96 per cent) R and add 5.0 mL of 0.01 M hydrochloric acid. 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 24.08 mg of C_{11<\/sub>H_{13<\/sub>ClN_{2<\/sub>S.<\/p>\n}}}
STORAGE<\/h2>\n
Protected from light.<\/p>\n
IMPURITIES<\/h2>\n
Specified impurities A, B, C, D, E.<\/p>\n
$\"Levamisole$ <\/p>\n
A. 3-[(2RS)-2-amino-2-phenylethyl]thiazolidin-2-one,<\/p>\n
$\"Levamisole$ <\/p>\n
B. 3-[(E)-2-phenylethenyl]thiazolidin-2-imine,<\/p>\n
$\"Levamisole$ <\/p>\n
C. (4RS)-4-phenyl-1-(2-sulfanylethyl)imidazolidin-2-one,<\/p>\n
$\"Levamisole$ <\/p>\n
D. 6-phenyl-2,3-dihydroimidazo[2,1-b]thiazole,<\/p>\n
$\"Levamisole$ <\/p>\n
E. 1,1\u2032-[(disulfane-1,2-diyl)bis(ethylene)]bis[(4RS)-4-phenylimidazolidin-2-one].<\/p>\n","protected":false},"excerpt":{"rendered":"
(Ph. Eur. monograph 0726) C11H13ClN2S\u00a0 \u00a0 \u00a0 \u00a0240.8\u00a0 \u00a0 \u00a0 \u00a016595-80-5 Action and use Immunostimulant; antihelminthic. DEFINITION (6S)-6-Phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole hydrochloride. Content 98.5 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), slightly soluble in methylene chloride. IDENTIFICATION A….<\/p>\n","protected":false},"author":2,"featured_media":16808,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-16482","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\/16482","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\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/comments?post=16482"}],"version-history":[{"count":4,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/16482\/revisions"}],"predecessor-version":[{"id":16811,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/16482\/revisions\/16811"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/16808"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=16482"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=16482"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=16482"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

Content<\/h3>\n98.5 per cent to 101.0 per cent (dried substance).<\/p>\n

CHARACTERS<\/h2>\n

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

Solubility<\/h3>\nFreely soluble in water, soluble in ethanol (96 per cent), slightly soluble in methylene chloride.<\/p>\n

IDENTIFICATION<\/h3>\nA. Specific optical rotation (see Tests).<\/p>\nB. Infrared absorption spectrophotometry (2.2.24).<\/p>\nComparison: levamisole hydrochloride CRS.<\/p>\nC. It gives reaction (a) of chlorides (2.3.1).<\/p>\n

TESTS<\/h2>\n

Solution S<\/h3>\nDissolve 2.50 g in carbon dioxide-free water R and dilute to 50.0 mL with the same solvent.<\/p>\n

Appearance of solution<\/h3>\nSolution S is clear (2.2.1) and not more intensely coloured than reference solution Y7<\/sub> (2.2.2, Method II).<\/p>\n

pH (2.2.3)<\/h4>\n3.0 to 4.5 for solution S.<\/p>\n

Specific optical rotation (2.2.7)<\/h4>\n-128 to -121 (dried substance), determined on solution S.<\/p>\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
98.5 per cent to 101.0 per cent (dried substance).<\/p>\n

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

Solubility<\/h3>\n
Freely soluble in water, soluble in ethanol (96 per cent), slightly soluble in methylene chloride.<\/p>\n

IDENTIFICATION<\/h3>\n
A. Specific optical rotation (see Tests).<\/p>\n
B. Infrared absorption spectrophotometry (2.2.24).<\/p>\n
Comparison: levamisole hydrochloride CRS.<\/p>\n
C. It gives reaction (a) of chlorides (2.3.1).<\/p>\n

Solution S<\/h3>\n
Dissolve 2.50 g in carbon dioxide-free water R and dilute to 50.0 mL with the same solvent.<\/p>\n

Appearance of solution<\/h3>\n
Solution S is clear (2.2.1) and not more intensely coloured than reference solution Y_{7<\/sub> (2.2.2, Method II).<\/p>\n}

pH (2.2.3)<\/h4>\n
3.0 to 4.5 for solution S.<\/p>\n

Specific optical rotation (2.2.7)<\/h4>\n
-128 to -121 (dried substance), determined on solution S.<\/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