{"id":30348,"date":"2025-11-11T17:14:28","date_gmt":"2025-11-11T10:14:28","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=30348"},"modified":"2025-11-14T16:46:43","modified_gmt":"2025-11-14T09:46:43","slug":"terfenadine","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/terfenadine\/","title":{"rendered":"Terfenadine"},"content":{"rendered":"

(Ph. Eur. monograph 0955)<\/p>\n

C_{32<\/sub>H_{41<\/sub>NO_{2<\/sub> 471.7 50679-08-8<\/p>\n}}}

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

Histamine H_{1<\/sub> receptor antagonist; antihistamine.<\/p>\n}

DEFINITION<\/h2>\n
(1RS)-1-[4-(1,1-Dimethylethyl)phenyl]-4-[4-(hydroxydiphenylmethyl)piperidin-1-yl]butan-1-ol.<\/p>\n
Content<\/strong><\/p>\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
Very slightly soluble in water, freely soluble in methylene chloride, soluble in methanol. It is very slightly soluble in dilute hydrochloric acid.<\/p>\n
It shows polymorphism (5.9).<\/p>\n
IDENTIFICATION<\/h2>\n
First identification: C.<\/p>\n
Second identification: A, B, D.<\/p>\n
A.\u2003Melting point (2.2.14): 146 \u00b0C to 152 \u00b0C.<\/p>\n
B.\u2003Ultraviolet and visible absorption spectrophotometry (2.2.25).<\/p>\n
Test solution Dissolve 50.0 mg in methanol R and dilute to 100.0 mL with the same solvent.<\/p>\n
Spectral range<\/em> 230-350 nm.<\/p>\n
Absorption maximum<\/em> At 259 nm.<\/p>\n
Shoulders<\/em> At 253 nm and 270 nm.<\/p>\n
Specific absorbance at the absorption maximum<\/em> 13.5 to 14.9.<\/p>\n
C. Infrared absorption spectrophotometry (2.2.24).<\/p>\n
Comparison<\/em> terfenadine CRS.<\/p>\n
D. Thin-layer chromatography (2.2.27).<\/p>\n
Test solution<\/em> Dissolve 50 mg of the substance to be examined in methylene chloride R and dilute to 10 mL with the same solvent.<\/p>\n
Reference solution<\/em> Dissolve 50 mg of terfenadine CRS in methylene chloride R and dilute to 10 mL with the same solvent.<\/p>\n
Plate<\/em> TLC silica gel F_{254<\/sub> plate R.<\/p>\n}
Mobile phase<\/em> methanol R, methylene chloride R (10:90 V\/V).<\/p>\n
Application<\/em> 10 \u00b5L.<\/p>\n
Development<\/em> Over a path of 15 cm.<\/p>\n
Drying<\/em> In air.<\/p>\n
Detection<\/em> Examine in ultraviolet light at 254 nm.<\/p>\n
Results<\/em> The principal spot in the chromatogram obtained with the test solution is similar in position and size to the principal spot in the chromatogram obtained with the reference solution.<\/p>\n
TESTS<\/h2>\n
Related substances<\/h3>\n
Liquid chromatography (2.2.29).<\/p>\n
Test solution<\/em> Dissolve 15 mg of the substance to be examined in the mobile phase and dilute to 10.0 mL with the mobile phase.<\/p>\n
Reference solution (a)<\/em> Dilute 1.0 mL of the test solution to 10.0 mL with the mobile phase. Dilute 1.0 mL of this solution to 20.0 mL with the mobile phase.<\/p>\n
Reference solution (b)<\/em> Dissolve 15 mg of terfenadine impurity A CRS in the mobile phase and dilute to 10.0 mL with the mobile phase. To 5.0 mL of this solution, add 5.0 mL of the test solution and dilute to 50.0 mL with the mobile phase.<\/p>\n
Reference solution (c)<\/em> Dilute 10.0 mL of reference solution (a) to 25.0 mL with the mobile phase.<\/p>\n
Reference solution (d)<\/em> Dissolve 0.1 g of potassium iodide R in the mobile phase and dilute to 100 mL with the mobile phase. Dilute 1 mL of this solution to 100 mL with the mobile phase.<\/p>\n
Column:<\/p>\n
\u2014 size: l = 0.25 m, \u00d8 = 4.6 mm;<\/p>\n
\u2014 stationary phase: octylsilyl silica gel for chromatography R (5 \u00b5m).<\/p>\n
Mobile phase<\/em> Dilute 600 mL of acetonitrile R1 to 1 L with diethylammonium phosphate buffer solution pH 6.0 R.<\/p>\n
Flow rate<\/em> 1 mL\/min.<\/p>\n
Detection<\/em> Spectrophotometer at 217 nm.<\/p>\n
Injection<\/em> 20 \u00b5L.<\/p>\n
Run time<\/em> 5 times the retention time of terfenadine.<\/p>\n
System suitability<\/em> Reference solution (b):<\/p>\n
\u2014 resolution: minimum 5.0 between the peaks due to terfenadine and impurity A;<\/p>\n
\u2014 mass distribution ratio: minimum 2.0 for the peak due to terfenadine; use potassium iodide R as the unretained compound (reference solution (d)).<\/p>\n
Limits:<\/p>\n
\u2014 impurities A, B, C, D, E, F, G, H, I, J: for each impurity, not more than the area of the principal peak in the chromatogram obtained with reference solution (c) (0.2 per cent);<\/p>\n
\u2014 total: not more than the area of the principal peak in the chromatogram obtained with reference solution (a) (0.5 per cent);<\/p>\n
\u2014 disregard limit: 0.025 times the area of the principal peak in the chromatogram obtained with reference solution (c) (0.005 per cent).<\/p>\n
Loss on drying (2.2.32)<\/h3>\n
Maximum 0.5 per cent, determined on 1.000 g by drying at 60 \u00b0C at a pressure not exceeding 0.5 kPa.<\/p>\n
Sulfated ash (2.4.14)<\/h3>\n
Maximum 0.1 per cent, determined on 1.0 g.<\/p>\n
ASSAY<\/h2>\n
Dissolve 0.400 g in 50 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 47.17 mg of C_{32<\/sub>H_{41<\/sub>NO_{2<\/sub>.<\/p>\n}}}
STORAGE<\/h2>\n
Protected from light.<\/p>\n
IMPURITIES<\/h2>\n
Specified impurities A, B, C, D, E, F, G, H, I, J.<\/p>\n
$\"Terfenadine\"$
\nA. 1-[4-(1,1-dimethylethyl)phenyl]-4-[4-(hydroxydiphenylmethyl)piperidin-1-yl]butan-1-one,<\/p>\n
$\"Terfenadine\"$
\nB. (1RS)-1-[4-(1,1-dimethylethyl)phenyl]-4-[4-(diphenylmethyl)piperidin-1-yl]butan-1-ol,<\/p>\n
$\"Terfenadine\"$
\nC. 1-[(4RS)-4-[4-(1,1-dimethylethyl)phenyl]-4-hydroxybutyl]-4-(hydroxydiphenylmethyl)piperidine 1-oxide,<\/p>\n
$\"Terfenadine\"$
\nD. (1RS)-1-[4-(1,1-dimethylethyl)phenyl]-4-[4-(diphenylmethylene)piperidin-1-yl]butan-1-ol,<\/p>\n
$\"Terfenadine\"$
\nE. 1-[(4RS)-4-[4-(1,1-dimethylethyl)phenyl]-4-hydroxybutyl]piperidine-4-carboxylic acid,<\/p>\n
$\"Terfenadine\"$
\nF. 1-[4-[4-(1,1-dimethylethyl)phenyl]but-3-enyl]-4-(diphenylmethylene)piperidine,<\/p>\n
$\"Terfenadine\"$
\nG. [1-[4-[4-(1,1-dimethylethyl)phenyl]but-3-enyl]piperidin-4-yl]diphenylmethanol,<\/p>\n
$\"Terfenadine\"$
\nH. [1-[4-[4-(1,1-dimethylethyl)phenyl]butyl]piperidin-4-yl]diphenylmethanol,<\/p>\n
$\"Terfenadine\"$
\nI. diphenyl(piperidin-4-yl)methanol,<\/p>\n
$\"Terfenadine\"$
\nJ. ethyl 1-[(4RS)-4-[4-(1,1-dimethylethyl)phenyl]-4-hydroxybutyl]piperidine-4-carboxylate.<\/p>\n","protected":false},"excerpt":{"rendered":"
(Ph. Eur. monograph 0955) C32H41NO2 471.7 50679-08-8 Action and use Histamine H1 receptor antagonist; antihistamine. DEFINITION (1RS)-1-[4-(1,1-Dimethylethyl)phenyl]-4-[4-(hydroxydiphenylmethyl)piperidin-1-yl]butan-1-ol. Content 98.5 per cent to 101.0 per cent (dried substance). CHARACTERS Appearance White or almost white, crystalline powder. Solubility Very slightly soluble in water, freely soluble in methylene chloride, soluble in methanol. It is very slightly soluble in…<\/p>\n","protected":false},"author":5,"featured_media":30392,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-30348","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\/30348","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=30348"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/30348\/revisions"}],"predecessor-version":[{"id":30406,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/30348\/revisions\/30406"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/30392"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=30348"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=30348"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=30348"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

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

Solubility<\/h3>\nVery slightly soluble in water, freely soluble in methylene chloride, soluble in methanol. It is very slightly soluble in dilute hydrochloric acid.<\/p>\nIt shows polymorphism (5.9).<\/p>\n

Sulfated ash (2.4.14)<\/h3>\nMaximum 0.1 per cent, determined on 1.0 g.<\/p>\n

ASSAY<\/h2>\nDissolve 0.400 g in 50 mL of anhydrous acetic acid R. Titrate with 0.1 M perchloric acid, determining the end-point potentiometrically (2.2.20).<\/p>\n1 mL of 0.1 M perchloric acid is equivalent to 47.17 mg of C32<\/sub>H41<\/sub>NO2<\/sub>.<\/p>\n

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

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

Solubility<\/h3>\n
Very slightly soluble in water, freely soluble in methylene chloride, soluble in methanol. It is very slightly soluble in dilute hydrochloric acid.<\/p>\n
It shows polymorphism (5.9).<\/p>\n

Sulfated ash (2.4.14)<\/h3>\n
Maximum 0.1 per cent, determined on 1.0 g.<\/p>\n

ASSAY<\/h2>\n
Dissolve 0.400 g in 50 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 47.17 mg of C_{32<\/sub>H_{41<\/sub>NO_{2<\/sub>.<\/p>\n}}}

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