{"id":26938,"date":"2025-11-06T14:40:36","date_gmt":"2025-11-06T07:40:36","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=26938"},"modified":"2025-11-06T14:40:36","modified_gmt":"2025-11-06T07:40:36","slug":"paracetamol","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/paracetamol\/","title":{"rendered":"Paracetamol"},"content":{"rendered":"

(Ph. Eur. monograph 0049)<\/p>\n

C8<\/sub>H9<\/sub>NO2<\/sub>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 151.2\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0103-90-2<\/p>\n

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

Analgesic; antipyretic.<\/p>\n

Preparations<\/strong><\/p>\n

Co-codamol Tablets<\/p>\n

Co-codamol Capsules<\/p>\n

Co-codamol Effervescent Tablets<\/p>\n

Paracetamol Effervescent Tablets<\/p>\n

Co-dydramol Tablets<\/p>\n

Co-proxamol Tablets<\/p>\n

Paracetamol Capsules<\/p>\n

Paracetamol Infusion<\/p>\n

Paediatric Paracetamol Oral Solution<\/p>\n

Paediatric Paracetamol Oral Suspension<\/p>\n

Paracetamol Oral Solution<\/p>\n

Paracetamol Oral Suspension<\/p>\n

Paracetamol Suppositories<\/p>\n

Paracetamol Tablets<\/p>\n

Paracetamol and Caffeine Tablets<\/p>\n

Paracetamol and Caffeine Soluble Tablets<\/p>\n

Paracetamol Dispersible Tablets<\/p>\n

Paracetamol Soluble Tablets<\/p>\n

Paracetamol, Codeine Phosphate and Caffeine Capsules<\/p>\n

Paracetamol, Codeine Phosphate and Caffeine Tablets<\/p>\n

DEFINITION<\/h2>\n

N-(4-Hydroxyphenyl)acetamide.<\/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, crystalline powder.<\/p>\n

Solubility<\/h3>\n

Sparingly soluble in water, freely soluble in ethanol (96 per cent), very slightly soluble in methylene chloride.<\/p>\n

IDENTIFICATION<\/h2>\n

First identification: B.<\/p>\n

Second identification: A.<\/p>\n

A. Melting point (2.2.14).<\/p>\n

Determination A: Determine the melting point of the substance to be examined.<\/p>\n

Result A: 168 \u00b0C to 172 \u00b0C.<\/p>\n

Determination B: Mix equal parts of the substance to be examined and paracetamol CRS and determine the melting point of the mixture.<\/p>\n

Result B: The absolute difference between the melting point of the mixture and the value obtained in determination A is not greater than 2 \u00b0C.<\/p>\n

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

Comparison: paracetamol CRS.<\/p>\n

TESTS<\/h2>\n

Related substances<\/h3>\n

Liquid chromatography (2.2.29).<\/p>\n

Solvent mixture: methanol R, water R (15:85 V\/V).<\/p>\n

Test solution: Dissolve 50.0 mg of the substance to be examined in 0.75 mL of methanol R and dilute to 5.0 mL with water R.<\/p>\n

Reference solution (a): Dilute 1.0 mL of the test solution to 100.0 mL with the solvent mixture. Dilute 1.0 mL of this solution to 20.0 mL with the solvent mixture.<\/p>\n

Reference solution (b): Dissolve 5.0 mg of paracetamol impurity J CRS in 25 mL of methanol R and dilute to 250.0 mL with the solvent mixture. Dilute 1.0 mL of the solution to 200.0 mL with the solvent mixture.<\/p>\n

Reference solution (c): Dissolve 5.0 mg of paracetamol impurity K CRS in the solvent mixture and dilute to 100.0 mL with the solvent mixture. Dilute 1.0 mL of the solution to 10.0 mL with the solvent mixture.<\/p>\n

Reference solution (d): Dilute 1.0 mL of reference solution (c) to 10.0 mL with the solvent mixture.<\/p>\n

Reference solution (e): Mix 1 mL of reference solution (a) and 1 mL of reference solution (c) and dilute to 10 mL with the solvent mixture.<\/p>\n

Column:<\/p>\n

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

\u2014 stationary phase: end-capped solid core octadecylsilyl silica gel for chromatography R (5 \u03bcm);<\/p>\n

\u2014 temperature: 30 \u00b0C.<\/p>\n

Mobile phase:<\/p>\n

\u2014 mobile phase A: dissolve 1.7 g of potassium dihydrogen phosphate R and 1.8 g of dipotassium hydrogen phosphate R in water for chromatography R and dilute to 1000 mL with the same solvent;<\/p>\n

\u2014 mobile phase B: methanol R;<\/p>\n\n\n\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 – 1.5<\/td>\n95<\/td>\n5<\/td>\n<\/tr>\n
1.5 – 14.4<\/td>\n95 \u2192 90<\/td>\n5 \u2192 10<\/td>\n<\/tr>\n
14.4 – 28.8<\/td>\n90<\/td>\n10<\/td>\n<\/tr>\n
28.8 – 57.6<\/td>\n90 \u2192 66<\/td>\n10 \u2192 34<\/td>\n<\/tr>\n
57.6 – 60<\/td>\n66<\/td>\n34<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Flow rate: 1.5 mL\/min.<\/p>\n

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

Autosampler: Set at 5 \u00b0C.<\/p>\n

Injection: 50 \u03bcL of the test solution and reference solutions (a), (b), (d) and (e).<\/p>\n

Identification of impurities: Use the chromatogram obtained with reference solution (b) to identify the peak due to impurity J; use the chromatogram obtained with reference solution (d) to identify the peak due to impurity K.<\/p>\n

Relative retention: With reference to paracetamol (retention time = about 4 min): impurity K = about 0.4; impurity J = about 10.1.<\/p>\n

System suitability: Reference solution (e):<\/p>\n

\u2014 resolution: minimum 5.0 between the peaks due to impurity K and paracetamol.<\/p>\n

Calculation of contents:<\/p>\n

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

\u2014 for impurity K, use the concentration of impurity K in reference solution (d);<\/p>\n

\u2014 for impurities other than J and K, use the concentration of paracetamol in reference solution (a).<\/p>\n

Limits:<\/p>\n

\u2014 impurity K: maximum 50 ppm;<\/p>\n

\u2014 impurity J: maximum 10 ppm;<\/p>\n

\u2014 unspecified impurities: for each impurity, maximum 0.05 per cent;<\/p>\n

\u2014 total: maximum 0.2 per cent;<\/p>\n

\u2014 reporting threshold: 0.03 per cent, except for impurities J and K.<\/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.<\/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 0.300 g in a mixture of 10 mL of water R and 30 mL of dilute sulfuric acid R. Boil under a reflux condenser for 1 h, cool and dilute to 100.0 mL with water R. To 20.0 mL of the solution add 40 mL of water R, 40 g of ice, 15 mL of dilute hydrochloric acid R and 0.1 mL of ferroin R. Titrate with 0.1 M cerium sulfate until a greenish-yellow colour is obtained.<\/p>\n

Carry out a blank titration. 1 mL of 0.1 M cerium sulfate is equivalent to 7.56 mg of C8<\/sub>H9<\/sub>NO2<\/sub>.<\/p>\n

STORAGE<\/h2>\n

Protected from light.<\/p>\n

IMPURITIES<\/h2>\n

Specified impurities J, K.<\/p>\n

Other detectable impurities (the following substances would, if present at a sufficient level, be detected by one or other of the tests in the monograph. They are limited by the general acceptance criterion for other\/unspecified impurities and\/or by the general monograph Substances for pharmaceutical use (2034). It is therefore not necessary to identify these impurities for demonstration of compliance. See also 5.10. Control of impurities in substances for pharmaceutical use) A, B, C, D, E, F, G, H, I, L, M, N, O.<\/p>\n

\"Paracetamol\"<\/p>\n

A. N-(2-hydroxyphenyl)acetamide,<\/p>\n

\"Paracetamol\"<\/p>\n

B. N-(4-hydroxyphenyl)propanamide,<\/p>\n

\"Paracetamol\"<\/p>\n

C. N-(3-chloro-4-hydroxyphenyl)acetamide,<\/p>\n

\"Paracetamol\"<\/p>\n

D. N-phenylacetamide,<\/p>\n

\"Paracetamol\"<\/p>\n

E. 1-(4-hydroxyphenyl)ethan-1-one,<\/p>\n

\"Paracetamol\"<\/p>\n

F. 4-nitrophenol,<\/p>\n

\"Paracetamol\"<\/p>\n

G. [1-(4-hydroxyphenyl)ethylidene]hydroxylamine,<\/p>\n

\"Paracetamol\"<\/p>\n

H. 4-acetamidophenyl acetate,<\/p>\n

\"Paracetamol\"<\/p>\n

I. 1-(2-hydroxyphenyl)ethan-1-one,<\/p>\n

\"Paracetamol\"<\/p>\n

J. N-(4-chlorophenyl)acetamide (chloroacetanilide),<\/p>\n

\"Paracetamol\"<\/p>\n

K. 4-aminophenol,<\/p>\n

\"Paracetamol\"<\/p>\n

L. N-[4-(4-acetamido-2-hydroxyphenoxy)phenyl]acetamide,<\/p>\n

\"Paracetamol\"<\/p>\n

M. 4,4\u2032-azanediyldiphenol,<\/p>\n

\"Paracetamol\"<\/p>\n

N. N,N\u2032-[oxydi(4,1-phenylene)]diacetamide,<\/p>\n

\"Paracetamol\"<\/p>\n

O. N-[4-(5-acetamido-2-hydroxyphenoxy)phenyl]acetamide.<\/p>\n","protected":false},"excerpt":{"rendered":"

(Ph. Eur. monograph 0049) C8H9NO2\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 151.2\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0103-90-2 Action and use Analgesic; antipyretic. Preparations Co-codamol Tablets Co-codamol Capsules Co-codamol Effervescent Tablets Paracetamol Effervescent Tablets Co-dydramol Tablets Co-proxamol Tablets Paracetamol Capsules Paracetamol Infusion Paediatric Paracetamol Oral Solution Paediatric Paracetamol Oral Suspension Paracetamol Oral Solution Paracetamol Oral Suspension…<\/p>\n","protected":false},"author":2,"featured_media":26976,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-26938","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\/26938","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=26938"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/26938\/revisions"}],"predecessor-version":[{"id":26978,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/26938\/revisions\/26978"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/26976"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=26938"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=26938"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=26938"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}