![\"Thiopental](\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/11\/Thiopental-Sodium-2.jpg\")
<\/p>\nBP 2025 (Ph. Eur. 11.6 update)<\/p>\n
<\/p>\n
C11<\/sub>H17<\/sub>N2<\/sub>NaO2<\/sub>S,xNa2<\/sub>CO3<\/sub> 264.3 (thiopental sodium)<\/p>\n Thiopental sodium 71-73-8<\/p>\n Action and use<\/strong><\/p>\n Intravenous barbiturate; general anaesthetic.<\/p>\n Preparation<\/strong><\/p>\n Thiopental Injection<\/p>\n Mixture of sodium 5-ethyl-4,6-dioxo-5-[(2RS)-pentan-2-yl]-1,4,5,6-tetrahydropyrimidine-2-thiolate and anhydrous sodium carbonate.<\/p>\n Content Appearance<\/strong><\/p>\n Yellowish-white, hygroscopic powder.<\/p>\n Solubility<\/strong><\/p>\n Freely soluble in water, partly soluble in anhydrous ethanol, practically insoluble in heptane.<\/p>\n First identification A, B, D.<\/p>\n Second identification A, C, D.<\/p>\n A. Melting point (2.2.14).<\/p>\n Determination A Acidify 10 mL of solution S (see Tests) with dilute hydrochloric acid R. An effervescence is produced. Shake with 20 mL of 1,1-dimethylethyl methyl ether R. Separate the upper layer, wash with 10 mL of water R, dry over anhydrous sodium sulfate R and filter. Evaporate the filtrate to dryness and dry the residue at 100-105 \u00b0C. Determine the melting point of the residue.<\/p>\n Result A About 160 \u00b0C.<\/p>\n Determination B Mix equal parts of the residue obtained in determination A and thiopental for ID and assay CRS and determine the melting point of the mixture. B. Infrared absorption spectrophotometry (2.2.24).<\/p>\n Preparation Use the residue obtained in Identification test A.<\/p>\n Comparison thiopental for ID and assay CRS.<\/p>\n C. Thin-layer chromatography (2.2.27).<\/p>\n Test solution Dissolve 0.1 g of the substance to be examined in water R and dilute to 100 mL with the same solvent. D. It gives reaction (a) of sodium (2.3.1).<\/p>\n Solution S<\/strong><\/p>\n Dissolve 5.0 g in carbon dioxide-free water R and dilute to 50 mL with the same solvent.<\/p>\n Appearance of solution<\/strong><\/p>\n Solution S is clear (2.2.1) and not more intensely coloured than reference solution GY3 (2.2.2, Method II).<\/p>\n pH (2.2.3)<\/strong><\/p>\n 10.6 to 11.2.<\/p>\n Dissolve 0.800 g in carbon dioxide-free water R and dilute to 10 mL with the same solvent.<\/p>\n Related substances<\/strong><\/p>\n Liquid chromatography (2.2.29). Prepare the solutions immediately before use. Column: Mobile phase acetonitrile for chromatography R, 1 g\/L solution of phosphoric acid R (35:65 V\/V). System suitability Reference solution (c): Limits: Chlorides (2.4.4)<\/strong><\/p>\n Maximum 330 ppm. Loss on drying (2.2.32)<\/strong><\/p>\n Maximum 2.5 per cent, determined on 0.500 g by drying in vacuo at 100 \u00b0C for 4 h.<\/p>\n Sodium<\/strong><\/p>\n Dissolve 0.400 g in 30 mL of water R. Add 0.1 mL of methyl red solution R and titrate with 0.1 M hydrochloric acid until a red colour is obtained. Boil gently for 2 min. Allow to cool and, if necessary, continue the titration with 0.1 M hydrochloric acid until the red colour is again obtained. Thiopental<\/strong><\/p>\n Liquid chromatography (2.2.29) as described in the test for related substances with the following modification. In an airtight container, protected from light.<\/p>\n Specified impurities B, D.<\/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, C.<\/p>\n BP 2025 (Ph. Eur. 11.6 update) C11H17N2NaO2S,xNa2CO3 264.3 (thiopental sodium) Thiopental sodium 71-73-8 Action and use Intravenous barbiturate; general anaesthetic. Preparation Thiopental Injection DEFINITION Mixture of sodium 5-ethyl-4,6-dioxo-5-[(2RS)-pentan-2-yl]-1,4,5,6-tetrahydropyrimidine-2-thiolate and anhydrous sodium carbonate. Content \u2014 thiopental: 84.0 per cent to 87.0 per cent (dried substance); \u2014 sodium: 10.2 per cent to 11.2 per cent (dried substance)….<\/p>\n","protected":false},"author":5,"featured_media":30453,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-30451","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\/30451","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=30451"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/30451\/revisions"}],"predecessor-version":[{"id":30474,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/30451\/revisions\/30474"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/30453"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=30451"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=30451"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=30451"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}DEFINITION<\/h2>\n
\n\u2014 thiopental: 84.0 per cent to 87.0 per cent (dried substance);
\n\u2014 sodium: 10.2 per cent to 11.2 per cent (dried substance).<\/p>\nCHARACTERS<\/h2>\n
IDENTIFICATION<\/h2>\n
\nResult 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
\nReference solution Dissolve 85 mg of thiopental for ID and assay CRS in 10 mL of dilute sodium hydroxide solution R and dilute to 100 mL with water R.
\nPlate TLC silica gel GF254 plate R.
\nMobile phase concentrated ammonia R, ethanol (96 per cent) R, methylene chloride R (5:15:80 V\/V\/V); use the lower layer.
\nApplication 10 \u03bcL.
\nDevelopment Over 3\/4 of the plate.
\nDetection Examine immediately in ultraviolet light at 254 nm.
\nResults 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>\nTESTS<\/h2>\n
\nTest solution Dissolve 20.0 mg of the substance to be examined in the mobile phase and dilute to 20.0 mL with the mobile phase.
\nReference solution (a) Dilute 1.0 mL of the test solution to 100.0 mL with the mobile phase. Dilute 1.0 mL of this solution to 10.0 mL with the mobile phase.
\nReference solution (b) Dissolve 17.0 mg of thiopental for ID and assay CRS in the mobile phase and dilute to 20.0 mL with the mobile phase.
\nReference solution (c) Dissolve the contents of a vial of thiopental impurity mixture CRS (impurities A, B, C and D) in 1 mL of the test solution.<\/p>\n
\n\u2014 size: l = 0.15 m, \u00d8 = 4.6 mm;
\n\u2014 stationary phase: base-deactivated end-capped octadecylsilyl silica gel for chromatography R (5 \u03bcm).<\/p>\n
\nFlow rate 1 mL\/min.
\nDetection Spectrophotometer at 225 nm.
\nInjection 10 \u03bcL of the test solution and reference solutions (a) and (c).
\nRun time Twice the retention time of thiopental.
\nIdentification of impurities Use the chromatogram supplied with thiopental impurity mixture CRS and the chromatogram obtained with reference solution (c) to identify the peaks due to impurities A, B, C and D.
\nRelative retention With reference to thiopental (retention time = about 19 min): impurity A = about 0.40; impurity B = about 0.45; impurity C = about 0.92; impurity D = about 1.34.<\/p>\n
\n\u2014 resolution: minimum 1.5 between the peaks due to impurities A and B; minimum 1.5 between the peaks due to impurity C and thiopental.
\nCalculation of percentage contents:
\n\u2014 correction factors: multiply the peak areas of the following impurities by the corresponding correction factor: impurity B = 1.6; impurity D = 1.9;
\n\u2014 for each impurity, use the concentration of thiopental sodium and sodium carbonate in reference solution (a).<\/p>\n
\n\u2014 impurity B: maximum 1.0 per cent;
\n\u2014 impurity D: maximum 0.5 per cent;
\n\u2014 unspecified impurities: maximum 0.10 per cent;
\n\u2014 total: maximum 2.0 per cent;
\n\u2014 reporting threshold: 0.05 per cent.<\/p>\n
\nTo 5 mL of solution S add 35 mL of water R and 10 mL of dilute nitric acid R. Shake with 3 quantities, each of 25 mL, of 1,1-dimethylethyl methyl ether R and discard the upper layer. Eliminate the organic solvent from the lower layer by heating on a water-bath. 15 mL of this solution complies with the test for chlorides.<\/p>\nASSAY<\/h2>\n
\n1 mL of 0.1 M hydrochloric acid is equivalent to 2.299 mg of Na.<\/p>\n
\nInjection Test solution and reference solution (b).
\nCalculate the percentage content of C11H18N2O2S taking into account the assigned content of thiopental for ID and assay CRS.<\/p>\nSTORAGE<\/h2>\n
IMPURITIES<\/h2>\n
![\"Thiopental](\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/11\/Thiopental-Sodium-3.jpg\")
\nA. 5-[(2RS)-pentan-2-yl]-2-sulfanylidene-1,3-diazinane-4,6-dione,<\/p>\n![\"Thiopental](\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/11\/Thiopental-Sodium-4.jpg\")
\nB. 5-ethyl-5-[(2RS)-pentan-2-yl]-1,3-diazinane-2,4,6-trione (pentobarbital),<\/p>\n![\"Thiopental](\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/11\/Thiopental-Sodium-5.jpg\")
\nC. 5-ethyl-5-(pentan-3-yl)-2-sulfanylidene-1,3-diazinane-4,6-dione,<\/p>\n![\"Thiopental](\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/11\/Thiopental-Sodium-6.jpg\")
\nD. mixture of the 4 stereoisomers of (2\u039e,3\u039e)-2-(carbamothioylcarbamoyl)-2-ethyl-3-methylhexanoic acid.<\/p>\n","protected":false},"excerpt":{"rendered":"