DEFINITION<\/h2>\n
Mixture of (S)-2-hydroxypropanoic acid, its condensation products, such as lactoyl-lactic acid and polylactic acids, and water. The equilibrium between lactic acid and polylactic acids depends on the concentration and temperature.<\/p>\n
Content<\/h3>\n
88.0 per cent m\/m to 92.0 per cent m\/m of C3H6O3, not less than 95.0 per cent of which is the (S)- enantiomer.<\/p>\n
CHARACTERS<\/h2>\nAppearance<\/h3>\n
Colourless or slightly yellow, syrupy liquid.<\/p>\n
Solubility<\/h3>\n
Miscible with water and with ethanol (96 per cent).<\/p>\n
IDENTIFICATION<\/h2>\n
A. Dissolve 1 g in 10 mL of water R. The solution is strongly acidic (2.2.4).<\/p>\n
B. Relative density (2.2.5): 1.20 to 1.21.<\/p>\n
C. It gives the reaction of lactates (2.3.1).<\/p>\n
D. It complies with the limits of the assay.<\/p>\n
TESTS<\/h2>\nSolution S<\/h3>\n
Dissolve 5.0 g in 42 mL of 1 M sodium hydroxide and dilute to 50 mL with distilled water R.<\/p>\n
Appearance<\/h3>\n
The substance to be examined is not more intensely coloured than reference solution Y6 (2.2.2, Method II).<\/p>\n
Ether-insoluble substances<\/h3>\n
Dissolve 1.0 g in 25 mL of ether R. The solution is not more opalescent than the solvent used for the test.<\/p>\n
Sugars and other reducing substances<\/h3>\n
To 1 mL of solution S add 1 mL of 1 M hydrochloric acid, heat to boiling, allow to cool and add 1.5 mL of 1 M sodium hydroxide and 2 mL of cupri-tartaric solution R. Heat to boiling. No red or greenish precipitate is formed.<\/p>\n
Methanol (2.4.24)<\/h3>\n
Maximum 50 ppm, if intended for use in the manufacture of parenteral preparations.<\/p>\n
Citric, oxalic and phosphoric acids<\/h3>\n
To 5 mL of solution S add dilute ammonia R1 until slightly alkaline (2.2.4). Add 1 mL of calcium chloride solution R. Heat on a water-bath for 5 min. Both before and after heating, any opalescence in the solution is not more intense than that in a mixture of 1 mL of water R and 5 mL of solution S.<\/p>\n
Sulfates (2.4.13)<\/h3>\n
Maximum 200 ppm.<\/p>\n
Dilute 7.5 mL of solution S to 15 mL with distilled water R.<\/p>\n
Calcium (2.4.3)<\/h3>\n
Maximum 200 ppm.<\/p>\n
Dilute 5 mL of solution S to 15 mL with distilled water R.<\/p>\n
Sulfated ash (2.4.14)<\/h4>\n
Maximum 0.1 per cent, determined on 1.0 g.<\/p>\n
Bacterial endotoxins (2.6.14)<\/h4>\n
Less than 5 IU\/g if intended for use in the manufacture of parenteral preparations without a further appropriate procedure for the removal of bacterial endotoxins. Before use, neutralise the test solution to pH 7.0-7.5 with strong sodium hydroxide solution R and shake vigorously.<\/p>\n
ASSAY<\/h2>\n
Place 1.000 g in a ground-glass-stoppered flask and add 10 mL of water R and 20.0 mL of 1 M sodium hydroxide. Close the flask and allow to stand for 30 min. Using 0.5 mL of phenolphthalein solution R as indicator, titrate with 1 M hydrochloric acid until the pink colour is discharged.<\/p>\n
1 mL of 1 M sodium hydroxide is equivalent to 90.1 mg of C3<\/sub>H6<\/sub>O3<\/sub>.<\/p>\n (S)-enantiomer<\/p>\n Transfer an amount of the substance to be examined equivalent to 2.00 g of lactic acid into a round-bottomed flask, add 25 mL of 1 M sodium hydroxide and boil gently for 15 min. Cool down and adjust to pH 7.0 using 1 M hydrochloric acid. Add 5.0 g of ammonium molybdate R, dissolve and dilute to 50.0 mL with water R. Filter and measure the angle of optical rotation (2.2.7). Calculate the percentage content of (S)-enantiomer using the expression:<\/p>\n \u03b1 = angle of optical rotation (absolute value),<\/p>\n m = mass of the substance to be examined, in grams,<\/p>\n c = percentage content of C3<\/sub>H6<\/sub>O3 <\/sub>in the substance to be examined.<\/p>\n The complex of (S)-lactic acid formed under these test conditions is laevorotatory.<\/p>\n The label states, where applicable, that the substance is suitable for use in the manufacture of parenteral preparations.<\/p>\n","protected":false},"excerpt":{"rendered":" (Ph. Eur. monograph 1771) C3H6O3 90.1 DEFINITION Mixture of (S)-2-hydroxypropanoic acid, its condensation products, such as lactoyl-lactic acid and polylactic acids, and water. The equilibrium between lactic acid and polylactic acids depends on the concentration and temperature. Content 88.0 per cent m\/m to 92.0 per cent m\/m of C3H6O3, not less than 95.0 per cent…<\/p>\n","protected":false},"author":1,"featured_media":6725,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-920","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\/920","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\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/comments?post=920"}],"version-history":[{"count":4,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/920\/revisions"}],"predecessor-version":[{"id":6727,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/920\/revisions\/6727"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/6725"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=920"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=920"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=920"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"(S)-Lactic](\"https:\/\/nhathuocngocanh.com\/bp\/wp-content\/uploads\/2025\/09\/S-Lactic-Acid-4-300x163.jpg\")
<\/p>\nLABELLING<\/h2>\n