{"id":12020,"date":"2025-10-10T15:10:51","date_gmt":"2025-10-10T08:10:51","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=12020"},"modified":"2025-11-15T15:21:32","modified_gmt":"2025-11-15T08:21:32","slug":"emulsifying-cetostearyl-alcohol-type-b","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/emulsifying-cetostearyl-alcohol-type-b\/","title":{"rendered":"Emulsifying Cetostearyl Alcohol (Type B)"},"content":{"rendered":"

(Ph. Eur. monograph 0802)<\/p>\n

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

Excipient.<\/p>\n

DEFINITION<\/h2>\n

Mixture of cetostearyl alcohol and sodium laurilsulfate. A suitable buffer may be added.<\/p>\n

Content<\/h3>\n

\u2014 cetostearyl alcohol: minimum 80.0 per cent (anhydrous substance);<\/p>\n

\u2014 sodium laurilsulfate: minimum 7.0 per cent (anhydrous substance).<\/p>\n

CHARACTERS<\/h2>\n

Appearance<\/h3>\n

White or pale yellow, waxy mass, plates, flakes or granules.<\/p>\n

Solubility<\/h3>\n

Soluble in hot water giving an opalescent solution, practically insoluble in cold water, slightly soluble in ethanol (96 per cent).<\/p>\n

IDENTIFICATION<\/h2>\n

First identification: B, C, D.<\/p>\n

Second identification: A, C, D.<\/p>\n

A. Thin-layer chromatography (2.2.27).<\/p>\n

Test solution (a): Dissolve 0.1 g of the substance to be examined in 10 mL of trimethylpentane R, heating on a water-bath. Shake with 2 mL of ethanol (70 per cent V\/V) R and allow to separate. Use the lower layer as test solution (b). Dilute 1 mL of the upper layer to 8 mL with trimethylpentane R.<\/p>\n

Test solution (b): Use the lower layer obtained in the preparation of test solution (a).<\/p>\n

Reference solution (a): Dissolve 24 mg of cetyl alcohol CRS and 16 mg of stearyl alcohol CRS in 10 mL of
\ntrimethylpentane R.<\/p>\n

Reference solution (b): Dissolve 20 mg of sodium laurilsulfate CRS in 10 mL of ethanol (70 per cent V\/V) R, heating on a water-bath.<\/p>\n

Plate: TLC octadecylsilyl silica gel F254 plate R.<\/p>\n

Mobile phase: water R, acetone R, methanol R (20:40:40 V\/V\/V).<\/p>\n

Application: 10 \u03bcL.<\/p>\n

Development: Over 2\/3 of the plate.<\/p>\n

Drying: In air.<\/p>\n

Detection: Spray with a 50 g\/L solution of phosphomolybdic acid R in ethanol (96 per cent) R; heat at 120 \u00b0C until spots appear (about 5 min).<\/p>\n

Results:<\/p>\n

\u2014 the 2 principal spots in the chromatogram obtained with test solution (a) are similar in position and colour to the
\nprincipal spots in the chromatogram obtained with reference solution (a);<\/p>\n

\u2014 1 of the spots in the chromatogram obtained with test solution (b) is similar in position and colour to the principal spot in the chromatogram obtained with reference solution (b).<\/p>\n

B. Examine the chromatograms obtained in the assay of cetostearyl alcohol.<\/p>\n

Results: The 2 principal peaks in the chromatogram obtained with the test solution are similar in retention time to the 2 principal peaks in the chromatograms obtained with reference solutions (a) and (b).<\/p>\n

C. It gives a yellow colour to a non-luminous flame.<\/p>\n

D. To 0.3 g add 20 mL of anhydrous ethanol R and heat to boiling on a water-bath with shaking. Filter the mixture immediately, evaporate to dryness and take up the residue in 7 mL of water R. To 1 mL of the solution add 0.1 mL of a 1 g\/L solution of methylene blue R, 2 mL of dilute sulfuric acid R and 2 mL of methylene chloride R and shake. A blue colour develops in the lower layer.<\/p>\n

TESTS<\/h2>\n

Acid value (2.5.1)<\/h3>\n

Maximum 2.0.<\/p>\n

Iodine value (2.5.4, Method A)<\/h3>\n

Maximum 3.0.<\/p>\n

Dissolve 2.00 g in 25 mL of methylene chloride R.<\/p>\n

Saponification value (2.5.6)<\/h3>\n

Maximum 2.0.<\/p>\n

Water (2.5.12)<\/h3>\n

Maximum 3.0 per cent, determined on 2.50 g.<\/p>\n

ASSAY<\/h2>\n

Cetostearyl alcohol<\/h3>\n

Gas chromatography (2.2.28).<\/p>\n

Internal standard solution: Dissolve 0.200 g of 1-nonadecanol CRS in anhydrous ethanol R and dilute to 100.0 mL with the same solvent.<\/p>\n

Test solution: Dissolve 0.200 g of the substance to be examined in 25.0 mL of the internal standard solution. Add 25 mL of water R and shake with 4 quantities, each of 25 mL, of pentane R, adding sodium chloride R, if necessary, to facilitate the separation of the layers. Combine the upper layers, wash with 2 quantities, each of 30 mL, of water R, dry over anhydrous sodium sulfate R and filter.<\/p>\n

Reference solution (a): Dissolve 0.100 g of cetyl alcohol CRS in 25.0 mL of the internal standard solution. Add 25 mL of water R and shake with 4 quantities, each of 25 mL, of pentane R, adding sodium chloride R, if necessary, to facilitate the separation of the layers. Combine the upper layers, wash with 2 quantities, each of 30 mL, of water R, dry over anhydrous sodium sulfate R and filter.<\/p>\n

Reference solution (b): Dissolve 0.100 g of stearyl alcohol CRS in 25.0 mL of the internal standard solution. Add 25 mL of water R and shake with 4 quantities, each of 25 mL, of pentane R, adding sodium chloride R, if necessary, to facilitate the separation of the layers. Combine the upper layers, wash with 2 quantities, each of 30 mL, of water R, dry over anhydrous sodium sulfate R and filter.<\/p>\n

Column:<\/p>\n

\u2014 material: fused silica;<\/p>\n

\u2014 size: l = 25 m, \u00d8 = 0.25 mm;<\/p>\n

\u2014 stationary phase: methylpolysiloxane R (film thickness 0.25 \u03bcm).<\/p>\n

Carrier gas: helium for chromatography R.<\/p>\n

Flow rate: 1 mL\/min.<\/p>\n

Split ratio: 1:100.<\/p>\n

Temperature:<\/p>\n\n\n\n\n\n\n
<\/td>\nTime<\/strong>
\n(min)<\/strong><\/td>\n		Temperature<\/strong>
\n(\u00b0C)<\/strong><\/td>\n<\/tr>\n
Column<\/td>\n0 – 20<\/td>\n150 \u2192 250<\/td>\n<\/tr>\n
Injection port<\/td>\n<\/td>\n250<\/td>\n<\/tr>\n
Detector<\/td>\n<\/td>\n250<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Detection: Flame ionisation.<\/p>\n

Injection: 1 \u03bcL.<\/p>\n

Elution order: Cetyl alcohol, stearyl alcohol, 1-nonadecanol.<\/p>\n

Calculate the percentage content of cetyl alcohol in the substance to be examined using the following expression and taking into account the assigned content of cetyl alcohol CRS:<\/p>\n

\"Emulsifying<\/p>\n

Ax<\/sub> = area of the peak due to cetyl alcohol in the chromatogram obtained with the test solution;<\/p>\n

Ax,y<\/sub> = area of the peak due to cetyl alcohol CRS in the chromatogram obtained with reference solution (a);<\/p>\n

A1<\/sub> = area of the peak due to the internal standard in the chromatogram obtained with the test solution;<\/p>\n

A2<\/sub> = area of the peak due to the internal standard in the chromatogram obtained with reference solution (a);<\/p>\n

m = mass of the substance to be examined in the test solution, in milligrams;<\/p>\n

mx,y<\/sub> = mass of cetyl alcohol CRS in reference solution (a), in milligrams.<\/p>\n

Calculate the percentage content of stearyl alcohol in the substance to be examined using the following expression and taking into account the assigned content of stearyl alcohol CRS:<\/p>\n

\"Emulsifying<\/p>\n

Az<\/sub> = area of the peak due to stearyl alcohol in the chromatogram obtained with the test solution;<\/p>\n

Az,y<\/sub> = area of the peak due to stearyl alcohol CRS in the chromatogram obtained with reference solution (b);<\/p>\n

A1<\/sub> = area of the peak due to the internal standard in the chromatogram obtained with the test solution;<\/p>\n

A3<\/sub> = area of the peak due to the internal standard in the chromatogram obtained with reference solution (b);<\/p>\n

m = mass of the substance to be examined in the test solution, in milligrams;<\/p>\n

mz,y<\/sub> = mass of stearyl alcohol CRS in reference solution (b), in milligrams.<\/p>\n

The percentage content of cetostearyl alcohol corresponds to the sum of the percentage contents of cetyl alcohol and stearyl alcohol.<\/p>\n

Sodium laurilsulfate<\/h3>\n

Disperse 0.300 g in 25 mL of methylene chloride R. Add 50 mL of water R and 10 mL of dimidium bromide-sulfan blue mixed solution R. Titrate with 0.004 M benzethonium chloride, using sonication, heating, and allowing the layers to separate before each addition, until the colour of the lower layer changes from pink to grey.<\/p>\n

1 mL of 0.004 M benzethonium chloride is equivalent to 1.154 mg of sodium laurilsulfate.<\/p>\n

LABELLING<\/h2>\n

The label states, where applicable, the name and concentration of any added buffer.<\/p>\n","protected":false},"excerpt":{"rendered":"

(Ph. Eur. monograph 0802) Action and use Excipient. DEFINITION Mixture of cetostearyl alcohol and sodium laurilsulfate. A suitable buffer may be added. Content \u2014 cetostearyl alcohol: minimum 80.0 per cent (anhydrous substance); \u2014 sodium laurilsulfate: minimum 7.0 per cent (anhydrous substance). CHARACTERS Appearance White or pale yellow, waxy mass, plates, flakes or granules. Solubility Soluble…<\/p>\n","protected":false},"author":2,"featured_media":12035,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-12020","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\/12020","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=12020"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/12020\/revisions"}],"predecessor-version":[{"id":12049,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/12020\/revisions\/12049"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/12035"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=12020"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=12020"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=12020"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}