{"id":31901,"date":"2025-11-14T16:45:38","date_gmt":"2025-11-14T09:45:38","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=31901"},"modified":"2025-11-14T16:45:38","modified_gmt":"2025-11-14T09:45:38","slug":"zinc-stearate","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/zinc-stearate\/","title":{"rendered":"Zinc Stearate"},"content":{"rendered":"

Edition: BP 2025 (Ph. Eur. 11.6 update)<\/p>\n

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

Excipient.<\/p>\n

DEFINITION<\/h2>\n

Zinc stearate [(C17<\/sub>H35<\/sub>COO)2<\/sub>Zn; Mr 632] may contain varying proportions of zinc palmitate [(C15<\/sub>H31<\/sub>COO)2<\/sub>Zn; Mr 576.2] and zinc oleate [(C17<\/sub>H33<\/sub>COO)2<\/sub>Zn; Mr 628].<\/p>\n

Content<\/strong><\/p>\n

10.0 per cent to 12.0 per cent of Zn.<\/p>\n

CHARACTERS<\/h2>\n

Appearance<\/h3>\n

Light, white or almost white, amorphous powder, free from gritty particles.<\/p>\n

Solubility<\/h3>\n

Practically insoluble in water and in anhydrous ethanol.<\/p>\n

IDENTIFICATION<\/h2>\n

A. Freezing point (2.2.18): minimum 53 \u00b0C, determined on the residue obtained in the preparation of solution S (see Tests).<\/p>\n

B. Neutralise 5 mL of solution S to red litmus paper R with strong sodium hydroxide solution R. The solution gives the reaction of zinc (2.3.1).<\/p>\n

TESTS<\/h2>\n

Solution S<\/h3>\n

To 5.0 g add 50 mL of ether R and 40 mL of a 7.5 per cent V\/V solution of nitric acid R in distilled water R. Heat under a reflux condenser until dissolution is complete. Allow to cool. In a separating funnel, separate the aqueous layer and shake the ether layer with 2 quantities, each of 4 mL, of distilled water R. Combine the aqueous layers, wash with 15 mL of ether R and heat on a water-bath until ether is completely eliminated. Allow to cool and dilute to 50.0 mL with distilled water R (solution S). Evaporate the ether layer to dryness and dry the residue at 105 \u00b0C.<\/p>\n

Appearance of solution<\/h3>\n

Solution S is not more intensely coloured than reference solution Y6 (2.2.2, Method II).<\/p>\n

Appearance of solution of fatty acids<\/h3>\n

Dissolve 0.5 g of the residue obtained in the preparation of solution S in 10 mL of chloroform R. The solution is clear (2.2.1) and not more intensely coloured than reference solution Y5 (2.2.2, Method II).<\/p>\n

Acidity or alkalinity<\/h3>\n

Shake 1.0 g with 5 mL of ethanol (96 per cent) R and add 20 mL of carbon dioxide-free water R and 0.1 mL of phenol red solution R. Not more than 0.3 mL of 0.1 M hydrochloric acid or 0.1 mL of 0.1 M sodium hydroxide is required to change the colour of the indicator.<\/p>\n

Acid value of the fatty acids (2.5.1)<\/h3>\n

195 to 210.<\/p>\n

Dissolve 0.20 g of the residue obtained in the preparation of solution S in 25 mL of the prescribed mixture of solvents.<\/p>\n

Chlorides (2.4.4)<\/h3>\n

Maximum 250 ppm.<\/p>\n

Dilute 2 mL of solution S to 15 mL with water R.<\/p>\n

Sulfates (2.4.13)<\/h3>\n

Maximum 0.6 per cent.<\/p>\n

Dilute 1 mL of solution S to 50 mL with distilled water R. Dilute 12.5 mL of this solution to 15 mL with distilled water R.<\/p>\n

ASSAY<\/h2>\n

To 1.000 g add 50 mL of dilute acetic acid R and boil for at least 10 min or until the layer of fatty acids is clear, adding more water R as necessary to maintain the original volume. Cool and filter. Wash the filter and the flask with water R until the washings are no longer acid to blue litmus paper R. Combine the filtrate and washings. Carry out the complexometric titration of zinc (2.5.11).<\/p>\n

1 mL of 0.1 M sodium edetate is equivalent to 6.54 mg of Zn.<\/p>\n","protected":false},"excerpt":{"rendered":"

Edition: BP 2025 (Ph. Eur. 11.6 update) Action and use Excipient. DEFINITION Zinc stearate [(C17H35COO)2Zn; Mr 632] may contain varying proportions of zinc palmitate [(C15H31COO)2Zn; Mr 576.2] and zinc oleate [(C17H33COO)2Zn; Mr 628]. Content 10.0 per cent to 12.0 per cent of Zn. CHARACTERS Appearance Light, white or almost white, amorphous powder, free from gritty…<\/p>\n","protected":false},"author":5,"featured_media":31902,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-31901","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\/31901","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=31901"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/31901\/revisions"}],"predecessor-version":[{"id":31916,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/31901\/revisions\/31916"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/31902"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=31901"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=31901"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=31901"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}