{"id":31895,"date":"2025-11-14T16:42:19","date_gmt":"2025-11-14T09:42:19","guid":{"rendered":"https:\/\/nhathuocngocanh.com\/bp\/?p=31895"},"modified":"2025-11-14T16:42:19","modified_gmt":"2025-11-14T09:42:19","slug":"zinc-oxide","status":"publish","type":"post","link":"https:\/\/nhathuocngocanh.com\/bp\/zinc-oxide\/","title":{"rendered":"Zinc Oxide"},"content":{"rendered":"

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

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

Mild astringent.<\/p>\n

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

Zinc Cream<\/p>\n

Coal Tar and Zinc Ointment<\/p>\n

Zinc Ointment<\/p>\n

Zinc and Castor Oil Ointment Compound<\/p>\n

Zinc Paste<\/p>\n

Zinc and Salicylic Acid Paste<\/p>\n

Zinc and Coal Tar Paste<\/p>\n

DEFINITION<\/h2>\n
Content<\/p>\n
99.0 per cent to 100.5 per cent (ignited substance).<\/p>\n
CHARACTERS<\/h2>\n
Appearance<\/h3>\n
Soft, white or faintly yellowish-white, amorphous powder, free from gritty particles.<\/p>\n
Solubility<\/h3>\n
Practically insoluble in water and in ethanol (96 per cent). It dissolves in dilute mineral acids.<\/p>\n
IDENTIFICATION<\/h2>\n
A. It becomes yellow when strongly heated; the yellow colour disappears on cooling.<\/p>\n
B. Dissolve 0.1 g in 1.5 mL of dilute hydrochloric acid R and dilute to 5 mL with water R. The solution gives the reaction of zinc (2.3.1).<\/p>\n
TESTS<\/h2>\n
Alkalinity<\/h3>\n
Shake 1.0 g with 10 mL of boiling water R. Add 0.1 mL of phenolphthalein solution R and filter. If the filtrate is red, not more than 0.3 mL of 0.1 M hydrochloric acid is required to change the colour of the indicator.<\/p>\n
Carbonates and substances insoluble in acids<\/h3>\n
Dissolve 1.0 g in 15 mL of dilute hydrochloric acid R. It dissolves without effervescence and the solution is not more opalescent than reference suspension II (2.2.1) and is colourless (2.2.2, Method II).<\/p>\n
Elemental impurities<\/h3>\n
Any method that fulfils the requirements of general chapter 2.4.20. Determination of elemental impurities may be used.<\/p>\n\n\n\n\n
Element<\/strong><\/td>\n Maximum content (ppm)<\/strong><\/td>\n<\/tr>\n
Cadmium<\/p>\n
Lead<\/p>\n
Thallium<\/td>\n
5<\/p>\n
10<\/p>\n
5<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
Iron (2.4.9)<\/h3>\n
Maximum 200 ppm.<\/p>\n
Dissolve 50 mg in 1 mL of dilute hydrochloric acid R and dilute to 10 mL with water R. Use 0.5 mL of thioglycollic acid R in this test.<\/p>\n
Loss on ignition<\/h3>\n
Maximum 1.0 per cent, determined on 1.00 g by ignition to constant mass at 500 \u00b1 50 \u00b0C.<\/p>\n
ASSAY<\/h2>\n
Dissolve 0.150 g in 10 mL of dilute acetic acid R. Carry out the complexometric titration of zinc (2.5.11). 1 mL of 0.1 M sodium edetate is equivalent to 8.14 mg of ZnO.<\/p>\n","protected":false},"excerpt":{"rendered":"
Edition: BP 2025 (Ph. Eur. 11.6 update) Action and use Mild astringent. Preparations Zinc Cream Coal Tar and Zinc Ointment Zinc Ointment Zinc and Castor Oil Ointment Compound Zinc Paste Zinc and Salicylic Acid Paste Zinc and Coal Tar Paste DEFINITION Content 99.0 per cent to 100.5 per cent (ignited substance). CHARACTERS Appearance Soft, white…<\/p>\n","protected":false},"author":5,"featured_media":31896,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-31895","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\/31895","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=31895"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/31895\/revisions"}],"predecessor-version":[{"id":31900,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/31895\/revisions\/31900"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/31896"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=31895"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=31895"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=31895"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

CHARACTERS<\/h2>\n

Appearance<\/h3>\nSoft, white or faintly yellowish-white, amorphous powder, free from gritty particles.<\/p>\n

Solubility<\/h3>\nPractically insoluble in water and in ethanol (96 per cent). It dissolves in dilute mineral acids.<\/p>\n

IDENTIFICATION<\/h2>\nA. It becomes yellow when strongly heated; the yellow colour disappears on cooling.<\/p>\nB. Dissolve 0.1 g in 1.5 mL of dilute hydrochloric acid R and dilute to 5 mL with water R. The solution gives the reaction of zinc (2.3.1).<\/p>\n

TESTS<\/h2>\n

Alkalinity<\/h3>\nShake 1.0 g with 10 mL of boiling water R. Add 0.1 mL of phenolphthalein solution R and filter. If the filtrate is red, not more than 0.3 mL of 0.1 M hydrochloric acid is required to change the colour of the indicator.<\/p>\n

Carbonates and substances insoluble in acids<\/h3>\nDissolve 1.0 g in 15 mL of dilute hydrochloric acid R. It dissolves without effervescence and the solution is not more opalescent than reference suspension II (2.2.1) and is colourless (2.2.2, Method II).<\/p>\n

Iron (2.4.9)<\/h3>\nMaximum 200 ppm.<\/p>\nDissolve 50 mg in 1 mL of dilute hydrochloric acid R and dilute to 10 mL with water R. Use 0.5 mL of thioglycollic acid R in this test.<\/p>\n

Loss on ignition<\/h3>\nMaximum 1.0 per cent, determined on 1.00 g by ignition to constant mass at 500 \u00b1 50 \u00b0C.<\/p>\n

Appearance<\/h3>\n
Soft, white or faintly yellowish-white, amorphous powder, free from gritty particles.<\/p>\n

Solubility<\/h3>\n
Practically insoluble in water and in ethanol (96 per cent). It dissolves in dilute mineral acids.<\/p>\n

IDENTIFICATION<\/h2>\n
A. It becomes yellow when strongly heated; the yellow colour disappears on cooling.<\/p>\n
B. Dissolve 0.1 g in 1.5 mL of dilute hydrochloric acid R and dilute to 5 mL with water R. The solution gives the reaction of zinc (2.3.1).<\/p>\n

Alkalinity<\/h3>\n
Shake 1.0 g with 10 mL of boiling water R. Add 0.1 mL of phenolphthalein solution R and filter. If the filtrate is red, not more than 0.3 mL of 0.1 M hydrochloric acid is required to change the colour of the indicator.<\/p>\n

Carbonates and substances insoluble in acids<\/h3>\n
Dissolve 1.0 g in 15 mL of dilute hydrochloric acid R. It dissolves without effervescence and the solution is not more opalescent than reference suspension II (2.2.1) and is colourless (2.2.2, Method II).<\/p>\n

Iron (2.4.9)<\/h3>\n
Maximum 200 ppm.<\/p>\n
Dissolve 50 mg in 1 mL of dilute hydrochloric acid R and dilute to 10 mL with water R. Use 0.5 mL of thioglycollic acid R in this test.<\/p>\n

Loss on ignition<\/h3>\n
Maximum 1.0 per cent, determined on 1.00 g by ignition to constant mass at 500 \u00b1 50 \u00b0C.<\/p>\n