(Ph. Eur. monograph 1562)<\/p>\n
Action and use<\/strong><\/p>\n Excipient.<\/p>\n Amorphous silica (precipitated, gel or obtained by flame hydrolysis).<\/p>\n 94.0 per cent to 100.5 per cent of SiO2 (ignited substance).<\/p>\n White or almost white, light, fine, amorphous powder.<\/p>\n Practically insoluble in water and in mineral acids. It dissolves in hydrofluoric acid and hot solutions of alkali hydroxides.<\/p>\n About 20 mg gives the reaction of silicates (2.3.1).<\/p>\n To 2.5 g add 50 mL of hydrochloric acid R and mix. Heat on a water-bath for 30 min, stirring from time to time. Evaporate to dryness. Add to the residue a mixture of 8 mL of dilute hydrochloric acid R and 24 mL of water R. Heat to boiling and filter under reduced pressure through a sintered-glass filter (16) (2.1.2). Wash the residue on the filter with a hot mixture of 3 mL of dilute hydrochloric acid R and 9 mL of water R. Wash with small quantities of water R, combine the washings and the filtrate, and dilute to 50 mL with water R.<\/p>\n 3.2 to 8.9.<\/p>\n Suspend 5 g in a mixture of 5 mL of a 7.46 g\/L solution of potassium chloride R and 90 mL of carbon dioxide-free water R.<\/p>\n Liquid chromatography (2.2.29) as described in the test for sulfates.<\/p>\n Retention time: Chlorides = about 4 min.<\/p>\n Limit:<\/p>\n \u2014 chlorides: not more than the area of the corresponding peak in the chromatogram obtained with the reference solution (0.3 per cent).<\/p>\n Liquid chromatography (2.2.29).<\/p>\n Test solution: To 0.625 g of the substance to be examined add 30 mL of water R and boil for 2 h. Allow to cool and quantitatively transfer to a 50 mL graduated flask. Dilute to 50.0 mL with water R. Dilute 5.0 mL of the supernatant to 50.0 mL with water R and filter through a membrane filter (nominal pore size 0.45 \u03bcm).<\/p>\n Reference solution: Dissolve 0.50 g of anhydrous sodium sulfate R and 0.062 g of sodium chloride R in water R and dilute to 1000.0 mL with water R. Dilute 5.0 mL of the solution to 50.0 mL with water R.<\/p>\n Column:<\/p>\n \u2014 material: non-metallic;<\/p>\n \u2014 size: l = 0.25 m, \u00d8 = 4.6 mm;<\/p>\n \u2014 stationary phase: suitable anion-exchange resin (30-50 \u03bcm).<\/p>\n Mobile phase: Dissolve 0.508 g of sodium carbonate R and 0.05 g of sodium hydrogen carbonate R in Flow rate: 1.2 mL\/min.<\/p>\n Detection: Conductivity detector.<\/p>\n Injection: 25 \u03bcL.<\/p>\n Retention time: Sulfates = about 8 min.<\/p>\n Limit:<\/p>\n \u2014 sulfates: not more than the area of the corresponding peak in the chromatogram obtained with the Maximum 400 ppm.<\/p>\n Dilute 2 mL of solution S to 40 mL with water R.<\/p>\n Loss on ignition<\/p>\n Maximum 25.0 per cent, determined on 0.200 g by heating in a platinum crucible at 100-105 \u00b0C for 1 h and To the residue obtained in the test for loss on ignition add 0.2 mL of sulfuric acid R and a quantity of ethanol (96 per cent) R sufficient to moisten the residue completely. Add 6 mL of hydrofluoric acid R and evaporate to dryness at 95-105 \u00b0C, taking care to avoid loss from sputtering. Wash the inside of the crucible with 6 mL of hydrofluoric acid R and evaporate to dryness again. Ignite at 900 \u00b1 50 \u00b0C, allow to cool in a desiccator and weigh. The difference between the mass of the final residue and that of the mass obtained in the test for loss on ignition corresponds to the mass of SiO2 in the test sample.<\/p>\n This section provides information on characteristics that are recognised as being relevant control Determine the specific surface area in the P\/P0<\/sub> range of 0.05 to 0.30.<\/p>\n Sample outgasing 60 min at 160 \u00b0C.<\/p>\n","protected":false},"excerpt":{"rendered":" (Ph. Eur. monograph 1562) Action and use Excipient. DEFINITION Amorphous silica (precipitated, gel or obtained by flame hydrolysis). Content 94.0 per cent to 100.5 per cent of SiO2 (ignited substance). CHARACTERS Appearance White or almost white, light, fine, amorphous powder. Solubility Practically insoluble in water and in mineral acids. It dissolves in hydrofluoric acid and…<\/p>\n","protected":false},"author":2,"featured_media":10060,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-10043","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\/10043","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=10043"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/10043\/revisions"}],"predecessor-version":[{"id":10065,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/10043\/revisions\/10065"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/10060"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=10043"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=10043"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=10043"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}DEFINITION<\/h2>\n
Content<\/h3>\n
CHARACTERS<\/h2>\n
Appearance<\/h3>\n
Solubility<\/h3>\n
IDENTIFICATION<\/h2>\n
TESTS<\/h2>\n
Solution S<\/h3>\n
pH (2.2.3)<\/h4>\n
Chlorides<\/h3>\n
Sulfates<\/h3>\n
\nwater R and dilute to 1000 mL with the same solvent.<\/p>\n
\nreference solution (4.0 per cent, expressed as sodium sulfate).<\/p>\nIron (2.4.9)<\/h3>\n
\nthen at 1000 \u00b1 50 \u00b0C for 2 h.<\/p>\nASSAY<\/h2>\n
FUNCTIONALITY-RELATED CHARACTERISTICS<\/h2>\n
\nparameters for one or more functions of the substance when used as an excipient (see chapter 5.15). Some of the characteristics described in the Functionality-related characteristics section may also be present in the mandatory part of the monograph since they also represent mandatory quality criteria. In such cases, a cross-reference to the tests described in the mandatory part is included in the Functionality-related characteristics section. Control of the characteristics can contribute to the quality of a medicinal product by improving the consistency of the manufacturing process and the performance of the medicinal product during use. Where control methods are cited, they are recognised as being suitable for the purpose, but other methods can also be used. Wherever results for a particular characteristic are reported, the control method must be indicated. The following characteristic may be relevant for dental type silica used as abrasive.<\/p>\nSpecific surface area (2.9.26, Method I)<\/h3>\n