Cystine assists in the formation of skin and plays an important role in detoxification. By reducing the body's ability to absorb copper, Cystine protects cells from copper poisoning.When it is metabolized, it will release sulfuric acid, and sulfuric acid will have chemical interaction with other substances, increasing the detoxification function of the whole metabolic system.In addition, it assists in the supply of insulin, which is necessary for the human body to use sugar and starch.It can also promote the oxidation and reduction of cells, make the liver function vigorous, promote the proliferation of white blood cells, and prevent the development of pathogenic bacteria.
Chinese name
Cystine
Foreign name
Cystine[2]
chemical formula
CsixHtwelveNtwoOfourStwo
molecular weight
two hundred and forty point three zero
melting point
260 to 261 ℃
boiling point
468.2 ℃
density
1.571 g/cm³
appearance
White crystalline powder
atlas
Science popularization in China
Committed to authoritative science communication
The certification expert of this term is
Zhang Zheng|Pharmacist in charge
Pharmacy Department of Beijing Chaoyang Hospitalto examine
Qiu Kui|Deputy Chief Pharmacist
Pharmacy Department of Beijing Chaoyang Hospitalto examine
Adverse reactions were mild, nausea, vomiting, dry mouth, stomachache and dry stool were occasionally seen.The patient can tolerate it without affecting the continued treatment.
matters needing attention
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If the product has deliquescence and discoloration, it should not be used.Pregnant women and lactating women should use drugs with caution.Children and elderly patients should take appropriate medication.
(Note: The above contents are only for introduction. Drug use must be carried out by a regular hospital under the guidance of a doctor.)
Pharmacopoeia information
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source
This product is L-3,3 '- disulfide bis (2-aminopropionic acid), calculated as dry product, containing CsixHtwelveNtwoOfourStwoNot less than 98.5%.
character
This product is white crystal or crystalline powder.
This product is almost insoluble in water or ethanol, but dissolved in dilute hydrochloric acid or sodium hydroxide test solution.
Specific curl
Take this product, weigh it precisely, add 1mol/L hydrochloric acid solution to dissolve it and dilute it quantitatively to make a solution containing about 20mg per 1mL. Determine according to the law (general rule 0621), and the specific rotation is - 215 ° to - 230 °.
identify
1. Take appropriate amount of this product and cystine control sample, add 2% ammonia solution to dissolve and dilute them to prepare a solution containing about 10mg per 1mL as the test solution and control solution.According to the method under other amino acids, the position and color of the main spot of the test solution should be the same as that of the control solution.
2. The infrared absorption spectrum of this product should be consistent with the control spectrum (spectrum set 1036 figure).
inspect
acidity
Take 1.0g of this product, add 100mL of water, shake it fully, and measure according to the law (general rule 0631). The pH value should be 5.0~6.5.
Transmittance of solution
Take 1.0g of this product, add 20mL of 1mol/L hydrochloric acid solution to dissolve it, and then measure the transmittance at the wavelength of 430nm by ultraviolet visible spectrophotometry (general rule 0401), which shall not be less than 98.0%.
chloride
Take 0.50g of this product, add 10mL of dilute nitric acid to dissolve it, add water to make it 50mL, divide 25mL, and check according to the law (general rule 0801). Compared with the control solution made of 5.0mL of standard sodium chloride solution, it should not be more concentrated (0.02%).
sulfate
Take 0.70g of this product, add 5mL of dilute hydrochloric acid to shake it to dissolve it, add water to make it 40mL, check according to the law (general rule 0802), and it shall not be more concentrated (0.02%) than the control solution made by adding 5mL of dilute hydrochloric acid to 1.4mL of standard potassium sulfate solution.
Other amino acids
Test according to thin layer chromatography (general rule 0502).
Test solution: take a proper amount of this product, add 2% ammonia solution to dissolve and dilute it to make a solution containing about 10mg per 1mL.
Reference solution: precisely measure 1mL of the test solution, place it in a 200mL volumetric flask, dilute it to the scale with 2% ammonia solution, and shake it up.
System suitability solution: Take appropriate amount of cystine control sample and arginine hydrochloride control sample, place them in the same measuring bottle, add 2% ammonia solution to dissolve and dilute them to make a solution containing 10 mg cystine and 1 mg arginine hydrochloride in every 1 mL respectively.
Chromatographic conditions: Silica gel G thin layer plate is used, isopropanol concentrated ammonia solution (7:3) is used as developing agent.
Determination method: take 2 µ L of each of the three solutions above, dab them on the same thin layer plate, develop them, dry them, spray 0.2% ninhydrin n-butanol glacial acetic acid solution (95:5), heat them at 80 ° C until spots appear, and inspect them immediately.
System suitability requirements: the reference solution should show a clear spot, and the system suitability solution should show two completely separated spots.
Limit: if the test solution shows impurity spots, its color shall not be deeper (0.5%) than the main spot of the control solution, and shall not exceed 1.
Loss on drying
Take the product and dry it at 105 ° C for 3 hours, and the weight loss shall not exceed 0.2% (general rule 0831).
Ignition residue
Take 1.0g of this product and check it according to the law (general rule 0841). The residual residue shall not exceed 0.1%.
ferric salt
Take the residue left under the item of burning residue, add 1mL nitric acid, evaporate it on a water bath, add 4mL dilute hydrochloric acid, dissolve it at low temperature, transfer it to a 50mL Nessler's colorimetric tube, and check according to the law (general rule 0807). Compared with the reference solution made of 1.0mL standard iron solution, it should not be deeper (0.001%).
heavy metal
Take 1.0g of this product and check it according to the law (General Rule 0821, the second method). The content of heavy metals should not exceed 10% per million.
Arsenite
Take 2.0g of this product, add 23mL of water, then add 5mL of hydrochloric acid to dissolve it, and check according to the law (the first method of general rule 0822), which should meet the requirements (0.0001%).
Assay
Take about 80mg of this product, precisely weigh it, put it into an iodine bottle, add 2mL of sodium hydroxide test solution and 10mL of water to shake and dissolve it, add 10mL of potassium bromide solution (20 → 100), precisely add 50mL of potassium bromate titrant (0.01667mol/L) and 15mL of dilute hydrochloric acid, close it, place it in a dark place in an ice bath for 10 minutes, add 1.5g of potassium iodide, shake it well, and titrate it with sodium thiosulfate titrant (0.1mol/L) after 1 minute,At the end point, add 2mL of starch indicator, continue to titrate until the blue disappears, and correct the titration result with blank test.Every 1mL of potassium bromate titrant (0.01667mol/L) is equivalent to 2.403mg of CsixHtwelveNtwoOfourStwo。
