Cysteine Hydrochloride Injection
» Cysteine Hydrochloride Injection is a sterile solution of Cysteine Hydrochloride in Water for Injection. It contains not less than 85.0 percent and not more than 115.0 percent of the labeled amount of C3H7NO2S·HCl·H2O.
Packaging and storage— Preserve in single-dose or multiple-dose containers, preferably of Type I glass.
USP Reference standards 11
USP l-Cysteine Hydrochloride RS
USP Endotoxin RS
A: To 2 mL of Injection add 3 mL of water, and mix. Add 10 mL of cupric sulfate TS: a bluish-gray precipitate is formed.
B: To 2 mL of Injection add 3 mL of water, and mix. Add 2 mL of 3 N sodium hydroxide and 2 drops of sodium nitroferricyanide solution (1 in 20): a red-purple color is produced, and it rapidly changes to yellow.
Bacterial endotoxins 85 It contains not more than 0.7 USP Endotoxin Unit per mg of cysteine hydrochloride.
pH 791: between 1.0 and 2.5.
Other requirements— It meets the requirements under Injections 1.
Standard stock preparation— Dissolve an accurately weighed quantity of USP l-Cysteine Hydrochloride RS in nitrogen-saturated water to obtain a solution having a known concentration of about 1 mg per mL.
Standard preparation— Transfer 20.0 mL of Standard stock preparation to a 200-mL volumetric flask, dilute with nitrogen-saturated 1.0 N sodium hydroxide to volume, and mix.
Assay preparation— Dilute an accurately measured volume of Injection, equivalent to about 250 mg of cysteine hydrochloride, quantitatively and stepwise with nitrogen-saturated 1.0 N sodium hydroxide, to obtain a solution having a concentration of about 0.1 mg per mL.
Procedure— Transfer a suitable amount of Standard preparation to a polarographic cell. With mercury dropping from the electrode, lower the dropping mercury electrode of a polarograph so that the end is submerged in the liquid. Bubble oxygen-free, water-saturated nitrogen through the liquid for 15 minutes. Record the polarogram from 0.2 volt to 1.10 volts, using a saturated calomel electrode as the reference electrode. In a similar manner, record the polarograms obtained using portions of the Assay preparation and of the nitrogen-saturated 1.0 N sodium hydroxide. Determine the height of the diffusion current wave at 0.4 volt. Calculate the quantity, in mg, of C3H7NO2S·HCl·H2O in each mL of the Injection taken by the formula:
2500(C / V)[(id)U / (id)S]
in which C is the concentration, in mg per mL, of USP l-Cysteine Hydrochloride RS. In the Standard preparation, V is the volume, in mL, of Injection taken; and (id)U and (id)S are the observed diffusion currents, corrected for the diffusion current of the 0.1 N sodium hydroxide, of the Assay preparation and the Standard preparation, respectively.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Natalia Davydova
Scientific Liaison
(DS2010) Monographs - Dietary Supplements
Reference Standards RS Technical Services
85 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
(GCM2010) General Chapters - Microbiology
USP35–NF30 Page 2799