Neostigmine Methylsulfate Injection
» Neostigmine Methylsulfate Injection is a sterile solution of Neostigmine Methylsulfate in Water for Injection. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of C13H22N2O6S.
Packaging and storage— Preserve in single-dose or in multiple-dose containers, protected from light.
Identification— Transfer a volume of Injection, containing the equivalent of 1 mg of neostigmine methylsulfate, to a small porcelain dish. Evaporate, if necessary, to 2 mL, add 0.5 mL of sodium hydroxide solution (2 in 5), and proceed as directed in Identification test B under Neostigmine Methylsulfate, beginning with “evaporate on a steam bath.”
pH 791: between 5.0 and 6.5.
Other requirements— It meets the requirements under Injections 1.
Standard preparation— Dissolve a suitable quantity of USP Neostigmine Methylsulfate RS, accurately weighed, in water, and dilute quantitatively and stepwise with water to obtain a solution having a known concentration of about 40 µg per mL.
Assay preparation— Pipet an accurately measured volume of Injection, equivalent to about 2 mg of neostigmine methylsulfate, into a 50-mL volumetric flask, add water to volume, and mix.
Procedure— Proceed as directed for Procedure in the Assay under Neostigmine Bromide Tablets. Calculate the quantity, in mg, of C13H22N2O6S in each mL of the Injection taken by the formula:
0.05(C / V)(AU / AS)
in which C is the concentration, in µg per mL, of USP Neostigmine Methylsulfate RS in the Standard preparation, V is the volume, in mL, of Injection taken, and AU and AS are the absorbances of the solutions from 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 Ravi Ravichandran, Ph.D.
Senior Scientist
(MDPP05) Monograph Development-Psychiatrics and Psychoactives
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 3071