Pyridostigmine Bromide Oral Solution
» Pyridostigmine Bromide Oral Solution contains, in each 100 mL, not less than 1.08 g and not more than 1.32 g of pyridostigmine bromide (C9H13BrN2O2).
Packaging and storage Preserve in tight, light-resistant containers.
Identification To 5 mL of Oral Solution in a separator add 100 mL of 2.5 N hydrochloric acid, and mix. Extract with five 20-mL portions of chloroform, place 2 mL of the aqueous solution in a 50-mL volumetric flask, and add water to volume: the UV absorption spectrum of this solution exhibits maxima and minima at the same wavelengths as that of a similar solution of USP Pyridostigmine Bromide RS, concomitantly measured.
Phosphate solution Dissolve 38 g of monobasic sodium phosphate and 2 g of anhydrous dibasic sodium phosphate in water to make 1000 mL. Adjust the pH, if necessary, by slight variation of the ratio of the two ingredients, to 5.3 ± 0.1.
Bromocresol green solution Dissolve 250 mg of bromocresol green sodium salt in 250 mL of Phosphate solution.
Standard preparation Dissolve a suitable quantity of USP Pyridostigmine Bromide RS, accurately weighed, in water, to obtain a solution having a known concentration of about 1.2 mg per mL.
Assay preparation Transfer an accurately measured volume of Oral Solution, equivalent to about 120 mg of pyridostigmine bromide, to a 100-mL volumetric flask, add water to volume, and mix.
Procedure Transfer 10 mL each, accurately measured, of the Assay preparation and the Standard preparation to separate 125-mL separators. Into each separator pipet 10 mL of water, 20 mL of Phosphate solution, and 5 mL of Bromocresol green solution. Extract each solution with six 15-mL portions of chloroform, collecting the chloroform extracts in respective 100-mL volumetric flasks, then add chloroform to volume in each flask, and mix. Concomitantly determine the absorbances of both solutions in 1-cm cells at the wavelength of maximum absorbance at about 415 nm, with a suitable spectrophotometer, using chloroform as the blank. Calculate the quantity, in mg, of pyridostigmine bromide (C9H13BrN2O2) in the portion of Oral Solution taken by the formula:
100C(AU / AS)in which C is the concentration, in mg per mL, of USP Pyridostigmine Bromide RS in the Standard preparation; and AU and AS are the absorbances of the solutions obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information Please check for your question in the FAQs before contacting USP.
USP32NF27 Page 3450Pharmacopeial Forum: Volume No. 28(2) Page 357