Demecarium Bromide Ophthalmic Solution
» Demecarium Bromide Ophthalmic Solution is a sterile, aqueous solution of Demecarium Bromide. It contains not less than 92.0 percent and not more than 108.0 percent of the labeled amount of C32H52Br2N4O4. It contains a suitable antimicrobial agent.
Packaging and storage— Preserve in tight, light-resistant containers.
USP Reference standards 11
USP Demecarium Bromide RS Click to View Structure
A: Mix about 10 mL with 12.5 mL of 1 N sodium hydroxide, and proceed as directed in Identification test B under Demecarium Bromide, beginning with “reflux for 15 minutes”: a violet-blue color is produced.
B: To 10 mL add 5 mL of a 1 in 50 solution of ammonium reineckate in methanol, and allow to stand for 30 minutes with occasional swirling: a pink reineckate of demecarium forms, and it melts between 131 and 136, with decomposition.
C: It responds to the tests for Bromide 191.
Sterility 71: meets the requirements.
Assay— Into each of two 50-mL volumetric flasks marked 1 and 2 pipet a volume of Ophthalmic Solution, equivalent to about 2.5 mg of demecarium bromide. Into each of two additional 50-mL volumetric flasks, marked 3 and 4, pipet 5.0 mL of a freshly prepared Standard solution made by dissolving about 50 mg of USP Demecarium Bromide RS, accurately weighed, in 100.0 mL of water. To flasks 1 and 3, add 1 N sodium hydroxide to volume, and mix. Transfer 10.0 mL of each of these solutions to separate glass-stoppered tubes, insert the stoppers loosely, heat the tubes in a water bath for 15 minutes, then cool to room temperature. The concentration of USP Demecarium Bromide RS in the Standard solution is about 50 µg per mL. To flasks 2 and 4, add pH 10.0 alkaline borate buffer (see under Solutions in the section Reagents, Indicators, and Solutions) to volume, and mix. Concomitantly determine the absorbances of the two sodium hydroxide solutions at the wavelength of maximum absorbance at about 292 nm, with a suitable spectrophotometer, using the corresponding borate buffer solutions as the respective solvent blanks. Calculate the quantity, in mg, of C32H52Br2N4O4 in each mL of the Ophthalmic Solution taken by the formula:
(50C / V)(AU / AS)
in which C is the concentration, in mg per mL, of USP Demecarium Bromide RS in the Standard solution; V is the volume, in mL, of Ophthalmic Solution taken; and AU and AS are the absorbances of the sodium hydroxide solution from the Ophthalmic Solution and the Standard solution, respectively.
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Monograph Ravi Ravichandran, Ph.D.
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71 Radhakrishna S Tirumalai, Ph.D.
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