Nitromersol Topical Solution
» Nitromersol Topical Solution yields, from each 100 mL, not less than 180.0 mg and not more than 220.0 mg of nitromersol (C7H5HgNO3).
| Nitromersol | 2 g |
| Sodium Hydroxide | 0.4 g |
| Sodium Carbonate, monohydrate | 4.25 g |
| Purified Water, a sufficient quantity, to make | 1000 mL |
Dissolve the Sodium Hydroxide and the monohydrated Sodium Carbonate in 50 mL of Purified Water, add the Nitromersol, and stir until dissolved. Gradually add Purified Water to make 1000 mL.
note—Prepare dilutions of Nitromersol Topical Solution as needed, since they tend to precipitate upon standing.
Packaging and storage—
Preserve in tight, light-resistant containers.
Identification—
A:
To 100 mL add 3 mL of 3 N hydrochloric acid: a yellowish precipitate is formed. Filter, and retain both the filtrate and the precipitate.
B:
Add the precipitate from Identification test A to 20 mL of water and 2.5 mL of 1 N sodium hydroxide. Add 500 mg of sodium hydrosulfite, and heat to boiling: a heavy deposit of metallic mercury is formed.
Specific gravity 
841
:
between 1.005 and 1.010.
841:
between 1.005 and 1.010.
Mercury ions—
To the filtrate obtained in Identification test A add an equal volume of hydrogen sulfide TS: no darkening in color is produced, although a small amount of a flocculent, light yellow precipitate may be formed.
Assay—
Transfer 50.0 mL of Topical Solution to a 500-mL Kjeldahl flask, add a few glass beads, and evaporate to about 5 mL. Proceed as directed in the Assay under Nitromersol, beginning with “Add 15 mL of sulfuric acid.”
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
| Monograph | Behnam Davani, Ph.D., M.B.A.
Senior Scientist 1-301-816-8394 |
(MDAA05) Monograph Development-Antivirals and Antimicrobials |
USP32–NF27 Page 3098