Ethambutol Hydrochloride
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C10H24N2O2·2HCl 277.23

1-Butanol, 2,2¢-(1,2-ethanediyldiimino)bis-, dihydrochloride, [S-(R*,R*)]-.
(+)-2,2¢-(Ethylenediimino)-di-1-butanol dihydrochloride [1070-11-7].
» Ethambutol Hydrochloride contains not less than 98.0 percent and not more than 100.5 percent of C10H24N2O2·2HCl, calculated on the dried basis.
Packaging and storage— Preserve in well-closed containers.
B: A solution (1 in 10) responds to the tests for Chloride 191.
Specific rotation 781S: between +6.0 and +6.7.
Test solution: 100 mg per mL, in water.
Loss on drying 731 Dry it at 105 for 2 hours: it loses not more than 0.5% of its weight.
Limit of aminobutanol—
Borate buffer— Transfer about 1.24 g of boric acid to a 100-mL volumetric flask, dissolve in 90 mL of water, and adjust with 5 N sodium hydroxide to a pH of 9.0, dilute with water to volume, and mix.
Standard solution— Dissolve an accurately weighed quantity of USP Aminobutanol RS in water, and dilute quantitatively, and stepwise if necessary, to obtain a solution having a known concentration of about 5 µg per mL.
Fluorescamine solution— Dissolve 5 mg of fluorescamine in 50 mL of acetone in a glass-stoppered, graduated cylinder.
Test solution— Transfer about 50 mg of Ethambutol Hydrochloride, accurately weighed, to a 100-mL volumetric flask, dissolve in and dilute with water to volume, and mix.
Procedure— Pipet a 10-mL portion of Test solution into a glass-stoppered, 100-mL conical flask, and add 10 mL of water and 20 mL of Borate buffer. To another 100-mL flask add 10.0 mL of Test solution, 10.0 mL of Standard solution, and 20 mL of Borate buffer. Place the flasks on a magnetic stirrer, and while the contents are being stirred rapidly, add 10 mL of Fluorescamine solution rapidly. Insert the stoppers in the flasks, invert, and shake briefly. After 1 minute, accurately timed, determine the relative fluorescence intensities of both solutions in 1-cm cells, with a suitable fluorometer, at about 485 nm, with the excitation wavelength at about 385 nm. The fluorescence intensity of the solution obtained from the Test solution is not greater than the difference between the intensities of the two solutions (not more than 1.0%).
Ordinary impurities 466
Test solution: methanol.
Standard solution: methanol.
Eluant: a mixture of methanol and ammonium hydroxide (18:1).
Visualization: 16.
Assay— Dissolve about 200 mg of Ethambutol Hydrochloride, accurately weighed, in a mixture of 100 mL of glacial acetic acid and 5 mL of mercuric acetate TS. Add crystal violet TS, and titrate with 0.1 N perchloric acid VS (the color change at the endpoint is from blue to blue-green). Perform a blank determination, and make any necessary corrections. Each mL of 0.1 N perchloric acid is equivalent to 13.86 mg of C10H24N2O2·2HCl.
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
(MDAA05) Monograph Development-Antivirals and Antimicrobials
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 2319
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.