Levobunolol Hydrochloride
(lee'' voe bue' noe lol hye'' droe klor' ide).
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C17H25NO3·HCl 327.85

1(2H)-Naphthalenone, 5-[3-[(1,1-dimethylethyl)amino]-2-hydroxypropoxy]-3,4-dihydro-, hydrochloride, ()-.
()-5-[3-(tert-Butylamino)-2-hydroxypropoxy]-3,4-dihydro-1(2H)-naphthalenone hydrochloride [27912-14-7].
» Levobunolol Hydrochloride contains not less than 98.5 percent and not more than 101.0 percent of C17H25NO3·HCl, calculated on the dried basis.
Packaging and storage— Preserve in well-closed containers.
USP Reference standards 11
USP Levobunolol Hydrochloride RS Click to View Structure
Solution: 10 µg per mL.
Medium: alcohol.
Melting range 741: between 206 and 211, within a range of 3, determined after drying.
Specific rotation 781S: between 19 and 20.
Test solution: 30 mg per mL, in methanol.
pH 791: between 4.5 and 6.5, in a solution (1 in 20).
Loss on drying 731 Dry about 1 g of it in vacuum over phosphorus pentoxide in a suitable drying tube at 110 for 4 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.1%.
Mobile phase— Dissolve 990 mg of sodium 1-heptanesulfonate in 890 mL of water, add 10 mL of glacial acetic acid and 1100 mL of methanol, mix, pass through a suitable filter having a 1-µm or finer porosity, and degas. Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard preparation— Dissolve an accurately weighed quantity of USP Levobunolol Hydrochloride RS in Mobile phase to obtain a solution having a known concentration of about 1.0 mg per mL.
Assay preparation— Transfer about 100 mg of Levobunolol Hydrochloride, accurately weighed, to a 100-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, and mix.
Chromatographic system (see Chromatography 621)—The liquid chromatograph is equipped with a 254-nm detector and a 4-mm × 30-cm column that contains packing L1. The flow rate is about 1.5 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the column efficiency determined from the analyte peak is not less than 1000 theoretical plates; the capacity factor, k¢, for levobunolol is between 1.0 and 1.4, the tailing factor for the analyte peak is not more than 2.5, and the relative standard deviation for replicate injections is not more than 0.5%.
Procedure— Separately inject equal volumes (about 20 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the area responses for the major peaks. Calculate the quantity, in mg, of C17H25NO3·HCl in the portion of Levobunolol Hydrochloride taken by the formula:
100C(rU / rS)
in which C is the concentration, in mg per mL, of USP Levobunolol Hydrochloride RS in the Standard preparation; and rU and rS are the peak area responses obtained from the Assay preparation and the Standard preparation, respectively.
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