Labetalol Hydrochloride Oral Suspension
» Labetalol Hydrochloride Oral Suspension contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of labetalol hydrochloride (C19H24N2O3·HCl). Prepare Labetalol Hydrochloride Oral Suspension 40 mg per mL as follows (see Pharmaceutical Compounding—Nonsterile Preparations 795):
Labetalol Hydrochloride 4 g
Vehicle: a mixture of Vehicle for Oral
Solution (regular or sugar-free), NF,
and Vehicle for Oral Suspension, NF
(1:1), a sufficient quantity to make 100 mL
If using Tablets, place the Labetalol Hydrochloride Tablets in a suitable mortar. Comminute the Tablets to a fine powder or add Labetalol Hydrochloride powder. Add about 20 mL of the Vehicle, and mix to a uniform paste. Add the Vehicle in small portions almost to volume. Transfer the contents of the mortar, stepwise and quantitatively, to a calibrated bottle. Add the Vehicle in portions to rinse the mortar, combine with the final preparation to final volume, and mix well.
Packaging and storage— Preserve in tight, light-resistant containers. Store at controlled room temperature, or in a cold place.
Labeling— Label it to state that it is to be well shaken, and to state the beyond-use date.
pH 791: between 4.0 and 5.0.
Beyond-use date: 60 days after the day on which it was compounded.
Mobile phase— Prepare a suitable filtered and degassed mixture of 0.1 M monobasic sodium phosphate and methanol (65 : 35). Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard preparation— Dissolve USP Labetolol Hydrochloride RS in water to obtain a solution having a known concentration of 400 µg per mL.
Assay preparation— Agitate the container of Oral Suspension for 30 minutes on a rotating mixer, remove a 5-mL sample, and store in a clear glass vial at –70 until analyzed. At the time of analysis, remove the sample from the freezer, allow it to reach room temperature, and mix with a vortex mixer for 30 seconds. Pipet 1.0 mL of the sample into a 100-mL volumetric flask, and dilute with Mobile phase to volume.
Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 230-nm detector and a 4.6-mm × 25-cm analytical column that contains 5-µm packing L1. The flow rate is about 1.3 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the retention time is about 7.5 minutes, and the relative standard deviation for replicate injections is not more than 1.6%.
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 responses for the major peaks. Calculate the quantity, in mg, of labetalol hydrochloride ( C19H24N2O3·HCl) in the volume of Oral Suspension taken by the formula:
100(C / V)(rU / rS)
in which C is the concentration, in µg per mL, of USP Labetalol RS in the Standard preparation; V is the volume, in mL, of Oral Suspension taken; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Rick G. Schnatz
Manager, Compounding Pharmacy Expert Committee
(CRX05) Compounding Pharmacy05
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 2744
Pharmacopeial Forum: Volume No. 32(1) Page 117