Verapamil Hydrochloride Oral Solution
» Verapamil Hydrochloride Oral Solution contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of verapamil hydrochloride (C27H38N2O4·HCl). Prepare Verapamil Hydrochloride Oral Solution 50 mg per mL as follows (see Pharmaceutical CompoundingNonsterile Preparations 795. See also Verapamil Hydrochloride Oral Suspension):
Add Verapamil Hydrochloride powder and about 40 mL of Vehicle to a mortar, and mix. Add the Vehicle in small portions almost to volume, and mix thoroughly after each addition. Transfer the contents of the mortar, stepwise and quantitatively, to a calibrated bottle. Add enough Vehicle to bring 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 indicate the beyond-use date.
USP Reference standards 11
pH 791: between 3.8 and 4.8.
Beyond-use date: 60 days after the day on which it was compounded.
Sodium acetate solution Dissolve an accurately weighed quantity of sodium acetate in acetic acid having a concentration of 33 mL per L to obtain a solution having a 0.01 M sodium acetate concentration.
Mobile phase Prepare a mixture of Sodium acetate solution, acetonitrile, and 2-aminoheptane (50:50:0.5), filter, and degas. Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard preparation Dissolve an accurately weighed quantity of USP Verapamil Hydrochloride RS in Mobile phase to obtain a solution having a known concentration of about 500 µg per mL.
Assay preparation Agitate containers of Oral Solution 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 on a vortex mixer for 30 seconds. Pipet 1.0 mL into a 10-mL volumetric flask, and dilute with Mobile phase to volume.
Chromatographic system (see Chromatography 621) The liquid chromatograph is equipped with a 278-nm detector and a 4.6-mm × 25-cm analytical column that contains 5-µm packing L1. The flow rate is about 0.5 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the retention time for verapamil hydrochloride is about 4.8 minutes, and the relative standard deviation for replicate injections is not more than 0.7%.
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 verapamil hydrochloride (C27H38N2O4·HCl) in the volume of Oral Solution taken by the formula:
100(C / V)(rU / rS)in which C is the concentration, in µg per mL, of USP Verapamil Hydrochloride RS in the Standard preparation; V is the volume, in mL, of Oral Solution taken; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 5012Pharmacopeial Forum: Volume No. 32(1) Page 155