Verapamil Hydrochloride Oral Suspension
» Verapamil Hydrochloride Oral Suspension 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 Suspension 50 mg per mL as follows (see Pharmaceutical Compounding—Nonsterile Preparations 795. See also Verapamil Hydrochloride Oral Solution):
Verapamil Hydrochloride 5 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 Verapamil Hydrochloride Tablets, comminute to a fine powder using a suitable mortar, or add Verapamil Hydrochloride powder. Add about 40 mL of the Vehicle in small portions, and mix to obtain a uniform paste. Transfer the mortar contents, stepwise and quantitatively, to a calibrated bottle. Add the Vehicle in portions to rinse the mortar, add sufficient Vehicle 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 before use, and to state the beyond-use date.
USP Reference standards 11
USP Verapamil Hydrochloride RS Click to View Structure
pH 791: between 3.8 and 4.8
Beyond-use date: 60 days after the day on which it was compounded.
Mobile phase— Prepare a suitable filtered and degassed mixture of 0.01 M sodium acetate with a mixture of acetic acid having a concentration of 33 mL per L, acetonitrile, and 2-aminoheptane (50:50:0.5). Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard preparation— Dissolve USP Verapamil Hydrochloride RS in Mobile phase to obtain a solution having a known concentration of 500 µg per mL.
Assay preparation— Agitate the container of Oral Suspension for 30 minutes on a rotating mixer, remove a 5-mL sample, store in a clear glass vial at –70 until analyzed. At 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 of the sample solution 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 Suspension 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 Suspension taken; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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Topic/Question Contact Expert Committee
Monograph Jeanne H. Sun
Assistant Scientific Liaison
(CMP2010) Compounding
Reference Standards RS Technical Services
USP35–NF30 Page 5013
Pharmacopeial Forum: Volume No. 32(1) Page 156