Labetalol Hydrochloride Injection
»Labetalol Hydrochloride Injection is a sterile solution of Labetalol Hydrochloride in Water for Injection.It contains not less than 90.0percent and not more than 110.0percent of the labeled amount of labetalol hydrochloride (C19H24N2O3·HCl).
Packaging and storage Preserve in single-dose containers,or in multiple-dose containers not exceeding 60mLin volume,preferably of Type Iglass,at a temperature between 2and 30.Avoid freezing and exposure to light.
Identification The retention time of the major peak in the chromatogram of the Assay preparationcorresponds to that of the Standard preparation,as obtained in the Assay.
Bacterial endotoxins á85ñ It contains not more than 1.2USP Endotoxin Units per mg of labetalol hydrochloride.
pHá791ñ: between 3.0and 4.5.
Other requirements It meets the requirements under Injections á1ñ.
Mobile phase Prepare a suitable filtered and degassed mixture of 0.1Mmonobasic sodium phosphate and methanol (65:35).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).
Standard preparation Dissolve an accurately weighed quantity of USP Labetalol Hydrochloride RSin Mobile phaseto obtain a solution having a known concentration of about 0.5mg per mL.
Resolution solution Dissolve a quantity of methylparaben in the Standard preparationto obtain a solution containing about 0.08mg per mL.
Assay preparation Transfer an accurately measured volume of Injection,equivalent to about 50mg of labetalol hydrochloride,to a 100-mLvolumetric flask,dilute with Mobile phaseto volume,and mix.
Chromatographic system (see Chromatography á621ñ)The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×20-cm column that contains packing L1and is maintained at 60±1.The flow rate is about 1.5mLper 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 700theoretical plates;the tailing factor for the analyte peak is not more than 2.0;and the relative standard deviation for replicate injections is not more than 1.5%.Chromatograph the Resolution solution,and record the peak responses as directed for Procedure:the relative retention times are about 0.6for methylparaben and 1.0for labetalol;and the resolution,R,between the methylparaben and labetalol is not less than 2.0.
Procedure Separately inject equal volumes (about 5µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the area responses for the major peaks.Calculate the quantity,in mg,of labetalol hydrochloride (C19H24N2O3·HCl)in each mLof the Injection taken by the formula:
100(C/V)(rU/rS),in which Cis the concentration,in mg per mL,of USP Labetalol Hydrochloride RSin the Standard preparation;Vis the volume,in mL,of Injection taken;and rUand rSare the peak area responses obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information Staff Liaison:Andrzej Wilk,Ph.D.,Senior Scientific Associate
Expert Committee:(PA5)Pharmaceutical Analysis 5