Comparison of high-performance liquid chromatography and radioimmunoassay in the determination of content uniformity of digoxin tablets.
Digoxin 0.25-mg tablets were dissolved and assayed by the standard high-performance liquid chromatography (HPLC) method specified in USP XX and by a radioimmunoassay (RIA) method modified for the assay of tablet solutions. For the RIA method, the filtrate was diluted to a theoretical concentration of 5 ng/ml. Aliquots of this dilution were then assayed for digoxin content using a commercial digoxin 125I RIA kit. Results from both methods were extrapolated to total tablet content and compared with the labeled amount for 20 individual tablets. All tablet assay results were within the USP standards for content uniformity of individual tablets. The individual tablet deviations from labeled amount by the RIA method were smaller when compared with the USP XX-specified HPLC method. Comparison of individual tablet assays show the RIA method to be both as precise and as accurate as the USP XX-specified HPLC method.
D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004077:Digoxin / Q000032:analysis*; D011863:Radioimmunoassay / Q000379:methods; D013607:Tablets / Q000592:standards
D013607:Tablets; D004077:Digoxin