Liquid chromatographic determination of levodopa and levodopa-carbidopa in solid dosage forms: collaborative study.
A liquid chromatographic method for the determination of levodopa in tablets and capsules and levodopa-carbidopa in tablets was collaboratively studied by 6 laboratories. Collaborators were supplied with duplicate powdered composites of levodopa (1 synthetic formulation, 1 commercial tablet, and 1 commercial capsule) and levodopa-carbidopa (1 synthetic formulation and 2 commercial tablets), along with individual levodopa-carbidopa tablets for content uniformity determinations. The repeatability coefficient of variation (CVo) and reproducibility coefficient of variation (CVx) for levodopa single component were 0.48 and 0.87%; for levodopa in combination, 0.50 and 0.90%; and for carbidopa, 0.77 and 1.20%, respectively. Overall, the recovery values for levodopa and carbidopa from synthetic formulations simulating tablets were 100.4 and 99.5%, respectively. The pooled CVDo and CVDx values for the individual tablet assays were 2.07 and 2.30% for levodopa, and 1.80 and 2.24% for carbidopa, respectively. The method has been adopted official first action for determination of the active ingredients in levodopa tablets and capsules and in levodopa-carbidopa tablets and for content uniformity testing in the combination dosage form.
Food and Drug Administration, New York Regional Laboratory, Brooklyn 11232.
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D002214:Capsules; D002230:Carbidopa / Q000032:analysis*; D002853:Chromatography, Liquid; D007202:Indicators and Reagents; D007980:Levodopa / Q000032:analysis*; D008750:Methyldopa / Q000032:analysis; D013607:Tablets
D002214:Capsules; D007202:Indicators and Reagents; D013607:Tablets; D007980:Levodopa; D008750:Methyldopa; D002230:Carbidopa