title: Liquid chromatographic determination of methyldopa and methyldopa-thiazide combinations in tablets: collaborative study.
abstract: A reverse phase liquid chromatographic method for the determination of methyldopa, methyldopa-hydrochlorothiazide, and methyldopachlorothiazide in tablets was collaboratively studied by 8 laboratories. Each collaborator received 20 samples that included drug substance, synthetic and commercial tablet compositions. The overall repeatability and reproducibility standard deviations for commercial tablets were 1.11 and 1.75% for methyldopa, 0.96 and 1.62% for chlorothiazide, and 1.21 and 2.15% for hydrochlorothiazide, respectively. The overall recoveries of methyldopa, chlorothiazide, and hydrochlorothiazide added to synthetic tablets were 100.78, 100.70, and 101.34%, respectively. The method has been adopted official first action.
mesh_terms: D002740:Chlorothiazide / Q000032:analysis; D002853:Chromatography, Liquid / Q000379:methods; D004338:Drug Combinations; D006852:Hydrochlorothiazide / Q000032:analysis; D008750:Methyldopa / Q000032:analysis*; D013607:Tablets
chemical_list: D004338:Drug Combinations; D013607:Tablets; D006852:Hydrochlorothiazide; D008750:Methyldopa; D002740:Chlorothiazide