Analytical Sciences


Abstract − Analytical Sciences, 19(7), 1007 (2003).

Separation and Determination ofSynthetic Impurities of Sildenafil (Viagra) by Reversed-PhaseHigh-Performance Liquid Chromatography
VelupulaNAGARAJU,*  Dasari SREENATH,** JammulaTIRUMALA RAO,** and Ramisetti NAGESWARA RAO***
*Chemistry Section, A. P. State ForensicScience Laboratory, Red Hills, Hyderabad-500 004, India
**Department ofChemistry, Dr. Hari Singh Gour University, Sagar-470 003,India
***Analytical Chemistry Division, Indian Institute of ChemicalTechnology, Tarnaka, Hyderabad-500 007, India
A simple and rapid high-performance liquidchromatographic method for the separation and determination ofprocessrelated impurities of sildenafil was developed. The separation wasachieved on a reversed-phase C18 column using acetonitrile-0.05M potassium dihydrogen orthophosphate (70:30 v/v) as a mobile solvent at aflow rate of 1.0 ml/min and UV detection at 230 nm. The method was usednot only for quality assurance, but also for monitoring the chemicalreactions during the synthesis of sildenafil. It was found to be specific,precise and reliable for the determination of all process-relatedimpurities of sildenafil in bulk drugs and formulations.