Abstract
The purpose of this study is to propose sensitive, accurate and reproducible methods for the determination of sildenafil citrate in pure pharmaceutical preparations. Sildenafil citrate is determined spectrophotometrically via charge-transfer complex formation. This includes the use of some pi-acceptors as 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 3,6-dichloro-2,5-dihydroxy-p-benzoquinone (p-CLA). The proposed methods can be used for routine analysis of the suggested drugs in pharmaceutical preparations. The solid ions of the CT complexes from the reaction of DDQ and p-CLA as pi-acceptors with sildenafil citrate as donor are isolated and the formed CT complexes are characterized via elemental analyses, IR, H-1 NMR and mass spectrometric studies.