title: The usefulness of 2D DOSY and 3D DOSY-COSY 1H NMR for mixture analysis: application to genuine and fake formulations of sildenafil (Viagra).
abstract: Two-dimensional diffusion ordered spectroscopy (DOSY) (1)H NMR is proposed to analyze drugs that are complex mixtures in order to discriminate genuine from fake formulations. The method was applied to the analysis of 17 formulations of sildenafil, one being genuine Viagra and the others illegally manufactured formulations of this drug coming from India, Syria and China. It enabled (i) distinguishing imitations or counterfeit from the authentic formulation, (ii) detecting the presence of sildenafil or adulterants, (iii) gaining information on the formulation process by detection of various excipients, thus giving a precise and global 'signature' of the manufacturer. Even though some samples are slightly overdosed, the quality of products manufactured in India and Syria was better than that of Chinese formulations which were adulterated with vardenafil and homosildenafil. This study also presents a three-dimensional DOSY-COSY (1)H NMR experiment that provides both virtual separation and structural information.
authors: Groupe de RMN Biomédicale, Laboratoire SPCMIB (UMR CNRS 5068), Université Paul Sabatier, 31062 Toulouse cedex, France.
authors: Saleh
authors: S
authors: Trefi
authors: Véronique
authors: V
authors: Gilard
authors: Stéphane
authors: S
authors: Balayssac
authors: Myriam
authors: M
authors: Malet-Martino
authors: Robert
authors: R
authors: Martino
mesh_terms: D002681:China; D002851:Chromatography, High Pressure Liquid; D045424:Complex Mixtures / Q000032:analysis; D004340:Drug Contamination; D007194:India; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure; D010879:Piperazines / Q000737:chemistry*; D011687:Purines / Q000737:chemistry; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000737:chemistry*; D013593:Syria
chemical_list: D045424:Complex Mixtures; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate