1.
J Pharm Sci
; 92(10): 2140-3, 2003 Oct.
Artigo
em Inglês
| MEDLINE
| ID: mdl-14502553
RESUMO
Sildenafil citrate (Viagra) [I] and sildenafil base [II] are easily and unequivocally characterized by a set of physicochemical methods that include X-ray diffractometry, infrared spectroscopy, and thermal analysis. Monoclinic lattice constants: [I]: a = 26.98 A; b = 11.95 A; c = 16.68 A; beta = 106.97 degrees. [II]: a = 8.66 A; b = 34.27 A; c = 8.93 A; beta = 96.63 degrees. Both compounds decompose at 189.4 degrees C [I] and 251.9 degrees C [II]. Densities and refractive indices are given.
