Five ion-associates of the drug sildenafil citrate (SC) with mono-chromotropic acid azo dyes, chromotrope 2B (I) and chromotrope 2R (II), and chromotropic acid bi-azo dyes, bis-3,6-(o-hydroxyphenylazo)-chromotropic acid (III), bis-3,6-(p-N,N-dimethylphenylazo)-chromotropic acid (IV) and 3-phenylazo-6-o-hydroxyphenylazo-chromotorpic acid (V) have been synthesized. Structural characterization of these novel sildenafil citrate ion-associates was carried out using elemental analysis and spectral techniques (VIS and IR). IR absorption spectra of the investigated ion-associates are studied and compared with those of the pure azo dyes and the drug. The spectral characteristics, oscillator strengths, transition dipole moments and resonance energy of the ion-associates in the ground state have also been
calculated.
Key words: sildenafil citrate, chromotropic acid azo dyes, Vis spectrophotometry, IR spectra
|
