Ai. Segall et al., Reversed-phase HPLC determination of sildenafil citrate in the presence ofits oxidative-induced degradation products, J LIQ CHR R, 23(9), 2000, pp. 1377-1386
The determination of sildenafil citrate in the presence of its oxidative-in
duced degradation products by reversed-phase HPLC is described. The method
was validated as stability-indicating by forced decomposition of sildenafil
citrate in acid, base, oxidative, thermal, and photochemical media. The ch
romatographic conditions employed a reversed-phase C-18 column (LiChrospher
, 5 mu m, 25 cm x 4.6 mm) isocratic elution with 70 mM potassium phosphate
monobasic containing 100 mM triethylamine (pH 3.0)-ACN (70:30, v/v) and ult
raviolet (UV) detection at 225 nm. The peak area versus sildenafil citrate
concentration proved linear over the 10-160% range of the working analytica
l concentration of 0.5-mg/mL. Mean absolute recovery of sildenafil citrate
using the described method was 100.9 +/- 1.1% (mean +/- SD, n = 9). The pre
cision, expressed as relative standard deviation (RSD), of ten replicate in
jections of sildenafil citrate reference solution, remained below 0.51%.