DETERMINATION OF PIROXICAM IN PHARMACEUTICAL PREPARATIONS BY ULTRAVIOLET DIRECT SPECTROPHOTOMETRY, ULTRAVIOLET DIFFERENCE SPECTROPHOTOMETRY AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Piroxicam in pharmaceutical preparations (capsules (C), tablets (T), oral drops (OD), suppositories (S) and simulated sample (SS)) was determined by UV direct spectrophotometry (UVS) at 333 nm, by UV difference spectrophotometry (UVDS) at 327 nm, and in C and T, by high performance liquid chromatography (HPLC). For UVS, Beer's law was obeyed in the range 3.0 - 8.5 mug/mL. The coefficient of correlation (CC), absolute precision (AP) and relative precision (RP) were 0.9999, 0.02 and 0.33%, respectively. The coefficient of variation (CV) for C, T, OD, S and SS were 0.48%, 0.35%, 0.32%, 0.48% and 0.19%, respectively. The recovery average (RA) was 100.22%. For UVDS, Beer's law was obeyed in the range 5.0 - 15.0 mug/mL The CC, AP and RP were respectively 0.9999, 0.05 and 0.47%. The CV for C, T, OD, S and SS were 0.64%, 0.84%, 0.62%, 0.54% and 0.15%, respectively. The RA was 99.02%. In HPLC determination, a LiChrospher(R) 100 RP - 18 (5 mum) in LiChroCART(R) 125-4 column at ambient temperature with a mobile phase consisting of methanol: (buffer solution citric acid - dibasic sodium phosphate pH 3.0) (55:45) and UV detection at 254 nm enabled the determination of piroxicam in C and T. The response peak area versus concentration presented linearity in the range 10.0-100.0 mug/mL The CC, AP and RP were 0.9997, 0.45 and 0.90%, respectively. The CV was 0.51% - 0.82% and the RA, 97.13%.