Abstract
Two simple, precise, accurate and sensitive UV spectrophotometric methods were developed and validated for the simultaneous determination of ofloxacin (OFX) and flavoxate HCl (FLX) in bulk and pharmaceutical formulations. In one method, first-derivative absorption at 303.6 nm (for OFX at its zero crossing) and 329.8 nm, (for FLX at its zero crossing) was used for the determination of the drugs and the linearity range was found to be 0.5–70 μg ml
−1
for FLX and 0.5–30 μg ml
−1
for OFX. In the second method, the ratio derivative spectrophotometry method was developed making use of amplitude in the first derivative of the corresponding ratio spectra at 290 nm (maxima) and 254 nm (minima) to estimate OFX and FLX, respectively. Further, the linearity range was found to be 0.5–25 μg ml
−1
for OFX and 0.5–30 μg ml
−1
for FLX. In both the methods, correlation coefficient was found to be more than 0.999. Both methods were validated according to ICH guidelines by assessing the linearity, accuracy, precision, limit of quantification, limit of detection and selectivity. The results demonstrate that both methods are accurate, precise and reproducible (relative standard deviation <2), while being simple, cheap and less time-consuming, and hence can be suitably applied for the simultaneous estimation of OFX and FLX in pharmaceutical formulation and for dissolution studies.