Development and validation of the HPLC method for simultaneous estimation of Paclitaxel and topotecan

A simple, rapid, accurate and precise high performance liquid chromatography (HPLC) method for simultaneous analysis of Paclitaxel and Topotecan was developed. Different analytical parameters, such as linearity, accuracy, precision, specificity with intentional degradation, limit of detection and limit of quantification (LOQ), were determined according to the ICH guidelines. Acetonitrile-water (70:30, 0.1% trifluoroacetic acid) was run on a Phenomenex Luna C-18(2) column in isocratic mode at a flow rate of 1.2 mL/min for simultaneous analysis of the two drugs using a UV detector set at 227 nm. The proposed method showed a retention time (Rt) of 14.56 min for Topotecan and 23.81 min for Paclitaxel with a continuous run up to 30 min. The linearity of the calibration curves for each analyte in the desired concentration range was found to be good (r(2) > 0.9995). The recovery ranged from 97.9 to 101% for each drug with a relative standard deviation (%RSD) of <2%. Peaks corresponding to each of the drugs exhibited  positive values for the minimum peak purity index over the entire range of integrated chromatographic peak indicating high purity of the peaks. Stability analysis revealed that the drugs remained stable for sufficient time. Thus, the developed method was found to be robust and it can be employed to quantify Paclitaxel and Topotecan in commercial sample and rat blood/serum.