Method development and validation for estimation of related substances in tilorone dihydrochloride using rp-hplc

A simple, precise and reproducible RP-HPLC method was developed for the estimation of related substances in tilorone dihydrochloride. Quantification was performed using a Zorbax SB-phenyl column (150 x 4.6mm, 5μ) with mobile phase A: 20mM potassium dihydro phosphate + 2ml of triethylamine, pH 2.30 and mobile phase B: acetonitrile, methanol and water 60: 20: 20% v/v. A gradient program was followed with a run time of 55 minutes at a flow rate of 1.0 ml/min. The column temperature was maintained at 40°C, the injection volume was 10 μl and the detection was performed at 269nm using a PDA detector. The retention time of Tilorone dihydrochloride was found to be 10.36 minutes. The proposed method has been validated according to the ICH guidelines for Linearity, Precision, Accuracy, LOD, and LOQ. The method was linear from 0.157 - 3.934μg/ml for standard, 0.153–3.820μg/ml and 0.166 - 4.140μg/ml for impurities, TLHC01 and TLHC02 respectively. The impurities TLHC01 and TLHC02 have been mapped in all stress conditions. The LOD and LOQ of TLHC01 were found at 1.757μg/ml and 5.857μg/ml and 1.919μg/ml and 6.396μg/ml respectively for TLHC02 respectively. Statistical analysis showed that the method was precision, reproducible, selective, specific and accurate for the analysis of Tilorone dihydrochloride and its impurities. The wide range of linearity, sensitivity, precision, short retention times and simple mobile phase have shown that the method is suitable for the routine quantification of mass impurities of tilorone hydrochloride and its dosage pharmaceutical forms with high precision and accuracy.