Stability indicating methods for the determination of loratadine in the presence of its degradation product.

Four stability-indicating procedures have been suggested for determination of the non sedating antihistaminic agent loratadine. Loratadine being an ester undergoes alkaline hydrolysis and the corresponding acid derivative is produced as a degradation product. Its identity was confirmed using IR and MS. The first procedure is based on determination of loratadine by HPLC with detection at wavelength, 250 nm. Mobile phase is acetonitrile:orthophosphoric acid (35:65) using benzophenone as an internal standard. Sensitivity range is 5.00-50.00 microg/ml. Second determination is a densitometric procedure based on determination of loratadine in the presence of its degradate at lambda 246 nm using the mobile phase; methanol:ammonia (10:0.15). Sensitivity range is 1.25-7.50 microg per spot. The third procedure is a spectrophotometric one where a mixture of loratadine and its degradate are resolved by first derivative ratio spectra. Sensitivity range is found to be 3.00-22.00 microg/ml, upon carrying out the measurements at wavelengths 236, 262.4 and 293.2 nm. The fourth procedure is based on second derivative spectrophotometry, where D(2) measurements are carried out at lambda 266 nm. The sensitivity range is 3.00-22.00 microg/ml. The validity of the described procedures was assessed by applying the standard addition technique. Statistical analysis of the results have been carried out revealing high accuracy and good precision. The suggested procedures could be used for determination of loratadine both in pure and dosage forms, as well as in the presence of its degradate.