Simultaneous determination of loratadine and pseudoephedrine sulfate in pharmaceutical formulation by RPLC and derivative spectrophotometry

Highly sensitive, simple and accurate reversed phase liquid chromatographic and first derivative spectrophotometric methods for determination of antihistaminic drug loratadine [I] and nasal decongestant drug pseudoephedrine sulfate [II] are described. The HPLC method involves separation of [I] and [II] on mu-BondaPak C18 column using mixture of (methanol: H2O: phosphoric acid:ammonium dihydrogen phosphate) (220:300:2:3 g) (V/V/V/W), 60 and 40% acetonitrile as mobile phase flowing at 2 ml/min with ultraviolet detection at 247 nm. The calibration graphs are linear from 5 to 100 mug/ml for [I] and from 120 to 1200 mug/ml for [II] the detection limits are 0.5 mug/ml for [I] and 60 mug/ml for [II]. The spectrophotometric method is based on recording the first derivative spectra for [I] and [II] at 307, 266 urn, respectively, of their solutions in 0.1 M hydrochloric acid using the acid as blank. The calibration graphs are linear in the range of 5 25 mug/ml for [I] and 240-720 mug/ml for [II]; the limits of detection are 0.16 mug/ml for [I] and 10 mug/ml for [II]. The mean percentage recoveries obtained for different synthetic mixtures by using this method are 97.6% with coefficient of variation 1.79 for [I] and 101.6% with coefficient of variation 1.95 for [II]. The two methods have been applied successfully for the determination of [I] in its combination with [II] Clarinase(R) tablets and [I] alone in different pharmaceutical dosage forms. (C) 2003 Published by Elsevier B.V.