Simultaneous determination of pseudoephidrine HCl (PSE) and terfanidine (TER) from formulations by reversed-phase ion pair high-performance liquid chromatography (RP-HPLC).

A new simple, precise, rapid, and selective reversed-phase ion pair high-performance liquid chromatography (RP-HPLC) method has been developed for the simultaneous determination of pseudoephidrine (PSE) and terfanidine (TER) from tablets using 60:15:25 acetontrile:methanol:water (v/v) containing 2.9 g sodium lauryl sulfate/liter, pH adjusted to 3.1 using phosphoric acid as a mobile phase and C18 Spherisorb ODS 2 (3 microns, 5 cm x 4.6 mm i.d.) as stationary phase. Detection was carried out using a UV detector at 254 nm. A constant flow of 1.0 ml/min was maintained throughout the analysis. Retention times for PSE and TER were 1.90 and 7.35 min, respectively. Linearity range and percentage recoveries for PSE and TER were 24-1200 and 12-600 micrograms/ml, and 100.01 and 100.4%, respectively.