UHPLC-ESI-QToF Analysis of Trandolapril and Verapamil Hydrochloride in Dosage Form and Spiked Human Plasma Using Solid Phase Extraction: Stability Indicating Assay Method

Background: A new UHPLC method was developed and subsequently validated for determination of the anti-hypertensive combination Trandolapril (TAD) and verapamil hydrochloride (VRP) in bulk powder, dosage form (Tarka® 2 mg TAD/ 180 mg VRP), and spiked human plasma. Moreover, the method was utilized for studying the stability of the combination under hydrolytic and thermal conditions. Methods: Separation was achieved by using BEH C18 (1.7 μm, 2.1 x 50 mm) analytical column (Waters ® Acquity UPLC) and a mobile phase composed of 15 mM tris buffer pH 6.5 adjusted with 1 M HCl acetonitrile (20:80 v/v). Forced degradation studied was carried out using Waters® Xevo G2-S QToF coupled with Waters® Acquity UPLC system with binary Solvent Manager (I-Class) via electrospray ionization (ESI) interface. Results: In bulk powder, the retention times were 0.450± 0.004 and 1.290± 0.011 minutes, where the linearity ranges were found to be 0.12 to 240 μg/mL and 0.10 to 360 μg/mL for TAD and VRP, respectively. Moreover, linearity was achieved in spiked human plasma samples by using Ledipasvir as an internal standard and linearity ranges were found to be 55 to 90 μg/mL and 15 to 80 μg/mL for TAD and VRP, respectively. The amount of trandolapril and verapamil hydrochloride present in the dosage form was determined in triplicate to give a concentration of 99.60%±0.48 (1.97 mg) and 99.96%0±0.63 (179.93 mg), respectively. The structure of the degradation products was elucidated by UHPLC-ESI-QToF. Conclusion: The method was able to extract 95.61% of trandolapril and 97.83% of verapamil hydrochloride from human plasma and found to be stable. Furthermore, the combination is stable towards acidic and thermal conditions used.