Stability-Indicating Liquid Chromatographic Method Development for the Simultaneous Determination of Amitriptyline Hydrochloride and Propranolol Hydrochloride in Tablet Dosage Form

The combination of the tricyclic antidepressant amitriptyline hydrochloride (AMH) and the non-selective beta-adrenergic blocker propranolol hydrochloride (PPH) is used for migraine prophylaxis. Higher doses of AMH trigger cardiac arrhythmias, anxiety, tachycardia, convulsions, hyperglycemia and anticholinergic side effects. The combined dosage formulation of AMH and PPH leads to drug-drug interactions; causes sedation, xerostomia, dysuria, insomnia and bradycardia; and results in patient non-compliance. The quantification of AMH and PPN becomes essential, especially for combination formulations, in addition to regular quality control to avoid clinical issues. Considering these facts into account, the reverse-phase -high-performance liquid chromatography (RP-HPLC) method was developed in accordance with International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use Q2(R1) guidelines for the simultaneous determination of AMH and PPH. The HPLC separation was performed on an HPLC system (Shimadzu, Japan, Prominence I series 2030C) using a Shimadzu Shim-Pack GIST C18 column (100 mm × 4.6 mm, 5 μ), which was equipped with an ultraviolet detector at the isosbestic point 238 nm. The mixture of acetonitrile and orthophosphoric acid (pH 3.5) in a ratio of 35:65 v/v with a flow rate of 0.75 mL/min was used as the mobile phase. The regression coefficients of AMH (r2 > 0.998) and PPH (r2 > 0.999) show good linearity between peak areas and drug concentration ranges. The limits of detection (AMH = 0.67 μg/mL, PPH = 0.67 μg/mL) and limits of quantification (AMH = 2.04 μg/mL, PPH = 2.05 μg/mL) demonstrated the higher detection sensitivity of the proposed method.