Development of Validated Analytical Methods for Levosimendan and its Application in in-vitro Interaction Studies

Abstract

This study outlines the development and validation of multiple analytical methods for the quantification of levosimendan in injectable formulations, including UV spectrophotometry, spectrofluorimetry, high-performance thin-layer chromatography (HPTLC), and stability-indicating reverse-phase high-performance liquid chromatography (RP-HPLC). Each method was optimized for sensitivity, specificity, and reproducibility, and successfully validated in accordance with ICH guidelines. The UV spectrophotometric method showed excellent linearity in the range of 1–5 μg/mL with a correlation coefficient (R²) of 0.9997 and λmax at 401 nm. Spectrofluorimetric analysis, based on the oxidation of levosimendan with ceric ammonium sulphate, demonstrated a sensitive response in the range of 400–2000 ng/mL with mean recoveries exceeding 98%. For HPTLC, levosimendan was effectively separated using a mobile phase of THF:DCM:ether (1:8:1, v/v), showing a sharp peak at Rf 0.74 and high accuracy and precision across a 200–1000 ng/band concentration range. The stability-indicating RP-HPLC method utilized a C18 column with a mobile phase of ammonium acetate buffer and methanol (48:52, v/v), achieving optimal separation with a retention time of ~11 min and excellent resolution, linearity (0.2–1.2 μg/mL), and robustness under various stress conditions. The validated RP-HPLC method was applied in in-vitro drug interaction studies with aspirin, clopidogrel, and atorvastatin using equilibrium dialysis. Results indicated significant displacement of levosimendan from protein binding sites, particularly with atorvastatin (14.74%) and aspirin (7.77%), suggesting potential pharmacokinetic interactions. Overall, the developed methods proved to be reliable, accurate, and robust for the quantitative analysis of levosimendan in injectable dosage forms, with the RP-HPLC method also demonstrating suitability for in-vitro interaction and stability studies.