Development and validation of a novel fluorometric approach utilizing flow injection analysis for the measurement of vilazodone: application to dosage form and spiked human plasma

A direct, precise, rapid and simple flow injection approach has been applied to determine vilazodone HCl (VZN) in pharmaceutical dosage forms and biological fluids. VZN has an indole ring as part of its structure, which gives it a significant native fluorescence. The study was based on determining the strong intrinsic fluorescence of VZN, which was measured at 486 nm after excitation at 241 nm. Phosphate buffer (pH 5, 10 mM): Acetonitrile (40:60, v/v) was utilized as the carrier solution, with a flow rate of 0.5 mL min^{- 1}. Based on peak area, the calibration graph was linear over a concentration range of 10-300 ng mL^{- 1} of VZN with a correlation coefficient (r) of 0.9999. The quantitation limit was 9.62 ng mL^{- 1}, while the detection limit was 3.17 ng mL^{- 1}. Moreover, the suggested method was used to accurately measure VZN in its tablet dosage form. Additionally, the studied drug was also satisfactorily measured in blood using the suggested flow injection methodology. The approach was validated according to ICH specifications.