The Sensitive Spectrophotometric Determination of Trifluoperazine Hydrochloride via Ion-Association with Aniline Blue in Acidic Medium

Abstract

A simple, sensitive, and cost-effective spectrophotometric method was developed for the determination of Trifluoperazine hydrochloride (TFPH) in an acidic medium using aniline blue as a chromogenic reagent. The method is based on the formation of an ion-association complex resulting from electrostatic interactions between the protonated drug and the anionic dye, leading to a measurable decrease in dye absorbance. The discoloration process was monitored at a maximum wavelength (λ_max) of 592 nm.

Key experimental parameters, including pH, reagent concentration, reaction time, and temperature, were systematically optimized to achieve maximum sensitivity and stability. Under the optimized conditions, a linear relationship was established between the decrease in absorbance (ΔA) and TFPH concentration over the range of 0.5–7.0 μg mL⁻¹, with a correlation coefficient (R²) of 0.9962.

The method demonstrated satisfactory analytical performance, with an average recovery of 97.80%, a limit of detection (LOD) of 0.3319 μg mL⁻¹, and a limit of quantification (LOQ) of 1.1065 μg mL⁻¹. Precision and accuracy were confirmed by relative standard deviation (RSD%) values ranging from 0.35 to 2.79 and relative error (RE%) between −1.2 and −3.2.

The proposed method was successfully applied for the quantitative determination of TFPH in pharmaceutical tablet formulations, showing high accuracy, precision, and suitability for routine quality control analysis without the need for complex instrumentation or extraction steps.