Analytical Method Development and Validation of Prazosin by UV–Vis Spectrophotometry

Abstract

Introduction: Prazosin hydrochloride, a selective α₁-adrenergic receptor antagonist used in hypertension management, requires sensitive and reliable analytical methods for formulation development, particularly in novel vesicular systems like spanlastics and invasomes where excipient interference is a concern.

Objectives: To develop a simple UV–Vis spectrophotometric method for prazosin quantification in phosphate buffer pH 7.4 and validate it according to ICH Q2(R1) guidelines for linearity, precision, accuracy, specificity, LOD/LOQ, robustness, and solution stability suitable for routine formulation analysis.

Methods: A double-beam UV spectrophotometer was used with methanol for stock solution (1000 µg/mL) and phosphate buffer pH 7.4 as diluent. λmax was determined by scanning 10 µg/mL solution (200–400 nm). Calibration standards (2–10 µg/mL) were analyzed at 257 nm. Validation included intra/inter-day precision (6 µg/mL, n=6), accuracy (80-120% recovery), specificity (blank/placebo/stressed samples), robustness (±1 nm wavelength, ±0.2 pH), and stability (0-48 h).

Results: Prazosin showed sharp λmax at 257 nm. Calibration curve exhibited excellent linearity (R²=0.9993) with equation A=0.0499C+0.006. LOD=0.099 µg/mL, LOQ=0.301 µg/mL. Intra-day RSD=0.46%, inter-day RSD=0.6-1.1%. Mean recovery=100.3% (98.5-101.5%). No interference from excipients; robust to parameter variations; solutions stable for 48 h (<2% absorbance change).

Conclusions: The developed UV spectrophotometric method is simple, precise, accurate, specific, and robust for prazosin quantification (2–10 µg/mL) in spanlastic/invasome formulations, suitable for routine quality control and stability studies.