Abstract
Herein, a selective and rapid spectrofluorimetric method coupled with experimental design approach for reliable and efficient determination of two α-blockers, namely: terazosin hydrochloride (TER) and doxazosin mesylate (DOX) in their marketed tablets was developed. The presented method adopts formation of a semi-quinoid form of the studied drugs in borate buffer. The effects of parameters influencing fluorescence intensity including pH, the volume of buffer and diluting solvent were optimized using an experimental design methodology. The optimum conditions were found to be pH: 9.8, the volume of buffer: 2.0 mL and diluting solvent: water. Under the optimum experimental conditions, a large enhancement of the studied drugs fluorescence was obtained, measured at 387 after excitation at 246 nm for either TER or DOX with limits of detection 0.05 and 0.14 ng mL−1 and limits of quantification 0.14 and 0.43 ng mL−1 in the concentration ranges of 0.2–30.0 ng mL−1 and 0.5–30.0 ng mL−1 for TER and DOX, respectively. The presented method was validated according to the ICH guidelines. Furthermore, it extended to perform the content uniformity testing and analysis of the studied drugs in spiked human plasma with % recovery (96.00 ± 0.45–101.42 ± 1.20%, n = 3).
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•A newly spectrofluorimetric method coupled with DOE approach for efficient and reliable determination of doxazosin and terazosin in human plasma was designed.•Interactive response optimizer was applied for optimization and validation of the proposed method.•The developed method was applied for content uniformity testing of doxazosin and terazosin in their tablets.