Abstract

A simple, sensitive, precise, and economical spectrophotometric method has been developed for the determination
of prazosin in pharmaceutical and biological fluid samples. Prazosin undergoes diazotization when treated with
sodium nitrite and hydrochloric acid. The excess of nitrous acid during the diazotization is removed by the addition
of urea solution. The diazonium cation reacts with the coupling reagent, β-naphthol by electrophilic substitution
at the o-position of the coupling agent to produce an orange azo product. This orange product shows maximum
absorbance at 480 nm. The method obeys Beer’s law in the concentration range of 40-225 mg.ml−1 of prazosin.
The optical characteristics of the proposed method such as molar absorptivity, Sandell’s sensitivity, slope, and
intercept were found to be 1.1286 L.mole−1 cm−1, 0.0025 μg.cm−2, 0.00243, and 0.0047, respectively. Validation
studies are statistically significant as all the statistical parameters are within the acceptance range (% relative
standard deviation [SD] < 2.0 and SD < 2.0) for both accuracy and precision study. The proposed method was
found to be simple, sensitive, accurate, precise, rapid, and economical for the routine quality control application
of prazosin in pharmaceutical formulations.