A flow-based analytical procedure exploiting multicommutation is proposed for captopril determination and the construction of dissolution curves. The procedure is based on the redox reaction between Cu(II) and the drug with the subsequent complexation of Cu(I) with 4,4'-dicarboxy-2,2'-bichinoline (BCA) and spectrophotometric detection. A linear response was observed between 25 and 300 µmol L-1 captopril and the detection limit was estimated as 7 µmol L-1 (99.7% confidence level). The coefficient of variation (n = 20) and sampling rate were 2.2% and 47 determinations per hour, respectively, consuming 290 µg of BCA and generating 3.6 mL of waste per determination. The results for seven pharmaceutical samples agreed with those obtained by the reference volumetric procedure at the 95% confidence level. The dissolution profiles attained with a lab-made dissolution apparatus agreed with those reported in the literature, with a coefficient of variation of 1.8% for three replicates of the reference product
flow analysis; multicommutation; dissolution profiles; captopril; spectrophotometry
