Flow injection-chemiluminescence determination of propranolol in pharmaceutical preparations

A rapid and precise continuous-flow method is described for the determination of propranolol based on the chemiluminescence (CL) produced by its reaction with potassium permanganate in a sulphuric acid medium. The optimum chemical conditions for the chemiluminescence emission were investigated. Two manifolds were tested and their characteristics such as the length of the reactor, injection volume and flow rate were compared. When using the selected manifold, propranolol gives a linear calibration graph over the concentration range 1.0-17.5 mg l(-1). The detection limit calculated as proposed by IUPAC was 70 ng ml(-1) and the detection limit calculated as proposed by Clayton was 0.87 mg l(-1). For analysis of 10 solutions of 10.0 mg l(-1) propranolol, if error propagation theory is assumed, the relative error was 0.1%. The standard deviation (S.D.) for 10 replicate samples was 0.07 mg l(-1). The method has been validated versus a published fluorimetric method. The present chemiluminescence procedure was applied to the determination of propranolol in simple British and Spanish pharmaceutical formulations, with excellent recoveries, as the determination is free from interference from common excipients. However, some drugs, such as hydralazine and bendroflumethizide which may also be present in the formulation, increase the emission intensity. (C) 2003 Elsevier B.V. All rights reserved.