Voltammetric determination of timolol maleate: A beta-adrenergic blocking agent

Timolol as a beta -adrenoceptor antagonist is a potent antihypertensive and antianginal drug, which was also proved to be effective for the secondary prevention of myocardial infarction. The analysis of timolol, as with other oxprenolols, in ophthalmic solutions and biological liquids using sensitiv e instrumental methods has gained importance. Investigation of the electroc hemical behavior of timolol maleate on a mercury drop electrode reveals the presence of a specific reduction peak of analytical significance. Analysis conditions affecting the properties of this peak were optimized by a syste matic study. The limit of detection of about 2.5 ppb, obtained for the DPV technique using SMDE, is comparable with the most sensitive techniques. Thi s method is suitable for routine analysis in that it is simpler and require s no preconcentration step for the analysis of therapeutic doses of the dru g.