Determination of dipyridamole in pharmaceutical preparations using square wave voltammetry

An analytical methodology using square wave voltammetry (SWV) at a hanging mercury drop electrode (HMDE) was developed for the quantitative determination of dipyridamole (DIP), a drug used for the treatment of several cardiovascular diseases, in pharmaceutical tablets and injections of Persantin® in phosphate buffer (pH 3.0; 0.1 M). After optimization of the parameters for SWV, analytical curves were obtained for application in the range of 1.28 × 10−6 M to 7.02 × 10−6 M. It was found a detection limit (DL) of 1.88 × 10−8 M (9.50 ng/ml). The repeatability and the reproducibility of the method were determinated by successive measurements of DIP solutions on the range of the analytical curve with a coefficient variation of 0.97% (n = 5) and 1.15%, respectively. The apparent recoveries were obtained by the IUPAC recommended procedure using the second reduction peak. Recoveries obtained by SWV were compared with the UV-vis spectrophotometric method. It was found that the determination of DIP in Persantin® tablets gave a mean value of 75.6 ± 0.4 mg (100.8%) and 68.9 ± 0.3 mg (91.8%) for SWV and UV-vis spectrophotometry, respectively. In the case of injections, it was found 10.4 ± 0.1 mg (103.4%) and 9.9 ± 0.2 mg (99.9%) for SWV and UV-vis spectrophotometry. Both apparent recoveries for the two types of formulations are in good accordance with the declared value of 75 mg (tablets) and 10 mg (injections).