| Resumo: | The voltammetric behaviour of quetiapine (QTP) was studied using direct current (DCt), differential pulse (DPP) and alternating current (ACt) polarography. The drug manifests cathodic waves over the pH range of 6 - 11.8. The waves were characterized as being irreversible, diffusion-controlled with limited adsorption properties. At pH 8, the diffusion current-concentration relationship was rectilinear over the range of 8 - 44 μg/mL and 4 - 44 μg/mL using DCt and DPP modes, respectively, with minimum detection limits (LOD) of 0.06 μg/mL and 0.04 μg/mL using the DCt and DPP modes, respectively. The diffusion-current constant (Id) is 1.36 ± 0.04 (n = 10). The proposed method was successfully applied to the determination of the studied compound both in pure form and in formulations. The results obtained were favourably compared with those obtained using a reference method. A pathway for the electrode reaction was postulated.
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