Assay of the anti-psychotic drug haloperidol in bulk form, pharmaceutical formulation and biological fluids using square-wave adsorptive stripping voltammetry at a mercury electrode

Abstract

The cyclic voltammetric behavior of haloperidol at a hanging mercury drop electrode was studied in Britton–Robinson buffer series of pH 2.5–11 containing 40% (v/v) ethanol. A single two-electron irreversible cathodic peak was obtained which attributed to reduction of the C O double bond. In addition, a small enhanced adsorptive pre-wave was observed at less negative potentials over the pH range 3.5–11. Controlled adsorptive accumulation of haloperidol onto the hanging mercury drop electrode provided the basis for its direct trace assay in bulk form, pharmaceutical formulation and human biological fluids using square-wave adsorptive cathodic stripping voltammetry. Following preconcentration of bulk haloperidol onto the HMDE a well-developed square-wave cathodic peak was generated in Britton–Robinson buffer especially at pH values 9–10; its peak current showed a linear dependence on the concentration of haloperidol over the range 1 × 10 −9 M to 1.5 × 10 −6 M depending on the preconcentration duration. The procedural parameters for assay of haloperidol were studied. The achieved limits of detection (LOD) and quantitation (LOQ) were 3.83 × 10 −10 M and 1.28 × 10 −9 M bulk haloperidol, respectively. The procedure was successfully applied to assay haloperidol in tablets (Safinace ®) and in spiked human serum and urine. LOD of 3.3 × 10 −9 M and 5.46 × 10 −9 M, and LOQ of 1.10 × 10 −8 and 1.82 × 10 −8 M haloperidol were achieved in spiked human serum and urine samples, respectively.