Boron-doped diamond film and multiple linear regression-based calibration applied to the simultaneous electrochemical determination of paracetamol, phenylephrine hydrochloride, and loratadine in fixed-dose combinations

In this work, we employed multiple linear regression analyses to satisfactorily determine cold symptoms treatment drugs paracetamol, phenylephrine hydrochloride, and loratadine in pharmaceutical formulations with combined dosage and spiked human urine sample. All the drugs are irreversibly oxidized on the boron-doped diamond electrode (BDDE) in diffusion-controlled oxidation processes with well-separated potentials in acidic media. A square-wave voltammetric (SWV) method was developed for their simultaneous determination in 0.1 mol L–1 H2SO4 and simple and multiple linear regression analyses were compared as calibration methods for SWV data. Precision and selectivity were also studied. The high concentration ratio between paracetamol and the other two drugs being minor components in the formulated dosage forms caused interference in their voltammetric responses. An assay based on multiple linear regression equations considering these multiple effects revealed statistically the same results as those obtained by a comparative HPLC-UV method at a 95% confidence level. We demonstrated that multiple linear regression provided adequate recovery for the determination of PAR, PHE, and LOR in spiked human urine sample. The developed SWV method is a very fast, low-cost, and environmentally friendly alternative to the routine simultaneous analysis of PAR, PHE, and LOR performed by HPLC-UV.