Screen printed diamond electrode as efficient “point-of-care” platform for submicromolar determination of cytostatic drug in biological fluids and pharmaceutical product

This work presents advanced electrochemical platform based on screen printed diamond electrode (SPDE) system for the single drop “point-of-care” testing. Proposed approach was applied for the quantification of doxorubicin hydrochloride (DOX) in biological fluids and pharmaceutical product. Using a single drop (~30 μL) of the tested solution at the electrode surface, DOX showed high electroactivity over a wide range of pHs. In these conditions, single oval shaped, well-defined and pH dependent oxidation peak was observed in the potential range from 0.5 V to 1.3 V. In the reverse scan, two cathodic peaks, were noted – around 0.3 V and – 0.5 V. Similarly, first reduction peak was pH dependent, while second one was independent in the studied range. Experimental conditions for DOX quantification were optimized and natures of the electrode reactions were investigated. Working linear range obtained for DOX detection was from 0.1 to 2.5 μM. Diffusion controlled electrode reaction reveal long life time of the proposed electrode as well high potential for practical application. Developed procedure was successfully applied for the DOX analysis in biological fluids – urine and pharmaceutical formulation. Obtained results clearly indicated that given procedure can be easily implemented for pharmaceutical control and medical analysis, in both, laboratory and field conditions