New carbon paste electrode for pazufloxacin mesylate determination modified with MWCNTs/ TiO₂/Chitosan nanocomposite was developed. It was based on the covalent linkage of chitosan to the MWCNTs/TiO₂ nanoparticle surface to enhance the sensor electrical properties, sensitivity and selectivity. The prepared nanocomposite was characterized by Fourier transform-Infrared, X-ray diffraction, Transmission electron microscope and Thermal gravimetric analysis. The sensor under optimal conditions exhibited high accuracy, precision and reproducibility with a stability of 123 days. It was efficiently applied for the determination of pazufloxacin mesylate in pure standard solution and spiked human plasma. It showed a linearity range of 1 × 10⁻⁹ to 1 × 10⁻³ mol L⁻¹ with a correlation coefficient of 0.994 and a nernestian slope of 56.76 mV/concentration decade. The LOD was 4.8 × 10⁻¹⁰ mol L⁻¹.

A new potentiometric sensor was efficiently applied for the analysis of melitracen hydrochloride. It was based on the use of a modified carbon paste electrode (CPE) with the incorporation of MWCNTs-TiO ₂ nano-hybrid that was covalently attached to the molecularly imprinted polymer (MIP). The prepared MWCNTs-TiO ₂ -MIP nanocomposite was characterized by some physicochemical characterization techniques. The fabricated sensor exhibited high selectivity and stability with concentration range of 1 × 10 ⁻⁹ − 1 × 10 ⁻³ mol l ⁻¹ and Nernstian slope of 60.17 mV/decade. It delivered high sensitivity with LOD of 5.4 × 10 ⁻¹⁰ mol l ⁻¹ and fast dynamic responses of 40 s. The studied sensor was implemented to determine the melitracen in bulk, pharmaceutical tablets and human plasma with reliable recovery. It was also applied to study the dissolution profile of the pharmaceutical tablets.