Electrochemical Detection of Miltefosine in Urine Using Amino Functionalised Multi-walled Carbon Nanotubes and [Fe(CN)6]−3/−4 as a Redox Couple

Abstract Miltefosine is an alkyllylosophospholipid analogue used to treat visceral leishmaniasis. Recently, reports have been made of suspected counterfeit miltefosine on the Indian market. With the risk counterfeit drugs pose to drug resistance development, quality control of antileishmanial drugs has become important. Hence, in this study, amino-functionalized multi-walled carbon nanotubes (MWCNT-NH 2 ) were synthesised and characterised using Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Also, electrochemical impedance spectroscopy and cyclic voltammetry were used to study the electrochemical properties of the synthesised MWCNT-NH 2 . A complex was formed between MWCNT-NH 2 and miltefosine (Mil-MWCNT-NH 2 ). Five microliters of Mil-MWCNT-NH 2 was drop-cast on glassy carbon electrode, and differential pulse voltammetry studies were carried out to assess the performance of the sensor. Using [Fe(CN) 6 ] -3/-4 as a redox couple, a calibration study was carried out at different concentrations (0–250 µM) to establish the concentration range of the sensor. A linear response was established. With a detection limit of 1 µM, the fabricated sensor is a viable tool for detecting antileishmanial drug miltefosine in urine samples and possible application in quality control of miltefosine against counterfeiting. Graphical Abstract