Solid-contact ion-selective sensor for the direct determination of procyclidine HCl and application of in-line dissolution profiling of its tablets

The ability to obtain accurate analytical results without sample pre-treatment or derivatization is a key element for an eco-friendly method of analysis. In this work, green electro analytical method was developed and evaluated for the selective determination of the anti-cholinergic drug Procyclidine Hydrochloride in both pure and dosage forms as well as in dissolution medium without sample pre-treatment. Firstly, screening of four ionophore-doped polyvinyl chloride-based membranes were conducted to detect the one with highest affinity towards the studied drug. Accordingly, calix[4]arene-doped membrane exhibited the optimum results. Then optimization was carried out by designing screen-printed and glassy carbon solid-contact ion-selective electrodes with multiwall carbon nanotube and graphene nanocomposite as ion to electron transducers. The fabricated screen-printed sensor with graphene nanocomposite was characterized according to IUPAC recommendations. It acquired the fastest and most stable response, along with thermal stability up to 30 °C. It also displayed a slope of 43.9±0.2 mV/decade in a pH range of 2–5. The proposed sensor successfully obtained a linear range of 1×10⁻⁵–1×10⁻² M and the theoretical limit of detection was 6.3×10⁻⁶ M. Finally, it was used in applications such as in-line dissolution monitoring and quantification of procyclidine in its dosage form without prior sample pre-treatment or derivatization steps. Furthermore, the graphene nanocomposite transducer has been imaged by Scanning Electron Microscope (SEM).