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).