Screen printed potentiometric sensor for therapeutic monitoring of rocuronium at the point of care.

Rocuronium bromide (ROC) is currently regarded as the 'gold-standard' in emergency medicine and anesthesia. Globally, millions of human beings are daily administered ROC at emergency settings where it is favored among all the neuromuscular blockers, particularly succinylcholine, for both its fast onset of action and short duration. However, it has been reported that 45% of patients in the post-anesthesia care unit are susceptible to residual postoperative paralysis, undesired ventilator effects and incomplete recovery after ROC administration. From an analytical chemistry perspective, direct determination of ROC is a difficult approach due to the complexity in isolation from biological specimens as well as the lack of a sensitive detection techniques and detectable chromophore. This contribution describes the development of a calix[6]arene-based screen-printed electrode (SPE) that is capable of ROC detection in biological samples at the point of care. This fabricated SPE (sensor 1) exhibited superior performance characteristics (slope, LOD and life time) with respect to an ionophore-free liquid-contact electrode, LCE, (sensor 2). The proposed SPE showed a linear response over a concentration from 1 µM to 10 mM, with a Nernstian slope of 57.9 mV/decade and a detection limit of 0.39 µM. Moreover, this sensor showed a considerable selectivity towards ROC in presence of the anticipated interfering ions. To investigate the ability of the SPE to detect ROC in real biological specimens, ROC has been spiked at a concentration comparable to its anticipated level in human plasma (Cmax ~ 40 µM) and the proposed SPE displayed an excellent platform for therapeutic drug monitoring (TDM) of ROC with respect to UV-spectrophotometry and LC/MS. Finally, the developed SPE was used for the determination of ROC in its commercial pharmaceutical formulation.