A target responsive benzimidazole-based self-assembled micellar system embedded smart hydrogel: an integrated approach for quantification and removal of phenylbutazone

Abstract

The unregulated use and improper disposal of active pharmaceutical ingredients (APIs), particularly phenylbutazone (PBZ), are contaminating water resources and posing serious risks to the food chain. PBZ is a nonsteroidal anti-inflammatory drug (NSAID) commonly used for treating pain and fever in animals, and its persistence in the environment due to inadequate waste management has become a cause of concern. To address this, we report the fabrication of benzimidazole-based self-assembled nanomicelles (R2 NMs) for selective detection and removal of PBZ. The successful fabrication of self-assembled R2 NMs was validated using various analytical techniques. Furthermore, the binding ability of R2 NMs was evaluated using spectroscopic and electrochemical techniques. They demonstrated a selective response toward PBZ with a response time of just 20 s and a positive cooperativity of 1.92. For on-site detection and removal of PBZ, R2 NMs were integrated into a biopolymer gel composed of starch–polyvinyl alcohol–glycerol (SPG). This system can potentially serve as a portable, smart analyte-responsive nanomicellar hydrogel (SAN hydrogel) that specifically targets and removes PBZ from contaminated water. The SAN hydrogel exhibited enhanced swelling, reduced porosity, and improved water retention. Furthermore, the removal efficiency of PBZ was assessed using the SAN hydrogel, following pseudo-first-order kinetics, with noticeable fluorescence changes occurring after various time intervals. Moreover, the PBZ removal was validated by the fluorescence switching ON–OFF mechanism, enabling real-time onsite detection of PBZ. Thus, these findings suggest that the proposed material could be effectively utilized for the on-site quantification and removal of PBZ from contaminated water.