The Development and Analytical Applications of Polymer-Based and Carbon-Based Sensors for the Determination of Nepafenac

Abstract

Nepafenac (NPC) is a topical nonsteroidal anti-inflammatory drug used to treat postoperative eye pain and inflammation following cataract surgery. It is also effective against photophobia, intraocular pressure, hyperemia, and itching. However, NPC has side effects, such as dry eyes, eye itching, eyelid flaking or drooping, eye discharge, dizziness, nausea, hypersensitivity, and allergic conjunctivitis (eye allergy). Therefore, the detection of NPC in physiological and biological samples is of great importance. Rapid, inexpensive, and practical advanced analytical methods are required for routine analysis. To date, there have been very few studies on NPC analysis. In this study, a sensitive and reproducible electrochemical sensor was developed for the determination of NPC. Voltammetric measurements were carried out using paste electrodes modified with multi-walled carbon nanotubes (MWCNTs: MWCNT, MWCNT-NH2, MWCNT-COOH) and polymer-based sensors using monomers (phenylalanine, lysine, glycine, and proline). Among these, MWCNT-NH2 modified paste electrode (PE) and poly(glycine)-modified glassy carbon electrode (GCE) showed the highest sensitivity and were selected for detailed analysis. Electrochemical behavior and electrode mechanisms of NPC were studied using different voltammetric methods. The optimum signals were observed at pH 9.0 for MWCNT-NH2PE and pH 10.0 for poly(glycine)/GCE in Britton-Robinson buffer. The linear detection range was 0.4-128.0 mu M for MWCNT-NH2 PE and 1.18-12.98 mu M for poly(glycine)/GCE. The limit of detection values (LOD and LOQ) were calculated as 0.025 mu M and 0.41 mu M, respectively. This work presents an electrochemical method and a new generation sensor that is more sensitive, selective and easy to fabricate than existing analytical techniques for NPC detection.