Analytical Quality by Design (AQbD)-Based RP-HPLC Method Development and Validation for Concurrent Determination of Meloxicam and Chlorhexidine in a Novel Dental <i>In-Situ</i> Gel for Odontalgia

Objective Odontalgia (Tooth pain) involves inflammation and infection, requiring anti-inflammatory and antibacterial agents to manage pain. Conventional gels containing NSAIDs, topical anesthetics, and antibacterial agents, individually or in combination, are not very effective due to rapid saliva washout, thereby necessitating frequent re-dosing.Significance As there are no oral in-situ gels containing anti-inflammatory and antibacterial agents available in the market for odontalgia, an in-situ gel containing meloxicam (prostaglandin inhibitor), thereby providing an anti-inflammatory effect, and chlorhexidine (antibacterial) was formulated for localized dual-action and prolonged contact at the targeted area. As there are no reported HPLC methods for the simultaneous estimation of meloxicam and chlorhexidine, an analytical quality-by-design-based reverse-phase high-performance liquid chromatography method was developed for the simultaneous quantification of both drugs in the formulated in-situ gel.Methods Taguchi screening design analyses the influence of key chromatographic parameters on method performance. A Box-Behnken design was used to generate the trial runs. The final method utilized a Cosmosil 5C18-MS-II column with an isocratic mobile phase consisting of an aqueous phase containing 0.025% orthophosphoric acid and acetonitrile in 20:80% v/v ratio, flow rate (1.0 mL/min), injection volume (10 μL) at a detection wavelength of 289 nm. Results: The developed method was validated as per ICH Q2(R1) guidelines. The assay value was calculated and found to be 98.53% for MLX and 99.02% for CHX.Conclusions The validated method applied for the quantitative analysis of meloxicam and chlorhexidine in the formulated in-situ gel.