Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Tenoxicam, Meloxicam, and Piroxicam in Bulk Drug Samples

A novel isocratic reversed-phase high-performance liquid chromatographic (RP-HPLC) procedure was developed and extensively validated for the simultaneous quantitative determination of three structurally related oxicam anti-inflammatory drugs (Tenoxicam sodium, Meloxicam and Piroxicam) in bulk form in pharmaceutical formulations. Chromatographic separation was achieved on a Syncronis C-18 column (250 × 4.5 mm, 5 µm) using a methanol–water mobile phase (70:30, v/v; pH 3.3) delivered at 0.80 mL/min with ultraviolet detection at 248 nm. Following the ICH Q2(R1) guidance, a comprehensive study of the parameters was carried out, which resulted in excellent linear ranges (r² ≥0.997) for all three compounds, a mean recovery of 99–103%, percent RSD values of intraday and interday repeatability of the method that were less than 2.0% and limits of detection and quantification that were adequate. ICH Q1A(R2) facilitates chemical stress testing under acidic, alkaline, oxidative, thermal and photolytic conditions, resulting in chromatographically distinguishable, baseline-resolved peaks for byproducts, confirming the stability-indicating property of the assay. The elution times for the analytes were 3.874 min (Meloxicam), 4.920 min (Piroxicam), and 6.404 min (Tenoxicam sodium). The validated assay provides an accurate and convenient analytical tool for the simultaneous quality assurance and chemical stability assessment of these three oxicam drugs in pharmaceutical development and regulatory environments.