A simple, cost-efficient stability-indicating RP-HPLC method for simultaneous estimation of embelin and piperine for routine analysis of marketed polyherbal capsules and tablets

Embelin (EMB) and Piperine (PIP) alkaloids are reported for ­antidiabetic, hypolipidemic, antioxidant, and anti-cancer properties. However, simultaneous analytical methods are scarce. A stability-indicating RP-HPLC method was developed with mobile phase MeOH: 0.1%TEA (pH 4.2 adjusted by OPA) (92:08 v/v ratio), CHEMSIL-ODS, C₁₈(4.6 × 250mm, 5 µm) column, and 1.2 mL/min ­flowrate. Retention times were 3.2, and 6.2 min for PIP and EMB respectively, at 289 nm, and validated as per Q2 (R1) ICH guidelines. Linearity ranging (2-10 µg/mL), with regression coefficients (<i>r</i>²), LOD, and LOQ for PIP were <i>r</i>² = 0.9979, 0.793 µg/mL, 2.403 µg/mL, and <i>r</i>² = 0.9974, 0.851 µg/mL, 2.578 µg/mL for EMB. Developed method precision, robustness, and ruggedness were confirmed by &lt;2%RSD. In tablet and capsule formulations, PIP %purity was 90.36%, 94.33%, and EMB 91.65, 92.85%. Additionally, forced-degradation studies ­indicated method stability through various stressed conditions. Hence, this ­validated method is specific, precise, linear, accurate, and robust, ­suitable for routine analysis of EMB and PIP in polyherbal ­formulations containing <i>Embelia ribes</i> Brum. and <i>Piper nigrum</i> Linn. extracts.