Stability-indicating high-performance liquid chromatographic analysis of lidocaine hydrochloride and lidocaine hydrochloride with epinephrine injectable solutions

A reversed-phase, high-performance liquid chromatographic (HPLC) procedure, which is specific and quantitative for lidocaine hydrochloride, epinephrine, and methylparaben, was developed for the analysis of lidocaine hydrochloride and lidocaine hydrochloride with epinephrine solutions for injection. Epinephrine sulfonic acid and adrenochrome are separated in this system. Also separated are lidocaine and methylparaben and their respective degradation products, 2-6-xylidine and p-hydroxybenzoic acid. The analysis requires that three detectors (two UV and one electrochemical) be connected in series. By using this arrangement, lidocaine hydrochloride and methylparaben are quantitated by UV at 254 and 280 nm, respectively, while epinephrine is quantitated electrochemically. The method is simple, accurate, precise, and rapid. No sample preparation or internal standard is necessary, and only a 2-microliter sample volume is required for analysis. Chromatographic conditions include a mu Bondapak CN column and a mobile phase of 0.01 M 1-octanesulfonic acid sodium salt, 0.1 mM edetate disodium, 2% acetic acid, 2% acetonitrile, and 1% methanol in water.