A stability-indicating assay for procaine, based on high-performance liquid chromatography (HPLC), is described. A mixture of methanol and 1% acetic acid (40 + 60) was employed as the mobile phase on a µBondapak C18 column for HPLC. This method is simple, accurate and requires no extraction procedure. It was used to study procaine stability in various aqueous solutions. Stability tests were conducted both at room temperature and at high temperatures (70–90 °C) at various pH values and with different vehicles. Solutions of procaine in mixed aqueous solution (propylene glycol - ethanol - water) can enhance the stability relative to aqueous solutions.
