Complexation of procainamide with hydroxide-containing compounds

The complexation of procainamide with hydroxide-containing compounds, ethanol, fructose, glucose, glycerin, lactose, maltose, propylene glycol, sorbitol, and sucrose, have been studied. Procainamide formed a complex with glucose, lactose, and maltose, all of which contain a hemiacetal group, whereas fructose and sucrose do not. The percent of complex formed was dependent on the pH of the solution, with an optimum range of approximately 4-5.2. As with glucose, the percent of complex formed was directly related to the concentration of lactose in the solution. In dry mixtures, procainamide did not form a complex with glucose or lactose. The complex formed with lactose or maltose could be completely reversed by adding hydrochloric acid. A similar observation with glucose was reported earlier. In the optimum pH range, equilibrium was established in approximately 24 hr, and the process of complexation followed the equation for reversible reactions.