SPECTROPHOTOMETRIC DETERMINATION OF COMPLEX FORMATION CONSTANTS OF NAPROXEN WITH CAFFEINE, NICOTINAMIDE AND SALICYLIC ACID IN AQUEOUS SOLUTION

The interaction between water insoluble drug naproxen with caffeine, nicotinamide and salicylic acid in aqueous solutions were determined by speetrophotometry. Naproxen was found to form 1:1 molecular complex with these substances. The complex formation constants were determined by spectrophotometry at room temperature.The thermodynamic functions associated with complexation of naproxen-drugs were also evaluated. It may be concluded that the complex formation may be attributed to hydrogen bonding since enthalpy changes were shown to be a few KJ·mol^-1.