A QUANTITATIVE CIRCULAR DICHROIC INVESTIGATION OF THE BINDING OF THE ENANTIOMERS OF IBUPROFEN AND NAPROXEN TO HUMAN SERUM-ALBUMIN

The binding constants for racemic, R and S naproxen and ibuprofen to h uman serum albumin have been determined by a circular dichroic techniq ue. The ibuprofens and naproxens show no measurable extrinsic optical activity on interaction with the protein, and so the extrinsic Cotton effect shown following the diazepam-albumin interaction is used as a p robe. The presence of the drugs reduce the amount of diazepam bound as shown by the reduced size of the induced ellipticity. The calculated primary binding constants show that the S form of both drugs bind to t he albumin more tightly than the R form and that the racemic forms bin d less tightly than either enantiomer. (C) 1997 Elsevier Science B.V.