Pharmacokinetics of a controlled release preparation of naproxen

The pharmacokinetics of a controlled release preparation of naproxen (750 mg) was compared with that of standard release naproxen, in 12 healthy volunteers. The plasma levels of naproxen and urinary recoveries of naproxen and metabolites were determined both after single doses and chronic administration. The experimental data show that the bioavailability of the controlled release preparation is equal to that of standard release naproxen; however, the controlled release preparation allows more constant plasma levels of naproxen and, when administered once a day for prolonged periods, is capable of maintaining effective concentrations for most of the dosing period.