[Determination of oxaprozin in human plasma with high performance liquid chromatography (HPLC) and its application]

The present research was aimed to develop a high performance liquid chromatography (HPLC) method to determine oxaprozin in plasma and to evaluate the bioavailability of two oxaprozin enteric coated tablets. A C18 column was used to separate the plasma after protein precipitation and the mobile phase was methanol-12. 5mmol/L ammonium acetate buffer solution (pH=3.0)(71:29). The calibration curve was linear in the concentration range of 0. 50-70. 56 microg . mL-1, and the intra and inter-day RSDs were less than 12. 33% and 10. 42% respectively. A single dose of 0. 4 g reference preparation or test preparation of oxaprozin enteric coated tablets was administered to 20 healthy volunteers according to a randomized crossover study. AUC0-->264h were (4 917. 44 +/- 629. 57) microg . h . mL-1 and (4 604. 30+/-737. 83) microg . h . mL-1, respectively; Cmax were (52. 34+/-7. 68) microg . mL-1 and (48. 66+/-4. 87) microg . mL-1, respectively; Tmax were (18. 70+/-2.27) h and (19. 30+/-1. 63) h, respectively; The relative bioavailability of test preparation was 94.0% +/- 13. 7%. The method is simple, rapid and selective for oxaprozin determination. There is no significant difference in the main pharmacokinetic parameters between the test formulation and reference formulation and the two formulations are in bioequivalence.