Table 1. Comparison of the effects of the NSAIDs and their metabolites upon the initial activity of COX-1.

	COX-1 activity (% of control)
NSAID	100 µM	300 µM	1000 µM
Ibuprofen	26±5	2±2	−9±0.3
1′-OH-Ibuprofen	112±21	81±21	102±18
2′-OH-Ibuprofen	102±17	91±5	95±3
3′-OH-Ibuprofen	81±16	97±10	68±15
Flurbiprofen	−3±7
4′-OH-Flurbiprofen	97±31	72±20	6±6

Initial activities were calculated as the change in oxygen tension between 10 and 30 seconds after start of reaction. The values are means ± s.e.m., n = 3.