. Author manuscript; available in PMC: 2012 May 7.

Published in final edited form as: Mol Pharm. 2009 Jan-Feb;6(1):29–39. doi: 10.1021/mp800148u

Table 3.

Relative intrinsic flux of ketoprofen and indomethacin in phosphate and bicarbonate buffer systems using rotating disk method.

Ketoprofen			Indomethacin

Buffer components	pH	Experimental^a (S.D._total)	Buffer components	pH	Experimental^a (S.D._total)
USP SIF, w/o pancreatin, 50 mM phosphate buffer	6.8	35.6 (1.7)	USP SIF, 50 mM phosphate buffer: 5% CO₂, 6.4 mM bicarbonate	6.8	2.4 (0.3)
FaSSIF w/o bile salts, 29 mM phosphate buffer	6.5	17.6 (0.9)	USP SIF, 50 mM phosphate buffer: 10% CO₂, 12.9 mM bicarbonate	6.8	1.7 (0.3)
5.0 mM bicarbonate buffer	6.5	6.1 (0.3)	USP SIF, 50 mM phosphate buffer: 15% CO₂, 19.3 mM bicarbonate	6.8	1.5 (0.3)
15 mM bicarbonate buffer	6.5	10.5 (0.5)	USP SIF, 50 mM phosphate buffer: 20% CO₂, 25.8 mM bicarbonate	6.8	1.4 (0.3)
20 mM bicarbonate buffer	6.5	14.2 (0.8)	USP SIF, 50 mM phosphate buffer: 15 mM bicarbonate	6.8:6.5	2.4 (0.5)

Relative Flux (N_total/N₀), where N_total is the total intrinsic drug flux including the ionized and unionized forms under buffered conditions, and N₀ is the intrinsic drug flux for unionized form only occurring under acidic conditions.