Table 6.

Estimated ranges of the average absorption rate coefficient in vivo (k_a) and the average partitioning rate coefficient in vitro (k_p) for BCS II compounds based on ranges for surface area to volume ratio in vivo (A/V) and in vitro (A_I/V_a), and average permeation rate in vivo (P_eff) and in vitro (P_I)

A/V a	Peff × 104b	ka × 104c	A I /V a d	PI × 104e	kp × 104f
cm−1	cm/s	s−1	cm−1	cm/s	s−1
2 (1 to 7)	1 to 14	2 to 28 (1 to 100)	0.16 to 0.47	0.01 to 100	0.002 to 50

^aEstimated based on an A/V of 2 and plausible percent compression based on Table 2.

^bApproximate range for measured human jejunal effective permeation rate for BCS II compounds from reference [32].

^cCalculated – equal to A/V* P_eff × 10⁴.

^dRange from Table 1 assuming standard USP guidelines for impeller positioning.

^eEstimated using equation 28 assuming h_a from 10 to 50 μm and D_a from 10⁻⁵ to 10⁻⁷cm²/s.

^fCalculated – equal to A_I/V_a* P_I × 10⁴.