Table 2

Comparison of brain to plasma partition (data is expressed as mean) in mdr1a/b KO and WT mice, and efflux ratio (data is expressed as mean ± S.D., n = 3) in MDR1-MDCK and parental MDCK cells of sedating and nonsedating H1-antagonists

Compound	Ratio of Brain to Plasma AUC Ratio between KO and WT Mice^2-a	Efflux Ratio in MDR1-MDCK (P_app, B-to-A/P_app, A-to-B)	Efflux Ratio in MDCK (P_app, B-to-A/P_app, A-to-B)	P-gp Substrate?	Sedating?
Cetirizine	4.4 (0.08/0.02)	5.8 ± 0.2^2-150	1.3 ± 0.2	Yes	No (Kay and Harris, 1999)
Loratadine	2.0 (3.30/1.60)	1.9^2-b		Yes^2-b	No (Kay and Harris, 1999)
Desloratadine	>14 (14.1/<1)	9.1 ± 0.3^2-150	1.4 ± 0.2	Yes	No (Kay and Harris, 1999)
Hydroxyzine	1.2 (4.75/3.83)	N.D.	N.D.	No	Yes (Simons, 1999)
Diphenhydramine	1.0 (9.42/9.02)	0.9 ± 0.2	1.2 ± 0.2	No	Yes (Simons, 1999)
Triprolidine	0.6 (3.60/5.92)	0.9 ± 0.3	1.1 ± 0.4	No	Yes (Simons, 1999)

N.D., not determined.
↵2-a The values in the parentheses are the brain-to-plasma AUC ratio for the KO and WT, respectively.
↵2-b Data were from Polli et al. (2001).
↵2-150 Significantly higher efflux ratio compared with the parental MDCK-II cells (P < 0.05).