TABLE 1

Physicochemical properties of GSK drugs used in clinical DDI studies

Drug	Mol. Wt.	ClogP	pKa	Predominant Ionized Form at pH 7.4	Nominal BCS Class
GSK-1	464	5.8	10.4	Base	4
GSK-2	421	4.0	7.6	Base	4
GSK-3	667	5.1	9.7	Base	4
GSK-4	353	1.8	8.6	Base	1
GSK-5	357	3.0	6.3	Acid	1
GSK-6	456	2.5	4.08	Neutral	2
GSK-7	478	3.2	0.12	Neutral	2
GSK-8	256	3.6	7.7	Base	1
GSK-9	491	5.7	7.9	Base	3
GSK-10^{^a}	617	5.6	7.13	Neutral	1
GSK-11	472	4.1	8.4	Base	4
GSK-12	382	5.8	6.7	Acid	2
GSK-13	442	4.7	4.0	Acid	4
GSK-14	327	3.2	3.5	Acid	ND^{^b}
GSK-15	454	4.8	3.2	Acid	2
GSK-16	448	3.1	4.5/9.5	Zwitterion	4
GSK-17	578	6.8	4.3/8.2	Zwitterion	2
GSK-18	373	1.9	7.04	Neutral	1
GSK-19	371	0.7	4.5	Acid	1
GSK-20^{^a}	240	2.3	7.2	Neutral	1
GSK-21	438	3.1	6.4	Neutral	2
GSK-22	480	0.1	6.8	Neutral	3
GSK-23	669	2.0	7.9	Base	4
GSK-24	463	3.0	5.9/7.6	Zwitterion	2
GSK-25	333	2.6	8.7	Base	2
GSK-26	645	2.5	7.7	Base	4

ND, not determined.
↵a Structures for GSK-10 (casopitant) and GSK-20 (bupropion) are given in Fig. 4.
↵b Insufficient information available to assign a nominal BCS class.