Table 4.

Calculated pKa values (at 25° C) of the antiplatelet drugs investigated.

Drug	pKa		% Ionized Form
	Acid Function	Basic Function	Acid Function	Basic Function
Ticlopidine		7.85		74
Ticlopidine active metabolite	3.41; 9.43	7.26	100; 1	42
Clopidogrel		4.61		0.2
Clopidogrel active metabolite	3.01; 9.15	4.43	100; 2	0.1
Prasugrel		5.50		1
Prasugrel active metabolite	3.29; 9.19	5.06	100; 1.5	0.5
Elinogrel	4.26; 11.37		100; 0
Ticagrelor	13.48	2.28	0	0
Ticagrelor active metabolite	13.27	2.59	0	0
Cangrelor	0.33–0.59		100