TABLE 1.

Physicochemical parameters for INH and its metabolites

Compound	Mol wt (g · mol−1)a	log Pa	fu	pKa/pKba	Solubility (g · liter−1) at pH 7.4a
Isoniazid	137.14	−0.67	0.9b	13.61/2.36, 3.36	42.15
Acetylisoniazid	179.18	−0.9	0.7c	11.43/9.04, 3.19	25.51
Isonicotinic acid	123.11	0.4	0.95c	3.73/2.35	5,326
Isonicotinylglycine	180.16	−0.7	0.95c	1.21/2.76, 3.88	2,400
Hydrazine	32.05	−1.96	0.99c	−/5.4, 3.71	200
Acetylhydrazine	74.08	−1.33	0.98c	13.18/3.28	4,183
Diacetylhydrazine	116.12	−1.62	0.99c	12.14, 10.83/−	125.76

^aEstimated; log P, partition-coefficient; pK_a, acid dissociation constant; pK_b, base dissociation constant.

^bTaken from reference 69.

^cIdentified from parameter optimization.