14
Table 1.2 Ionization Constants of Common Drugs
Weak acids
pK a
Weak bases
pK a
Acetaminophen
9.5
Alprenolol
9.6
Acetazolamide
7.2
Amiloride
8.7
Ampicillin
2.5
Amiodarone
6.5
Aspirin
3.5
Amphetamine
9.8
Chlorpropamide
5.0
Atropine
9.7
Cromolyn
2.0
Bupivacaine
8.1
Ethacrynic acid
2.5
Chlordiazepoxide
4.6
Furosemide
3.9
Chlorpheniramine
9.2
Levodopa
2.3
Chlorpromzaine
9.3
Methotrexate
4.8
Clonidine
8.3
Penicillamine
1.8
Codeine
8.2
Pentobarbital
8.1
Desipramine
10.2
Phenobarbital
7.4
Diazepam
3.0
Phenytoin
8.3
Diphenhydramine
8.8
Propylthiouracil
8.3
Diphenoxylate
7.1
Salicylic acid
3.0
Ephedrine
9.6
Sulfadiazine
6.5
Epinephrine
8.7
Sulfapyridine
8.4
Ergotamine
6.3
Theophylline
8.8
Hydralazine
7.1
Tolbutamide
5.3
Imipramine
9.5
Warfarin
5.0
Isoproterenol
8.6
Kanamycin
7.2
Lidocaine
7.9
Methadone
8.4
Methamphetamine
10.0
Methyldopa
10.6
Metoprolol
9.8
Morphine
7.9
Norepinephrine
8.6
Pentazocine
7.9
Phenylephrine
9.8
Pindolol
8.6
Procainamide
9.2
Procaine
9.0
Promazine
9.4
Promethazine
9.1
Propranolol
9.4
Pseudoephedrine
9.8
Pyrimethamine
7.0
Scopolamine
8.1
Terbutaline
10.1
Thioridazine
9.5