Table 2.

Commonly used buffers in rhGH products, their concentration range and buffering capacity.

Buffer	pH range	pKa
Phosphate	3.0-8.0	2.1, 7.2 and 12.3
Citrate	2.1-6.2	3.1, 4.8 and 6.4
Glycine	8.8-10.8	2.3-9.7
Acetate	3.8-5.8	4.8
Tromethamine	7.0-9.0	8.1
Carbonate	7-8	6.3-10.3
Histidine	5.0-6.5	1.8, 6.1 and 9.2
Succinic acid	4.3-6.6	4.2 and 5.6