Pharmaceutical-grade albumin: impaired drug-binding capacity in vitro

Table 4 Effects of charcoal-treatment on naproxen, warfarin, and digitoxin binding in albumin solutions with/without stabilisers^#

	Not charcoal treated albumin		Charcoal treated albumin
	In-process	Final product	In-process	Final product
Naproxen
K₁ (µmol/L)	0.1* (0.01)	75.5 (3.9)	0.2 (0.02)	0.2 (0.02)
n₁	0.9* (0.2)	5.7 (0.3)	0.9 (0.1)	1.1 (0.1)
Warfarin
K₁ (µmol/L)	13.1* (1.6)	43.1 (7.1)	13.5 (0.6)	14.6 (2.4)
n₁	1.9 (0.2)	1.7 (0.2)	1.7 (0.1)	2.0 (0.2)
Digitoxin
K₁ (µmol/L)	19.7* (1.0)	67.6 (6.8)	20.8 (1.0)	31.0 (4.2)
n₁	0.8 (0.03)	1.1 (0.1)	0.8 (0.03)	1.3 (0.2)

Effects of charcoal treatment on naproxen, warfarin, and digitoxin binding in two different albumin solutions. The in-process albumin solution (collected from the albumin manufacturing process before addition of the stabilisers and final heating) and the final product. Values are means (SDs) of 5 separate experiments. #: The concentration of N-acetyl-DL-tryptophan was 3 mmol/L in the final product before charcoal treatment, but not detectable (<0.2 µmol/L) after charcoal treatment (separate analysis). *p < 0.05 compared with the final product not charcoal treated.