The binding of amsacrine to human plasma proteins
Paxton, J.W.; Jurlina, J.L.; Foote, S.E.
Journal of Pharmacy and Pharmacology 38(6): 432-438
1986
ISSN/ISBN: 0022-3573 PMID: 2873219 Document Number: 275143
Determination of amsacrine plasma protein binding by both equilibrium dialysis and ultracentrifugation gave similar results and indicated that amsacrine is highly bound (approximately 97%) in human plasma. This binding is independent of amsacrine concentration over the range 1-100 .mu.mol litre-1, but is very sensitive to plasma pH and, to a lesser extent, to temperature. Approximately 20% of the drug appeared to be covalently bound to plasma proteins. Amsacrine was bound by all plasma proteins investigated including albumin, .alpha.1-acid glycoprotein and various .gamma.-globulins. The binding to albumin appeared to occur by two processes, a saturable process at a single site with a KD of 13.9 .mu.mol litre-1 and a non-saturable process. Despite differences in individual protein concentrations, no significant difference was observed in the unbound amsacrine fraction in plasma from patients receiving this drug for treatment of acute myelogenous leukaemia and plasma from healthy individuals.