Amiodarone partitioning with phospholipid bilayers and erythrocyte membranes.
The apparent partition coefficient (P) of amiodarone between aqueous buffer and lipid vesicles or erythrocyte ghosts was determined by equilibrium distribution using [125I]amiodarone as a tracer. The lipid vesicles consisted of total lipids extracted from erythrocyte or of egg phosphatidylcholine alone or mixed with a varying amount of stearic acid, phosphatidylethanolamine, sphingomyelin, phosphatidylserine, or cholesterol. All the conditions yielded a similar value of P (P approximately equal to 17,000). The log value of the partition coefficient of the neutral form of the drug is log PN = 5.95. The value of the extrapolated 1-octanol-buffer partition coefficient is log PN,oct = 6.66. Partition coefficient measurements on erythrocyte ghosts suggested that amiodarone partitioned to a similar extent in the protein and lipid content of the membrane.
D000638:Amiodarone / Q000032:analysis* / Q000097:blood; D000818:Animals; D001572:Benzofurans / Q000032:analysis*; D002021:Buffers; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004910:Erythrocyte Membrane / Q000378:metabolism*; D066298:In Vitro Techniques; D008051:Lipid Bilayers; D010743:Phospholipids; D051381:Rats; D012995:Solubility
D001572:Benzofurans; D002021:Buffers; D008051:Lipid Bilayers; D010743:Phospholipids; D000638:Amiodarone