Protein binding of doxepin and desmethyldoxepin.

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Virtanen R, Iisalo E, Irjala K

Protein binding of doxepin and desmethyldoxepin.

Acta Pharmacol Toxicol (Copenh). 1982 Aug;51(2):159-64.

PubMed ID

7113722 [ View in PubMed

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Abstract

The protein binding of doxepin (DOX) and desmethyldoxepin (DDOX) were studied in serum and plasma samples from healthy volunteers and psychiatric patients. Binding was measured by equilibrium dialysis (16 hrs at 37 degrees) and drug concentrations by radioimmunoassay. In addition, albumin and alpha 1-acid glycoprotein concentrations of the samples were measured by radial immunodiffusion. The mean +/- SEM percentages of unbound DOX were: 20.4 +/- 1.2 and 15.9 +/- 1.2 in healthy subjects (n = 16) and patients (n = 15) respectively, and those of DDOX: 21.4 +/- 0.9 and 19.0 +/- 1.4 for healthy subjects and patients, respectively. There was a significant negative correlation between serum alpha 1-acid glycoprotein concentration and free fraction of DOX in both groups. In healthy subjects a significant negative correlation was also found between albumin concentrations and free fraction of both DOX and DDOX. Binding experiments with isolated protein fractions revealed that all of the total binding in plasma could be explained by binding to albumin and alpha 1-acid glycoprotein. The observed 2--4-fold interindividual variability in the free fractions of these drugs is probably less important than the much larger variability in the total serum concentrations.

DrugBank Data that Cites this Article

Drug Carriers

Drug	Carrier	Kind	Organism	Pharmacological Action	Actions
Doxepin	Alpha-1-acid glycoprotein 1	Protein	Humans	No	Binder	Details
Doxepin	Serum albumin	Protein	Humans	No	Binder	Details