Plasma protein binding of basic drugs. I. Selective displacement from alpha 1-acid glycoprotein by tris(2-butoxyethyl) phosphate.

Author(s): Borgå O, Piafsky KM, Nilsen OG

Publication: Clin Pharmacol Ther, 1977, Vol. 22, Page 539-44

PubMed ID: 913020 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effects of collection container, and TBEP concentration on free aprenolol and imipramine in plasma specimens and protein fractions. Some plasma specimens were frozen before analysis.

   Summary of Findings:

   Free aprenolol and imipramine were increased in plasma specimens collected in Vacutainer instead of glass tubes (p<0.002). The percent changes in aprenolol and imipramine binding correlated with TBEP concentration (r=0.86, p<0.001 and r=0.66, p<0.01, respectively). The concentration of TBEP in plasma collected in Vacutainers was variable between individuals, but tended to correlate with alpha 2-acid glycoprotein concentrations (r=0.56, p<0.05). Alpha 2-acid glycoprotein in isolated plasma fractions had a high binding affinity for aprenolol and imipramine which was inhibited by TBEP. In contrast, aprenolol and imipramine binding to albumin was only slightly affected by TBEP and binding to lipoprotein was not affected at all.

   Biospecimens

   • Bodily Fluid - Plasma
   • Bodily Fluid - Blood

   Preservative Types

   • None (Fresh)
   • Frozen

   Diagnoses:

   • Normal
   • Not specified

   Platform:

   Analyte	Technology Platform
   Small molecule	GC- flame ionization
   Small molecule	Radioassay
   Small molecule	Equilibrium dialysis

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Acquisition	Type of collection container/solution	Vacutainer tube Glass tube
   Biospecimen Preservation	Type of fixation/preservation	Frozen None (fresh)

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