The Development of a Pharmacokinetic Description of Lipophilic Chemical Transport in Mammary Tissue

Date of Award

9-1994

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Systems Engineering and Management

Abstract

This study developed a pharmacokinetic description to describe the excretion of lipophilic contaminants into breast milk. Areas of interest included the pathways In, which contaminants are transferred in breast milk and the development of physiologically based pharmacokinetic model equations to describe these pathways. A literature search revealed that while a few studies had addressed the passage of pharmaceutical drugs into breast milk, the exact excretion mechanisms were not well understood. In general the literature assumed that transfer of drugs occurred by passive diffusion. This assumption was applied to xenobiotics without regard to the difference between pharmaceutical drugs and environmental contaminants, especially lipophilic contaminants.

This work developed equations to describe, 1, the passive diffusion of unbound lipophilic contaminants into milk; 2, the passive diffusion of lipophilic contaminants bound to fat, and 3., the carrier mediated transport of lipophilic contaminants bound to fat. Transport was described by expressions for the mass balance of HCB entering and leaving the mammary tissue. For carrier mediated transport, the amount entering the tissue was described by a Michaelis-Menten type expression for saturable kinetics. The results of this work illustrated that the possible mechanisms of contaminant transport into mammary tissue can be described by simple mass balance equations.

AFIT Designator

AFIT-GEE-ENV-94S-15

DTIC Accession Number

ADA284642

Comments

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