Drug distribution within human milk phases.

Area of Science:

• Pharmacology
• Biochemistry
• Human Milk Analysis

Background:

• Understanding drug transfer into human milk is crucial for infant safety.
• Accurate measurement of drug distribution and protein binding in milk is needed.

Purpose of the Study:

• To quantify the phase distribution and protein binding of specific drugs in human milk.
• To identify physicochemical properties that predict drug concentrations in human milk.

Main Methods:

• Developed a reproducible, rapid analytical method using small human milk sample volumes.
• Studied five drugs (diazepam, phenobarbital, warfarin, phenytoin, disopyramide) at 37°C.
• Analyzed drug distribution between skimmed-milk and fat-rich phases and performed dialysis.

Main Results:

• Drug distribution and protein binding varied based on milk composition (fat and protein content).
• Lipid solubility was identified as the most significant physicochemical property influencing drug concentrations in milk.
• Dialysis experiments provided insights into drug binding in skimmed milk.

Conclusions:

• Lipid solubility is a primary determinant of drug distribution in human milk.
• Findings aid in predicting in vivo drug transfer and potential infant exposure.
• The developed analytical method is suitable for routine drug analysis in human milk.