Method Profile

RISKmilk Machine-Learning and PBPK Assessment of Lactational Drug Transfer

Molecular structure is used to estimate milk-transfer parameters for a lactation PBPK model, with predictions compared against observed clinical milk-to-plasma ratios.

Multiple OrgansComputational Models
Breast-milk storage containers and bottles.
Containers used to store breast milk. (Beukbeuk, Public domain)

Research Applications

Research prioritization of medicine exposure during breastfeeding using milk concentrations, relative infant dose and pharmacological context.

Model & Design

Support vector regression estimates milk partitioning and permeability–surface-area parameters, which feed a postpartum whole-body PBPK model.

Experimental Format

Compare clinical milk-to-plasma ratio predictions with a conventional equation-based lactation PBPK benchmark, then screen drug exposure scenarios.

Model Components

  • Component

    Inputs

    Description

    Molecular fingerprints, physicochemical descriptors, milk-to-plasma partitioning and permeability–surface-area parameters.

  • Component

    Evaluation

    Description

    Observed clinical milk-to-plasma ratios and a conventional equation-based PBPK benchmark.

Measurements & Endpoints

  • Milk-to-plasma prediction error
  • Relative infant dose in selected drug scenarios

Analysis

Compare the proportion of predictions within two-, three- and fivefold error; assess the effects of maternal clearance, blood-to-plasma ratio and milk partitioning.

Published Evidence

  • Study Design

    Clinical milk-to-plasma ratios are compared with predictions from RISKmilk and a conventional lactation PBPK model.

    Study Sample

    Drugs with observed clinical milk-to-plasma ratios, plus marketed-drug screening scenarios.

    Comparison

    Prediction-error distributions for RISKmilk versus the conventional model.

    Finding

    Twofold agreement increased from 29.6% to 66.4%. Four of 14 drugs with predicted milk-to-plasma ratios of at least 1 exceeded 10% relative infant dose in the maximum scenario.

    Interpretation & Limits
    • The authors assess milk partitioning together with relative infant dose and pharmacological context.

Sources

  1. A RISKmilk framework for predicting drug and chemical exposure in human milk during breastfeeding. Pharmacological research. 2026-09-24. DOI: 10.1016/j.phrs.2026.109639 ↗