Pharmacokinetic investigation of 1,8-cineol after oral administration: correlation of blood and breath concentration to establish non-invasive kinetic quantification

This biomedical study investigates the pharmacokinetics of 1,8-cineol from a dietary supplement after oral administration in adults. The aim is to establish a correlation between blood and breath concentrations in order to establish a non-invasive measurement method that makes it possible to quantify 1,8-cineol levels in the body without invasive blood sampling. The datasets established in this way will subsequently be used to develop and evaluate a physiologically-based pharmacokinetic (PBPK) model for 1,8-cineol (PK-Sim ®​ , part of the OSP Suite). This model will enable the prediction of drug exposure in pediatrics based on age-related physiological differences, by extrapolating adult data. The aim is to determine appropriate dose recommendations for pediatric patients. The ICH guideline E11A, which deals with the extrapolation of data for dose determination for pediatric patients, serves as guidance [ 1 ]. The pre-study methodological validation for determining blood concentration by head-space GC-MS, as well as the sampling and measurement of breath samples, has been validated according to ICH guidelines [ 2 ]. Blood and breath samples are currently under analysis and final data will be presented soon. The introduction of breath analysis as a non-invasive measurement method could significantly enhance patient comfort while providing new insights into the pharmacokinetics of 1,8-cineol. By developing a PBPK model, we aim to bridge knowledge gaps in pediatric dosing for herbal medicinal products (HMPs). This approach could contribute to a better understanding of pharmacokinetics in children, reduce the need for pediatric clinical trials, optimize drug development, and increase the availability of safe, evidence-based HMPs for pediatric use. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany