Focus on Alternative and Complementary Therapies
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Focus Alternat Complement Ther©2005 Pharmaceutical Press
Focus Altern Complement Ther 1997; 2: 186
Non-invasive measurement of volatile compounds in the respiratory system.
Exposure of various organic polymers to expired air induces electrical conductivity changes. The quick reaction, the reversible stationary level and the good sensitivity of this material allows online-monitoring of exhaled compounds by online-recording of the conductivity data. The sensors have a surface of approximately 0.25 cm2. Adsorption and desorption of vapour molecules are measured online by breath-temperature. A combination of sensors with different characteristics leads to information with high specifity about the agents. Determination of the volatile compounds by gas chromatography validates the organic polymer sensor. These sensors can be used to measure volatile compounds in the expired breath, conclusions regarding the bioavailability of the substance in the lung can be drawn.
Expired thymol, the main constituent of the essential oil of thyme, can be detected online in concentrations below 0.5 ppm after ingestion of a finished preparation containing thyme and ivy. With this particular preparation (Bronchipret tablets), thymol appeared in measurable amounts after 30 minutes and was present for approximately 100 minutes.
The sensor may allow continuous non-invasive measurement of the bioavailability of this active compound in the target organ.
