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Detection of Dose Concentration in Droplets Generated by Pulmonary Drug Delivery Devices



Cary Presser


Using aerosol delivery devices to administer new therapeutic drugs through the pulmonary system is emerging as an efficacious way to engage several diseases.  Little quantitative information on spatially or temporally resolved concentration of the drug throughout the aerosol (i.e., presence of the active agent within any particular droplet) is available; concentration along with droplet size is critical for proper dosage and transport efficiency to the site of action.  The importance of such measurements is even more acute in suspensions (or colloids) where drug can float, settle, or agglomerate, adhere to surfaces, and contribute to inconsistent medication dose delivery and particle size distribution.  In this study, a measurement approach was developed to obtain droplet dose concentration of pharmaceutical-laden, multiphase aerosols.  Since many biological molecules either are naturally fluorescent or can be chemically modified with fluorophores, one can relate fluorescence intensity to concentration (or mass) of these inclusions within the droplet volume.  The approach used distinguishes between aerosol droplets that may or may not contain fluorescing agent (i.e., to identify droplet-to-droplet variations in agent concentration).  The results demonstrate how one can identify fluorescing droplets using this approach.
NIST Interagency/Internal Report (NISTIR) -


Absorption coefficient, climate change, laser-driven thermal reactor, particle optical properties, radiative loading


Presser, C. (2008), Detection of Dose Concentration in Droplets Generated by Pulmonary Drug Delivery Devices, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD (Accessed May 27, 2024)


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Created May 21, 2008, Updated February 19, 2017