Overcoming barriers in drug delivery to the lung, what have we learnt and where are we going?
Hugh D C Smyth1
1The University of Texas at Austin, 2401 University Ave., College of Pharmacy, Austin, Texas 78713, U.S.A.
Summary
Although the science and technology of inhaled products has advanced markedly over the past 20 years, our increased knowledge has also allowed us to uncover critical gaps. For many years, it seemed much of the scientists in this area were on a quest for improved efficiency and performance from inhaled devices and formulations. This focus on aerosol dispersion was addressed from many angles and led to the discovery of several technologies that have advanced our understanding of drug delivery to the lung. These discoveries have also now revealed new avenues for research that need to address important issues in the field. Importantly these include (1) understanding how small changes in formulations and delivery lead to significant changes in pharmacokinetics, thus potentially revealing the most critical parameters for aerosol dispersion (2) how new therapeutic modalities can fit in with the understanding built from the traditional inhaled potent small molecules widely studied, (3) and the development of technologies that minimize patient to patient and breath to breath variability. In this paper a synopsis of this work will be presented and the authors provide their vision on the future directions of this exciting field.
Key Message
In the quest for higher fine particle fractions, research efforts led to the use of many new techniques, development of new delivery technologies, and significant improvements in aerosol dispersion efficiencies. These advances in turn have revealed important barriers to drug delivery to the lung that remain to be overcome.