Ultra-fast absorption of amorphous pure drug aerosols via deep lung inhalation

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Abstract

A deficiency of most current drug products for treatment of acute conditions is slow onset of action. A promising means of accelerating drug action is through rapid systemic drug administration via deep lung inhalation. The speed of pulmonary drug absorption depends on the site of aerosol deposition within the lung and the dissolution rate and drug content of the deposited particles. Alveolar delivery of fast-dissolving, pure drug particles should in theory enable very rapid absorption. We have previously shown that heating of thin drug films generates vapor-phase drug that subsequently cools and condenses into pure drug particles of optimal size for alveolar delivery. Here we present a hand held, disposable, breath-actuated device incorporating this thermal aerosol technology, and its application to the delivery of alprazolam, an anti-panic agent, and prochlorperazine, an anti-emetic with recently discovered anti-migraine properties. Thermal aerosol particles of these drugs exist in an amorphous state, which results in remarkably rapid drug absorption from the lung into the systemic circulation, with peak left ventricular concentrations achieved within 20 s, even quicker than following rapid (5 s) intravenous infusion. Absorption of the thermal aerosol is nearly complete, with >80% absolute bioavailability found in both dogs and human normal volunteers. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95:2438–2451, 2006

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