Respirable aerosol exposures of nicotine dry powder formulations to in vitro, ex vivo, and in vivo pre-clinical models demonstrate consistency of pharmacokinetic profiles

Abstract

Background: Nicotine, because of its volatility, has a complex dosimetry following inhalation as a vapor/aerosol mix. To better control the dosimetry, nicotine could be formulated with a suitable dry powder excipient for use in a clinical inhaler.

Aim and Methods: The aim of this study was to investigate the pharmacokinetic PK profile of two dry powder formulations containing 2.5% or 5% nicotine using three experimental models associated to the PreciseInhale™ aerosolization system: the in vitro DissolvIt dissolution system; the ex vivo isolated, ventilated, and perfused lung (IPL) of the rat; and the in vivo intratracheally intubated rat.

Results and Discussion: Following exposure, both nicotine formulations had very rapid and similar dissolution and absorption kinetics in both the DissolvIt and IPL exposure models, with an initial half-time of absorption to the single-pass perfusate of 34 and 72 seconds, respectively. In the intratracheally intubated rat, following a rapid initial equilibration between the lungs and systemic compartments, nicotine had a systemic elimination half-time of 2.3–2.4 hours for both formulations. The rapid pulmonary PK of nicotine was likely close to the theoretical equilibration of a low-binding substance with a tissue-blood partition coefficient close to 1.

Conclusions: The data generated with the three experimental models provided a comprehensive picture of the inhalation PK of the two nicotine formulations. In particular, the results showed a very rapid dissolution and absorption of the two nicotine formulations and these results could be highly useful for improving the design and calibration of physiologically based PK models to produce more robust predictions. Abbreviations: AED: animal equivalent dose; BW: body weight; HPLC: high-performance liquid chromatography; IPL: isolated, ventilated, and perfused lung; PK: pharmacokinetics; SEM: scanning electron microscopy; USP: United States Pharmacopeia.

Keywords:

• Nicotine
• pharmacokinetics
• inhalation
• isolated perfused lung
• PreciseInhale™
• powder aerosol

Acknowledgements

The authors would like to thank the Inhalation Sciences team as well as Daniel Mascher and pharm-analyt Labor GmbH for the technical assistance and the constructive discussions. The authors thank also Stefan Lebrun for the administrative assistance and Arkadiusz Kuczaj for the technical advice and expertise.

Disclosure statement

All authors are employees of Philip Morris International.

Additional information

Funding

Philip Morris International is the sole source of funding and sponsor of this research.