correlations (IVIVC) for lung deposition may be established by testing inhalers with realistic mouth-throat (MT) models and inhalation profiles (IP). This study was designed to compare the currently available MT models and their ability to predict lung deposition. Budelin Novolizer, Ventolin Evohaler, and Respimat fenoterol were chosen to represent a dry powder inhaler (DPI), metered dose inhaler (MDI), and soft mist inhaler (SMI) in tests using eight MT models: small, medium, and large Virginia Commonwealth University (VCU) models; small, medium, and large oropharyngeal consortium (OPC) models, the medium adult Alberta Idealized Throat (AIT), and the United States Pharmacopeia (USP) Induction Port, with IPs that simulated those used by volunteers in lung scintigraphy studies.
View Article and Find Full Text PDFBackground: The dose and aerodynamic particle size distribution (APSD) of drug aerosols' exiting models of the mouth and throat (MT) during a realistic inhalation profile (IP) may be estimated in vitro and designated Total Lung Dose, TLD, and APSD, respectively. These aerosol characteristics likely define the drug's regional distribution in the lung.
Methods: A general method was evaluated to enable the simultaneous determination of TLD and APSD for budesonide aerosols' exiting small, medium and large VCU-MT models.
Background: The amount of drug aerosol from an inhaler that can pass through an in vitro model of the mouth and throat (MT) during a realistic breath or inhalation flow rate vs. time profile (IP) is designated the total lung dose in vitro, or TLDin vitro. This article describes a clinical study that enabled us to recommend a general method of selecting IPs for use with powder inhalers of known airflow resistance (R) provided subjects followed written instructions either alone or in combination with formal training.
View Article and Find Full Text PDFBackground: In vitro-in vivo correlations (IVIVCs) are needed to relate in vitro test results for deposition to mean data from clinical trials, as well as the extremes in a population. Because drug deposition variations are related to differences in airway dimensions and inhalation profiles, this article describes the development and validation of models and methods to predict in vivo results.
Methods: Three physical models of the upper airways were designed as small, medium, and large versions to represent 95% of the normal adult human population.