Comparison of in vitro and in vivo efficiencies of a novel unit-dose liquid aerosol generator and a pressurized metered dose inhaler

• Published in: International journal of pharmaceutics 2000-03, Vol.198 (1), p.63-70
• Main Authors: Farr, Stephen J., Warren, Simon J., Lloyd, Peter, Okikawa, Jerry K., Schuster, Jeffrey A., Rowe, Antony M., Rubsamen, Reid M., Taylor, Glyn
• Format: Article
• Language: English
• Subjects: Adult; Aerosol deposition; Aerosols; Biological and medical sciences; Gamma scintigraphy; General pharmacology; Humans; Krypton Radioisotopes; Liquid aerosol generator; Lung - diagnostic imaging; Male; Medical sciences; Metered dose inhaler; Microprocessor-controlled device; Nebulizers and Vaporizers; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Pressure; Radionuclide Imaging; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Technetium Tc 99m Pentetate
• ISSN: 0378-5173; 1873-3476
• DOI: 10.1016/S0378-5173(99)00452-4

Gamma scintigraphic imaging was employed in 10 healthy volunteers to compare the total and regional lung deposition of aerosols generated by two delivery platforms that permitted microprocessor-controlled actuation at an optimal point during inhalation. An aqueous solution containing 99mTc-DTPA was used to assess the deposition of aerosols delivered by inhalation from two successive unit-dosage forms (44 μl volume) using a prototype of a novel liquid aerosol system (AERx™ Pulmonary Delivery System). This was compared with aerosol deposition after inhalation of two 50 μl puffs of a 99mTc-HMPAO-labeled solution formulation from a pressurized metered dose inhaler (MDI). The in vitro size characteristics of the radiolabeled aerosols were determined by cascade impaction. For the AERx system, the predicted lung delivery efficiency based on the product of emitted dose (60.8%, coefficient of variation (CV)=12%) and fine particle fraction (% by mass of aerosol particles