Worth Longest1,2, Amr Hassan3, Dale Farkas4, Michael Hindle3. 1. Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, 401 West Main Street, P.O. Box 843015, Richmond, Virginia, 23284-3015, USA. pwlongest@vcu.edu. 2. Department of Pharmaceutics, Virginia Commonwealth University, 410 North 12th Street, P.O. Box 980533, Richmond, Virginia, 23298-0533, USA. pwlongest@vcu.edu. 3. Department of Pharmaceutics, Virginia Commonwealth University, 410 North 12th Street, P.O. Box 980533, Richmond, Virginia, 23298-0533, USA. 4. Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, 401 West Main Street, P.O. Box 843015, Richmond, Virginia, 23284-3015, USA.
Abstract
PURPOSE: The objective of this study was to implement computational fluid dynamics (CFD) simulations and aerosol characterization experiments to determine best-case spray drying conditions of a tobramycin excipient enhanced growth (Tobi-EEG) formulation for use in a pediatric air-jet dry powder inhaler (DPI). METHODS: An iterative approach was implemented in which sets of spray drying conditions were explored using CFD simulations followed by lead candidate selection, powder production and in vitro aerosol testing. CFD simulations of a small-particle spray dryer were performed to capture droplet drying parameters and surface-averaged temperature and relative humidity (RH) conditions in the powder collection region. In vitro aerosol testing was performed for the selected powders using the pediatric air-jet DPI, cascade impaction, and aerosol transport through a pediatric mouth-throat (MT) model to a tracheal filter. RESULTS: Based on comparisons of CFD simulations and in vitro powder performance, recommended drying conditions for small-particle powders with electrostatic collection include: (i) reducing the CFD-predicted drying parameters of κavg and κmax to values below 3 μm2/ms and 114 μm2/ms, respectively; (ii) maintaining the Collector Surface RH within an elevated range, which for the Tobi-EEG formulation with l-leucine was 20-30 %RH; and (iii) ensuring that particles reaching the collector were fully dried, based on a mass fraction of solute CFD parameter. CONCLUSIONS: Based on the newly recommended spray dryer conditions for small particle aerosols, delivery performance of the lead Tobi-EEG formulation was improved resulting in >60% of the DPI loaded dose passing through the pediatric MT model.
PURPOSE: The objective of this study was to implement computational fluid dynamics (CFD) simulations and aerosol characterization experiments to determine best-case spray drying conditions of a tobramycin excipient enhanced growth (Tobi-EEG) formulation for use in a pediatric air-jet dry powder inhaler (DPI). METHODS: An iterative approach was implemented in which sets of spray drying conditions were explored using CFD simulations followed by lead candidate selection, powder production and in vitro aerosol testing. CFD simulations of a small-particle spray dryer were performed to capture droplet drying parameters and surface-averaged temperature and relative humidity (RH) conditions in the powder collection region. In vitro aerosol testing was performed for the selected powders using the pediatric air-jet DPI, cascade impaction, and aerosol transport through a pediatric mouth-throat (MT) model to a tracheal filter. RESULTS: Based on comparisons of CFD simulations and in vitro powder performance, recommended drying conditions for small-particle powders with electrostatic collection include: (i) reducing the CFD-predicted drying parameters of κavg and κmax to values below 3 μm2/ms and 114 μm2/ms, respectively; (ii) maintaining the Collector Surface RH within an elevated range, which for the Tobi-EEG formulation with l-leucine was 20-30 %RH; and (iii) ensuring that particles reaching the collector were fully dried, based on a mass fraction of solute CFD parameter. CONCLUSIONS: Based on the newly recommended spray dryer conditions for small particle aerosols, delivery performance of the lead Tobi-EEG formulation was improved resulting in >60% of the DPI loaded dose passing through the pediatric MT model.
Authors: Jeffry G Weers; John Bell; Hak-Kim Chan; David Cipolla; Craig Dunbar; Anthony J Hickey; Ian J Smith Journal: J Aerosol Med Pulm Drug Deliv Date: 2010-12 Impact factor: 2.849
Authors: Susan Hoe; James W Ivey; Mohammed A Boraey; Abouzar Shamsaddini-Shahrbabak; Emadeddin Javaheri; Sadaf Matinkhoo; Warren H Finlay; Reinhard Vehring Journal: Pharm Res Date: 2013-08-23 Impact factor: 4.200