In vitro performance testing of the novel Medspray wet aerosol inhaler based on the principle of Rayleigh break-up.
OBJECTIVE
A new inhaler (Medspray) for pulmonary drug delivery based on the principle of Rayleigh break-up has been tested with three different spray nozzles (1.5; 2.0 and 2.5 mum) using aqueous 0.1% (w/w) salbutamol and 0.9% (w/w) sodium chloride solutions.


METHODS
Particle size distributions in the aerosol were measured with the principles of time of flight (APS) and laser diffraction (LDA).


RESULTS
The Medspray inhaler exhibits a highly constant droplet size distribution in the aerosol during dose emission. Droplets on the basis of Rayleigh break-up theory are monodisperse, but due to some coalescence the aerosols from the Medspray inhaler are slightly polydisperse. Mass median aerodynamic diameters at 60 l.min(-1) from APS are 1.42; 1.32 and 1.27 times the theoretical droplet diameters (TD's) and median laser diffraction diameters are 1.29; 1.14 and 1.05 times TD for 1.5; 2.0 and 2.5 mum nozzles (TD: 2.84; 3.78 and 4.73 mum respectively).


CONCLUSIONS
The narrow particle size distribution in the aerosol from the Medspray is highly reproducible for the range of flow rates from 30 to 60 l.min(-1). The mass median aerodynamic droplet diameter can be well controlled within the size range from 4 to 6 mum at 60 l.min(-1).
de Boer
Anne H
AH
Department of Pharmaceutical Technology and Biopharmacy, University of Groningen, Groningen, The Netherlands. A.H.de.Boer@rug.nl
Wissink
Jeroen
J
Hagedoorn
Paul
P
Heskamp
Iwan
I
de Kruijf
Wilbur
W
Bünder
Ralf
R
Zanen
Pieter
P
Munnik
Paul
P
van Rijn
Cees
C
Frijlink
Henderik W
HW
D000336:Aerosols; D000420:Albuterol / Q000737:chemistry; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D009330:Nebulizers and Vaporizers; D010316:Particle Size; D012965:Sodium Chloride; D012996:Solutions
D000336:Aerosols; D012996:Solutions; D012965:Sodium Chloride; D000420:Albuterol