Applicability of Bipolar Charge Analyzer (BOLAR) in Characterizing the Bipolar Electrostatic Charge Profile of Commercial Metered Dose Inhalers (MDIs).
OBJECTIVE
To investigate the applicability of Bipolar Charge Analyzer (BOLAR), a new commercial instrument developed by Dekati Ltd., in simultaneously characterizing the bipolar electrostatic charge profile and measuring the size distribution of commercial metered dose inhalers (MDIs).


METHODS
Intal Forte(®) (sodium cromoglycate), Tilade(®) (nedocromil sodium), Ventolin(®) (salbutamol sulphate), and QVAR(®) (beclomethasone dipropionate) were used as model MDIs in this study. Three individual actuations of each MDI were introduced into the BOLAR at an air flow rate of 60 l/min. Charge and mass profiles for each actuation were determined.


RESULTS
The BOLAR was found to have better performance in collecting valid charge data (≥80%) than valid mass data (≥50%). In all tested products, both positively and negatively charged particles were found in five defined size fractions between zero and 11.6 μm, with the charge magnitude decreased with increasing particle size. The net charge profiles obtained from the BOLAR qualitatively agreed with the results reported previously. In all suspension type MDIs, negligible masses were detected in the smallest size fraction (<0.95 μm), for which the charge was most likely caused by the propellant and excipients. QVAR was the only solution MDI tested and the charge and mass profiles were significantly different from the suspension-type MDIs. Its mass profile was found to follow closely with the charge profile.


CONCLUSIONS
Positively and negatively charged MDI particles of different size fractions and their corresponding charge-to-mass profiles were successfully characterized by the BOLAR.
Faculty of Pharmacy, The University of Sydney, Sydney, NSW 2006, Australia.
Sharon Shui Yee
SS
Leung
Faculty of Pharmacy, The University of Sydney, Sydney, NSW 2006, Australia.
Adam Chong Ming
AC
Chiow
Dekati Ltd., Tykkitie 1, FIN-36240, Kangasala, Finland.
Ari
A
Ukkonen
Faculty of Pharmacy, The University of Sydney, Sydney, NSW 2006, Australia. kim.chan@sydney.edu.au.
Hak-Kim
HK
Chan
D000336:Aerosols / Q000737:chemistry*; D000420:Albuterol / Q000737:chemistry; D018927:Anti-Asthmatic Agents / Q000737:chemistry; D001507:Beclomethasone / Q000737:chemistry; D001993:Bronchodilator Agents / Q000737:chemistry; D002626:Chemistry, Pharmaceutical / Q000295:instrumentation; D004205:Cromolyn Sodium / Q000737:chemistry; D004867:Equipment Design; D006801:Humans; D036501:Metered Dose Inhalers; D017835:Nedocromil / Q000737:chemistry; D010316:Particle Size; D055672:Static Electricity
D000336:Aerosols; D018927:Anti-Asthmatic Agents; D001993:Bronchodilator Agents; D017835:Nedocromil; D001507:Beclomethasone; D004205:Cromolyn Sodium; D000420:Albuterol
BOLAR; aerosols; bipolar charge; electrostatic charge; particle deposition