caa a22 4500 477127444 CHVBK 20180405111654.0 cr unu---uuuuu 170330e19970401xx s 000 0 eng 10.1023/A:1012087130114 doi (NATIONALLICENCE)springer-10.1023/A:1012087130114 Influence of Metering Chamber Volume and Water Level on the Emitted Dose of a Suspension-Based pMDI Containing Propellant 134a [Elektronische Daten] [Robert Williams III, Jie Liu, John Koleng] Purpose. To determine the influence of metering chamber volume of a valve and water content of an aerosol formulation containing propellant 134a on dose delivery through the valve (DDV) and aerodynamic particle size distribution of the emitted dose. Methods. The drug was admixed with ethanol, sonicated, and metered into cans. Valois DF10 RC valves were crimped onto the cans and propellant 134a was gassed through the valve. The DDV was determined using a dosage sampling tube. Aerodynamic particle size distributions were determined by cascade impaction. The water content was determined by Karl Fisher titration. Results. The DDV increased linearly and the aerodynamic particle size distribution was not influenced as the metering chamber volume of the valve was increased. More drug was emitted from the valve from the initial actuations of the can than from the end. Valves with larger metering chamber volumes demonstrated less variability in DDV than those with smaller metering chamber volumes for the initial actuations. The DDV determined for actuations at the end of the can decreased as water was added extemporaneously. The mass median aerodynamic diameter (MMAD) increased as the water level was increased in the formulation. The geometric standard deviation (GSD) and percent respirable fraction (RF) were not influenced by metering chamber volume or water content. Conclusions. The valve chosen for the development of pressurized metered dose inhaler (pMDI) formulations with propellant HFA 134a must be investigated to determine the uniformity of drug delivery. The presence of water influences the characteristics of the emitted dose. Plenum Publishing Corporation, 1997 pMDI nationallicence propellant 134a nationallicence metering chamber nationallicence water content nationallicence suspension formulation nationallicence Williams III Robert Division of Pharmaceutics, College of Pharmacy, University of Texas at Austin, 78712-1074, Austin, Texas aut Liu Jie Division of Pharmaceutics, College of Pharmacy, University of Texas at Austin, 78712-1074, Austin, Texas aut Koleng John Division of Pharmaceutics, College of Pharmacy, University of Texas at Austin, 78712-1074, Austin, Texas aut Pharmaceutical Research Kluwer Academic Publishers-Plenum Publishers 14/4(1997-04-01), 438-443 0724-8741 14:4<438 1997 14 11095 https://doi.org/10.1023/A:1012087130114 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1012087130114 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Williams III Robert Division of Pharmaceutics, College of Pharmacy, University of Texas at Austin, 78712-1074, Austin, Texas aut NATIONALLICENCE 700 1- Liu Jie Division of Pharmaceutics, College of Pharmacy, University of Texas at Austin, 78712-1074, Austin, Texas aut NATIONALLICENCE 700 1- Koleng John Division of Pharmaceutics, College of Pharmacy, University of Texas at Austin, 78712-1074, Austin, Texas aut NATIONALLICENCE 773 0- Pharmaceutical Research Kluwer Academic Publishers-Plenum Publishers 14/4(1997-04-01), 438-443 0724-8741 14:4<438 1997 14 11095 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer