Tuning Aerosol Particle Size Distribution of Metered Dose Inhalers Using Cosolvents and Surfactants

Table 4

Comparison of HFA 227 formulations with different concentrations of ethanol (data represent mean ± SD, 𝑛=3).

	Ethanol concentration (% w/w)/(vapor pressure, psi)
	5 (59.8 psi)	10 (54.6 psi)	13 (52.8 psi)	15 (50.2 psi)
ED (μg)	195.08 ± 23.25	194.26 ± 14.19	193.31 ± 12.44	209.52 ± 11.02
FPF (%)	54.31 ± 5.65	45.39 ± 2.90	35.02 ± 2.26**	29.27 ± 0.77*
FPD (μg)	105.07 ± 2.31^±	87.91 ± 1.73^±	67.52 ± 0.38^±	61.28 ± 1.79^±
MMAD (μm)	5.13 ± 0.23	5.05 ± 0.15	5.55 ± 0.18	5.79 ± 0.05*
GSD	1.74 ± 0.12	2.07 ± 0.01	1.73 ± 0.03	1.78 ± 0.01
VMD (μm)	5.32 ± 0.54	8.03 ± 0.36	9.72 ± 0.56	12.0 ± 0.44*

ED: emitted dose, MMAD: mass median aerodynamic diameter, FPF: fine particle fraction, FPD: fine particle dose, and GSD: geometric standard deviation. *𝑃<0.05 (ANOVA/Tukey’s) 15% w/w EtOH versus 10 and 5% w/w EtOH, **𝑃<0.05 (ANOVA/Tukey’s) 13% w/w EtOH versus 10 and 5% w/w EtOH, and ^±𝑃<0.05 comparing all formulations (ANOVA/Tukey’s).