Investigation of some commercially available spacer devices for the delivery of glucocorticoid steroids from a pMDI

Five commercially available spacers were investigated to determine their in fluence on the percentage of drug retained in the spacer device, percentage fine particle fraction (FPF), percentage deposited in the induction port, mass median aerodynamic diameter (MMAD), and geometric standard deviation ( GSD). Betamethasone valerate (BMV) and triamcinolone acteonide (TAA) were u sed as model drugs in the pressurized metered dose inhaler (pMDI) formulati on containing the propellant HFA 134a. The BMV was dissolved in an ethanol/ HFA 134a system, and the TAA was suspended in HFA 134a using ethanol as a d ispersing agent. The metering chamber volume of the valve was either 50 mul or 150 mul. The spacer devices investigated included the ACE(R), Aerochamb er(R), Azmacort(R), Easivent(R), and Ellipse(R) spacers. Eacher spacer devi ce was attached to an Andersen Cascade Impactor powered by a vacuum pump. C ascade impaction data were used to derive the percentage drug deposited in the induction port, MMAD, GSD, and FPF. The BMV particles emitted from the spacer were finer than the TAA particles because the dissolved drug precipi tated as the cosolvent evaporated. The TAA particles had significantly larg er MMADs because many undissolved drug particles were contained within each droplet following actuation. After evaporation of the liquid continuous ph ase, the suspended drug aggregated to form larger agglomerates than those p articles precipitated from the BMV pMDI solution droplets. The addition of a spacer device lowered the MMAD to less than 4.7 mum for particles from bo th the BMV pMDI solution and the TAA pMDI suspension. The addition of a spa cer device also lowered the percentage drug deposited in the induction port . The FPF was significantly increased when a spacer device was used. The MM AD significantly decreased when a spacer device was added for the two model drugs when using the 150-mul metering valves, bur the difference was not s tatistically significant when the 50-mul valves were used (P<.05). The GSD was not influenced by the use of a spacer device. The use of a spacer devic e will enhance pMDI therapy by reducing the amount of drug deposited in the oropharyngeal region, which will lead to fewer instances of local and syst emic side effects. In addition. the spacer devices investigated will allow a higher dose of drug to reach the deep lung, which may permit the use of l ower dosage regimens with increased therapeutic efficacy.