THE EFFECT OF POSITIVE EXPIRATORY PRESSURE (PEP) ON AEROSOLIZED ALBUTEROL DELIVERY.
J.L. Rau, Ph.D., RRT, Georgia State University, Atlanta, GA.
The combination of positive expiratory pressure (PEP) with inhalation of aerosolized albuterol may improve lung delivery. Purpose: The purpose of the study is to determine the effect of PEP on delivery of albuterol by metered dose inhaler (MDI) with either a chlorofluorocarbon (CFC) or hydrofluoroalkane (HFA) propellant.
Methods: MDI delivery of CFC albuterol (ProventilÒ) and HFA albuterol (ProventilÒ HFA) was assessed with an Aerosol Cloud Enhancer (ACE, DHD) reservoir, with and without a PEP device (TheraPEP, DHD) attached. Drug delivery was assessed using an Anderson 8 stage particle size impactor operated at 28.3 Lpm (± 0.5). Aerosol delivery systems were attached to the USP throat for impaction testing. The PEP device was inserted between the reverse-firing ACE and the USP induction throat. Drug collected on impactor plates was analyzed spectrophotometrically at 276 nm, and the fine particle fraction determined as the mass of drug £ 4.7 mm. Amounts of drug were predicted from sample absorbances using previously fitted linear regression equations for the base (CFC albuterol) and sulfate (HFA albuterol) respectively.
Results: Total drug mass, fine particle fractions (% fine), and mass median aerodynamic diameters (MMAD, mm) are reported for each delivery system. Means (and standard deviations) are given. HFA albuterol sulfate is reported as the sulfate, with 120 mg of the sulfate equivalent to 100 mg of albuterol base.
There was no significant difference in delivery between the MDI/ACE alone, and with the PEP device attached (Wilcoxon signed ranks test, p > 0.05), for either CFC or HFA albuterol. Conclusion: The use of the TheraPEP device does not reduce either the total or respirable dose or the MMAD of MDI albuterol with either CFC or HFA propellants.