[Evaluation of the performance of three spacers]

Several aspects are known to influence the drug distribution within the low respiratory tract, with particular emphasis on those related to the inhalation device. The aim of this work was to assess the performance of three spacers in the drug release, and also the quantity of active agent deposited inside these devices.

In order to evaluate the behaviour of particles in suspension delivered through the Ventilan®HFA inhaler coupled to three different spacers (Volumatic®, AeroChamber MAX® and NebuChamber®) the Multistage Liquid Impinger (MSLI) was used, according to the Portuguese Pharmacopoeia. The mass of salbutamol sulphate deposited on the different impinger compartments and inside the spacer was determined by spectrophotometry, with the purpose of determining the percentage of cumulative mass for each spacer, and then the fine particle fraction. The results were compared statistically using a one-way analysis of variance (one-way ANOVA) with a Bonferroni post-hoc test.

About 40 to 50% of salbutamol sulphate was found deposited in the body of the three spacers. This deposition was slightly lower for NebuChamber® (average ± standard deviation of 43.8 % ± 11.6 %), in relation to Volumatic® (p=0.351) or AeroChamber MAX® (p=0.115). The fine particle fraction reached values of 28.2 ± 4.1%, 29.6 ± 2.4% and 30.9 ± 6.7% for Volumatic®, AeroChamber MAX® and NebuChamber®, respectively.

The spacers showed to have similar efficiencies in the delivery of salbutamol sulphate in the last stages, and there was no relation between the results and the spacers characteristics such as volume, shape and material. Therefore, Volumatic® appears to be perfect for hospital use, since its big volume does not constitute a disadvantage, and its lower cost, when compared to the remaining two spacers, represents an advantage of utmost importance for public hospitals.