Beclomethasone dipropionate 250 µg per dose metered dose inhalers: effect of Volumatic spacer on potentially respirable dose.
The aerodynamic particle size distribution of beclomethasone dipropionate from 250 µg per dose metered dose inhalers tested in conjunction with a Volumatic spacer, was studied using a multistage liquid impinger. The products tested were Becloforte (Allen and Hanburys), Becloforte (parallel import from Spain), Beclazone 250 (Norton Healthcare) and Filair Forte (3M Health Care). Tests were performed with either zero or 3 s time delay between actuation of the inhaler and sampling. Filair Forte gave significantly lower deposition than all the other products in both the <6.8 and <3.1 µm size ranges with both zero and 3 s residence times (49.8% less than Becloforte, UK-origin, at <6.8 µm, zero residence time). This was despite fitting well in the Volumatic. Testing a second batch of Filair Forte confirmed the low deposition results. The only other significant differences were greater depositions from Becloforte (Spanish) compared to Beclazone 250 (<6.8 µm, zero residence time and <3.1 µm, 3 s residence time) and between Becloforte (Spanish) and all the other products (<3.1 µm, zero residence time). The magnitude of these differences were, however, less marked than those shown by Filair Forte. Increasing the residence time of the aerosol in the Volumatic to 3 s, simulating how patients may use the inhaler/spacer combination, gave similar results to those obtained with zero residence time. Filair Forte, used with the Volumatic, delivered a relatively low dose in the potentially respirable size range, compared to Becloforte. No substantial differences were seen at <6.8 µm between Becloforte (UK or Spanish) or Beclazone 250. Further work would be required to determine the importance of the differences observed between the products in the <3.1 µm range.
Barnes
AR
Pharmaceutical Sciences Institute, Aston University, Birmingham, UK
Nash
S