Beclomethasone/cyclodextrin inclusion complex for dry powder inhalation

Cyclodextrins can be used in order to suitably modify the biopharmaceutical properties of drugs. A complex of beclomethasone dipropionate/hydroxypropy l-beta-cyclodextrin was formed as shown by the apparent solubility constant , differential scanning calorimetry and X-ray spectroscopy. With a view to developing a suitable formulation for pulmonary delivery of the above compl ex, a comparative study of the drug/cyclodextrin complex, the physical mixt ure of the drug and the cyclodextrin and the chug alone was performed as th e in vitro aerosol deposition of the emitted close from an inhalation devic e, the Micro-haler dry powder inhaler using the twin impinger apparatus (Eu ropean Pharmacopoeia). The results show a significant respirable fraction f or both the complex and drug/hydroxypropyl-beta-cyclodextrin mixtures used, which indicates the potential of the above formulation for pulmonary deliv ery. The results are in the following order: complex alone > micronized dru g + cyclodextrin physical mixture much greater than micronized drug alone.