Study of beta-cyclodextrin and ethylated beta-cyclodextrin salbutamol complexes, in vitro evaluation of sustained-release behaviour of salbutamol

Solid complexes of salbutamol with beta-cyclodextrin (beta-CD) and different batches of ethylated beta-cyclodextrin (Et-beta-CD) in a 1 : 1 molar ratio were prepared by the freeze-drying method. Inclusion complexation of salbutamol with all the CD used was confirmed in the solid state by differential scanning calorimetry (DSC), and in aqueous solution by circular dichroism analysis and electrospray mass spectrometry (ES-MS). The dissolution rate of salbutamol from the inclusion complexes was determined in water. We discuss the behaviour of the dissolution profiles obtained, since the Et-beta-CD complexes displayed a slower release of salbutamol compared with the beta-CD complex.