A spectroscopic and molecular modeling studies of the inclusion complexes of orciprenaline and terbutaline drugs with native and modified cyclodextrins

The inclusion complexation behavior of orciprenaline (ORC) and terbutaline (TER) with α-CD, β-CD, HP-α-CD and HP-β-CD are examined by absorption, fluorescence, life time and molecular modeling methods. ORC and TER forms 1:1 (CD/drug) inclusion complexes in lower CD concentrations and 1:2 (CD/drug) inclusion complexes with higher CD concentrations. The inclusion of both drugs with HP-CDs was stronger than that of native CDs. Both drugs exhibit dual emission (excimer) in the CD solution, whereas in water single emission is seen. The hydrogen bonding and van der Waals interaction between the drugs and the CD plays an important role in the inclusion complexes. Computational results show the side chain of the drugs encapsulated in the CD cavity. The molecular modeling results by PM3 were in good agreement with the experimental results.