Sustained release and intestinal absorption of drug from the hydrophobic α, β- and γ-cyclodextrin complexes

Hydrophobic cyclodextrin derivatives, peracylated alpha-, beta- and gamma-cyclodextrin (CyD) with different alkyl chains (acetyl; butanoyl and propanoyl), were used to form a complex with flufenamic acid (FA). The hydrophobic CyD complex formation was demonstrated by differential scanning calorimetry and powder X-ray diffractometry. The release rate of FA from the hydrophobic CyD derivatives were divided into two groups in phosphate buffer pH 6.8, but the release rate in all complexes was significantly retarded compared to that of the FA mixture. An increased mean residence time of FA following the hydrophobic CyD complex administration was observed. These results indicate that the hydrophobic CyD complex may serve as a hydrophobic carrier in sustained-release preparations of FA for oral and transdermal application.