In vitro investigations of α-amylase mediated hydrolysis of cyclodextrins in the presence of ibuprofen, flurbiprofen, or benzo[a]pyrene

[Display omitted] ► Porcine pancreatic α-amylase degrades γ- and hydroxypropyl-γ-cyclodextrins. ► α-, β- and hydroxypropyl-β-cyclodextrins are only degraded to a very limited extent. ► Degradation of hydroxylpropyl-γ-cyclodextrin depends on the degree of substitution. ► Complexation affects the degradation of the cyclodextrins in a limited way. ► γ-Cyclodextrins and derivatives seem as suitable vehicles for early animal experiments. In vitro studies of α-amylase degradation of α-, β- and γ-cyclodextrins and 2-hydroxypropyl-β- and -γ-cyclodextrins were investigated spectrophotometrically by measuring the formation of reducing sugars, the reaction products of α-amylase degradation. This was done to evaluate potential degradation and thereby biological conversion of the cyclodextrins if dosed orally, as the intestinal tract contains α-amylase for digestive purposes. The results demonstrated that only γ- and 2-hydroxypropyl-γ-cyclodextrins can be degraded by α-amylase to a relevant extent, that is, γ- and 2-hydroxypropyl-γ-cyclodextrins have different biopharmaceutical behaviours than the other evaluated cyclodextrins. The rate of degradation was affected by the addition of the inclusion complex forming additives flurbiprofen, ibuprofen and benzo[a]pyrene. This effect between the degradation dynamics and the included additives was caused by a correlation between solubility of the additives and the stability of the complex.