Sivifene

Electrospray-ionization mass spectrometric (ESIMS) studies of several A007 prodrugs in aqueous cyclomaltohexaose (alpha-cyclodextrin, alpha-CD), cyclomaltoheptaose (beta-cyclodextrin, beta-CD), and cyclomaltooctaose (gamma-cyclodextrin, gamma-CD) were performed. The acetic acid derivative of A007 should metabolize in vivo before becoming the A007 prodrug, while on the other hand, the glycine-modified A007 prodrug has surfactant-like physical properties and slowly hydrolyzed in the aqueous cyclodextrins by releasing free A007. ESIMS studies give insight into the process of prodrug hydrolysis in the presence of cyclodextrins and, hence, the influence of cyclodextrins on the timely release of the A007 prodrug. Formation of various molecular aggregates and cyclodextrin inclusion complexes of A007 prodrugs and their hydrolyzed products was demonstrated by ESIMS.

One- and two-dimensional NMR spectroscopy was used to demonstrate the formation of inclusion cyclodextrin complexes with several A-007 prodrugs. These complexes are comprised from the encapsulation of the two phenol moieties of the A-007 prodrugs within the cyclodextrin cavity. Considering the size of the two phenol moieties of the A-007 prodrugs compared to the sizes of alpha-, beta-, and gamma-cyclodextrin cavities, we observed complementary binding of the A-007 prodrug with only beta-cyclodextrin, which was also demonstrated spectroscopically. The beta-cyclodextrin inclusion complexes increased the prodrug solubility and modified the prodrug half-life in water. Therefore, beta-cyclodextrin inclusion complexes can be used as an essential form of A-007 prodrug delivery.