Novel 1-indanone Thiosemicarbazone Antiviral Candidates: Aqueous Solubilization and Physical Stabilization by Means of Cyclodextrins

Pharm Res. 2012 Mar;29(3):739-55. doi: 10.1007/s11095-011-0599-y. Epub 2011 Oct 6.

Abstract

Purpose: To investigate cyclodextrin-mediated solubilization and physical stabilization of novel 1-indanone thiosemicarbazone (TSC) candidate drugs that display extremely high self-aggregation and precipitation tendency in water.

Methods: TSC/CD complexes were produced by co-solvent method, and TSC/CD phase-solubility diagrams were obtained by plotting TSC concentration as a function of increasing CD concentration. Size, size distribution, and zeta-potential of the different TSC/CD complexes and aggregates were fully characterized by dynamic light scattering. The morphology of the structures was visualized by atomic force microscopy.

Results: Results indicated the formation of Type A inclusion complexes; the solubility of different TSCs was enhanced up to 215 times. The study of physical stability revealed that, as opposed to free TSCs that self-aggregate, crystallize, and precipitate in water very rapidly, complexed TSCs remain in solution for at least 1 week. On the other hand, a gradual size growth was observed. This phenomenon stemmed from the self-aggregation of the TSC/CD complex.

Conclusions: 1-indanone TSC/CD inclusion complexes improved aqueous solubility and physical stability of these new drug candidates and constitute a promising technological approach towards evaluation of their activity against the viruses hepatitis B and C.

Keywords: 1-indanone thiosemicarbazone antiviral candidates; inclusion complexes; native and modified cyclodextrins; self-assembly; water-solubilization.