Development of an adhesive tablet for the delivery of Diospyros villosa root for the treatment of oral cavity diseases

Abstract

The Diospyros villosa root extract (DVR) has the potential to treat oral cavity diseases (DOC), as confirmed by its frequent use as a toothbrush among Mozambicans. In the present work, a tablet with adhesive properties was developed with properties that have the potential to overcome the expected difficulties in delivering the drug into the oral cavity. The chemical profile of the extract marker secondary metabolites was established by TLC and LC-UV/DAD, and the quantification of its main classes was performed by UV and IR spectrophotometries. The size of the particles of the extract was determined by laser diffractometry. The tablets manufactured were evaluated to confirm the extract chemical stability based on the major marker secondary metabolite profile, throughout processing (differential scanning calorimetry, DSC and Fourier transform infrared spectroscopy, FTIR) and their performance based on adhesion forces (i.e., force required to remove a tablet from a flat surface) and for their ability to release the main marker secondary metabolites (dissolution test). The study has shown that the use of colloidal silica in the preparation of the extract delivered a powder containing particles with improved flow and by adding an adhesive polyacrylic acid derivative to the composite extract particles it was possible to obtain a blend enabling the manufacture of adhesive tablets by direct compression. Overall, the study demonstrated the ability to produce DVR-containing adhesive tablets for buccal use against DOC.