Drug delivery system based on PVA and clay for potential treatment of COVID-19

Tremendous efforts are being made around the world to develop efficient ways to prevent/treat the novel β-coronavirus disease (COVID-19) caused by SARS-CoV-2. There are currently many studies and clinical trials (either based on computational predictions or clinical experiences), in progress, focusing on finding relevant protein targets and medications anti-COVID-19. In the present study, we report a hydrogel drug delivery system based on Laponite® RD (Lap) entrapped in a poly(vinyl alcohol) (PVA) matrix obtained by freezing/thawing method. The PVA/Lap hydrogels were characterized in terms of their morphological, rheological, and swelling properties. Moreover, in vitro drug delivery investigations were performed with a promising drug, Rifampicin (Rif). Rif is an antitubercular drug and was selected for this study in order to demonstrate its efficacy as an anti-COVID-19 repurposed drug. In vitro studies were supplemented by in silico molecular docking simulations of Rif capacity of inhibition against SARS-CoV-2 target protein 3-chymotrypsin-like protease (3CLpro). The results obtained in this study are encouraging and we propose the Rif loaded PVA/Lap hydrogels as promising drug delivery systems for COVID-19 treatment, promoting a synergistic therapeutic effect by dual targeting of viral 3CLpro and S proteins.