Nanoemulsion-Loaded Hydrogels for Topical Administration of Pentyl Gallate.

The aim of this study is to describe the development of nanoemulsion-loaded hydrogels to deliver pentyl gallate (PG), a gallic acid n-alkyl ester, through the skin. PG is an antioxidant agent; however, it seems to be a promising agent for herpis labialis treatment. Aristoflex AVC® and chitosan were used as gelling agents for nanoemulsion thickening. The developed formulations presented suitable PG content (94.4-100.3% w/w), nanometric droplet sizes (162-297 nm), high zeta potentials, and a non-Newtonian pseudoplastic behavior. Both vehicles neither enhanced PG penetration nor delayed its release from the nanoemulsion. Formulations remained physically stable at 8°C during 3 months of storage.

Anti-HSV-1 and anti-HIV-1 activity of gallic acid and pentyl gallate

The synthetic n-alkyl esters of gallic acid (GA), also known as gallates, especially propyl, octyl and dodecyl gallates, are widely employed as antioxidants by food and pharmaceutical industries. The inhibitory effects of GA and 15 gallates on Herpes Simplex Virus type 1 (HSV-1) and Human Immunodeficiency Virus (HIV-1) replication were investigated here. After a preliminary screening of these compounds, GA and pentyl gallate (PG) seemed to be the most active compounds against HSV-1 replication and their mode of action was characterized through a set of assays, which attempted to localize the step of the viral multiplication cycle where impairment occurred. The detected anti-HSV-1 activity was mediated by the inhibition of virus attachment to and penetration into cells, and by virucidal properties. Furthermore, an anti-HIV-1 activity was also found, to different degrees. In summary, our results suggest that both compounds could be regarded as promising candidates for the development of topical anti-HSV-1 agents, and further studies concerning the anti-HIV-1 activity of this group of molecules are merited.