In this study, syringic acid-loaded TPGS liposome (SA-TPGS-Ls) was successfully prepared to improve oral bioavailability of syringic acid (SA). SA is a natural and notable antioxidant activity compound with its limited bioavailability ascribable to its poor aqueous solubility and fast elimination. Recently, TPGS has become a perfect molecular biomaterial in developing several carrier systems with sustained, controlled, and targeted the drug delivery. SA-TPGS-Ls was prepared via thin-film dispersion method and characterized in terms of particle size, stability, morphology, and encapsulation efficiency (EE). The results showed that SA-TPGS-Ls had regular spherical-shaped nanoparticles with EE of 96.48 ± 0.76%. The pharmacokinetic studies demonstrated a delayed MRT and prolonged t1/2, while relative oral bioavailability increased by 2.8 times. Tissue distribution showed that SA-TPGS-Ls maintained liver drug concentration while delayed elimination was also observed in the kidney. In CCl4-induced hepatotoxicity study, the activities of hepatic T-AOC, GSH-Px, CAT, GSH, and SOD were greatly elevated, while serum biological markers ALT, AST, and AKP were reduced after treatment of mice with SA-TPGS-Ls. Histopathological studies confirmed that SA-TPGS-Ls could remarkably improve the status of hepatic tissues. Collectively, SA-TPGS-Ls significantly improved the drug encapsulation efficiency, stability coupled with bioavailability of SA, hence increasing in vivo antioxidant activity of the drug.
Keywords: antioxidant activity; liposome; syringic acid; tissue distribution; vitamin E D-α-tocopheryl polyethylene glycol succinate.