Drug stabilization and controlled release from AB₃ type tetra block copolymer based polymersome

In order to increase the bioavailability of hydrophilic unstable drugs, polymersomes from AB₃ type tetra block copolymers composing of poly(ethylene glycol)-b-(3) poly(lactic acid) (EO-3LA) as a water-soluble drug delivery carrier have been investigated due to its unique properties such as high stability and high water soluble drug loading efficiency. The sizes of EO-3LA polymersomes determined by dynamic light scattering were ranged in 190-220 nm with monodispersion. Its polymeric layer with 10-20 nm at the outershell was observed by field emission scanning electron microscopy. The polymersomes showed low critical aggregation concentrations (9. 2-14. 9 ug/ml). Anthocyanin was employed as a model drug for unstable drug in this study. The anthocyanin loading contents of EO-3LA polymersomes are depending on PLLA content in the polymers. The high loading contents (6. 6-7. 0 wt%) of the polymersomes are due to their tight and rigid polymeric membranes. The polymeric membrane in EO-3LA polymersomes contributed to improve drug stability on various pHs. Moreover, this property induced sustained anthocyanin release pattern from the polymersome. Therefore, the polymersome has potential as a drug carrier for water-soluble and unstable drugs.