Self assembly of amphiphilic (PEG)(3)-PLA copolymer as polymersomes: preparation, characterization, and their evaluation as drug carrier.

(PEG)(3)-PLA copolymer has been explored for the formation of polymersomes. For this, three chains of methoxy-PEG(1100) were directly attached to citric acid by esterification. (Methoxy-PEG(1100))(3)-citrate was then reacted at its hydroxyl terminal with different moles of d,l-lactide by ring-opening polymerization to obtain polymers with five different PEG-to-PLA ratios ranging from 10:90 to 90:10. Polymers were characterized by GPC, FTIR, (1)H NMR, and DSC, films were characterized for hydrophilicity by contact angle, and surface topography was observed by SEM and AFM. All five polymers were evaluated for the formation of polymersomes. Among these, polymers with PEG content of 10-30% were able to self-assemble into polymersomes. To affirm their self-arrangement and drug carrier properties, hydrophilic and hydrophobic dyes were simultaneously encapsulated in these structures. SEM and TEM analysis of the blank polymersomes confirmed the vesicular nature of the polymersomes, whereas CLSM analysis of dye-loaded polymersomes demonstrated the presence of two separate regions viz. hydrophilic core and hydrophobic wall. Hydrophobic dye, fluorescein was released relatively faster from the wall of polymersomes, whereas hydrophilic dye, propidium iodide, was released in controlled fashion up to 18 days. It is expected that these systems may serve as a suitable carrier for simultaneous or separate delivery of drug molecules with varying physicochemical properties.