Abstract
We newly designed poly(ethyleneoxide monooleate-block-D,L-lactide) (MOPEO-PLA), which is oil-soluble biodegradable polymer surfactant and found that this polymer surfactant provided a brand-new reverse micelle system. This finding is expected as a new procedure for the preparation of PLA microcapsules enclosing proteins with a potential for long-term release of stable proteins. In order to realize the proposed technique, we investigated the extraction behavior of cytochrome c in MOPEO-PLA reverse micellar solution by liquid-liquid extraction. The water content in chloroform phase drastically increased with an increase in a MOPEO-PLA concentration, indicating that MOPEO-PLA reverse micelle was formed with a large amount of water molecules. The extraction of cytochrome c in MOPEO-PLA reverse micellar solution showed the maximum value when the pH of the aqueous phase was adjusted to pI of cytochrome c. This suggested that the electrostatic interaction between the cytochrome c and the MOPEO-PLA was weak. The temperature dependence on the extraction performance of cytochrome c indicated that the extraction percentage increased at the higher temperature. From these results, the main factor for the extraction of the cytochrome c was found to be the hydrophobic interaction with the MOPEO-PLA. As a result of preparing the PLA microcapsules enclosing the cytochrome c using a MOPEO-PLA reverse micelle, the microcapsules was spherical with high entrapment of cytochrome c.
