Biomedical Engineering Reference
In-Depth Information
Figure 3.2
Representative H1-NMR spectra of a PEO-PCL triblock copolymer
in (a) CDCl3 and (b) water. From reference [62].
This synthesis has become routine to the point that yields are
often >90% with relatively monodisperse polymers (1.0-1.2). The
preparation of PEO-PCL micelles in aqueous solution usually relies
on polymer and drug in organic solvent being slowly added drop
wise to aqueous solvent [20-23]. Sonication can also be used to
solubilize PCL directly in aqueous solution [24, 25]. Dialysis followed
by lyophilization or solvent evaporation is then used to remove free
drug and organic solvent [22, 26]. Lyoprotectants, such as sugars
can be used during freeze drying to ensure colloidal stability upon
resuspension in aqueous solution [27]. Following purification and
drying, these polymers can be evaluated by a variety of conventional
solid characterization techniques.
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