Wednesday, December 19, 2012

mPEG-P(DL)La and mPEG-PLLA EA solubility difference...

Recently a customer noted solubility differences between polyscitech mPEG-PLA's AK45 and AK31 and that AK31 is soluble in ethyl acetate while AK45 is not.  The difference between AK45 and AK31 relative to solubility is a technical issue related lactide chirality. Ethyl acetate is a solvent which would be considered "ok" for dissolving PLA's but not "great" and there is some difference between L-lactide (AK45) and DL-lactide (AK31) in terms of solubility performance based on chirality.  Similar problems also affect acetone, it will dissolve P(DL)La but not PLLa. This issue doesn't affect dichloromethane however as it dissolves both very well. Previous lab experience indicates that in this situation it is best to predissolve the polymer in DCM then mix with other solvents.
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