Polylactide, enhanced drug release

FONG ET AL. Enhancing Drug Release from Polylactide Microspheres... 

These polylactides are known to degrade by hydrolysis (4.) Therefore, the most obvious explanation is that the molecular weight of the polymer is decreased by the NaOH. It has been reported (6) that drug release is increased when the polymer molecular weight is lowered. This would then account for the enhanced drug release observed. 

In the preparation of microspheres by solvent evaporation from oil-in-water emulsions, the presence of base (NaOH) was found to enhance the release of thioridazine from polylactide micro-spheres. The amount of drug release as a function of time was dependent on the amount of base added to the aqueous phase of the emulsion. Scanning electron micrographs indicate that this increased drug release may be due to modification of the internal structure of the microspheres by sodium hydroxide during fabrication. 

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