Biomedical Engineering Reference
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Figure 32.2. The effect of the addition of H 2 O 2 on the continuous phase
duringthesynthesisofmicrospheres.Encapsulatione ciencyisdependent
ontheconcentrationofH 2 O 2 addedtothecontinuousphaseduetotheback-
ward concentration gradient. Percentage values stated on the graph rep-
resent the concentration of H 2 O 2 added to the continuous solution during
synthesis.
The pH condition of the continuous phase is also an influencing
parameter during the synthesis, which needs to be controlled. Dur-
ing the encapsulation of H 2 O 2 , a slight basic condition produces a
smoothersurfaceofmicrospherescomparedwiththelowerpHthat
seems to produce tiny holesand uneven-shaped spheres (Fig. 32.3).
Although H 2 O 2 is stable at a neutral condition, while it usually
decomposes in a highly alkaline medium, this observation was not
Figure 32.3. The effect of pH at continuous phase during synthesis
towards the morphology of PLGAmicrospheres encapsulated with H 2 O 2 .
 
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