Intracellular pH-Sensitive PEG-<i>block</i>-Acetalated-Dextrans as Efficient Drug Delivery Platforms
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Abstract
Intracellular
pH-sensitive micelles of PEG-<i>block</i>-acetalated-dextran
(PEG-<i>b</i>-AC-Dex) were prepared and used for acid-triggered
intracellular release of anticancer drug. The hydrodynamic radii (<i>R</i><sub>h</sub>) of PEG-<i>b</i>-AC-Dex micelles
could increase after incubation in PBS solution at pH 5.5. Based on
the pH-responsive <i>R</i><sub>h</sub> variation behavior,
it was expected that the PEG-<i>b</i>-AC-Dex micelles should
be interesting for intracellular drug delivery. Thus, doxorubicin
(DOX), a wide-spectrum anticancer drug, was loaded into the micelles
and the pH-dependent release of the payload DOX was tested <i>in vitro</i>. The <i>in vitro</i> drug release profiles
showed that only a small amount of the loaded DOX was released in
PBS solution at pH 7.4, while up to about 90% of the loaded DOX could
be quickly released in PBS solution at pH 5.5. Compared to pH-insensitive
PEG-PLA micelles, the PEG-<i>b</i>-AC-Dex micelles displayed
a faster drug release behavior in tumor cells. Moreover, higher cellular
proliferation inhibition efficacy was achieved toward tumor cells.
These features suggested that DOX could be efficiently loaded and
delivered into tumor cells <i>in vitro</i> by the intracelluar
pH-sensitive micelles, leading to enhanced inhibition of tumor cell
proliferation. Therefore, the pH-sensitive micelles may provide a
promising carrier for acid-triggered drug release for cancer therapy