Chemistry Reference
In-Depth Information
SCHEME 11.15
The design and synthesis of “click” CD-decorated PCL. (Adapted from
ref. 41.)
via amidation. Catalyzed by Cu(I), mono-(6-azido-6-deoxy)-
-CD-N
3
)was
“clicked” onto the PCL as pendent functionalities with high efficiency (Scheme
11.15). As a proof of principle for the “click” CD-functionalized PCL to be used as
a delivery vehicle, potassium adamantyl carboxylate was complexed with the
-CD (
-CD-
grafted PCL. Dynamic light scattering (DLS) measurement suggests that the hydrody-
namic diameter of the polyesters was increased substantially as a result of electrostatic
repulsion of negatively charged carboxylate groups. Similar to this approach, “click”
CD-decorated dextran and glycodendrimer were also developed [27, 28].
Utilizing the guest/host capability of CDs, noncovalently connected micelles
(NCCMs) were developed as a novel drug delivery system. For regular micelle for-
mulations, the inner core of micelles is hydrophobic and serves as a nano-depot for
the payload and the outer shells are hydrophilic, which maintains the micelle stability
in water. Typically, micelles were formulated via the self-assembly of amphiphilic
molecules. For NCCMs, the most unique feature is that the linker between the
hydrophilic and hydrophobic segments of the amphiphilic molecules is of noncova-
lent nature. For example, Quan et al. developed an NCCM for cancer chemotherapy.
In their design, the hydrophobic segment is PCL terminated with an adamantyl group;
and the hydrophilic segment is a copolymer of NIPAAm and N-acryloxysuccinimide
(NAS), which is terminated with a smaller phenyl group. An
-CD dimmer was
“click” synthesized to join the hydrophilic and the hydrophobic segment together.
Due to different cavity sizes,
/
-CD
favors the complexation with adamantyl group (Scheme 11.16). By this host/guest
-CD prefers to complex with phenyl group while
O
N
N
H
N
O
N
H
R
2
R
1
O
SCHEME 11.16
The general design of “click”
/
-CD dimmer that noncovalently assem-
bles the hydrophilic/hydrophobic segments of the micelle construct. (Adapted from ref. 42.)
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