(83f) Poly(lactic acid) Based Biodegradable Surfactants and Their Potentials for Drug Delivery

Poly(Lactic
Acid)-based nanoparticles or nanoclusters are often used as drug carriers,
nevertheless these carriers need to be stabilized by a surfactant. In order to
be used for biological purposes, these surfactants have to be primarily
non-toxic and preferably biodegradable. Biodegradability of these compounds
allows their complete elimination after a certain time. In this work two
families of PLA-based biodegradable surfactants have been produced as a result
of two different synthetic routes.

Firstly, direct
initiation of L,L-Lactide with an FDA-approved catalyst and different monomeric
cocatalysts has been carried out to produce PLA di- or tri-block copolymers or
the precursors for producing ionic surfactants through bulk Ring-Opening
Polymerization (ROP).

Secondly, short
PLA chains produced by ROP have been properly end-modified to yield a
monofunctional PLA-based ATRP (Atom Transfer Radical Polymerization)
macro-initiator, from which a second hydrophilic polymer block is initiated by
ATRP to produce PLA di-block copolymers.

The reaction
kinetics and structures of the corresponding amphiphilic copolymers are studied
by SEC and 1H-NMR respectively. After confirming their solubility in water,
their Critical Micellization Concentrations are determined by surface tension
measurements. Experiments utilizing these surfactants are performed to prove
their stabilization effect and biodegradability. Moreover, in order to test
their toxicity, the surfactants are cultivated with U266 human myeloma cells.
According to the results of the above mentioned studies, their applicability as
bio-vesicles stabilizers is assessed.