TY  - JOUR
A1  - Machatschek, Rainhard Gabriel
A1  - Lendlein, Andreas
T1  - Fundamental insights in PLGA degradation from thin film studies
T2  - Journal of controlled release : official journal of the Controlled Release Society and of the Japanese Society of Drug Delivery Systems
N2  - Poly(lactide-co-glycolide)s are commercially available degradable implant materials, which are typically selected based on specifications given by the manufacturer, one of which is their molecular weight. Here, we address the question whether variations in the chain length and their distribution affect the degradation behavior of Poly[(rac-lactide)-co-glycolide]s (PDLLGA). The hydrolysis was studied in ultrathin films at the air-water interface in order to rule out any morphological effects. We found that both for purely hydrolytic degradation as well as under enzymatic catalysis, the molecular weight has very little effect on the overall degradation kinetics of PDLLGAs. The quantitative analysis suggested a random scission mechanism. The monolayer experiments showed that an acidic micro-pH does not accelerate the degradation of PDLLGAs, in contrast to alkaline conditions. The degradation experiments were combined with interfacial rheology measurements, which showed a drastic decrease of the viscosity at little mass loss. The extrapolated molecular weight behaved similar to the viscosity, dropping to a value near to the solubility limit of PDLLGA oligomers before mass loss set in. This observation suggests a solubility controlled degradation of PDLLGA. Conclusively, the molecular weight affects the degradation of PDLLGA devices mostly in indirect ways, e.g. by determining their morphology and porosity during fabrication. Our study demonstrates the relevance of the presented Langmuir degradation method for the design of controlled release systems.
KW  - PDLLGA
KW  - Degradation
KW  - Langmuir monolayer
Y1  - 2019
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/61471
SN  - 0168-3659
SN  - 1873-4995
VL  - 319
SP  - 276
EP  - 284
PB  - Elsevier
CY  - New York
ER  -