The Effect of Branching (Star Architecture) on Poly(d,l-lactide) (PDLLA) Degradation and Drug Delivery

This study focuses on the comparative evaluation of star (branched) and linear poly(L,D-lactic acid) (PDLLA) as degradable materials employed in controlled release. The polymers were prepared via ring-opening polymerization initiated by decanol (linear), pentaerythritol (4-armed star) and dipentaerythritol (6-armed star), and processed both in the form of films and nanoparticles. Independently on the length or number of their arms, star polymers degrade slower than linear polymers, possibly through a surface (vs. bulk) mechanism Further, the release of a model drug (atorvastatin) followed a zero-order-like kinetics for the branched polymers, and a first order kinetics for linear PDLLA. Using NHOst osteoblastic cells, both linear and star polymers were devoid of any significant toxicity and released atorvastatin in a bioavailable form; cell adhesion was considerably lower on star polymer films, and the slower release from theirnanoparticles appeared to be beneficial to avoid atorvastatin overdosing.