Peroral administration of 14C-poly(D,L-lactic acid) nanoparticles coated with human serum albumin or polyvinyl alcohol to guinea pigs.

Biodegradable 14C-poly(D,L-lactic acid) (PLA50) nanoparticles coated either with a readily digestible protein albumin or with a non-digestible coating agent, polyvinyl alcohol (PVA), were prepared by the solvent evaporation technique. The nanoparticles were administered perorally to guinea pigs to evaluate the gastro-intestinal degradation of their PLA50 matrix. In the case of PLA50 nanoparticles coated with digestible albumin, substantial gastro-intestinal degradation of the PLA50 matrix occurred, leading to the passage of considerable amount (> or =45%) of water-soluble products across the gastrointestinal barrier.

Interactions of poly(lactic acid) and poly(lactic acid-co-ethylene oxide) nanoparticles with the plasma factors of the coagulation system.

When surfactant-stabilized biodegradable poly(lactic acid) (PLA) particles are injected into rats, the rate of clearance from blood is fast. The rate can be strongly reduced by using particles made from diblock copolymers of PLA and poly(ethylene oxide) (PLA-PEO), resulting in an increased duration of contact with the components of the coagulation system. Thus, possible adverse effects such as activation of the coagulation cascade could occur.

Effect of PEO surface density on long-circulating PLA-PEO nanoparticles which are very low complement activators.

The rapid uptake of injected nanoparticles by cells of the mononuclear phagocytes system (MPS) is a major obstacle when a long blood circulation time is needed. Whereas nanoparticles made from PLA and stabilized by surfactants (PLA-F68) are rapidly phagocytized, the rate of phagocytosis is strongly reduced in case of nanoparticles made from a diblock copolymer (PLA-PEO). Because of the role of the complement system in opsonization, this difference of phagocytosis was hypothesized to be related to this system.

Degradation of poly(D,L-lactic acid) nanoparticles coated with albumin in model digestive fluids (USP XXII).

Entirely biodegradable poly(D, L-lactic acid) (PLA50) nanoparticles coated with albumin were prepared by the solvent evaporation technique. Their degradative properties were investigated in simulated gastric and intestinal fluids (USP XXII). The degradation of the albumin coating was monitored by HPLC, whereas PLA50 degradation was determined by size exclusion chromatography (SEC) as well as by the detection of lactate in bulk solution by enzymatic assay.

Stealth Me.PEG-PLA nanoparticles avoid uptake by the mononuclear phagocytes system.

Nanoparticles were prepared from methoxy poly(ethylene glycol)poly(d,l-lactic acid) block copolymers (Me.PEG-PLA) or blends of Me.PEG-PLA and PLA by the precipitation-solvent diffusion method.