Polymeric nanoparticles based on polylactide and related copolymers

Abstract

The preparation of nanoparticle suspensions was carried out by using commercial biodegradable polymers as poly(d,l‐lactide), poly(d,l‐lactide‐co‐glycolide) and poly(d,l‐lactide‐co‐ϵ‐caprolactone). The method of preparation was based on the controlled addition of polymer organic solution to an aqueous phase containing dispersing agents. Poly(ethylene glycol) (10, 20, and 35 kDa grade), Tween 20, and Pluronic F‐127 were used as dispersing agents in the aqueous phase. Content and type of both polymeric matrix and dispersing agent resulted of paramount relevance for the attainment of monodispersed nanoparticles with average diameter of about 130 nm. The addition of a steric stabilizer allowed for nanoparticle purification and isolation while preventing their agglomeration. The best results were obtained by using 35 kDa grade poly(ethylene glycol) as dispersing agent and either mannitol or glycidylisopropylidenglyceryl‐β‐cyclo‐dextrin as steric stabilizer. The adopted procedure afforded biodegradable nanoparticle suspensions that could be used for the incapsulation and intravenous administration of biologically active proteins and oligopeptides.

Effect of wood flour loading and thermal annealing on viscoelastic properties of poly(lactic acid) composite films

“…As seen in Table II, tan δ is inversely proportional to WF c for a given annealing temperature 27. The restriction of molecular chain movements is driven by two factors: (1) matrix crystallinity40 and (2) presence of WF. The crystalline portions in PLA matrices filled with 20–50% wood fibers, annealed at T A = 90–100°C, turned out to be constant, whereas though tan δ decreased within the same T A range.…”

Methods for the Preparation and Manufacture of Polymeric Nanoparticles

“…The main problem of this technique is that nanospheres are not always easy to re-disperse after ultracentrifugation (106,(219)(220)(221). Aggregates may remain and the uses of vortex or ultrasounds are often mentioned as methods used to redispersed pellets after ultracentrifugation (39,217).…”

Comparison of Diafiltration and Tangential Flow Filtration for Purification of Nanoparticle Suspensions

“…Furthermore, it is very difficult to recover all nanoparticles of fine size even with ultracentrifugation. Other authors also raised the same concern on the impact of the centrifugation forces on the redispersibility and morphology of polylactide (PLA)-based nanoparticles (20). To overcome this problem, we initially utilized a dialysis technique to remove PVA.…”

“…Centrifugation or ultracentrifugation, in combination with washing nanoparticles with an appropriate medium such as deionized water, is the most common approach to remove large quantities of process impurities (17,18). However, the impact of the centrifugation force can cause caking and difficulties in redispersing nanoparticles (19,20). A significant loss of nanoparticles to the supernatant can also occur when insufficient centrifugation force is applied, resulting in a low yield of nanoparticles.…”