Development of prilling process for biodegradable microspheres through experimental designs.

The prilling process proposes a microparticle formulation easily transferable to the pharmaceutical production, leading to monodispersed and highly controllable microspheres. PLGA microspheres were used for carrying an encapsulated protein and adhered stem cells on its surface, proposing a tool for regeneration therapy against injured tissue. This work focused on the development of the production of PLGA microspheres by the prilling process without toxic solvent. The required production quality needed a complete optimization of the process. Seventeen parameters were studied through experimental designs and led to an acceptable production. The key parameters and mechanisms of formation were highlighted.

New PLGA-P188-PLGA matrix enhances TGF-ß3 release from pharmacologically active microcarriers and promotes chondrogenesis of mesenchymal stem cells.

The use of injectable scaffolding materials for in vivo tissue regeneration has raised great interest in various clinical applications because it allows cell implantation through minimally invasive surgical procedures. In case of cartilage repair, a tissue engineered construct should provide a support for the cell and allow sustained in situ delivery of bioactive factors capable of inducing cell differentiation into chondrocytes. Pharmacologically active microcarriers (PAMs), made of biodegradable poly(d,l-lactide-co-glycolide acid) (PLGA), are a unique system, which combines these properties in an adaptable and simple microdevice. However, a limitation of such scaffold is low and incomplete protein release that occurs using the hydrophobic PLGA based microspheres. To circumvent this problem, we developed a novel formulation of polymeric PAMs containing a P188 poloxamer, which protects the protein from denaturation and may positively affect chondrogenesis. This poloxamer was added as a free additive for protein complexation and as a component of the scaffold covalently linked to PLGA. This procedure allows getting a more hydrophilic scaffold but also retaining the protective polymer inside the microcarriers during their degradation. The novel PLGA-P188-PLGA PAMs presenting a fibronectin-covered surface allowed enhanced MSC survival and proliferation. When engineered with TGFß3, they allowed the sustained release of 70% of the incorporated TGF-ß3 over time. Importantly, they exerted superior chondrogenic differentiation potential compared to previous FN-PAM-PLGA-TGF-ß3, as shown by an increased expression of specific cartilage markers such as cartilage type II, aggrecan and COMP. Therefore, this microdevice represents an efficient easy-to-handle and injectable tool for cartilage repair.

Chemical constituents of the leaves of Glochidion obliquum and their bioactivity.

A new flavonoid glycoside, globlin A (1), and eleven known compounds were isolated from methanolic extracts of the leaves of Glochidion obliquum. The structure of this new compound was established with a combination of 2D NMR techniques (COSY, NOESY, HMQC and HMBC) and HR-ESI-MS analyses. Chemical structures of the other known compounds were identified by comparison of their spectroscopic and physical data with those reported in the literature. Some of the isolates were examined for their bioactivities. Among the tested compounds, rotundic acid (4) displayed significant cytotoxicity and anti-inflammatory activities.