10 research outputs found
Critical review: Injectability of calcium phosphate pastes and cements
Calcium phosphate cements (CPC) have seen clinical success in many dental and orthopaedic applications in recent years. The properties of CPC essential for clinical success are reviewed in this article, which includes properties of the set cement (e.g. bioresorbability, biocompatibility, porosity and mechanical properties) and unset cement (e.g. setting time, cohesion, flow properties and ease of delivery to the surgical site). Emphasis is on the delivery of calcium phosphate (CaP) pastes and CPC, in particular the occurrence of separation of the liquid and solid components of the pastes and cements during injection; and established methods to reduce this phase separation. In addition a review of phase separation mechanisms observed during the extrusion of other biphasic paste systems and the theoretical models used to describe these mechanisms are discussed
Injectable gellan gum-based nanoparticles-loaded system for the local delivery of vancomycin in osteomyelitis treatment
Infection spreading in the skeletal system
leading to osteomyelitis can be prevented by the prolonged
administration of antibiotics in high doses. However systemic
antibiotherapy, besides its inconvenience and often
low efficacy, provokes numerous side effects. Thus, we
formulated a new injectable nanoparticle-loaded system for
the local delivery of vancomycin (Vanc) applied in a
minimally-invasive way. Vanc was encapsulated in poly(Llactide-
co-glycolide) nanoparticles (NPs) by double-emulsification.
The size (258 ± 11 nm), polydispersity index
(0.240 ± 0.003) and surface potential (-25.9 ± 0.2 mV)
of NPs were determined by dynamic light scattering and
capillary electrophoresis measurements. They have a
spherical morphology and a smooth topography as
observed using atomic force microscopy. Vanc loading and
encapsulation efficiencies were 8.8 ± 0.1 and
55.2 ± 0.5 %, respectively, based on fluorescence spectroscopy
assays. In order to ensure injectability, NPs were
suspended in gellan gum and cross-linked with ; also a
portion of dissolved antibiotic was added to the system.
The resulting system was found to be injectable (extrusion
force 11.3 ± 1.1 N), reassembled its structure after
breaking as shown by rheology tests and ensured required
burst release followed by sustained Vanc delivery. The
system was cytocompatible with osteoblast-like MG-63
cells (no significant impact on cells’ viability was detected). Growth of Staphylococcus spp. reference strains
and also those isolated from osteomyelitic joints was
inhibited in contact with the injectable system. As a result
we obtained a biocompatible system displaying ease of
application (low extrusion force), self-healing ability after
disruption, adjustable drug release and antimicrobial
properties