67-72 After preparing the inverted emulsions they can be poured into a dish, followed by immediate freezing in a liquid nitrogen bath selleck kinase inhibitor so as to form a porous drug-loaded film. It can also coat any structure (dense fiber, stent or any bulky 3D structure). The following freeze drying process enables to preserve the micro/nano-structure of the inverted emulsion and get a solid implant encapsulated with drug molecules. The whole process of preparation in described in Figure 1. Examples for implant structures are presented in Figure 2. These include a porous film (Fig. 2A), a composite mesh/matrix structure composed of a mesh made of dense fibers and porous matrix (Fig. 2B), and a core/shell composite fiber (Fig. 2C). All porous elements in these structures are prepared using the freeze drying of inverted emulsion technique.
Their microstructure is shown in high SEM magnification in a separate circled part of Figure 2. Figure 1. A schematic representation of the freeze drying of inverted emulsion process. Figure 2. SEM micrographs of biodegradable drug-loaded porous structures derived from freeze-dried inverted emulsions: (A) cross section of a film, (B) composite mesh/matrix structure and (C) cross section of core/shell fiber. High magnification … The freeze-drying of inverted emulsions technique is unique in being able to preserve the liquid structure in solids and was employed in our studies in order to produce highly porous micro and nano-structures, as those presented in Figure 2, that can be used as basic elements or parts of various implants and scaffolds for tissue regeneration.
This fabrication process enables the incorporation of both water-soluble and water-insoluble drugs into the film in order to obtain an ��active implant�� that releases drugs to the surrounding in a controlled manner and therefore induces healing effects in addition to its regular role (of support, for example). Water-soluble bioactive agents are incorporated in the aqueous phase of the inverted emulsion, whereas water-insoluble drugs are incorporated in the organic (polymer) phase. Sensitive bioactive agents, such as proteins, can also be incorporated in the aqueous phase. This prevents their exposure to harsh organic solvents and enables the preservation of their activity. There are numerous medical applications for our freeze-dried drug-eluting structures.
For example: porous films, fibers, or composite structures loaded with water-soluble drugs, such as antibiotics, can be used for wound dressing applications, treatment Carfilzomib of periodontal diseases, meshes for Hernia repair, as well as coatings for fracture fixation devices. Fibers loaded with water insoluble drugs such as antiproliferative agents can be used as basic elements of drug-eluting stents and also for local cancer treatment. Films and fibers loaded with growth factors can be used as basic elements of highly porous scaffolds for tissue regeneration.