SLMs embedded within bioactive dressings as dermal matrices for wound repair

The abilities of an ideal wound dressings can be summarised as follows: increase healing, decrease pain, safety, cost-effectiveness, flexibility, moisture-permeability and long term activity. However, controlling the release of water soluble drugs from bioactive dressings is challenging because of their hydrophilic nature. To that aim, several approaches have been undertaken, involving the formation of inter- and intra-molecular covalent bonds, control of morphology and surface modification options or synthesis of new composite polymers. This study concerns on an original formulative/manufacturing approach for the development of a multi-composite wound dressing able to control the release of a water soluble API (lidocaine HCl) for several days. The prepared multi-composite wound dressing is a microstructured spongy matrix, which embeds solid lipid microparticles (SLMs). The release control is due to a particular ratio between two biopolymers (chitosan and alginate) and to the presence of SLMs within the polycomplex. SLMs have been prepared by spray congealing, a low cost, easy and solvent free technology; then they have been incorporated into different polyelectrolyte complexes, which have been freeze dried to obtain the spongy matrices. Moreover, the long-term delivery system, with the addition of extra cellular matrix components as hyaluronan and cysteine, is able to improve the proliferation of fibroblasts as observed by confocal laser scanning microscope, suggesting the potential usefulness of this multifunctional platform in the wound healing process. It can be concluded that the combination of two simple technologies and of different ready available biomaterials produced interesting results in the wound healing process.