Polymer-Based Systems for Controlled Release and Targeting of Drugs

Abstract

The current need to find new advanced approaches to carry biologically active substances (conventional organic drugs, peptides, proteins (such as antibodies), and nucleic acid-based drugs (NABDs such as siRNA and miRNA)) in the body fluids, to realize targeted therapies and even personalized ones, goes hand in hand with research on the performance of new materials to better realize appropriate drug vectors [1].Polymeric materials can be designed and manufactured to obtain delivery systems with the appropriate characteristics in terms of drug release and performance [2]. For use in human applications, the polymer must primarily be biocompatible and non-toxic, and then functionalizable to give the appropriate structural and functional characteristics, such as to make it easily workable, processed, and engineered to obtain the desired system, and to be applied in drug delivery and targeting and/or in diagnosis of diseases.The further possibility of decorating the surface of these polymeric systems (due to the characteristics of the material that constitutes the matrix) with ligands capable of interacting specifically with membrane receptors on cells represents a unique advantage for obtaining targeted drug release to a specific organ, tissue, or cell type [3][4][5][6][7].In this issue, some current examples of design and production of polymeric materials, as well as of searching strategies to modify existing ones, for the making of innovative systems for drug delivery and/or regenerative medicine are collected.In particular, polymeric systems from nanoscale (micelles [8,9], nanoparticles [10,11]) to microscale structures (microparticles [12,13]), and to macrodevices (hydrogels [14] and films [15]) were produced. All the described systems were designed for the controlled and targeted release of conventional or biological drugs, such as paclitaxel [10], or siRNA [11] in the treatment of diseases such as cancer [8] and buccal and skin infections [15,16] by the systemic or local administration route [17]. The starting polymeric materials were chosen from hydrophilic polysaccharides [11,16] to hydrophobic polyesters [9,14], obtaining blended materials or copolymers, which were used to obtain drug delivery systems by using techniques such as microfluidics or hot punching [12,13].Polymeric porous microparticles are currently emerging due to their potential for various applications, such as floating drug delivery systems and inhaled formulations. Amoyav and coworkers described the preparation of porous microspheres (MPs) starting from poly(lactic-co-glycolic) acid (PLGA) and poly(d,l-lactide) (PLA), with varying sizes and morphologies, by a simple flow-focusing microfluidic device [13].Characterization of obtained systems to predict the in vivo fate is a fundamental aspect for researchers. Abid and coworkers described the production of microdevices, starting from different polyesters (i.e., poly-ε-caprolactone (PCL) and poly(lactic-co-glycolic acid) (PLGA)) by hot punching, and their characterization in terms of mucoadhesi...

Hydrogels in Biomedicine: Granular Controlled Release Systems Based on 2-Hydroxyethyl Methacrylate Copolymers. A Review

“…One of the important areas of creating polymeric materials with special functional properties is the development of polymeric systems and devices for the controlled release of substances into the environment. The stimulus for the creation of such systems was the need of various fields of human activity for means of dosing chemically or biologically active substances in very small quantities for a long time 1,2 . This applies, in particular, to such industries as medicine and pharmacy, especially when it comes to the long-term continuous administration of small doses of drugs into the human or animal body at a constant rate.…”

Influence of Polyvinyl Alcohol (PVA) on PVA-Poly-N-hydroxyethyl-aspartamide (PVA-PHEA) Microcrystalline Solid Dispersion Films

“…Furthermore, it is odorless and non-toxic. PVA was combined with novel polymer PHEA (25)(26)(27) that has many attractive properties, such as water solubility and absence of toxicity (28). Additionally, it is biodegradable and was used previously in drug delivery systems (29).…”