Hyaluronic Acid/Chitosan-g-Poly(ethylene glycol) Nanoparticles for Gene Therapy: An Application for pDNA and siRNA Delivery

Using drug-excipient interactions for siRNA delivery

SiRNA is the trigger of RNA interference, a mechanism discovered in the late 1990s. To release the therapeutic potential of this versatile but large and fragile molecule, excipients are used which either interact by electrostatic interaction, passively encapsulate siRNA or are covalently attached to enable specific and safe delivery of the drug substance. Controlling the delicate balance between protective complexation and release of siRNA at the right point and time is done by understanding excipients–siRNA interactions. These can be lipids, polymers such as PEI, PLGA, Chitosans, Cyclodextrins, as well as aptamers and peptides. This review describes the mechanisms of interaction of the most commonly used siRNA delivery vehicles, and looks at the results of their clinical and preclinical studies.

Propellant-based inhalers for the non-invasive delivery of genes via oral inhalation

In this work we describe the development of a propellant-based, portable oral inhalation platform for the pulmonary delivery of genes. A core-shell strategy is utilized to efficiently disperse cationic-polymer-DNA nanoparticles in hydrofluoroalkane propellants, and to generate aerosols from the corresponding pressurized metered-dose inhaler formulations (pMDIs) that have excellent aerosol characteristics, suitable for deep lung deposition. The engineered polyplexes and core-shell structures were fully characterized, and their ability to transfect model lung alveolar epithelium cells in vitro was demonstrated. We also show that the propellant does not affect the biological activity of the plasmid DNA, and that the core-shell formulations have no in vitro cytotoxicity. The relevance of this work stems from the fact that pMDIs are the least expensive and most widely used portable oral inhalation devices, and are thus promising platforms for targeting genes to the lungs for the treatment of medically relevant diseases including asthma, cystic fibrosis, chronic obstructive pulmonary disease, and lung cancer.

Biomedical Applications of Biodegradable Polymers

Utilization of polymers as biomaterials has greatly impacted the advancement of modern medicine. Specifically, polymeric biomaterials that are biodegradable provide the significant advantage of being able to be broken down and removed after they have served their function. Applications are wide ranging with degradable polymers being used clinically as surgical sutures and implants. In order to fit functional demand, materials with desired physical, chemical, biological, biomechanical and degradation properties must be selected. Fortunately, a wide range of natural and synthetic degradable polymers has been investigated for biomedical applications with novel materials constantly being developed to meet new challenges. This review summarizes the most recent advances in the field over the past 4 years, specifically highlighting new and interesting discoveries in tissue engineering and drug delivery applications.