The rapid recognition of intravenously injected colloidal carriers, such as liposomes and polymeric nanospheres from the blood by Kupffer cells, has initiated a surge of development for "Kupffer cell-evading" or long-circulating particles. Such carriers have applications in vascular drug delivery and release, site-specific targeting (passive as well as active targeting), as well as transfusion medicine. In this article we have critically reviewed and assessed the rational approaches in the design as well as the biological performance of such constructs. For engineering and design of long-circulating carriers, we have taken a lead from nature. Here, we have explored the surface mechanisms, which affords red blood cells long-circulatory lives and the ability of specific microorganisms to evade macrophage recognition. Our analysis is then centered where such strategies have been translated and fabricated to design a wide range of particulate carriers (e.g., nanospheres, liposomes, micelles, oil-in-water emulsions) with prolonged circulation and/or target specificity. With regard to the targeting issues, attention is particularly focused on the importance of physiological barriers and disease states.

Long-Circulating and Target-Specific Nanoparticles: Theory to Practice

Opsonization, biodistribution, and pharmacokinetics of polymeric nanoparticles

The return of a forgotten polymer—Polycaprolactone in the 21st century

A coated implantable medical device 10 includes a structure 12 adapted for introduction into the vascular system, esophagus, trachea, colon, biliary tract, or urinary tract; at least one layer 18 of a bioactive material positioned over the structure 12; and at least one porous layer 20 positioned over the bioactive material layer 18. Preferably, the structure 12 is a coronary stent, and the bioactive material is at least one of heparin, dexamethasone or a dexamethasone derivative. The device 10 includes layers 18 and 22 of heparin and dexamethasone, the layer 22 of dexamethasone being positioned above the layer 18 of heparin. The layers of bioactive material also can be individual materials or a combination of different materials. Unexpectedly, the more soluble heparin markedly promotes the release of the less soluble dexamethasone above it. The porous layer 20 is composed of a polymer applied by vapor or plasma deposition and provides a controlled release of the bioactive material. It is particularly preferred that the polymer is a polyimide, parylene or a parylene derivative, which is deposited without solvents, heat or catalysts, merely by condensation of a monomer vapor.

Coated implantable medical device

Microemulsion-based media as novel drug delivery systems

The present invention provides compositions comprising an anti-angiogenic factor, and a polymeric carrier. Representative examples of anti-angiogenic factors include Anti-Invasive Factor, Retinoic acids and derivatives thereof, and paclitaxel. Also provided are methods for embolizing blood vessels, and eliminating biliary, urethral, esophageal, and tracheal/bronchial obstructions.

Anti-angiogenic compositions and methods of use

Implants are used in combination with a fibrosis-inducing agent in order to induce fibrosis that may otherwise not occur when the implant is placed within an animal or increase fibrosis between the implant and the host tissue.

Medical implants and fibrosis-inducing agents

Compositions comprising anti-fibrotic agent(s) and/or polymeric compositions can be used in various medical applications including the prevention of surgical adhesions, treatment of inflammatory arthritis, treatment of scars and keloids, the treatment of vascular disease, and the prevention of cartilage loss.

Polymer compositions and methods for their use

Implants are used in combination with an anti-scarring agent in order to inhibit scarring that may otherwise occur when the implant is placed within an animal. The agent may be any suitable anti-scarring agent, e.g., a cell cycle inhibitor, and may be used in conjunction with a second pharmaceutical agent, e.g., an antibiotic. Suitable implants include intravascular implants, a vascular graft or wrap implant, an implant for hemodialysis access, an implant that provides an anastomotic connection, ventricular assist implant, a prosthetic heart valve implant, an inferior vena cava filter implant, a peritoneal dialysis catheter implant, a central nervous system shunt, an intraocular lens, an implant for glaucoma drainage, a penile implant, an endotracheal tube, a tracheostomy tube, a gastrointestinal device, and a spinal implant.

Medical implants and anti-scarring agents

Intravascular devices (e.g., stents, stent grafts, covered stents, aneurysm coils, embolic agents and drug delivery catheters and balloons) are used in combination with fibrosing agents in order to induce fibrosis that may otherwise not occur when the implant is placed within an animal or to promote fibrosis betweent the devices and the host tissues. Compositions and methods are described for use in the treatment of aneurysms and unstable arterial (vulnerable) plaque.

William L. Hunter

Papers

Anti-angiogenic compositions and methods of use

Medical implants and fibrosis-inducing agents

Polymer compositions and methods for their use

Medical implants and anti-scarring agents

Intravascular devices and fibrosis-inducing agents