Navigation Links
Nanosponge drug delivery system more effective than direct injection
Date:6/2/2010

When loaded with an anticancer drug, a delivery system based on a novel material called nanosponge is three to five times more effective at reducing tumor growth than direct injection.

That is the conclusion of a paper published in the June 1 issue of the journal Cancer Research.

"Effective targeted drug delivery systems have been a dream for a long time now but it has been largely frustrated by the complex chemistry that is involved," says Eva Harth, assistant professor of chemistry at Vanderbilt, who developed the nanosponge delivery system. "We have taken a significant step toward overcoming these obstacles."

The study was a collaboration between Harth's laboratory and that of Dennis E. Hallahan, a former professor of radiation oncology at Vanderbilt who is now at the Washington University School of Medicine. Corresponding authors are Harth and Roberto Diaz at Emory University, who was working in the Hallahan laboratory when the studies were done.

To visualize Harth's delivery system, imagine making tiny sponges that are about the size of a virus, filling them with a drug and attaching special chemical "linkers" that bond preferentially to a feature found only on the surface of tumor cells and then injecting them into the body. The tiny sponges circulate around the body until they encounter the surface of a tumor cell where they stick on the surface (or are sucked into the cell) and begin releasing their potent cargo in a controllable and predictable fashion.

Targeted delivery systems of this type have several basic advantages: Because the drug is released at the tumor instead of circulating widely through the body, it should be more effective for a given dosage. It should also have fewer harmful side effects because smaller amounts of the drug come into contact with healthy tissue.

"We call the material nanosponge, but it is really more like a three-dimensional network or scaffold," says Harth. The backbone is a long length of polyester. It is mixed in solution with small molecules called cross-linkers that act like tiny grappling hooks to fasten different parts of the polymer together. The net effect is to form spherically shaped particles filled with cavities where drug molecules can be stored. The polyester is biodegradable, so it breaks down gradually in the body. As it does, it releases the drug it is carrying in a predictable fashion.

"Predictable release is one of the major advantages of this system compared to other nanoparticle delivery systems under development," says Harth. When they reach their target, many other systems unload most of their drug in a rapid and uncontrollable fashion. This is called the burst effect and makes it difficult to determine effective dosage levels.

Another major advantage is that the nanosponge particles are soluble in water. Encapsulating the anti-cancer drug in the nanosponge allows the use of hydrophobic drugs that do not dissolve readily in water. Currently, these drugs must be mixed with another chemical, called an adjuvant reagent, that reduces the efficacy of the drug and can have adverse side-effects.

It is also possible to control the size of nanosponge particles. By varying the proportion of cross-linker to polymer, the nanosponge particles can be made larger or smaller. This is important because research has shown that drug delivery systems work best when they are smaller than 100 nanometers, about the depth of the pits on the surface of a compact disc. The nanosponge particles used in the current study were 50 nanometers in size. "The relationship between particle size and the effectiveness of these drug delivery systems is the subject of active investigation," says Harth.

The other major advantage of Harth's system is the simple chemistry required. The researchers have developed simple, high-yield "click chemistry" methods for making the nanosponge particles and for attaching the linkers, which are made from peptides, relatively small biological molecules built by linking amino acids. "Many other drug delivery systems require complicated chemistry that will be difficult to scale up for commercial production, but we have continually kept this in mind," Harth says.

The targeting peptide used in the animal studies was developed by the Hallahan laboratory, which also tested the system's effectiveness in tumor-bearing mice. The peptide used in the study is one that selectively binds to tumors that have been treated with radiation.

The drug used for the animal studies was paclitaxel (the generic name of the drug Taxol) that is used in cancer chemotherapy. The researchers recorded the response of two different tumor types slow-growing human breast cancer and fast-acting mouse glioma to single injections. In both cases they found that it increased the death of cancer cells and delayed tumor growth "in a manner superior to know chemotherapy approaches."

The next step is to perform an experiment with repeated injections to see if the nanosponge system can stop and reverse tumor growth. Harth is also planning to perform the more comprehensive toxicity studies on her nanoparticle delivery system that are required before it can be used in clinical trials.


'/>"/>

Contact: David F. Salisbury
david.salisbury@vanderbilt.edu
615-343-6803
Vanderbilt University
Source:Eurekalert  

Related medicine news :

1. A New Firefox Add-on Revolutionizes the Delivery of Discounts for Online Shoppers
2. Drug now used to treat erectile dysfuncton may enhance delivery of herceptin to certain brain tumors
3. FreshDirect Celebrates Nurse Appreciation Week with Delivery of Complimentary 4-Minute Meals for Nurses at Hospitals in Westchester and Greenwich, CT
4. New Nasal Drug Delivery Device for Chronic Sinusitis Patients Now Available from ASL Pharmacy
5. Magnetic Fields Concentrate Drug Delivery
6. Panel questions VBAC bans, advocates expanded delivery options for women
7. Electronic Health Information Leader Says Physician Practice Redesign is Vital Next Step Towards Safer, More Effective Care Delivery
8. Targeted delivery of losartan reduces liver inflammation and scarring
9. Gourmet Diet Delivery Unites with First Lady's Battle Against Obesity The Fresh Diet Begins Delivering Meals to DC
10. GE Healthcare, Intel and Mayo Clinic explore new models of health care delivery
11. Launch of On Time Air Filters: Home Air Filter Delivery Service Helps Homeowners Replace All-Important Home HVAC Filters On Time
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Nanosponge drug delivery system more effective than direct injection
(Date:2/13/2016)... , ... February 13, 2016 , ... Many individuals looking ... protein for a multitude of reasons. IsoPasta by Isolator Fitness has delved into ... once more, but without the high-carb repercussions. IsoPasta has 30 grams of protein ...
(Date:2/13/2016)... ... 2016 , ... When an Au Pair comes all the way around the world ... for and they are often worried things won’t go well. More often than not, however, ... Au Pair of the Year winner’s all commented how their Au Pairs have become a ...
(Date:2/12/2016)... LA (PRWEB) , ... February 12, 2016 , ... The ... St. Landry and Evangeline Parishes. The purpose of these scholarships is to encourage ... encourage those individuals to seek employment within these two parishes. , “We have ...
(Date:2/12/2016)... ... February 12, 2016 , ... Each year, the American Physical ... in Anaheim, CA at the Anaheim Convention Center. Almost 10,000 physical therapists across the ... products in action, learn more about their chosen field and network with their colleagues. ...
(Date:2/12/2016)... ... February 12, 2016 , ... Itopia, a leader in cloud ... Clarity Intelligence Platform (CIP) into Cielo®, a discovery, migration and cloud orchestration engine. ... their small and medium business (SMB) clients. , In recent years, ...
Breaking Medicine News(10 mins):
(Date:2/12/2016)... SAN DIEGO and SEOUL, ... -- Silicon Biosys­tems Menarini and Macrogen, Inc. today ... clinical assays and innovative procedures for precision medicine ... to combine Silicon Biosystems, DEPArray™ digital-sorting technology with ... development of tests certified under the Clinical Laboratory ...
(Date:2/12/2016)... , Feb. 12, 2016  Apellis ... completed a $47.1 million Series D preferred ... Asset Management, Hillhouse Capital Group and venBio ... Venture Investments, AJU IB Investment, and Epidarex ... used to further advance clinical trials in ...
(Date:2/11/2016)... 2016 Stem cells are primitive cells found ... and the capacity to differentiate into mature cell types ... the first mouse embryonic stem cells were derived from ... that the first culturing of embryonic stem cells from ... produced until 2006 As a result of these discoveries, ...
Breaking Medicine Technology: