New technique can help nanoparticles deliver drug treatments

May 7, 2013

A Wayne State University researcher has successfully tested a technique that can lead to more effective use of nanoparticles as a drug delivery system.

Joshua Reineke, Ph.D., assistant professor of pharmaceutical sciences in the Eugene Applebaum College of Pharmacy and Health Sciences, examined how a particle called polylactic-co-glycolic acid (PLGA) breaks down in live tissue.

He believes the potential impact of his work is broad, as increasingly have been developed as carriers of treatments for numerous diseases and as imaging agents; they also are used in numerous consumer products. The kinetics of nanoparticle biodegradation is an important factor that can control how and where a drug is released, impacting treatment efficacy as well as potential toxicity to nontarget tissues from nanoparticle exposure.

"If nanoparticles given to a patient release a drug before particles can ever get to target tissue, then we get high toxicity and low effect," Reineke said. "Conversely, if particles are drawn to a tissue but don't release the drug until long afterward, then we also don't get the therapeutic effect."

Much previous research has studied nanoparticle biodegradation in vitro, but Reineke and the study's lead author, Abdul Khader Mohammad, Ph.D., a recent WSU graduate, believe they are the first to quantify biodegradation rates after systemic administration.

Their study, "Quantitative Detection of PLGA Nanoparticle Degradation in Tissues following Intravenous Administration," was published recently in the journal Molecular Pharmaceutics. It was supported by funds from the Department of Pharmaceutical Sciences and the Office for the Vice President of Research at Wayne State.

Keeping the same, Reineke and Mohammad administered PLGA as particles in sizes of 200 and 500 nanometers (nm) intravenously in mice, an important administration route of nanomedicines for cancer applications, for example, and measured the quantity of the nanoparticles in all tissues and the rates at which it degraded. They then compared those rates to those predicted by in vitro measurements.

Reineke said the 200 nm particles degraded much faster in the body than in vitro, while the 500 nm particles degraded similarly to in vitro analyses. The liver and spleen had the highest concentration of polymers and therefore were easiest to analyze.

Researchers found that 500 nm particles degraded faster in the liver than the spleen, but for the 200 nm size the degradation rate in the liver and the spleen were similar.

"It's known that larger particles degrade differently, and we verified that," Reineke said, "but they didn't quite degrade in vivo the way we would expect. We found that among tissue types there are differences in how they degrade."

"That tells us that in vitro degradation doesn't predict in vivo degradation very well, because we see so many differences."

Reineke said that by in vivo testing of other types of nanoparticles, a mathematical model can be developed to help determine which are most effective and have the lowest toxicity for a given application.

"Optimizing a therapeutic system that utilizes nanoparticles is really about getting that timing correct. In order to do that, we have to know how and when the particles are going to release the drug."

Explore further: Flares on the move: Nanoparticle test kit shows how nanoparticles of different size disperse in tumor tissue

Related Stories

Are silver nanoparticles harmful?

March 14, 2012

Silver nanoparticles cause more damage to testicular cells than titanium dioxide nanoparticles, according to a recent study by the Norwegian Institute of Public Health. However, the use of both types may affect testicular ...

Biodegradable nanoparticles slip through mucus

July 5, 2012

( -- Researchers at Johns Hopkins University (JHU) have created biodegradable, ultra tiny, nanosized particles that can easily slip through the body's sticky and viscous mucus secretions to deliver a sustained-release ...

Recommended for you

Mathematicians identify limits to heat flow at the nanoscale

November 24, 2015

How much heat can two bodies exchange without touching? For over a century, scientists have been able to answer this question for virtually any pair of objects in the macroscopic world, from the rate at which a campfire can ...

New sensor sends electronic signal when estrogen is detected

November 24, 2015

Estrogen is a tiny molecule, but it can have big effects on humans and other animals. Estrogen is one of the main hormones that regulates the female reproductive system - it can be monitored to track human fertility and is ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.