Featured Research

from universities, journals, and other organizations

Unique gel capsule structure enables co-delivery of different types of drugs

Date:
July 6, 2011
Source:
Georgia Institute of Technology Research News
Summary:
Chemists have designed a multiple-compartment gel capsule that can simultaneously deliver hydrophilic and hydrophobic drugs. The microcapsules could be used for the treatment of diseases like cancer, which is often treated using combination chemotherapy.

This is a schematic diagram of the approach used by chemists at Georgia Tech to synthesize poly(N-isopropylmethacrylamide) semi-hollow microgel capsules containing a low density of trapped poly(N-isopropylacrylamide) chains. The capsule's multiple-compartment structure makes it a good candidate for simultaneously delivering hydrophobic and hydrophilic drugs into the body.
Credit: Georgia Tech/L. Andrew Lyon

Researchers at the Georgia Institute of Technology have designed a multiple-compartment gel capsule that could be used to simultaneously deliver drugs of different types. The researchers used a simple "one-pot" method to prepare the hydrogel capsules, which measure less than one micron.

The capsule's structure -- hollow except for polymer chains tethered to the interior of the shell -- provides spatially-segregated compartments that make it a good candidate for multi-drug encapsulation and release strategies. The microcapsule could be used to simultaneously deliver distinct drugs by filling the core of the capsule with hydrophilic drugs and trapping hydrophobic drugs within nanoparticles assembled from the polymer chains.

"We have demonstrated that we can make a fairly complex multi-component delivery vehicle using a relatively straightforward and scalable synthesis," said L. Andrew Lyon, a professor in the School of Chemistry and Biochemistry at Georgia Tech. "Additional research will need to be conducted to determine how they would best be loaded, delivered and triggered to release the drugs."

Details of the microcapsule synthesis procedure were published online on July 5, 2011 in the journal Macromolecular Rapid Communications.

Lyon and Xiaobo Hu, a former visiting scholar at Georgia Tech, created the microcapsules. As a graduate student at the Research Institute of Materials Science at the South China University of Technology, Hu is co-advised by Lyon and Zhen Tong of the South China University of Technology. Funding for this research was provided to Hu by the China Scholarship Council.

The researchers began the two-step, one-pot synthesis procedure by forming core particles from a temperature-sensitive polymer called poly(N-isopropylacrylamide). To create a dissolvable core, they formed polymer chains from the particles without a cross-linking agent. This resulted in an aggregated collection of polymer chains with temperature-dependent stability.

"The polymer comprising the core particles is known for undergoing chain transfer reactions that add cross-linking points without the presence of a cross-linking agent, so we initiated the polymerization using a redox method with ammonium persulfate and N,N,N',N'-tetramethylethylenediamine. This ensured those side chain transfer reactions did not occur, which allowed us to create a truly dissolvable core," explained Lyon.

For the second step in the procedure, Lyon and Hu added a cross-linking agent to a polymer called poly(N-isopropylmethacrylamide) to create a shell around the aggregated polymer chains. The researchers conducted this step under conditions that would allow any core-associated polymer chains that interacted with the shell during synthesis to undergo chain transfer and become grafted to the interior of the shell.

Cooling the microcapsule exploited the temperature-sensitivities of the polymers. The shell swelled with water and expanded to its stable size, while the free-floating polymer chains in the center of the capsule diffused out of the core, leaving behind an empty space. Any chains that stuck to the shell during its synthesis remained. Because the chains control the interaction between the particles they store and their surroundings, the tethered chains can act as hydrophobic drug carriers.

Compared to delivering a single drug, co-delivery of multiple drugs has several potential advantages, including synergistic effects, suppressed drug resistance and the ability to tune the relative dosage of various drugs. The future optimization of these microcapsules may allow simultaneous delivery of distinct classes of drugs for the treatment of diseases like cancer, which is often treated using combination chemotherapy.


Story Source:

The above story is based on materials provided by Georgia Institute of Technology Research News. The original article was written by Abby Robinson. Note: Materials may be edited for content and length.


Journal Reference:

  1. Xiaobo Hu, Zhen Tong, L. Andrew Lyon. One-Pot Synthesis of Microcapsules with Nanoscale Inclusions. Macromolecular Rapid Communications, 2011; DOI: 10.1002/marc.201100338

Cite This Page:

Georgia Institute of Technology Research News. "Unique gel capsule structure enables co-delivery of different types of drugs." ScienceDaily. ScienceDaily, 6 July 2011. <www.sciencedaily.com/releases/2011/07/110706101610.htm>.
Georgia Institute of Technology Research News. (2011, July 6). Unique gel capsule structure enables co-delivery of different types of drugs. ScienceDaily. Retrieved August 20, 2014 from www.sciencedaily.com/releases/2011/07/110706101610.htm
Georgia Institute of Technology Research News. "Unique gel capsule structure enables co-delivery of different types of drugs." ScienceDaily. www.sciencedaily.com/releases/2011/07/110706101610.htm (accessed August 20, 2014).

Share This




More Health & Medicine News

Wednesday, August 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola-Hit Sierra Leone's Freetown a City on Edge

Ebola-Hit Sierra Leone's Freetown a City on Edge

AFP (Aug. 19, 2014) Residents of Sierra Leone's capital voice their fears as the Ebola virus sweeps through west Africa. Duration: 00:56 Video provided by AFP
Powered by NewsLook.com
101-Year-Old Working Man Has All The Advice You Need

101-Year-Old Working Man Has All The Advice You Need

Newsy (Aug. 19, 2014) Herman Goldman has worked at the same lighting store for almost 75 years. Find out his secrets to a happy, productive life. Video provided by Newsy
Powered by NewsLook.com
Researcher Testing on-Field Concussion Scanners

Researcher Testing on-Field Concussion Scanners

AP (Aug. 19, 2014) Four Texas high school football programs are trying out an experimental system designed to diagnose concussions on the field. The technology is in response to growing concern over head trauma in America's most watched sport. (Aug. 19) Video provided by AP
Powered by NewsLook.com
American Ebola Patient Apparently Improving, Outbreak Is Not

American Ebola Patient Apparently Improving, Outbreak Is Not

Newsy (Aug. 19, 2014) Nancy Writebol, an American missionary who contracted Ebola, is apparently getting better, according to her husband. The outbreak, however, is not. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins