Biodegradable Capsule Designed for Hemophilia Drug

(Alden Chadwick, Wikimedia Commons

29 November 2016. A chemical engineering group designed a capsule to deliver blood coagulating proteins for people with hemophilia B who now require injections or infusions. The team from the lab of Nicholas Peppas at University of Texas in Austin describes its discovery in the 30 November 2016 issue of the International Journal of Pharmaceutics (paid subscription required).

Peppas and colleagues from the university’s Institute for Biomaterials, Drug Delivery, and Regenerative Medicine are seeking a more practical and less expensive way to deliver clotting factor IX or 9, a protein needed for normal blood coagulation, but missing from people with hemophilia B. In nearly all cases, hemophilia B is an inherited disorder, accounting for about 20 percent of people with hemophilia. The university cites data showing some 400,000 people worldwide, mainly males, have some form of hemophilia.

Clotting factor IX is given to people today with hemophilia B using injections or infusions, since the protein is too unstable to travel through the digestive tract, due to changes in acidic and alkaline levels. The team led by recent doctorate and first author Sarena Horava developed an alternative delivery method that packages synthetic clotting factor IX in a capsule made with a material that can withstand the acidic rigors of the stomach, yet still deliver its payload in the small intestine.

The researchers devised a biodegradable hydrogel carrier made with the polymer poly(methacrylic acid)-grafted-poly(ethylene glycol), or P(MAA-g-EG). Hydrogels with this polymer were previously shown capable of delivering proteins, such as insulin, through the digestive tract, when the proteins are formulated into micro- or nanoscale particles. The UT-Austin team added to the polymer hydrogel a peptide that reacts to the enzyme trypsin in the small intestine, which triggers the release of clotting factor IX.

The team tested clotting factor IX delivery with capsules in lab simulations of the digestive tract, observed through microscopes and measurements of chemical reactions. Results show the capsules work as designed to withstand the acidic nature of the stomach, but swell when in contact with the higher pH levels in the small intestine. Also in the small intestine, the capsules begin to degrade when in contact with the enzyme trypsin, slowly releasing clotting factor IX.

Horava, now an engineer at Triton Systems in Massachusetts, says further development is needed for the capsules to be ready for human clinical trials. “Based on the current capabilities of this system,” Horava notes in a university statement, “approximately two capsules would be equivalent to one injection. However, we anticipate that we will make further improvements to the delivery capacity of the oral delivery system and therefore decrease the capsule amount.”

UT-Austin applied for a patent on the drug delivery technology with Peppas and Horava listed as its inventors.

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