Scientists have developed new skin patches that could offer a more convenient and less painful way to administer antibody-based medicines to people with multiple sclerosis (MS) and other disorders.
“The developed [skin] patch is minimally invasive, self-administrable, and designed to be fully embedded into the skin with a short application time,” the researchers wrote in “Single-Administration Long-Acting Microarray Patch with Ultrahigh Loading Capacity and Multiple Releases of Thermally Stable Antibodies,” which was published in Molecular Pharmaceutics.
Antibodies are proteins made by the immune system to help fend off infectious invaders. They are able to stick to a specific molecular target with extremely high specificity and help coordinate immune responses. These properties have made them useful as a platform for developing therapies.
Several approved treatments for MS contain antibodies as their main ingredient and antibody-based therapies are widely used to manage other autoimmune disorders and diseases — from cancers to viral infections.
In order to be effective, antibody therapies usually require a fairly high amount of the antibody to be present in a person’s body. This often means patients have to routinely get injections or infusions, which can be burdensome and painful.
Transdermal microneedle array (MA) patches are a system for drug delivery that’s applied to the skin. Tiny needles on the patch stick into the top layer of skin where there aren’t any pain-sensing nerve cells, allowing it to deliver therapy without discomfort and pain.
MA patch systems have been developed for some medications, such as for certain forms of birth control. They generally involve loading the medication as a liquid formulation, however, which is difficult to get large quantities of a drug into the patch, due to physical constraints. As a result, liquid-based patches aren’t suitable for delivering antibody-based therapies, where a substantial amount of the antibody needs to be delivered to be effective.
A powdered antibody treatment
To get around this, researchers led by scientists at the University of Connecticut developed a method using specific sugar molecules to stabilize antibodies as a powder. The powdered antibodies remained stable at body temperature for months, allowing about 20 times more medication to be loaded onto the MA patches compared with conventional liquid formulations.
The method “offers a simple and effective manufacturing process for MA patches containing large amounts of therapeutics, being particularly beneficial for [antibody] therapies and potentially other applications requiring a high drug or protein dosage,” the researchers wrote.
To control the rate of antibody release from the patches, the researchers devised a MA system wherein the tiny needles were made of “shells” of PLGA, a biodegradable polymer widely used in medical devices because it’s safe in the body. As the PLGA shells break down, they release the medication. The researchers found they could fine-tune the rate of the medicine’s release by tweaking the number and composition of the PLGA shells.
The scientists conducted proof-of-concept tests of the patch system in rats, with positive results. “We successfully utilized the MA patch to deliver a high dosage and multiple types of human [antibody] in a rat model,” the researchers wrote. “Our core-shell PLGA MA system was capable of sustaining the desired high dose of the [antibody] concentration [in living rats] for over 25 days, a remarkable duration in this animal model with only a single-time skin insertion.”
The researchers suggested the patch system could be an alternative to injections or infusions for antibody therapies. Along with minimizing patient burden, it could reduce medical waste by requiring fewer needles and allow better access to treatments because the patches don’t need to be stored at cold temperatures.
“It solves a lot of problems,” Thanh Duc Nguyen, co-author of the study at the University of Connecticut, said in a university news release.