Glide Pharma’s Glide SDI® Solid Dose Injector incorporates a solid drug formulation smaller than a grain of rice that is pushed under the skin, reported Charles Potter, Ph.D., CEO. “One of the challenges is making sure the dosage is sufficiently robust so it will penetrate the skin,” he added. This property is achieved by mixing the drug with excipients for the required release kinetics. A quick-dissolving formulation uses a sugar and a controlled-release version uses a polymer.
The drug is pushed via a spring-powered, re-usable actuator, which is about the size of a fountain pen. “When the user stops pushing, the drug stops moving, meaning we’re delivering it to the same depth every time. That’s very important to our technology,” Dr. Potter said.
Although the drugs have to be re-formulated, the solid dose provides better storage, safety, stability, easy transportation, accurate dosing, minimal skin response, and is cost-effective, he added.
Other drug formulations routinely use polymer microspheres for controlled release. “The difficulty is you can get clogged needles and then you are relying on the spheres to release drugs as you want them. We have a solid piece of drug going into the skin, and we should be able to get a better release profile than the spheres.”
The Solid Dose Injector is currently being evaluated in several clinical studies. A Phase I trial has been completed involving a fentanyl product for acute pain, and another one is starting using a Novartis drug to reduce human growth hormone levels. Another big application area is vaccines. The company has participated in five preclinical vaccine studies with three different antigens, Dr. Potter said.
Sumavel™ DosePro™ is an FDA-approved prefilled, single-use, needle-free, disposable injection system for treatment of migraines and cluster headaches, according to Stephen Farr, Ph.D., president and COO at Zogenix.
One of the key goals in designing Sumavel was obtaining the best pressure profile for selective subcutaneous administration. Dr. Farr said this is characterized by relatively high pressure (driven by nitrogen gas) for a fraction of the injection time, no more than a millisecond. This is enough time to penetrate the skin.
Other current needle-free devices have a propensity for an inadvertent IM injection, he said, which can cause bruising and alter the drug absorption. “If that’s critical to efficacy, then clearly, that would be a problem.”
Three single-dose early-phase studies using DosePro in human pilot studies are ongoing. The company is waiting for proof-of-concept data before it announces what drugs are being evaluated. Preclinical work with mAbs has shown that the device has no effect on drug integrity nor any enhanced immunogenicity, Dr. Farr said. The device currently delivers from 0.5 mL down to 0.15 mL, and a second-generation unit will offer increased volume up to 1.0 mL, he added.