| TECHNOLOGY |
Through the skin Co., Fremont, Calif., has developed a technology that could be considered a hybrid of transdermal and parenteral (injection): a needleless injection. The company's device propels powder drugs with a supersonic jet of helium gas. Co.'s senior vice president of science & technology, explains that when a high-pressure ampule of helium within the device is broken open, the gas flows through a cassette that is holding the powder between two membranes. The membranes rupture and the gas stream picks up the particles. The particles are propelled fast enough to penetrate the stratum corneum, the outer layer of the skin. The drug is targeted to the boundary between the epidermis and the dermis. Drugs then dissolve and either reach systemic circulation or exert a local effect. Vaccines can be picked up by antigen-presenting cells in the epidermis or by the lymph system. Co.'s technology requires that the formulation be a powder. However, those few drugs that are in a liquid state when pure can also be delivered if they are suitably formulated or adsorbed on a carrier particle, Sr. VP says. Because the delivery is driven by momentum, Sr. VP says the particles, which are between 20 and 70 micro.m, should be as dense as possible. "The higher the density, the more momentum, given the velocity that we impart to the particles," he says. The particles also must be strong because they hit the skin at high velocities. He says the particles have been clocked as fast as 900 meters per second, with 400 to 600 meters per second being the more typical range. What does it feel like to have particles penetrating the skin at such high speeds? He says the process is completely painless. "People feel the tap of the gas on the skin. It's like flicking your finger against your skin." Clinical trials indicate that the gas is causing the sensation, because patients can't tell if there is powder in the cassette. One limitation of Co.'s method is the amount of drug that can be delivered, He says. The upper threshold is about 3 mg, with 1 to 2 mg preferred. This limits the application to potent drugs, but most commercially attractive biotechnology drug molecules and vaccines fall in this range, He says. "The ideal candidate is something that is now delivered by needle and syringe," he notes. Drugs delivered with Co.'s technology reach the circulatory system faster than those administered by subcutaneous injection. "Because it's an intradermal delivery and the capillary blood supply is immediately adjacent to where you're placing the drug, in most cases--all the cases we've looked at so far--the drug appears in the systemic circulation a bit sooner. Not as fast as [intravenous], but definitely faster than subcutaneous needle and syringe, which is what we compare ourselves to," He explains. The company has engineered all control of the delivery into the device, He says. "It has an interlock, so it has to be pressed [against the skin] with a certain amount of force before you can press the button to release the gas," he comments. Co. is focusing on vaccines because the technology delivers the vaccines more directly to antigen-presenting cells. "We put our particles right there in the epidermis where they're desired," He asserts. "Either for traditional vaccines, which are protein subunits or killed viruses, or DNA vaccines, which are plasmids on gold, we're delivering automatically to the most sensitive tissue." However, the product that Co. is using to initially prove the technology is the local anesthetic lidocaine hydrochloride, which is a small-molecule drug. That drug must be used anywhere on the body it's needed. "We've tested all over the body," He says. "For delivery of a drug, just like with patches, we would recommend a site for each specific application." |
| UPDATE | 09.00 |
| COMPANY | This data is not available for free |
| CONTACT | This data is not available for free |
| LITERATURE REF. | This data is not available for free |
|
Want more information ? Interested in the hidden information ? Click here and do your request. |