U.S. patent for new bioadhesive drug delivery system awarded to SRI International

SRI International, an independent nonprofit research and development organization, announced today the award of U.S. patent 7,592,021 for a new bioadhesive drug delivery system that enables enhanced release of drugs through the human body's mucous membranes. This needle-free option uses gels for drug delivery and allows for a much longer release time compared to alternatives such as sprays or liquids.

Transmucosal delivery is an effective means to introduce drugs across the mucous membrane to the systemic circulation, avoiding the gastrointestinal tract and "first pass liver metabolism," which can result in only a small proportion of a drug reaching the desired targets in the body. The ease of transmucosal administration, by nebulizers or bottles, for example, often improves patient compliance compared to other forms of drug delivery. The sustained and enhanced release of therapeutic and preventive treatments enabled by SRI's bioadhesive drug delivery invention can significantly improve effectiveness and outcomes.

"This needle-free system can be used for drug delivery in any environment, even in locations where sterile medical supplies are unavailable," said Gita Shankar, Ph.D., director of formulations R&D at SRI and an inventor of the system. "Offering this option to patients can increase access to safe, effective medical care for a wide variety of conditions."

SRI's patented formulation is a two-component polymeric solution: one is responsive to pH and the other to temperature. On mixing and application to the physiological site, the two components form an adhesive gel that attaches to the mucosa, creating a platform for drug release.

Choice of application site varies depending on a variety of factors, including the duration and frequency of drug administration, and the desirability of controlled release. SRI's transmucosal drug delivery system is equally well suited for both systemic conditions that affect the whole body and localized conditions that affect specific parts of the body.

The mucous membrane of the nasal cavity is most frequently used for delivery of antigens and medications against localized infections. Because mucous membranes respond strongly to foreign matter and can offer a hospitable environment for pathogens and antigens, they are ideally suited for the introduction of vaccines, where both systemic and local immune responses are desired. Most pediatric vaccines are injections, which can be painful to children and difficult to administer safely in poorer regions of the world. SRI's needle-free technology can be used to safely deliver vaccines nasally, including those for pediatric use. The system can also be used to administer contraceptive formulations or to provide topical microbicides that protect against sexually transmitted diseases, such as HIV and genital herpes.

The novel bioadhesive drug delivery system was developed as part of an SRI project funded in part under a National Institutes of Health grant to develop a nasal formulation for anthrax antigens, suitable for mass-immunization in the event of a bioterrorism emergency. Other applications being developed include use of the drug delivery system to deliver therapeutics that protect against chemical warfare agents.