Lexaria Bioscience Corp. (LXRP) New Patent Application for Enhancement of Delivery of Lipophilic Agents

In recent laboratory testing, Lexaria’s breakthrough discovery evidenced greatly enhanced drug delivery to brain tissue. Nicotine in-vivo (animal) studies showed that up to 560% more nicotine was delivered to brain tissue utilizing DehydraTECH^TM than concentration-matched controls lacking DehydraTECH^TM enhancements. The study provided evidence of surprising effectiveness in crossing the blood-brain barrier (“BBB”) which the Company is investigating more extensively, leading to Lexaria’s patent application titled: “Enhancement of Delivery of Lipophilic Active Agents Across the Blood-Brain Barrier and Methods for Treating Central Nervous System Disorders.”

It is well documented that nicotine – while addictive – does not cause cancer. It is the tar and other chemicals formed when cigarettes are combusted that cause cancer. Thus, an efficient delivery mechanism of minute quantities of nicotine that does not require combustion could lead to greatly reduced death and disease through the avoidance of smoking, while also potentially aiding reduced chemical dependence on nicotine until such time as addictive-avoidance behaviours can be empowered.

Lexaria’s surprising discovery of the DehydraTECH^TM apparent effectiveness in crossing the BBB also opens the door to possibilities of delivering other therapeutic drugs in the treatment of intractable diseases.

The BBB, while providing effective protection to the brain against circulating toxins, also creates major difficulties in the pharmacological treatment of brain diseases. Most charged molecules, and most molecules over 700 Daltons in size, are unable to pass through the barrier, and smaller molecules may be conjugated in the liver. These factors create major difficulties in the pharmacological treatment of diseases of the brain and central nervous system (“CNS”), such as Alzheimer’s disease, Parkinson’s disease, bacterial and viral infections and cancer.

Many therapeutic agents for the treatment of diseases and disorders of the brain and CNS are sufficiently hydrophilic to preclude direct transport across the BBB. Furthermore, these drugs and agents are susceptible to degradation in the blood and peripheral tissues that increase the dose necessary to achieve a therapeutically effective serum concentration. However, as described above, although lipophilicity is generally associated with molecules that are easily able to cross the blood-brain barrier, lipophilicity is not the leading characteristic for molecules that transverse the blood-brain barrier. Seelig and colleagues studied the association of different factors with the ability of molecules to diffuse across the blood-brain barrier, including lipophilicity, Gibbs Adsorption Isotherm, a Co CMC Plot, and the surface area of the drug to water and air (Seelig et al. (1994) Proc. Nat. Acad. Sci. (USA) 91:68-72). Their results showed that barrier permittivity is based on a complex interaction between relative size and the surface activity of the molecule, in which the surface activity includes the molecular properties of both hydrophobic and charged residues (Seelig et al. (1994) Proc. Nat. Acad. Sci. (USA) 91:68-72).

Prior methods for delivering drugs across the BBB involve three general categories: (1) liposome-based methods, where the therapeutic agent is encapsulated within the carrier; (2) synthetic polymer-based methods, where particles are created using synthetic polymers to achieve precisely-defined size characteristics; and (3) direct conjugation of a carrier to a drug, where the therapeutic agent is covalently bound to a carrier such as insulin. Liposomes are attractive for transporting drugs across the BBB because of their large carrying capacity. However, liposomes are generally too large to effectively cross the BBB, are inherently unstable, and their constituent lipids are gradually lost by absorption by lipid-binding proteins in the plasma. Synthetic polymers have run into difficulties having the drug carried across the cell only to be trapped in an endothelial cell or a lysosome, instead of the desired result of being ejected into the brain parenchyma.