Commonly Asked Questions With Regards to Azaya’s PSN Technology

Is this technology patent protected?
Azaya Therapeutics has received a Notice of Allowance dated November 21, 2006 from the US Patent and Trademark Office allowing the issuance of the Azaya patent application 10/703,187 titled Protein-Stabilized Liposomal Formulations of Pharmaceutical Agents. This is the core technology patent for Azaya and we expect issuance of this patent in February 2007. This allows Azaya to further develop its primary product ATI-1123 and various opportunities utilizing to the full extent the PSL Nanotechnology.

  • Simplified manufacturing process—Single step manufacturing process of protein stabilized nanoparticles (outlined below)
  • Broad scope—PSN Technology has the dynamic scope of encapsulate a large array of water insoluble drugs
  • Early discovery—PSN Technology can be used as an alternative formulation method to further explore compounds with poor water solubility (prospective drugs that would otherwise not be developed)

Overview Questions

What is a Protein Stabilized Nanoparticle (PSN)?
Azaya has discovered and developed a proprietary Protein Stabilized Nanoparticle (PSNTM) technology platform to enhance delivery of water insoluble drugs including safer and more efficacious chemotherapeutics.

The PSN Technology:

  • Allows further development of experimental drugs that up to now have been difficult to deliver to the marketplace due to toxicity or formulation issues
  • Allows reformulation of approved, marketed drugs with proven efficacy
  • Prolongs the life cycle of currently available chemotherapeutics or drugs in development
  • Will explore the future for delivering cancer drugs in combination in a single, targeted drug delivery system
  • Extensive product pipeline and potential to expand to non-oncology therapeutics
  • Initial presclinical xenograph studies have shown improved safety and efficacy verses the parent compounds
  • Robust cost-effective manufacturing process producing nanosized particles
  • This process solves major problems of earlier generation liposomes with many potential therapeutic benefits over currently available technologies
  • Utilizes 100% FDA approved ingredients
  • Allows entry into existing multi-billion dollar markets
  • Excellent IP position
  • Strong competitive advantages verses other drug delivery technologies
  • Highly experienced management team

How does PSN technology prevent the API from leaking out of the liposome?

Conventional Liposomes; Retention and Encapsulation

Fundamentally, liposomes are particles made up of thousands of small molecules that arrange (self assemble) in an orderly fashion to form a sphere with an inner core. The inner core of the sphere is filled with water (aqueous interior) and the shell is made of thousands for phospholipids that are assembled in an orderly arrangement (fatty acids; see figure 2).

A phospholipid is a unique molecule that possesses a polar head group, e.g. a charged phosphate with a polar moiety (choline) that is water soluble and a hydrophobic or nonpolar fatty acid chains that are water insoluble. The proverb that oil and water do not mix applies in this case. The oily tails of the phospholipid align to form a layer of oil, while the polar heads align to the outside or inner core forming a shell or lipid bilayer (figure 3). The shell is solvated by water from the exterior (polar heads, water soluble) and the inner core is also lined with polar heads forming an interior aqueous core.

Figure 2: Phospholipid (Choline—phosphatidyl choline)

Figure 3: Lipid bilayer: hydrophobic interior and hydrophilic exterior

These small molecules are held together by non-covalent interactions; hydrophobic interactions (oil characteristics), hydrogen bonds or hydrophilic interactions (water soluble characteristics), ionic and Vander Walls interactions (electro static charges or dipole moments).

These thousands of loose interactions, forming the lipid bilayer, can open and close releasing the contents of the inner aqueous core to the extra cellular media (leakage of inner core material). Thus, drugs encapsulated in the inner aqueous core will rapidly escape through momentary cracks or openings in the lipid bilayer, exchanging aqueous media from the outside with the inner core where the aqueous soluble drug is encapsulated.

PSN Technology:

Azaya’s PSNtechnology utilizes the lipid bilayer, encapsulating the water insoluble compound in the lipid layer. The basic principle of oil and water do not mix applies: as oil repels water, the retention of hydrophobic (water insoluble) compounds in the lipid layer (oil or hydrophobic region) is enhanced. Thus, if the liposome momentarily breaks open or cracks, the inner aqueous core can exchange contents with the outer aqueous media, while the lipid membrane stays intact without mixing with the aqueous environment. Hence, the water insoluble compounds stay completely intact in the lipid layer (oil), resulting in very little premature leakage of the hydrophobic API material.

Protein Stabilization:

Although conventional liposomal drug products can be loaded in the aqueous core, there are several issues that have not yet been overcome e.g. drug retention, leakiness and loading capacity within the lipid bilayer. Azaya Therapeutics developed protein stabilized Nanoparticle (PSN) to address these and many other profound issues found with conventional liposomes. Conventional technologies have been unable to encapsulate water insoluble molecules with reasonable efficiency. When conventional liposomes are sized, typically by filter excursion, the large multi-lamellar liposome are sheared apart (ripped into smaller pieces, disrupting molecular interactions of the lipids) forcing the drug to become disassociated with the lipid layer becoming exposed to the aqueous medium. As a result, water insoluble compounds will precipitate from solution, preventing interactions with the amphiphilic excipients, resulting in poor loading efficiencies.

Natural proteins that possess amphiphilic and amphoteric characteristics are used to stabilize the liposomal product. This unique protein primarily assists in the pre-emulsion process, stabilizing an emulsion particle, which contains the API and lipid materials. Immediate removal of the organic solvents form the emulsion droplet force the lipid materials to rapidly assemble into a liposome, with API material encapsulated in the lipid bilayer with a high degree of efficiency. Hence, Azaya Therapeutics has developmed a one-step process that sizes and encapsulate the active pharmaceutical ingredient resolving many issues found with conventional encapsulation methods.

Protein stabilization of the liposome—interactions
Side note: The pre-sized liposome loaded with hydrophobic material can not undergo resizing. The techniques used to resize the liposome subject it to shear forces that will disrupt the molecular interactions releasing the hydrophobic drug from the lipid bilayer.

How does the PSN technology improve on the delivery of drug products?

Drug Circulation:

The PSN technology has revolutionized liposome encapsulation therapies, enabling the formulation of a number of known drug products that are poorly water soluble, including, among others, the taxanes. Moreover, this technology offers early discovery opportunities to evaluate potential drug products that would other wise fail because of a lack of solubility and ability to formulate with conventional formulation technologies.

As described above, the retention of the drug is dramatically improved and leakage of APIs is reduced. This results in longer product shelf life, longer than expected circulation and an increased propensity to target cancerous tumors. ATI-1123 has exhibited a dramatically improved PK profile relative to the parent drug. Hence, Azaya’s goal is to reduce adverse toxicological effects and improve effectiveness of PSN formulated drugs i.e. taxanes, by making improved therapies for cancer.

Can the PSN technology be scaled up and reproduced at a GMP facility (technology transfer)?

Technology Transfer:

The Azaya manufacturing process of PSN products have been successfully transferred to a full GMP compliant contract manufacturing facility (Brookwood Pharmaceuticals in Birmingham, Alabama) and efforts for process development are underway. Currently, Azaya has successfully scaled the manufacturing process from a research size batch of 50 ml scale to a 350 ml batch. The manufacturing process is completely scaleable and little if any gross modification to the process will be necessary for full scale manufacturing. Azaya is confident that the manufacturing processes of PSN products are scalable for commercialization.