(111d) Impermeable Metal Nano-Capsules for Drug Delivery without Side Effects

Cancer therapeutics have dramatic side effects on healthy tissues. A prominent research area focuses on encapsulating cytotoxic drugs for targeted delivery to cancer tissues and for reduction of off-tissue side-effects. However, significant challenges remain for encapsulated clinical drugs (e.g. liposomal doxorubicin):

1. Drug encapsulation remains very expensive.

2. Drug loading is low and the manufacturing process is inefficient

3. Once encapsulated drug leaching over time is often high (especially on dilution)

4. Typically release specifically within tumours is not achieved

Recently, we have demonstrated the efficient manufacture of impermeable metal-shell/liquid core microcapsules (Hitchcock ‘Long-term Retention of Small, Volatile Molecular Species within Metallic Microcapsules’, ACS Appl. Mater. Interfaces, 2015, 7, 14808) that permit localised delivery of active (pharmaceutical) ingredient high doses by triggering release with ultrasound at the target location. This delivery method has the potential to be superior to all previously developed encapsulation strategies because it would address all of the above challenges simultaneously:

1. Capsules can easily be manufactured at industrial scale,

2. High drug content can be achieved within capsule cores,

3. No drug leaching occurs, thus preventing any side-effects prior to release activation via ultrasound treatment,

4. Complete release of high drug concentrations can be achieved in cancer-affected areas only.

Recent Relevant Publications:

• 4 recent patents – James Hitchcock, Coated microcapsules 20160168509, 20160168511, 20160177221 and 20160168510 publication dates 16/6/16
• The effect of surfactant chain length on the morphology of poly(methyl methacrylate) microcapsules for fragrance oil encapsulation Alison Tasker*, James Hitchcock, Ling He, Elaine Baxter, Simon Biggs and Olivier J. Cayre (Journal of colloid and interface science Volume 484, 15 December 2016, Pages 10–16)
• Long-Term Retention of Small, Volatile Molecular Species within Metallic Microcapsules J. P. Hitchcock*, A. L. Tasker, E. A. Baxter, S. Biggs, and O. J. Cayre, ACS Applied Materials & Interfaces, vol. 7, pp. 14808-14815, 2015/07/15 2015
• Adsorption of catalytic nanoparticles onto polymer substrates for controlled deposition of metal microcapsule shells J. P. Hitchcock*, A. L. Tasker, S. Biggs, and O. J. Cayre (submission to ACS Langmuir Feb, 2017)