Challenging the CNS Targeting Potential of Systemically Administered Nanoemulsion Delivery Systems: a Case Study with

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Ekta Kadakia1, Pratiksha Harpude1, Neha Parayath1

  • 1Department of Pharmaceutical Sciences, School of Pharmacy, Northeastern University, Boston, Massachusetts, 02115, USA.

Pharmaceutical Research
|July 13, 2019
PubMed
Abstract

Insights

Nanoemulsions did not improve brain drug delivery of rapamycin, as formulation characteristics did not impact targeting efficiency. Encapsulation in nanoemulsions may not enhance blood-brain barrier penetration for drugs.

Area of Science:

  • Pharmacology
  • Nanotechnology
  • Neuroscience

Background:

  • Systemic administration of nanoemulsions is a strategy for enhancing drug delivery to the central nervous system (CNS).
  • Understanding the in-vivo properties and formulation characteristics influencing CNS drug delivery of nanoemulsions is crucial but remains incomplete.

Purpose of the Study:

  • To evaluate the CNS targeting potential of systemically administered nanoemulsions.
  • To investigate the impact of formulation characteristics, such as circulation half-life and particle size, on CNS delivery of rapamycin-loaded nanoemulsions.

Main Methods:

  • Rapamycin-loaded fish oil nanoemulsions were formulated and characterized.
  • The effect of circulation half-life and particle size distribution on CNS delivery of nanoemulsions was assessed in mice.
  • Targeting efficiency (TE) was calculated as the ratio of brain to systemic exposure of rapamycin after intravenous dosing.

Main Results:

  • Circulation half-life and particle size distribution did not significantly affect the brain targeting efficiency of rapamycin nanoemulsions.
  • Nanoemulsions did not demonstrate superior CNS drug delivery compared to their aqueous counterparts when systemic exposures were not improved.
  • The blood-brain barrier (BBB) penetration of rapamycin was not enhanced by encapsulation in these nanoemulsions.

Conclusions:

  • Blood-brain barrier penetration is primarily governed by intrinsic drug properties, not significantly improved by nanoemulsion encapsulation.
  • Current nanoemulsion formulations may not be an effective strategy for enhancing CNS drug delivery for all drugs.
  • Further research is needed to identify formulation strategies that can overcome BBB limitations for CNS drug delivery.
Keywords:
CNS targetingblood-brain barrierdrug deliverynanoemulsionspharmacokineticsrapamycin

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