Fabrication Principles and Their Contribution to the Superior In Vivo Therapeutic Efficacy of Nano-Liposomes Remote Loaded with Glucocorticoids

Yuval Avnir,Deborah Tulchinsky,Keren Turjeman,Yechezkel Barenholz,Alberto Gabizon,Dina Tzemach,Alex Sigal,Pablo Kizelsztein,Dimitris Fatouros

doi:10.1371/journal.pone.0025721

Yuval Avnir, Deborah Tulchinsky + Show 7 more

Open Access

https://doi.org/10.1371/journal.pone.0025721

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Abstract

We report here the design, development and performance of a novel formulation of liposome- encapsulated glucocorticoids (GCs). A highly efficient (>90%) and stable GC encapsulation was obtained based on a transmembrane calcium acetate gradient driving the active accumulation of an amphipathic weak acid GC pro-drug into the intraliposome aqueous compartment, where it forms a GC-calcium precipitate. We demonstrate fabrication principles that derive from the physicochemical properties of the GC and the liposomal lipids, which play a crucial role in GC release rate and kinetics. These principles allow fabrication of formulations that exhibit either a fast, second-order (t1/2 ∼1 h), or a slow, zero-order release rate (t1/2 ∼ 50 h) kinetics. A high therapeutic efficacy was found in murine models of experimental autoimmune encephalomyelitis (EAE) and hematological malignancies.

Highlights

Glucocorticoids (GCs) are widely used drugs in treatment of inflammatory diseases and cancer [1,2,3]
This unfavorable pharmacokinetics can be overcome by the use of a drug delivery system (DDS) providing a slow, zero-order release kinetics that, while keeping plasma drug concentration below toxicity level, will allow for the drug concentration needed to achieve a therapeutic effect [5]
This study focuses on the relevance of the physicochemical aspects of these nSSL-GC to their superior therapeutic performance and it complements our 1995 publication [28], which describes some basic principles of the remote loading of amphipathic weak acids using model molecules in vitro

Summary

Introduction

Glucocorticoids (GCs) are widely used drugs in treatment of inflammatory diseases and cancer [1,2,3]. In order to address this challenge we decided to apply the strategy of transmembrane ion gradient-driven remote loading of amphipathic weak acid or base drugs into pegylated nanoliposomes (nano-sterically stabilized liposomes, referred to as nSSL). In our laboratory the remote loading approach began from the need to achieve a highly efficient and stable liposomal drug encapsulation that would be stable during storage and have a long circulation time in the blood This approach, which was recently discussed by us in detail for 9 different drugs [16], was applied for remote loading of the amphipathic weak base anticancer drug doxorubicin [16,17,18,19,20] and was the basis for the first FDA-approved pegylated nanoliposomal anticancer drug, DoxilTM. This study focuses on the relevance of the physicochemical aspects of these nSSL-GC to their superior therapeutic performance and it complements our 1995 publication [28], which describes some basic principles of the remote loading of amphipathic weak acids using model molecules in vitro

Results and Discussion

Materials and Methods

Methods