Optimization of Biocompatibility for a Hydrophilic Biological Molecule Encapsulation System

Abstract

Despite considerable advances in recent years, challenges in delivery and storage of biological drugs persist and may delay or prohibit their clinical application. Though nanoparticle-based approaches for small molecule drug encapsulation are mature, encapsulation of proteins remains problematic due to destabilization of the protein. Reverse micelles composed of decylmonoacyl glycerol (10MAG) and lauryldimethylamino-N-oxide (LDAO) in low-viscosity alkanes have been shown to preserve the structure and stability of a wide range of biological macromolecules. Here, we present a first step on developing this system as a future platform for storage and delivery of biological drugs by replacing the non-biocompatible alkane solvent with solvents currently used in small molecule delivery systems. Using a novel screening approach, we performed a comprehensive evaluation of the 10MAG/LDAO system using two preparation methods across seven biocompatible solvents with analysis of toxicity and encapsulation efficiency for each solvent. By using an inexpensive hydrophilic small molecule to test a wide range of conditions, we identify optimal solvent properties for further development. We validate the predictions from this screen with preliminary protein encapsulation tests. The insight provided lays the foundation for further development of this system toward long-term room-temperature storage of biologics or toward water-in-oil-in-water biologic delivery systems.

Effective nanoparticulate-type encapsulation delivery system for hydrophilic proteins and peptides

“…One of the most desirable features of the system is the high structural fidelity achieved upon encapsulation [19]. Furthermore, the 10MAG/LDAO surfactant combination shows promise as an encapsulation system for therapeutic bioactive molecules, particularly for oral protein delivery [20], due to its ability to preserve the native, functional state of proteins. Our aim was to develop a nanocarrier system for proteins/peptides with the capability of preserving their structural integrity and possessing the advantageous properties of nanoparticles.…”

Characterization of 10MAG/LDAO reverse micelles: Understanding versatility for protein encapsulation

“…Proteins were originally solubilized in reverse micelles to study reactions and interactions with surfactants that closely resembled biological membranes [ 38 , 39 ]. Since then, they have become an important tool for various biophysical applications, including studies of biological water dynamics [ 40 – 45 ], nanoconfinement effects on protein stability [ 46 – 51 ], enzymatic catalysis [ 10 , 52 , 53 ], and as possible vehicles for drug delivery [ 33 , 54 ]. RMs are an especially advantageous system for high resolution NMR spectroscopy studies of protein structure and dynamics.…”

“…A necessary precursor for effective encapsulation is precise optimization of the RM water core size, determined by the water loading, . Proteins encapsulated in optimized RMs are often stable for weeks to months at room temperature, without the need for preservation agents like sodium azide [ 33 , 35 ]. However, in the RM systems CTAB / hexanol and AOT, the must be finely tuned individually for each protein to produce long term, stable samples [ 55 ].…”