Triblock Copolymer Micelles with Tunable Surface Charge as Drug Nanocarriers: Synthesis and Physico-Chemical Characterization.

Radostina Kalinova,Ivaylo Dimitrov

doi:10.3390/nano12030434

Radostina Kalinova, Ivaylo Dimitrov

Open Access

https://doi.org/10.3390/nano12030434

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Abstract

Polymeric micelles have gained increasing interest as efficient drug delivery systems for cancer treatment and diagnosis. The aim of the present study was to construct and to evaluate novel polymeric nanosized drug carriers with tunable surface charges. Initially, amphiphilic triblock copolymers with predetermined molar mass characteristics were synthesized by applying controlled polymerization techniques. The copolymers self-assembled in aqueous media into core–shell spherical micelles, comprising a biodegradable hydrophobic poly(D,L-lactide) core, positively charged middle layer of poly((2-dimethylamino)ethyl methacrylate), and an outer shell of neutral hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate), with various densities of the short polyether side chains. The block copolymer micelles with average diameters of about 70 nm and surface charges varying from strongly positive to neutral were characterized and loaded with the model, natural, hydrophobic drug curcumin. Characteristics such as drug loading efficiency, in-vitro drug release profiles, and stability under physiological conditions were evaluated and discussed in terms of nanocarriers’ composition. As a result, the most promising candidates for potential application in nanomedicine were identified.

Highlights

Bioavailability is a key pharmacokinetic property of drugs defining the part of initially introduced amount of active drug which is available for systemic circulation and subsequently reaches the target site of action [1]
Oligo methyl ether methacrylate (OEGMA, Mn ~ 500 Da) was passed under an argon pressure firstly through a column packed with a neutral Al2 O3 and through a column packed with a basic Al2 O3 in order to remove the inhibitors
The results indicate slight increase their average jected to dynamic light scattering (DLS)

Summary

Introduction

Bioavailability is a key pharmacokinetic property of drugs defining the part of initially introduced amount of active drug which is available for systemic circulation and subsequently reaches the target site of action [1]. Drugs characterized with a poor bioavailability are not able to reach the concentration required to reveal their pharmacological action. Low drug bioavailability usually is due to poor aqueous solubility, since more than 70% of newly developed drug candidates are hydrophobic in nature [2]. Other factors affecting drug bioavailability are inappropriate hydrophilic–lipophilic balance (HLB), metabolism of a drug before it reaches systemic circulation, and degradation in the gastrointestinal tract [3,4,5]. The optimal size range of nanoparticles used as drug carriers is usually within 10–200 nm [7]

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