Polymeric micelles for oral drug administration enabling locoregional and systemic treatments

Abstract

Introduction: Amphiphilic block copolymers are recognized components of parenteral drug nanocarriers. However, their performance in oral administration has barely been evaluated to any great extent.

Areas covered: This review provides an overview of the methods used to prepare drug-loaded polymeric micelles and to evaluate their stability in gastrointestinal (GI) fluids, and then analyzes in detail recent in vitro and in vivo results about their performance in oral drug delivery. Oral administration of polymeric micelles has been tested for a variety of therapeutic purposes, namely, to increase apparent drug solubility in the GI fluids and facilitate absorption, to penetrate in pathological regions of the GI tract for locoregional treatment, to carry the drug directly toward the blood stream minimizing presystemic loses, and to target the drug after oral absorption to specific tissue or cells in the body.

Expert opinion: Each therapeutic purpose demands micelles with different performance regarding stability in the GI tract, ability to overcome physiological barriers and drug release patterns. Depending on the block copolymer composition and structure, a wealth of self-assembled micelles with different morphologies and stability can be prepared. Moreover, copolymer unimers can play a role in improving drug absorption through the GI mucosa, either by increasing membrane permeability to the drug and/or the carrier or by inhibiting drug efflux transporters or first-pass metabolism. Therefore, polymeric micelles can be pointed out as versatile vehicles to increase oral bioavailability of drugs that exhibit poor solubility or permeability and may even be an alternative to parenteral carriers when targeting is pursued.

Keywords:

• drug solubilization
• efflux inhibition
• locoregional treatment
• micelle architecture
• oral administration
• polymeric micelles

Declaration of interest

This work was financially supported by Fundação para a Ciência e a Tecnologia of Portugal (EXPL/CTM-NAN/1151/2012), Ministerio de Ciencia e Innovación of Spain (MICINN, SAF2011-22771) and FEDER. The authors also acknowledge the support of the Galician Network for Colorectal Cancer Research (REGICC). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Notes

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