Advances in lyotropic liquid crystal systems for skin drug delivery

ABSTRACT

Introduction

Lyotropic liquid crystals (LLCs) are organized mesophases with intermediate properties between liquids and solids. The LLC and its liquid crystalline nanoparticles (LCNPs) have attracted great interest from the scientific community in recent years as potential drug delivery systems due to the high internal ordering and symmetry with a wide interfacial area.

Areas covered

This article aims to gather information and to provide a description of the highly organized structures of LLCs. Updates on production methods and new insights for LCNPs optimization and physico-chemical and morphological caracterization techniques were discussed. We also discussed why these systems proved to be a platform for the design of nanocarrier drug delivery, with an emphasis on topical and transdermal applications.

Expert opinion

Drug delivery platforms are of particular importance to improve the biopharmaceutical aspects of therapies topically. Although several systems can be used, LLC or LCNPs appear to be favored due to their similarity to the lipid structure of the skin. The highly ordered structure and the possibility of chemical modifications make it possible to obtain better clinical responses. The results of several studies support the innovations in this field and predict that these systems can innovate the market of technologies for the treatment of cutaneous diseases and cosmetology.

KEYWORDS:

• Lyotropic liquid crystal
• liquid crystalline nanoparticle
• nanodispersions
• skin
• topical drug delivery

Article highlights

• LLC is an outstanding platform for designing the drug delivery of nanocarriers for therapy, diagnosis, and theranostics.

• Strategies such as experimental statistical designs are currently applied to optimize the production of LCNPs.

• Several modalities of physical-chemical techniques have been employed to elucidate liquid-crystalline structures and to investigate inter- and intra-molecular interactions.

• LCNPs show high versatility, biocompatibility, and multifunctionality by opening the range of possibilities of topical and/or transdermal treatment.

• Their high internal ordering properties and ability to deliver hydrophilic, lipophilic, or amphiphilic molecules, as well as their wide solubilization spectrum, high drug encapsulation rates, physical-chemical stabilization, drug side effect minimization, and protection of drugs susceptible to degradation, define LLC and LCNPs as promising pharmaceutical carriers.

• The incorporation of chemical additives appears to be a simple alternative to contribute to drug release rates or to allow better skin penetration.

• Several topical LCNPs have been applied to the treatment of psoriasis, vitiligo, inflammatory skin conditions, skin cancer, and other skin diseases.

• LLC and LCNPs are used in conventional therapy to transport synthetic and natural drugs, photosensitizers, and, more recently, nucleic acid delivery (gene therapy).

• The use of LCNPs for the delivery of siRNA deserves extensive attention due to the high efficiency of interaction, enzymatic protection and cytoplasmic delivery in target cells.

Declaration of interest

The authors have no 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. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

National Institute of Science and Technology of Pharmaceutical Nanotechnology (INCT-Nanofarma), which is supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (Fapesp, Brazil, grant #2014/50928-2) and Conselho Nacional de Pesquisa (CNPQ, Brazil, grant #465687/2014-8).