SLN and NLC for topical, dermal, and transdermal drug delivery

ABSTRACT

Introduction

From a biopharmaceutical standpoint, the skin is recognized as an interesting route for drug delivery. In general, small molecules are able to penetrate the stratum corneum, the outermost layer of the skin. In contrast, the delivery of larger molecules, such as peptides and proteins, remains a challenge. Nanoparticles have been exploited not only to enhance skin penetration of drugs but also to expand the range of molecules to be clinically used.

Areas covered

This review focus on Solid lipid nanoparticles (SLN) and Nanostructured lipid carriers (NLC) for skin administration. We discuss the selection criteria for lipids, surfactants, and surface modifiers commonly in use in SLN/NLC, their production techniques, and the range of drugs loaded in these lipid nanoparticles for the treatment of skin disorders.

Expert opinion

Depending on the lipid and surfactant composition, different nanoparticle morphologies can be generated. Both SLN and NLC are composed of lipids that resemble those of the skin and sebum, which contribute to their enhanced biocompatibility, with limited toxicological risk. SLN and NLC can be loaded with very chemically different drugs, may provide a tunable release profile, can be produced in a sterilized environment, and be scaled-up without the need for organic solvents.

KEYWORDS:

• Solid lipid nanoparticles
• nanostructured lipid carriers
• skin administration
• lipids
• surfactants

Article highlights

• Lipid nanoparticles possess important application for topical, dermal, and transdermal drug delivery.

• Both SLN and NLC can be prepared by different techniques, with the advantage of being an easy scale up production.

• Tailoring their composition in terms of lipids and surfactants it is possible to obtain important therapeutic outcomes with the site-specific targeting.

• Their constituents are biocompatible, which limits the risk of toxicity and irritation when applied onto the skin.

• SNL and NLC can be composed of lipids capable of enhancing the permeation of the drug, which requires less of the drug to exhibit its therapeutic effect and reduces possible side effects.

This box summarizes the key points contained in the article.

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.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The authors acknowledge CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for the financial support and for the fellowship of the second author (88887.368385/2019-00). Authors also acknowledge the support received from the Portuguese Science and Technology Foundation, Ministry of Science and Education (FCT/MEC) through national funds, and co-financed by FEDER, under the Partnership Agreement PT2020, for the projects M-ERA-NET-0004/2015-PAIRED and UIDB/04469/2020 (strategic fund).