An update on liposomes in drug delivery: a patent review (2014-2018)

ABSTRACT

Introduction: Pharmacotherapy is limited by the inefficient drug targeting of non-healthy cells/tissues. In this pharmacological landscape, liposomes are contributing to the impulse given by Nanotechnology to optimize drug therapy.

Areas covered: The analysis of the state-of-the-art in liposomal formulations for drug delivery purposes have underlined that lately published patents (since 2014) are exploring alternative compositions and ways to optimize the stability and drug loading content/release profile. These improvements are complemented by improved long-circulating structures and further liposome functionalizations, which have definitively opened the road for the (co-)delivery of therapeutics to the site of action. Liposomes are also contributing to new drug delivery approaches involving the generation of extracellular vesicles by targeted cells, while opening new ways to combine disease diagnosis and therapy (theranosis).

Expert opinion: Patent publications on liposomal formulations have expanded new ways in drug delivery. New lipid compositions and strategies to optimize stability and drug vehiculization capabilities have settle solid pillars in liposome fabrication. Despite, their architecture has been satisfactorily adapted for combining passive and active drug targeting concepts, new inputs of liposomes into the disease arena should answer for: a simple/scalable/cost-effective formulation; a safe/stable/controllable formulation meeting quality control regulations; and, a confirmed therapeutic efficiency in clinical investigations.

KEYWORDS:

• Active loading
• active targeting
• combined targeting
• dual drug delivery
• liposome
• liposome stability
• passive targeting
• theranosis

Article highlights

• Innovative designs in liposomal architectures are contributing to the optimization of drug activity in vitro and, more promisingly, in vivo.

• Since 2014, published patents are describing new hopeful possibilities to engineer stable liposomes exhibiting excellent drug delivery capabilities.

• Gaining control of the in vivo fate of liposomes has been demonstrated to be feasible if passive and ligand-mediated targeting capabilities are combined into the nanostructure.

• Liposome formulation has evolved to establish new drug targeting approaches, including co-delivery strategies, and theranostic functionalities that are expected to generate superior therapeutic outcomes.

• Continue introduction of liposomes into the disease arena relies on: (i) defining easy, economic and stable formulations to be scaled up in the pharmaceutical industry; and, (ii) the exact confirmation of their therapeutic efficiency and safety in clinical investigations.

This box summarizes 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.

Additional information

Funding

Financial support from Consejería de Innovación, Ciencia y Empresa (Junta de Andalucía, Spain; grant number: PE-2012-FQM-694), Consejería de Salud (Junta de Andalucía, Spain; grant number: PI-0476-2016), and Ministerio de Economía, Industria y Competitividad (Spain; grant number: BFU2016-80316-R).