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Liposome Terminology and Nomenclature: U.S. Leads Efforts in Development of ISO/TS 4958, Nanotechnologies – Vocabulary – Liposomes


A new international document defines terms relative to liposomes in nanotechnologies: ISO/TS 4958, Vocabulary – Liposomes. The U.S. acted as Project Leader for this work item within ISO Technical Committee (TC) 229, Nanotechnologies, Joint Working Group 1, Terminology and nomenclature, to facilitate communications between organizations and individuals that use the vesicles.

TAG WG 1 chair Dr. Scott Brown of GSK and Dr. Vince Hackley of the National Institute of Standards and Technology (NIST) led the development of this Technical Specification.

What are Liposomes?

Liposomes are used in drug delivery, including cancer therapeutics, as well as vaccines, cosmetics, and, more recently, dietary supplements. They are synthetic vesicles consisting of one or more lipid bilayers that form both hydrophobic and hydrophilic compartments that can encapsulate active pharmaceutical ingredients.

Dr. Hackley noted that, “Liposomes are not new. The first liposomal drug formulation was approved by FDA in 1996 for cancer treatment, and liposomes currently represent the largest class of nanomaterial-containing drug products submitted to the FDA. Nevertheless, standards that address the quality attributes of liposomes and that define technical vocabulary are long overdue.”

A lack of standardization in liposome terminology has resulted in challenges in scientific and technical communications, impacting trade. ISO/TS 4958 provides foundational terminology, incorporating input from international experts and diverse stakeholder communities, including both industry and regulators alike. Ultimately, the specification is intended to facilitate communications between organizations and individuals, including academic researchers, industry, regulatory agencies, and other interested parties and those who interact with them.

ISO/TS 4958 Scope

ISO/TS 4958 defines terms relative to liposomes in nanotechnologies, within the context of biological systems and biomedical applications. In this context, liposomes are one form of lipid-based nanomaterials. The document does not address terms that can be relevant to other types of lipid-based particles (e.g., solid lipid nanoparticles).

“This terminology document will promote the further advancement of biomedical liposome technologies by clarifying terminology for all stakeholders,” noted Dr. Brown. “It was wonderful to see private sector, academic, NGO, and regulating communities come together to work on this foundational document. Many thanks to the due diligence and dedication of all the experts involved in this project. A lot of work goes into achieving consensus in foundational standards, particularly for topics that have been around for decades without normalization.”

The United States is also currently developing a relevant preliminary work item, Nanotechnologies – Total and free drug quantitation in doxorubicin hydrochloride liposomal formulations, under JWG 2, Measurement and characterization. This project is led by Dr. Jeff Clogston of the National Cancer Institute/Nanotechnology Characterization Laboratory.

About the U.S. TAG TO ISO/TC 229, Nanotechnologies

ANSI administers the U.S. TAG to ISO/TC 229, Nanotechnologies. The scope of the U.S.TAG mirrors the scope of ISO/TC 229, as follows:

Standardization in the field of nanotechnologies that includes either or both of the following:

  • Understanding and control of matter and processes at the nanoscale, typically, but not exclusively, below 100 nanometers in one or more dimensions where the onset of size-dependent phenomena usually enables novel applications
  • Utilizing the properties of nanoscale materials that differ from the properties of individual atoms, molecules, and bulk matter to create improved materials, devices, and systems that exploit these new properties

Participation on the U.S. Technical Advisory Group (TAG) to ISO TC 229 is open to all materially affected U.S. national interested parties. For more information, contact the TAG administrator, Heather Benko ([email protected]).


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