Drug Products, 
Including Biological 
Products, that Contain 
Nanomaterials 
Guidance for Industry 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Drug Evaluation and Research (CDER) 
Center for Biologics Evaluation and Research (CBER) 
 
April 2022 
Pharmaceutical Quality/CMC 
 
19640025 FNL 
   
Drug Products, 
Including Biological 
Products, that Contain 
Nanomaterials 
Guidance for Industry 
 
Additional copies are available from: 
Office of Communications, Division of Drug Information  
Center for Drug Evaluation and Research 
Food and Drug Administration 
10001 New Hampshire Ave., Hillandale Bldg., 4th Floor  
Silver Spring, MD 20993-0002  
Phone: 855-543-3784 or 301-796-3400; Fax: 301-431-6353 
Email: druginfo@fda.hhs.gov  
https://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/default.htm 
and/or 
Office of Communication, Outreach and Development  
Center for Biologics Evaluation and Research 
 Food and Drug Administration 
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Silver Spring, MD 20993-0002 
Phone: 800-835-4709 or 240-402-8010 
Email: ocod@fda.hhs.gov 
https://www.fda.gov/vaccines-blood-biologics/guidance-compliance-regulatory-information-biologics/biologics-guidances 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Drug Evaluation and Research (CDER) 
Center for Biologics Evaluation and Research (CBER) 
 
April 2022 
Pharmaceutical Quality/CMC 
  Contains Nonbinding Recommendations 
 
TABLE OF CONTENTS 
 
 
 
I.  INTRODUCTION............................................................................................................. 1 
II.  SCOPE ............................................................................................................................... 2 
III.  RISK-BASED FRAMEWORK:  POTENTIAL RISK FACTORS FOR  
PRODUCTS CONTAINING NANOMATERIALS ...................................................... 5 
IV.  QUALITY RECOMMENDATIONS .............................................................................. 7 
A.  Description of the Nanomaterial(s) in the Drug Product ........................................................... 7 
B.  Nanomaterial Quality Attributes and Structural Characterization ......................................... 8 
C.  Nanomaterial Physicochemical Characterization Methods ..................................................... 10 
D.  Dissolution/In Vitro Drug Release Methods for Quality Testing ............................................ 11 
E.  Manufacturing Process and In-Process Controls ..................................................................... 12 
F.  Excipients ...................................................................................................................................... 13 
1. Function ......................................................................................................................................... 13 
2. Safety .............................................................................................................................................. 14 
G.  Stability ......................................................................................................................................... 14 
H.  Postmarket CMC Changes .......................................................................................................... 15 
V.  NONCLINICAL STUDIES FOR DRUG PRODUCTS .............................................. 16 
A.  General Applicability of Guidance ............................................................................................. 16 
B.  Absorption, Distribution, Metabolism, and Excretion (ADME) Considerations ................... 16 
C.  Risk Considerations for Specific Routes of Administration .................................................... 16 
1. Topically Applied Products ............................................................................................................ 17 
2. Subcutaneous Administration ........................................................................................................ 17 
3. Inhalation ....................................................................................................................................... 17 
4. Intravenous Products ..................................................................................................................... 17 
5. Oral Products ................................................................................................................................ 17 
D.  Testing of Representative Nanomaterial .................................................................................... 18 
E.  Bridging Toxicology from a Drug Product not Containing Nanomaterials to a Drug  
Product Containing Nanomaterials ............................................................................................ 18 
VI.  CLINICAL DEVELOPMENT ...................................................................................... 18 
A.  505(b)(2) Submissions .................................................................................................................. 19 
1. General Considerations ................................................................................................................. 19 
2. Clinical Studies .............................................................................................................................. 20 
B.  505(j) Submissions ....................................................................................................................... 22 
C.  351(k) Submissions ...................................................................................................................... 24 
i  Contains Nonbinding Recommendations 
 
D.  Bioanalytical Methods ................................................................................................................. 24 
E.  In Vitro Tests With Human Biomaterials .................................................................................. 25 
F.  Immunogenicity ........................................................................................................................... 25 
VII.  ENVIRONMENTAL IMPACT CONSIDERATIONS ............................................... 26 
GLOSSARY................................................................................................................................. 27 
ii  Contains Nonbinding Recommendations 
 
Drug Products, Including Biological Products,  
that Contain Nanomaterials1 
Guidance for Industry2 
 
 
This guidance represents the current thinking of the Food and Drug Administration (FDA or Agency) on 
this topic.  It does not establish any rights for any person and is not binding on FDA or the public.  You 
can use an alternative approach if it satisfies the requirements of the applicable statutes and regulations.  
To discuss an alternative approach, contact the FDA office responsible for this guidance as listed on the 
title page.   
 
 
 
I.  INTRODUCTION 
 
Nanotechnology can be used in a broad array of FDA-regulated products, such as human drug 
products, including those that are biological products.3  Nanotechnology may be used to create 
drug products in which nanomaterials (as explained in section II of this document), serve a 
variety of functions, as active ingredients4 or inactive ingredients, including carriers loaded 
with an active ingredient.  The inclusion of such materials may result in product attributes that 
differ from those of products that do not contain such materials, and thus may merit particular 
examination.  This document provides guidance on the development of human drug products, 
including those that are biological products, in which a nanomaterial is present in the finished 
dosage form. 
 
Note that FDA does not categorically judge all products containing nanomaterials or otherwise 
involving the use of nanotechnology as intrinsically benign or harmful.  Rather, for all products 
(nanotechnology-derived or otherwise), FDA considers the characteristics of the product and its 
safety and effectiveness for its use.  FDA issued a guidance document to industry on the 
Agencys considerations related to applications of nanotechnology in FDA-regulated products 
 
1 This guidance document is one of several FDA guidance documents related to FDA-regulated products that may 
involve the use of nanotechnology.  The use of the term nanomaterial in this document, as in other FDA guidance 
documents, does not constitute the establishment of a regulatory definition.  Rather, we use this term for ease of 
reference only.  See section II of this document for additional discussion. 
2 This guidance has been prepared by the CDER Nanotechnology Working Group in the Center for Drug Evaluation 
and Research (CDER) with participation from the Center for Biologics Evaluation and Research (CBER) at the 
Food and Drug Administration. 
3 Refers to those drug products that are biological products under 42 USC 262(i) and subject to licensure under 
section 351(a) or (k) of the Public Health Service Act (PHS Act) (42 U.S.C. 262(a) or (k)).  See 42 U.S.C. 262(j).  
According to 42 USC 262(i), the term biological product means a virus, therapeutic serum, toxin, antitoxin, 
vaccine, blood, blood component or derivative, allergenic product, protein, or analogous product, or arsphenamine 
or derivative of arsphenamine (or any other trivalent organic arsenic compound), applicable to the prevention, 
treatment, or cure of a disease or condition of human beings. 
4 For the purposes of this guidance, the terms active ingredient and drug substance are used interchangeably. 
  1  Contains Nonbinding Recommendations 
 
(referred to as FDAs nanotechnology considerations guidance).5  FDAs consideration of the 
use of nanomaterials in drug products, including those that are biological products, in this 
document is consistent with FDAs nanotechnology considerations guidance, and with the 
broader federal guidance on regulatory oversight of emerging technologies6 and 
nanotechnology.7 
 
The contents of this document do not have the force and effect of law and are not meant to bind 
the public in any way, unless specifically incorporated into a contract. This document is intended 
only to provide clarity to the public regarding existing requirements under the law. FDA 
guidance documents, including this guidance, should be viewed only as recommendations, unless 
specific regulatory or statutory requirements are cited. The use of the word should in FDA 
guidance means that something is suggested or recommended, but not required. 
 
II.  SCOPE 
 
This document provides guidance on the development of human drug products, including those 
that are biological products, in which a nanomaterial (as explained in this section) is present in 
the finished dosage form.  This guidance focuses on considerations relevant to FDAs regulation 
of these drug products under the Federal Food, Drug, & Cosmetic Act (FD&C Act) and Public 
Health Service Act (PHS Act), and includes recommendations for applicants and sponsors of 
investigational, premarket, and postmarket submissions for these products.8 
 
For purposes of this guidance: 
 
  The term drug product or drug products hereafter, refers to any human drug product 
or products in finished dosage form, including those that are also biological products, 
unless otherwise specified. 
  The term biological products refers specifically to those drug products that meet 
o
the definition of a biological product under 42 U.S.C. 262(i) and are subject to 
licensure under section 351(a) or (k) of the PHS Act (42 U.S.C. 262(a) or (k)).  
According to 42 U.S.C. 262(i), the term biological product means a virus, 
therapeutic serum, toxin, antitoxin, vaccine, blood, blood component or 
 
5 See FDAs guidance for industry Considering Whether an FDA-Regulated Product Involves the Application of 
Nanotechnology (June 2014).  For the most recent version of a guidance, check the FDA guidance web page at:  
https://www.fda.gov/regulatory-information/search-fda-guidance-documents. 
6 Office of Science and Technology Policy, Office of Management and Budget, and the United States Trade 
Representative.  Principles for Regulation and Oversight of Emerging Technologies, March 2011; available online 
at: https://obamawhitehouse.archives.gov/sites/default/files/omb/inforeg/for-agencies/Principles-for-Regulation-and-
Oversight-of-Emerging-Technologies-new.pdf. 
7 Office of Science and Technology Policy, Office of Management and Budget, and the United States Trade 
Representative.  Policy Principles for the U.S. Decision-Making Concerning Regulation and Oversight of 
Applications of Nanotechnology and Nanomaterials, June 2011; available online at: 
https://obamawhitehouse.archives.gov/sites/default/files/omb/inforeg/for-agencies/nanotechnology-regulation-and-
oversight-principles.pdf. 
8 This guidance also includes recommendations regarding the National Environmental Policy Act (NEPA), as 
relevant to potential FDA regulatory decisions on these drug products (see also 21 CFR part 25), but does not 
comprehensively address considerations that may be advisable to address compliance with legal obligations under 
other authorities, including those related to protection of occupational safety and health. 
  2  Contains Nonbinding Recommendations 
 
derivative, allergenic product, protein, or analogous product, or arsphenamine or 
derivative of arsphenamine (or any other trivalent organic arsenic compound), 
applicable to the prevention, treatment, or cure of a disease or condition of human 
beings. 
 
  This guidance also encompasses the drug or biologic constituent part of a 
o
combination product, as defined in FDA regulations at 21 CFR 3.2(e).9 
 
  FDA has not established regulatory definitions of nanotechnology, nanomaterial, 
nanoscale, or other related terms.  As described in FDAs nanotechnology 
considerations guidance (issued in June 2014), at this time, when considering whether an 
FDA-regulated product involves the application of nanotechnology, FDA will ask:  
(1) whether a material or end product is engineered to have at least one external 
dimension, or an internal or surface structure, in the nanoscale range 
(approximately 1 nm to 100 nm).  
In addition, because materials or end products can also exhibit related properties or 
phenomena attributable to a dimension(s) outside the nanoscale range of approximately 1 
nm to 100 nm that are relevant to evaluations of safety, effectiveness, performance, 
quality, public health impact, or regulatory status of products, we will also ask:  
(2) whether a material or end product is engineered to exhibit properties or 
phenomena, including physical or chemical properties or biological effects, that 
are attributable to its dimension(s), even if these dimensions fall outside the 
nanoscale range, up to one micrometer (1,000 nm). 
 
We will apply these considerations broadly to all FDA-regulated products, including 
products within the scope of this guidance.  This guidance covers the manufacturing and 
evaluation of drug products (i.e., finished dosage forms) intended for human use.  It does 
not cover manufacturing of drug components, such as active ingredients and excipients 
(i.e., inactive ingredients).  The recommendations in this guidance concern the 
characterization, control, testing and qualification of nanomaterial components in the 
drug product.  
 
For the purpose of this guidance only, we use the term nanomaterial generally to refer 
to materials falling within either point 1 or 2 above.  The use of this term in this manner 
is consistent with its use in FDAs nanotechnology considerations guidance.  In addition, 
use of this term in this document is for the purpose of communicating FDAs current 
thinking elaborated in this document only. 
 
  The term premarket application refers to Investigational New Drug (IND) 
applications, New Drug Applications (NDAs), Biologics License Applications (BLAs), 
Abbreviated New Drug Applications (ANDAs), and Drug Master Files (DMF), including 
any referenced DMF, unless noted otherwise. 
 
9 If the classification of a product as a drug, device, biological product, or combination product is unclear or in 
dispute, applicants can contact the Office of Combination Products for assistance.  See, e.g., guidance for industry 
and FDA staff Classification of Products as Drugs and Devices and Additional Product Classification Issues 
(September 2017). 
  3  Contains Nonbinding Recommendations 
 
 
A Glossary of these and other terms used in this guidance document appears at the end of the 
document, and words found in the Glossary are bolded at first use. 
 
This guidance does not apply to biological products composed of proteins, cells, viruses, nucleic 
acids, or other biological materials that naturally occur at particle sizes ranging up to 1 
micrometer (1,000 nm), such as gene therapy or vaccine products, unless a material that has been 
deliberately manipulated to have dimensions between 1-100 nm or to exhibit dimension-
dependent properties or phenomena up to 1 micrometer, is also present in the product.  
 
In alignment with FDAs nanotechnology considerations guidance, this guidance also does not 
apply to drug products that incidentally contain or may contain particles in the nanoscale range 
due to conventional manufacture or storage.10 
 
This guidance also does not apply to products not regulated by FDA as human drugs, for 
example, those regulated solely as drugs for animals, devices, foods, or cosmetic products. 
 
This guidance discusses both general principles and specific considerations for the development 
of drug products containing nanomaterials, including considerations for developing products 
through abbreviated pathways.  Considerations for quality, nonclinical, and clinical studies are 
discussed as they relate to drug products containing nanomaterials throughout product 
development and production.  This guidance also includes recommendations on the specific 
content of premarket applications for products containing nanomaterials where the nanomaterial 
is present in the finished dosage form. 
 
Certain nonprescription drug products can be legally marketed without review and approval of a 
product-specific premarket application under section 505 of the FD&C Act, if they satisfy 
applicable requirements under section 505G of the FD&C Act, 21 U.S.C. 355h.  These are 
commonly referred to as over-the-counter (OTC) monograph drugs.  The requirements in section 
505G for marketing OTC monograph drugs include conformity with applicable conditions of 
nonprescription use for the drug or class of drug,11 such as specified active ingredients and 
dosage strengths.  Such drugs also must meet the general requirements for nonprescription drugs, 
which include requirements that these drugs contain only safe and suitable inactive ingredients 
and be manufactured according to current good manufacturing practices.12  If a nanomaterial will 
be present in an OTC monograph drug in finished dosage form, its manufacturer is responsible 
for ensuring that the product satisfies all applicable legal requirements.  We encourage OTC 
monograph drug manufacturers to consider the general principles and specific considerations 
described in this guidance concerning drug development, safety evaluation, and quality.  We also 
 
10 However, evaluations of conventionally-manufactured drug products may include a consideration of effects, if 
any, of such incidental presence of particles in the nanoscale range on the safety or effectiveness of the product. 
11 These include conditions described in FD&C Act section 505G(a)(1)-(3) and those established by order under 
section 505G(b).   
12 See FD&C Act section 505G(a)(1) & (3); 505G(b)(1)(B), and 21 CFR 330.1. Section 505G of the FD&C Act, 
enacted on March 27, 2020, as part of P.L. 116-136, does not change the substance of the general requirements for 
nonprescription drugs. 
  4  Contains Nonbinding Recommendations 
 
encourage such manufacturers to meet with FDA before production and distribution of drug 
products that contain nanomaterials.  
 
This guidance does not limit or classify the types of nanomaterials that can be used in drug 
products.  Rather, it is focused on the deliberate and purposeful manipulation and control of 
dimensions to produce specific physicochemical properties which may warrant further evaluation 
with regards to safety, effectiveness, performance, and quality. 
 
This guidance does not address, or presuppose, what ultimate regulatory outcome, if any, will 
result for a particular drug product that contains nanomaterials.  Issues such as the safety, 
effectiveness, public health impact, or the regulatory status of drug products that contain 
nanomaterials are currently addressed on a case-by-case basis using FDAs existing review 
processes.  Current CDER and CBER guidance documents and requirements for the evaluation 
and maintenance of quality, safety, and efficacy, apply to drug products containing 
nanomaterials that otherwise fall within their scopes.  As such, this guidance should be viewed as 
supplementary to other guidances for drug products.  In addition, the Agency may continue to 
develop guidance addressing certain specific commonly-used types of nanomaterials, e.g., some 
liposomes,13 to better address the challenges in evaluating and characterizing the quality and 
performance of drug products that incorporate them. 
 
III.  RISK-BASED FRAMEWORK:  POTENTIAL RISK FACTORS FOR PRODUCTS 
CONTAINING NANOMATERIALS14 
 
There is great diversity in drug products containing nanomaterials, including in their route of 
administration, indication, function of the nanomaterial, structural complexity, and maturity of 
the technology (including manufacturing processes, analytical techniques, and product design).  
In some instances, nanomaterials may take on different chemical, physical, or biological 
properties than their larger-scale counterparts that may impact quality, safety, or efficacy.  For 
example,15 
 
  Nanomaterials may have modified rates of dissolution and may alter bioavailability 
(BA) compared to the same material that is not manufactured to be a nanomaterial.  In 
addition, after entry into the systemic circulation, nanomaterials can affect the 
distribution, the exposure-response profile, and the residence time of a therapeutic 
moiety.  These changes may be partly due to the interaction of nanomaterials with 
multiple plasma proteins resulting in the formation of a protein corona.  The bound 
plasma proteins may endow nanomaterials with new biological properties.  Through 
endocytosis, the nanomaterial-protein complex can be taken up by tissue cells.  
Elimination of the nanomaterial-protein complex occurs mainly through phagocytosis by 
macrophages of the mononuclear phagocyte system, predominantly in the liver and 
 
13 See FDAs guidance for industry Liposome Drug Products (April 2018).  
14 As explained in section II of this document, we use the term nanomaterial in this document for ease of 
reference.  See footnote 5 for more information. 
15 Tyner, KM et al. WIREs Nanomed Nanobiotechnol 2015. doi: 10.1002/wnan.1338; Tyner, KM et al. The AAPS 
Journal 2017. doi: 10.1208/s12248-017-0084-6; Cruz, CN et al. The AAPS Journal 2013. doi: 10.1208/s12248-013-
9466-6; Palombo M, et al. Annu Rev Pharmacol Toxicol. 2014doi: 10.1146/annurev-pharmtox-010611-134615. 
  5  Contains Nonbinding Recommendations 
 
spleen.  Thus, nanomaterials can enable targeting of a therapeutic moiety to specific sites 
but at the same time they may become targets of the complement and mononuclear 
phagocyte systems.  Small hydrophilic nanomaterials may be eliminated by the kidney. 
 
  Nanomaterials can be passively and/or actively targeted to different sites within the body.  
For example, passive targeting to different organs (e.g., liver) may be accomplished 
based on size or charge, while active targeting typically requires attachment of specific 
molecules (e.g., ligands, monoclonal antibodies, small molecules) to the surface of 
nanomaterials that are recognized by receptors. 
 
Compared to other products, more information may be needed regarding the interactions of 
nanomaterials with biological systems.  These interactions include, but are not limited to, the 
impact of intrinsic (e.g., disease, age, sex) and extrinsic factors (e.g., co-administered drugs) on 
exposure and response, the role of enzymes and transporters in their disposition, and their 
immunogenic potential. 
 
FDA believes that a suitable framework for evaluating potential risk(s) associated with drug 
products containing nanomaterials should assure (1) adequate characterization of the 
nanomaterial, and (2) adequate understanding of a nanomaterials intended use and application, 
and of how the nanomaterial attributes relate to product quality, safety, and efficacy.  We 
recommend a risk-based approach focusing on the following risk factors, which are further 
addressed in this guidance.  This list is not comprehensive and other risk factors may need to be 
evaluated during product development.  As for all drug products, manufacturers of drug products 
containing nanomaterials should use information accumulated over the life cycle of the product 
to facilitate continual reduction of residual uncertainty.  The characterization and extent of 
product understanding will vary by product as well as the stage of its life cycle and should be 
justified in consideration of the risk-based approach outlined in this guidance. 
 
Recommended Factors for Assessment of the Nanomaterial: 
 
  Adequacy of characterization of the material structure and its function. 
 
  Complexity of the material structure. 
 
  Understanding of the mechanism by which the physicochemical properties of the material 
impact its biological effects (e.g., effect of particle size on pharmacokinetic parameters). 
 
  Understanding the in vivo release mechanism based on the materials physicochemical 
properties. 
 
  Predictability of in vivo release based upon established in vitro release methods.  
 
  Physical and chemical stability. 
 
  Maturity of the nanotechnology (including manufacturing and analytical methods). 
 
  6  Contains Nonbinding Recommendations 
 
  Potential impact of manufacturing changes, including in-process controls and the 
robustness of the control strategy on critical quality attributes (CQAs) of the drug 
product. 
 
  Physical state of the material upon administration. 
 
  Route of administration. 
 
  Dissolution, BA, distribution, biodegradation, accumulation and their predictability based 
on physicochemical parameters and animal studies.16 
 
IV.  QUALITY RECOMMENDATIONS 
 
A.  Description of the Nanomaterial(s) in the Drug Product 
 
A description of nanomaterials in the drug product should be included in the premarket 
application, as part of the sections on product composition and description (e.g., electronic 
common technical document (eCTD) 3.2.P.2.1).  The description of the nanomaterial should 
include information that sufficiently describes the product (e.g., size, charge, morphology, 
composition, and complexation) at a level appropriate for the stage of the product life cycle.  For 
example, at the IND stage, sufficient description of the nanomaterial should be included to 
ensure safety during use in clinical trials as well as to collect sufficient data to bridge early 
development batches to late stage clinical trial material and the proposed commercial 
material.17,18  Sufficient description of the nanomaterial in an ANDA, NDA, or BLA allows for 
control over the material properties to ensure consistent quality of the drug product.  A narrative 
description and a complementary diagram of the structure being described should be included.  
The description of the nanomaterial structure is particularly important for more complex 
structures involving multiple components or compartments (e.g., layers, core-shell structures), 
ligands, and coatings.  Providing only an ingredient list may not be sufficient to explain the 
resulting structure of the nanomaterial after assembly, formulation, and/or processing. 
   
In addition to the description of the nanomaterial structure, a description of the functionality of 
the nanomaterial should be included (e.g., used for solubilization of the active ingredient, as a 
carrier, as the active ingredient, for targeting and delivery). 
 
FDA acknowledges that as product development progresses, more information will become 
available on the structure and function of the nanomaterial.  For example, approximate values for 
nanomaterial particle size or coating thickness may be provided in the description portion during 
 
16 FDA supports the principles of the 3Rs (reduce/refine/replace) for animal use in testing when appropriate. FDA 
encourages applicants to consult with review divisions when considering a nonanimal testing method believed to be 
suitable, adequate, validated, and feasible. FDA will consider if the alternative method could be assessed for 
equivalency to an animal test method. 
17 See FDAs guidance for industry Content and Format of Investigational New Drug Applications (INDs) for Phase 
1 Studies of Drugs, Including Well-Characterized, Therapeutic, Biotechnology-derived Products (November 1995). 
18 See FDAs guidance for industry INDs for Phase 2 and Phase 3 Studies Chemistry, Manufacturing, and Controls 
Information (May 2003). 
  7  Contains Nonbinding Recommendations 
 
early stages of development.  However, as the product enters late stage development (e.g., 
pivotal clinical and safety trials), the description of the material and understanding of the 
material functionality should be revised, as applicable, and supported with characterization data 
accordingly.  Depending on the characterization and analytical methods being applied, such 
testing may be a one-time developmental activity and not needed for routine analysis. 
 
Generally, information on the structure of a specific nanomaterial can also be referenced with an 
appropriate letter of authorization to other submissions, such as a DMF, as appropriate.19,20  
However, as with any drug product, the drug product manufacturer is responsible for ensuring 
the quality of all components,21 including nanomaterials used in the product. 
 
B.  Nanomaterial Quality Attributes and Structural Characterization 
 
As with any formulation, a full description of the physical and chemical characteristics of the 
drug substance must be provided in a premarket application, including proper characterization of 
identity, strength, stability, and quality of the product.22   The nanomaterials CQAs should be 
determined with regard to its function and potential impact on product performance.  The 
nanomaterial properties that can impact product performance should be defined along with the 
potential risks due to changes in those properties, whether as final product quality attributes or as 
intermediate material attributes.  The applicant should utilize risk assessments that link the 
structure-function relationship of the nanomaterial to attributes that need to be examined during 
development and controlled if changes are made during development of the final product 
formulation or manufacturing process. 
 
As with most aspects of the drug product development process, the specific CQAs for a 
nanomaterial will be product-specific and will most likely include a combination of attributes 
that are specific to the nanomaterial (e.g., particle size distribution and physical stability) and 
those that are not necessarily nanomaterial-specific (e.g., impurities).  The applicant should 
justify the level of nanomaterial characterization based on the impact of its quality attributes on 
the function of the drug product as well as the general knowledge of the nanomaterial published 
in the literature.  The CQAs should capture attributes that potentially impact the quality, safety, 
or efficacy of the final product. 
 
 
19 See, e.g.,  21 CFR 314.50(g)(1); 21 CFR 314.420, and FDAs draft guidance for industry Drug Master Files 
(October 2019). When final, this guidance will represent the FDAs current thinking on this topic. 
20 In general, FDA expects drug substance, drug substance intermediate, and drug product information to be 
submitted directly to a BLA rather than being incorporated by reference to a master file.  See Biologics License 
Applications and Master Files, 84 Fed. Reg. 30968 (proposed Jun. 28, 2019). 
21 See 21 CFR 211 subpart E; 21 CFR 211.22.  See also section 501 of the FD&C Act as amended by the Food and 
Drug Administration Safety and Innovation Act (Public Law 112-144, Title VII, section 711), explaining that, for 
purposes of section 501(a)(2)(B), the term current good manufacturing practice includes the implementation of 
oversight and controls over the manufacture of drugs to ensure quality, including managing the risk of and 
establishing the safety of raw materials, materials used in the manufacturing of drugs, and finished drug products.   
22 See 21 CFR 314.50(d)(1)(ii)(a); 21 CFR 314.94(a)(9) (requiring, among other things, an ANDA to contain the 
information required under 21 CFR 314.50(d)(1)); 21 CFR 601.2. 
  8  Contains Nonbinding Recommendations 
 
For any nanomaterial in a drug product, the following attributes should be reported as part of the 
premarket application:23  
 
  Chemical composition; 
 
  Average particle size; 
 
  Particle size distribution (PSD) (description of d10, d50, d90 or polydispersity; 
modality); 
 
  General shape and morphology (aspect ratio); and 
 
  Stability, both physical (e.g., aggregation and agglomeration or separation) and chemical. 
 
Additional quality attributes may also apply to nanomaterials in drug products, depending on the 
characteristics of a particular drug product (e.g., route of administration), its indication, and 
patient population.  Examples can include, but are not limited to: 
 
  Assay of drug substance;  
 
  Distribution of any drug substance associated with the nanomaterial and free in solution 
(e.g., surface bound or liposome encapsulated versus free drug substance); 
 
  Structural attributes that relate to function (e.g., lamellarity, core-shell structure); 
 
  Surface properties (e.g., surface area, surface charge, chemical reactivity, ligands, 
hydrophobicity, and roughness); 
 
  Coating properties, including how coatings are bound to the nanomaterial; 
 
  Porosity (if it relates to a function, e.g., capacity to load a drug); 
 
  Particle concentration; 
 
  In vitro release; 
 
  Crystal form; 
 
  Impurities; 
 
  Sterility, endotoxin levels, and pyrogenicity;24 
 
23 The methodology, sampling and testing frequency, and acceptance criteria for these attributes will depend on the 
control strategy considerations (review and inspection) for each product.  Drug products containing nanomaterials 
should include information in the submission regarding the characterization and understanding of these attributes. 
24 See FDAs guidance for industry Pyrogen and Endotoxins Testing: Questions and Answers (June 2012). 
  9  Contains Nonbinding Recommendations 
 
 
  Biodegradability of the nanomaterials and their constituents; and 
 
  Compatibility of the nanomaterial relevant to in-use conditions. 
 
C.  Nanomaterial Physicochemical Characterization Methods 
 
Some standardized methods for nanomaterial characterization exist or are currently being 
developed (e.g., ISO 22412:2017, ASTM E2859-11(2017)).  As with any method used in support 
of a premarket application, adequacy for a standardized method should be demonstrated and 
justified for the product being tested (e.g., the particle size range or the presentation of the 
sample).  In addition, corresponding validation and verification and related protocols should be 
provided as recommended in FDAs guidance on methods validation.25 
 
Applicants should consider the following factors when selecting and using specific 
characterization methods: 
 
  Method suitability:  Applicants should ask:  (1) Is the method capable of detecting and 
characterizing the material in the size range of interest (e.g., laser diffraction versus light 
scattering, or various forms of microscopy)?  (2) Does the methodology require a sample 
preparation that may significantly alter the nanomaterial attribute being measured during 
analysis (e.g., dilution, drying, or sonication)?  (3) Can the analytical equipment have 
unintended interactions with the nanomaterial (e.g., filters)? 
 
  Complementary methods:  In some cases, several different analytical techniques may be 
available to characterize a given material attribute, for example particle size or 
morphology.  Due to inherent differences in analytical techniques for measuring a given 
attribute, different instruments may provide different endpoint measurements.  To address 
technique-related differences, we recommend the use of complementary methods when 
measuring material attributes that have been established as critical (e.g., use both 
dynamic light scattering and transmission electron microscopy for size).  In addition, a 
description of what is being measured should also be provided (e.g., hydrodynamic radius 
versus projected radius, ensemble versus single particle results) in order to account for 
potential differences.  If different techniques are needed at different stages of processing 
(e.g., in-process, on final product release, and on stability), justification and any 
correlation of the measurement should be discussed.  The analysis of raw data also should 
take into account the behavior of nanomaterials (e.g., diffusion). 
 
  Sampling:  Whenever possible, testing of the nanomaterial should be performed in a state 
that is most representative of the process stage being evaluated (e.g., in-process, isolated 
intermediate, final formulation, during storage, and in-use conditions), taking into 
consideration how each process stage may impact quality. 
 
 
25 See FDAs guidance for industry Analytical Procedures and Methods Validation for Drugs and Biologics (July 
2015).  
  10  Contains Nonbinding Recommendations 
 
  Sample preparation:  Diluting or drying out a formulation or sample for analysis may 
produce substantial changes in the nanomaterial such that it is no longer representative of 
the nanomaterial contained in the final product.  Therefore, any change made to the 
material from the original sample aliquot should be evaluated for relevance to the 
attribute being measured.  Filtration steps may also confound results.  Nanomaterials may 
interact with the filter medium, causing a loss of sample.  Alternatively, in some methods 
a filtration step may lead to an erroneous conclusion that all material passing through the 
filter is in a dissolved state, because nanomaterials may pass through filters while 
remaining discrete entities (e.g., as nanocrystals instead of dissolved molecules).  
Therefore, the sample preparation steps for a nanomaterial should be adequately 
controlled to ensure these steps do not substantially change the product from its intended 
state. 
 
In addition to the specific points above, additional general considerations for analysis include: 
 
  Shape assumptions in analysis (e.g., assuming a sphere). 
 
  Sufficient sample size (number of samples analyzed to ensure adequate statistical rigor). 
 
  Reporting of results (e.g., cumulant analysis or distribution analysis; intensity, volume, or 
number weighted distributions; number or histogram for dynamic light scattering data). 
 
  Use of viscosity in particle size measurements (e.g., dynamic viscosity or apparent 
viscosity). 
 
  Sample preparation protocols (e.g., microscopy). 
 
D.  Dissolution/In Vitro Drug Release Methods for Quality Testing 
 
A fully validated dissolution/in vitro release method is one of the control tools to ensure that 
quality and clinical performance are maintained throughout the life cycle of the drug product.  
For example, in vitro release methods may aid in the characterization of liposome integrity, and 
in quantifying free versus encapsulated drug.  Like drug products without nanomaterials, drug 
products containing nanomaterials should have dissolution/in vitro release methods capable of 
discriminating formulation and manufacturing differences which may impact the clinical 
performance of the drug product.  In general, the dissolution/in vitro release testing should be 
conducted with the drug products manufactured under target conditions and compared to drug 
products that are intentionally manufactured with meaningful variations in formulation and 
manufacturing parameters, such as particle size, drug loading, types and/or amounts of inactive 
ingredients.  Ideally, the dissolution/in vitro release method should be able to discriminate 
batches that are not bioequivalent to the pivotal clinical batch, which will have demonstrated 
efficacy and safety.  Detailed descriptions of the proposed dissolution/in vitro release test and the 
developmental parameters (selection of equipment/apparatus, media, agitation/rotation speed, 
pH, sink conditions, surfactant type and concentration) should be included in the submission.  
Drug release profiles should be complete; that is, drug release should reach a plateau (no 
significant increase over three consecutive time points) and achieve at least 85 percent release of 
  11  Contains Nonbinding Recommendations 
 
the labeled amount of active ingredient(s), or, if not complete, the premarket application should 
provide additional data to explain the reasons for incomplete release.  As mentioned above, in 
vitro methods involving filtration that are used for testing during development and quality 
control (e.g., dissolution and assay) may need to be revised for appropriate use in the 
formulations containing nanomaterials.  For example, using current United States Pharmacopeia 
(USP) dissolution methods that require filtration may lead to misinterpretation of results. 
 
Due to the complex nature of some drug products containing nanomaterials, an applicant may be 
motivated to develop a novel in vitro release/dissolution method for its product.  If an applicant 
develops novel drug release/dissolution methods, we recommend consultation with the Agency26 
regarding feasibility, scientific rationale, and method validation to ensure that such a method is 
reproducible, reliable, and sensitive to variations in the products formulation and manufacturing 
processes. 
 
E.  Manufacturing Process and In-Process Controls 
 
All drug products containing nanomaterials must be manufactured in accordance with current 
good manufacturing practice (CGMP) as set forth in section 501(a)(2)(B) of the FD&C Act.  In 
addition, the CGMP regulations in 21 CFR parts 210, 211, & 212, and the regulations in 21 CFR 
parts 600-680, as applicable, apply to finished drug products, including OTC monograph drugs.  
(See 21 CFR 330.1(a).)  The variety of nanomaterials and their uses in drug products continue to 
grow.  A comprehensive body of knowledge of nanomaterial attributes and the effects of these 
attributes on the quality and manufacturing process of drug products does not currently exist.  
Building a knowledge base to better understand potential risks to product safety, identity, 
strength, quality and purity characteristics during manufacturing of drug products containing 
nanomaterials is essential to establishing robust control strategies and implementing effective 
process validation protocols.  It is, therefore, critical that the applicant apply manufacturing 
experience and increased understanding of potential risks to improve both the manufacturing 
process and associated control strategy over time.27 
 
Nanomaterials are engineered and manufactured to elicit novel product properties and clinical 
outcomes.  The quality, safety, or efficacy of drug products containing nanomaterials can, 
however, be very sensitive to process conditions and production scales.  Moreover, appropriate 
controls should be established early in the development stage to prevent cross-contamination 
 
26 When the drug will be subject to an NDA or a BLA (whether under section 351(a) or (k) of the PHS Act), contact 
the specific drug product review division with questions.  See FDAs draft guidances for industry on Formal 
Meetings Between the FDA and Sponsors or Applicants of PDUFA Products (December 2017) and Formal 
Meetings Between the FDA and Sponsors or Applicants of BsUFA Products (June 2018). When final, these 
guidances will represent the FDAs current thinking on the topics addressed by those guidances. When the 
submission is for an ANDA, submit questions through the Pre-ANDA Meeting or Controlled Correspondence 
processes.  See FDAs draft guidances for industry on Formal Meetings Between FDA and ANDA Applicants of 
Complex Products Under GDUFA (October 2017) and Controlled Correspondence Related to Generic Drug 
Development (November 2017). When final, these guidances will represent the FDAs current thinking on the topics 
addressed by those guidances. 
27 See also other FDA guidances for industry that establish recommendations for process improvement as 
manufacturing experience is gained; e.g., ICH Q10 Pharmaceutical Quality System (April 2009), and Process 
Validation: General Principles and Practices (January 2011). 
  12  Contains Nonbinding Recommendations 
 
with other drugs or operations.  This type of process and scale dependency, coupled with 
inherent polydispersity of some nanomaterials, makes it a priority to assess the risk to quality 
associated with the nanomaterial attributes, and develop adequate detectability of both 
nanomaterial and process failures at the development stage.  As such, the earlier that CQAs can 
be identified during development, the more quickly in-process controls can be designed and 
implemented in the manufacturing process.  A well-disciplined design control approach can 
generate key process knowledge, especially for those areas where, in the absence of 
comprehensive understanding, variability is not predictable, scale effects are unknown, and 
where results cannot be extrapolated or interpolated to demonstrate safety and efficacy. 
 
A different shape or size of a nanomaterial could be considered a batch consistency issue if it 
impacts the quality, safety, or efficacy of the product.  In addition, nanomaterial carriers (i.e., a 
carrier that is a nanomaterial) that are empty or have missing or incomplete surface coatings 
could be considered an impurity and may need to be quantified. 
 
For drug products containing nanomaterials, changes in analytical methods, manufacturing 
process, scale, and manufacturing sites may make the bridging of early development lots to large 
commercial scale lots difficult.  It is important to ensure that a sufficient amount of product is 
retained from all batches to allow any future analysis by updated or complementary methods.  
This will help to establish a bridge between developmental and commercial batches.  This 
applies to stability samples as well as stable in-process materials. 
 
F.  Excipients 
 
1.  Function 
 
Nanomaterials can be present as excipients in drug products and may serve specific functions to 
ensure or enhance desired product attributes.  For the purposes of this guidance, an excipient is 
any inactive ingredient that is intentionally included in a drug product, but that is not intended to 
exert therapeutic, prophylactic, or diagnostic effect(s) at the intended dosage, although it may act 
to improve product delivery (e.g., enhance absorption or control release of the drug substance).  
Excipients (e.g., polymers, targeting agents, coating agents, and lipids) in some cases are also  
used as matrices to assemble structures or to stabilize more complex nanomaterials.  The 
material attributes of these excipients are a critical element of the control strategy relating to 
product performance.  For example, the purity of lipids used in a liposome or the molecular 
weight distribution of the polymers used in nanomaterial drug delivery systems may be critical.  
Therefore, the properties of these types of nanomaterial excipients need to be fully characterized 
based on their functionality and intended use.  Proper controls, including test methods and 
acceptance criteria, a description of material source, and grade should be defined in a premarket 
application, with justification for how those acceptance criteria enable the product to meet its 
desired quality target product profile.  Changes in the grade and source of nanomaterial 
excipients during development should be addressed with regard to how these changes may 
impact the safety or efficacy of the product. 
 
Some nanomaterials (whether as primary particles or in an agglomerated or aggregated state) 
are commonly used as excipients (e.g., diluents, surfactants, glidants, emulsifiers, pigments and 
  13  Contains Nonbinding Recommendations 
 
lubricants), to improve processability and formulation performance.  As a general matter, if there 
is documented prior human exposure to a nanomaterial excipient under circumstances relevant to 
the proposed use (including the same route of administration, dosage forms, function, and 
maximum potency), it is sufficient to describe that excipient in terms of the excipients overall 
function and control specification.  This is the same approach expected for other commonly used 
excipients that are not nanomaterials.  These common nanomaterials may represent a low risk to 
product safety and efficacy; however, excipient functionality may still be important for overall 
product quality. 
 
2.  Safety 
 
The incorporation of an excipient into a nanomaterial structure or reducing the size of an 
excipient below 1 micrometer (1,000 nm) may have implications for the safety and/or efficacy of 
the finished product.  Current FDA guidance on evaluating the safety of new excipients28 applies 
when an excipient is deliberately modified into a nanomaterial.  An adequate safety evaluation 
should be provided when the nanomaterials safety is not fully demonstrated by existing safety 
data with respect to level of exposure, duration of exposure, and route of administration.  In the 
event that an excipient has been deliberately modified to be a nanomaterial or incorporated into a 
nanomaterial, we recommend that applicants consult with the Agency regarding any impact on 
potential exposure to and safety of the material. 
 
G.  Stability 
 
Current FDA guidance documents related to the extent of stability data and testing conditions to 
support drug product premarket applications29 apply to drug products containing nanomaterials.  
As discussed in those guidance documents, container closure system suitability, storage 
conditions, shelf life, and in-use conditions for a drug product containing nanomaterials should 
be supported by chemical and physical stability of that product, as justified by data. 
 
In particular, when assessing the stability of the drug product, the developer should consider 
potential factors impacting the product performance, including interactions of nanomaterial 
properties, prior to reaching the patient.  The study of the stability of nanomaterials in products 
should involve the evaluation of physical and chemical changes in the material during handling 
and storage.  There are particular risk factors that are more specific to the physical stability of 
nanomaterials.  Stress stability studies can be useful in elucidating changes and pathways of 
those changes in the nanomaterials.  Stability issues that can impact nanomaterial properties 
include, but are not limited to: 
 
  Changes to nanomaterial size and size distribution; 
 
 
28 See FDAs guidance for industry Nonclinical Studies for the Safety Evaluation of Pharmaceutical Excipients 
(May 2005).  
29 See FDAs guidances for industry ICH Q1A(R2) Stability Testing of New Drug Substances and Products 
(November 2003); ICH Q5C Quality of Biotechnological Products: Stability Testing of Biotechnological/Biological 
Products (July 1996); ANDAs: Stability Testing of Drug Substances and Products (July 2013); and ANDAs: 
Stability Testing of Drug Substances and Products, Questions and Answers (May 2014).  
  14  Contains Nonbinding Recommendations 
 
  Changes to nanomaterial morphology; 
 
  Self-association (agglomeration/aggregation); 
 
  Change in surface charge (e.g., zeta potential); 
 
  Changes in dissolution/release rate of drug substance; 
 
  Drug leakage from a nanomaterial carrier; 
 
  Degradation of nanomaterial (e.g., removal/exchange of surface ligands); 
 
  Interaction with formulation or container closure (e.g., compatibility, denaturing of 
proteins); 
 
  Changes to reconstitution properties of the product; and 
 
  Changes in the solid state (e.g., crystal structure). 
 
In addition, if the drug product must be diluted prior to use, the dilution medium may affect 
surface charge and/or particle size, altering colloidal stability of nanomaterials and triggering 
release of the drug substance.  For this reason, FDA may request in-use stability studies at 
clinically relevant concentrations and under relevant storage conditions.  Such studies should 
evaluate nanomaterial interactions with surfaces in the primary package, since these can result in 
changes to CQAs.  Note that stability issues during storage can include interaction with the 
storage container, contact with administration or delivery devices (e.g., syringe walls, catheters), 
and dispersion media. 
 
H.  Postmarket CMC Changes 
 
Additional risk factors may arise when making a major or moderate change30 to drug products 
containing certain nanomaterials after approval.  The comparison between a drug product before 
a change and after a change may require physicochemical comparison of CQAs and may require 
in vivo bioequivalence (BE) studies, depending on the impact of the change and the type of 
product.31  As stated above, retention of samples from pivotal batches through development to 
 
30 See 21 CFR 314.70(b) & (c) (classifying as major changes and moderate changes, respectively, changes in the 
drug substance, drug product, production process, quality controls, equipment, or facilities that have substantial 
potential (for major changes) or moderate potential (for moderate changes) to have an adverse effect on the 
identity, strength, quality, purity, or potency of the drug product as these factors may relate to the safety or 
effectiveness of the drug product).  Such changes require supplemental premarket applications prior to 
implementation. See 21 CFR 314.97 (changes to approved ANDAs also subject to 21 CFR 314.70, see also 601.12 
(regulation defining and governing changes to licensed biological products). 
31 For general information/examples of change categories, see the following FDA guidances for industry SUPAC-
MR: Modified Release Solid Oral Dosage Forms: Scale-Up and Postapproval Changes: Chemistry, Manufacturing, 
and Controls (September 1997); In Vitro Dissolution Testing and In Vivo Bioequivalence Documentation (August 
 
  15  Contains Nonbinding Recommendations 
 
enable bridging between manufacturing process changes, scale-up, and site transfers may be a 
suitable strategy.  For manufacturing changes that may affect the BE of certain drug products 
containing nanomaterials, please refer to section VI of this guidance. 
 
V.  NONCLINICAL STUDIES FOR DRUG PRODUCTS 
 
A.  General Applicability of Guidance 
 
The recommendations set forth in International Council for Harmonization (ICH) guidances 
adopted by FDA, and CDER and CBER guidances addressing nonclinical safety of drug 
products and their components are generally applicable to drug products containing 
nanomaterials.  New drug products that contain nanomaterials should be as thoroughly tested as 
for any new drug product.  However, depending on the water solubility of the component or 
aggregation under in vitro conditions, some in vitro assays may not be appropriate, or the 
conditions under which these assays are conducted might need to be adjusted. 
 
B.  Absorption, Distribution, Metabolism, and Excretion (ADME) 
Considerations 
 
Components that are nonbiodegradable can accumulate and persist longer than biodegradable 
components and can consequently produce effects related to chronic exposure to these 
components.  A nanomaterial can sometimes cross biological barriers in greater amounts than the 
larger particle size version.  This can lead to increased safety concerns in some cases, such as 
increased penetration of the blood-brain barrier, or the placenta.32  If a product contains 
nanomaterials, including those that function as drug carriers, the biological fate of the 
nanomaterials and their potential impact on safety should be determined.  
 
To conduct biodistribution studies of nanomaterials, it may be necessary for the material to be 
labeled in some manner (e.g., radiolabeled, fluorescence) to allow for enhanced detection in 
vivo.  Impact of such labeling of nanomaterials in the study on biodistribution should be 
considered. 
 
C.  Risk Considerations for Specific Routes of Administration 
 
Route-specific issues should be considered when assessing the safety of a drug product 
containing nanomaterials, and may warrant special assessment in addition to the nonclinical 
studies normally conducted in support of drug product development.  The following are 
examples of considerations for commonly used administration routes. 
 
1997); and SUPAC-SS: Nonsterile Semisolid Dosage Forms: Scale-Up and Postapproval Changes: Chemistry, 
Manufacturing, and Controls (May 1997); In Vitro Release Testing and In Vivo Bioequivalence Documentation; and 
Immediate Release Solid Oral Dosage Forms Scale-Up and Postapproval Changes: Chemistry, Manufacturing, and 
Controls, In Vitro Dissolution Testing, and In Vivo Bioequivalence Documentation (November 1995); and ICH Q5E 
Comparability of Biotechnological/Biological Products Subject to Changes in Their Manufacturing Process (June 
2015).  
32 Pietroiusti, A et al. Small 2013. doi: 10.1002/smll.201201463; Landsiedel,  R et al. Arch Toxicol. 2012. doi: 
10.1007/s00204-012-0858-7; Hubbs, AF et al. Toxicol Pathol. 2011 Feb;39(2):301-24. doi: 
10.1177/0192623310390705. 
  16  Contains Nonbinding Recommendations 
 
 
1.  Topically Applied Products 
 
Increased hair follicle penetration or distribution to local lymph nodes is a possibility for 
nanomaterials.33  In addition, nanomaterials can interact with sunlight differently than larger size 
particles and this can impact the interaction of light with the skin.  Penetration of a nanomaterial 
through the skin in human patients can be impacted by the condition of the skin (e.g., intact, 
damaged, diseased).  The evaluation of effects and exposures achieved in the nonclinical studies 
should consider this impact. 
 
2.  Subcutaneous Administration 
 
Materials introduced below the stratum corneum can possess an increased sensitization potential 
compared to some other (e.g., dermal) routes.  It has been reported that nanomaterials injected 
subcutaneously can enhance sensitization to other allergens.34  The biological fate of non-soluble 
nanomaterials should be considered. 
 
3.  Inhalation 
 
Local/respiratory toxicity of nanomaterials can differ from larger particles, as can lung 
deposition, distribution in respiratory tissues, and systemic BA.35  The biological fate 
(accumulation/translocation, clearance) of non-soluble carrier nanomaterials should be 
considered. 
 
4.  Intravenous Products 
 
Drug products containing nanomaterials can have a different tissue distribution of the therapeutic 
moiety and a different half-life compared to the same drug products without nanomaterials.  
Changes in hemocompatability can occur.36 
 
5.  Oral Products 
 
For orally administered drug products, use of nanomaterial ingredients is often intended to 
increase BA of the therapeutic moiety.  Other than possible local effects and an increased 
absorbed dose (which should be detected with existing methods), if the oral toxicology studies 
with a micrometer scale material were adequate, new effects are not expected for soluble drugs.  
If an insoluble nanomaterial is included in an oral product, toxicology studies should take this 
into consideration and include assessment of tissues where such materials might accumulate. 
 
 
33 Gulson, B et al. Arch Toxicol 2015. DOI 10.1007/s00204-015-1564-z.; Almeida, JP et al. Nanomedicine (Lond). 
doi: 10.2217/nnm.11.79. 
34 Dobrovolskaia, MA et al. Nat Nanotechnol 2007. doi: 10.1038/nnano.2007.223; Ilinskaya, AN et al. Toxicol Appl 
Pharmacol 2016. doi: 10.1016/j.taap.2016.01.005; Smith, AR et al. Curr Allergy Asthma Rep. 2017 
doi: 10.1007/s11882-017-0674-5.  
35 Stone, V et al. Environ Health Perspect. 2016. doi: 10.1289/EHP424. 
36 See footnote 13. 
  17  Contains Nonbinding Recommendations 
 
D.  Testing of Representative Nanomaterial 
   
Before toxicity studies are conducted with a drug product containing nanomaterials, it is 
important to know that the nanomaterial has been manufactured in a reproducible manner and 
that it is representative of the nanomaterial to which humans will be exposed.  The different 
factors, vehicles, and media that affect the aggregation and surface properties of the drug, in vitro 
and in vivo, should be understood.  Appropriately validated analytical methods should be used to 
characterize the test articles used in nonclinical studies.  These analytical methods should include 
methods suitable for the unique properties of nanomaterials, as discussed elsewhere in this 
guidance (section IV), when test articles contain nanomaterials. 
 
Generally, nonclinical evaluations of the kind typically conducted to support development of any 
drug product will be adequate to assess drug products containing nanomaterials when the clinical 
material is tested in the nonclinical studies.  However, as noted above, some in vitro assays may 
not be appropriate for drugs that contain nanomaterials, or the conditions under which these 
assays are conducted might need to be adjusted in order to obtain accurate results. 
 
E.  Bridging Toxicology from a Drug Product not Containing Nanomaterials to a 
Drug Product Containing Nanomaterials 
 
When a previously-approved drug product is modified to include a nanomaterial (active 
ingredient or inactive ingredient), ADME and a bridging toxicology study can often be 
appropriate and sufficient to allow reliance on the Agencys findings of safety or effectiveness of 
the previously-approved drug product, including those regarding the nonclinical information, 
assuming other regulatory requirements are met.  Consideration should be given to how the 
change may affect drug ADME and what potential impact any change may have on toxicity, e.g., 
increased penetration through the placenta (refer to section V.B).  Additional studies can be 
warranted if changes suggest the possibility of an altered effect in a particular tissue.  In some 
cases, when the nanomaterial is not the active ingredient, assessment of its contribution to any 
observed toxicity can be useful in interpreting such bridging studies.  Therefore, inclusion of 
treatment groups with only the nanomaterial should be considered. 
 
VI.  CLINICAL DEVELOPMENT 
 
The clinical development of drug products containing nanomaterials should follow all policies 
and guidances relevant to clinical safety and efficacy studies as they pertain to development of 
IND, NDA, ANDA, and BLA submissions.  This section addresses the particular topic of clinical 
development of drug products containing nanomaterials developed in reference to a listed drug 
or reference listed drug or reference product, e.g., for the 505(b)(2), 505(j), or 351(k) pathways. 
 
   
  18  Contains Nonbinding Recommendations 
 
A.  505(b)(2) Submissions 
 
1.  General Considerations 
 
From a pharmacokinetic-pharmacodynamic (PK-PD) point of view, drug products that contain 
nanomaterials can be differentiated into two different types:  (1) those where the nanomaterial is 
the therapeutic moiety, or (2) those where the nanomaterial carries the therapeutic moiety 
solubilized, conjugated, associated, or encapsulated for delivery.  For the first type, 
determination of PK and PD is focused on the therapeutic moiety as the nanomaterial.  For the 
second type, determination of PK and PD is focused on the released therapeutic moiety and the 
PK of the carrier.  An example for the first category is a stabilized nanocrystal suspension.  
Examples of the second category include liposomes, polymeric nanoparticles, and dendrimers.  
Note that nanomaterial carriers may exhibit inherent biological activity that is not related to the 
loaded therapeutic moiety (e.g., immunogenicity) and could also affect the safety and 
effectiveness of the drug product. 
 
The disposition and exposure-response relationship of an active ingredient formulated as a 
nanomaterial (whether a nanomaterial itself or within a nanomaterial carrier) may not be the 
same as for a drug product that does not contain nanomaterials.  Nanomaterial carriers can 
deliver the therapeutic moiety to the target tissue by various routes, such as the endocytic route 
or via an enhanced permeation retention (EPR) effect.  Consequently, the tenet for products 
containing the same active ingredient, i.e., that equivalent exposure in plasma supports a 
demonstration of equivalent therapeutic performance, may not hold for proposed drug products 
containing nanomaterials relative to the listed drug relied upon that does not contain 
nanomaterials.  In some cases, demonstration of comparable BA between a proposed product 
containing nanomaterials and the listed drug relied upon (whether or not the listed drug also 
contains nanomaterials) may not be sufficient to bridge the proposed product to the listed drug.  
Additional nonclinical and clinical evidence may be needed to demonstrate comparable 
disposition and exposure-response relationship for the therapeutic moiety between a proposed 
product containing nanomaterials and the listed drug relied upon.  For example, if the goal of an 
applicants development program for a proposed drug product containing nanomaterials 
developed pursuant to the 505(b)(2) pathway is to demonstrate no relevant difference in 
disposition and exposure-response relationship relative to the listed drug relied upon, the 
magnitude of the development program depends on the amount of evidence required to support 
this demonstration or bridge. 
 
In development programs attempting to bridge the performance of a proposed drug product 
containing nanomaterials to a listed drug, FDA recommends that applicants apply a risk-based 
approach to determine if the product in development will exhibit clinically significant changes in 
exposure, safety, and/or effectiveness relative to the listed drug.  The risk of a drug product 
exhibiting such clinically significant changes may vary; factors that can influence that risk 
include certain characteristics of the nanomaterial contained within the drug product, route of 
administration, and frequency of use.  With medium and high risk drug products containing 
nanomaterials, the uncertainty about exposure and therapeutic performance is greater than with 
low risk drug products containing nanomaterials.  To reduce the uncertainty with medium and 
high risk drug products containing nanomaterials, the exposure-response profile may have to be 
  19  Contains Nonbinding Recommendations 
 
explored.  In addition, whether the performance of a proposed drug product containing 
nanomaterials can be bridged to that of a listed drug may depend on other clinical or safety 
information.  Such considerations should be demonstrated in development programs attempting 
to bridge the performance of a drug product containing nanomaterials to a listed drug. 
 
Below, we present examples that are meant to be illustrative of the risk categories, derived from 
the Agencys preliminary thinking and experience with drug products containing nanomaterials.  
Note that these examples are not comprehensive. 
 
  Low risk to exhibit clinically significant changes in exposure, safety, and/or effectiveness 
relative to the listed drug relied upon:  For example, drug products containing 
nanomaterials that revert to their molecular constituents immediately after administration 
are likely to present low risk, whether these drug products are administered by oral, 
topical, or parenteral routes.  Examples include oral nanocrystals and some intravenous 
lipid nanoparticles. 
 
  Medium risk to exhibit clinically significant changes in exposure, safety, and/or 
effectiveness relative to the listed drug relied upon:  For example, drug products 
containing non-targeted nanomaterials intended for systemic action that are administered 
parentally are likely to present medium risk.  Examples include drug products with 
known bioactivity or predictable therapeutic moiety release characteristics. 
 
  High risk to exhibit clinically significant changes in exposure, safety, and/or effectiveness 
relative to the listed drug relied upon:  For example, drug products containing targeted 
nanomaterials intended for systemic action and that are administered intravenously are 
likely to present high risk.  Examples include drug products with complex and difficult to 
predict therapeutic moiety release characteristics, stability and/or bioactivity. 
 
2.  Clinical Studies 
 
In the clinical development of drug products that follow a 505(b)(2) approval pathway and are 
low risk, demonstration of comparable BA between the proposed product and the listed drug 
relied upon based on a comparative plasma PK may be generally sufficient to bridge to the 
Agencys finding of safety and effectiveness for the listed drug.  Products in the medium and 
high risk categories should initially include single and multiple dose studies assessing PK, PD, 
and tolerability to characterize the proposed product.  These studies should be followed by a 
single dose relative BA study comparing the proposed and the listed drug relied upon.  For orally 
administered nanomaterials, a single dose fed relative BA study is also necessary to provide a 
sufficient bridge. 
 
For medium and high risk drug products containing nanomaterials, demonstration of comparable 
BA between the proposed and the listed drug may need additional evidence to show that the 
disposition and exposure-response relationship of the therapeutic moiety is comparable between 
the proposed product and listed drug upon which it seeks to rely. 
 
  20  Contains Nonbinding Recommendations 
 
For medium and high risk drug products containing nanomaterials that are proposed to have BA 
comparable to the listed drug relied upon, a single dose ADME study can provide additional 
assurance of comparable disposition of the therapeutic moiety with the listed drug relied upon.  
However, ADME studies may not be able to detect discrete but clinically significant differences 
between products in rate and extent of release of the therapeutic moiety into the target tissues.  
Single and multiple dose studies examining the PK and PD characteristics of the proposed 
product and the listed drug relied upon may be better suited because they allow an exploration of 
the exposure-response relationship.  Both therapeutic- and toxicity-related PD biomarkers, 
ideally related to clinical outcomes, should be selected in these studies.  Recognition of a 
difference in the exposure-response relationship between the proposed drug product containing 
nanomaterials and the listed drug relied upon may be facilitated if the selected PD biomarkers 
vary over the blood/plasma concentration range of interest and exhibit a reasonably rapid onset 
and offset of the response. 
 
If PD biomarkers suitable for establishing comparative exposure-response relationships are not 
available, the development program of drug products containing nanomaterials may have to 
include comparative safety and effectiveness studies.  Specific safety or effectiveness concerns 
regarding the listed drug and its pharmacological class also may necessitate additional 
comparative clinical safety and effectiveness data for drug products containing nanomaterials.  
Clinical studies may be designed to demonstrate that the proposed drug product containing 
nanomaterials does not have decreased activity compared to the listed drug relied upon, as 
decreased activity usually would preclude approval.  Alternatively, clinical studies to 
demonstrate superiority may be used if the applicant wishes to make a superiority claim over the 
listed drug relied upon.  A study employing a sequential test in which non-inferiority is tested 
first and superiority is tested second may be a useful design if an applicant believes its drug 
product containing nanomaterials provides an efficacy advantage over the listed drug relied 
upon.  This study should be based on a pre-specified non-inferiority margin that is scientifically 
justified and adequate to enable the detection of relevant differences in effectiveness and safety 
between the proposed product and the listed drug upon which it seeks to rely. 
 
An applicant may use endpoints that are different from those in the listed drugs clinical trials if 
they are scientifically justified.  For example, response rate may be an appropriate endpoint for a 
non-inferiority trial in the oncology setting where the listed drug was approved based on a 
progression-free survival endpoint.  Certain endpoints that are effectively PD biomarkers, as 
discussed above, also may be acceptable. 
 
It is generally appropriate for the applicant of a proposed drug product containing nanomaterials 
to seek approval only for indications that have been previously approved for the listed drug 
relied upon, unless new clinical trials to demonstrate safety and efficacy are conducted in the 
proposed new indication. 
 
   
  21  Contains Nonbinding Recommendations 
 
B.  505(j) Submissions 
 
An applicant may seek approval of a generic product that references a drug product containing 
nanomaterials by submitting an ANDA under section 505(j) of the FD&C Act.  An ANDA 
applicant must demonstrate, among other things, that the generic drug product is bioequivalent to 
the reference listed drug (RLD) (section 505(j)(2)(A)(iv) of the FD&C Act).37  In addition, an 
ANDA must contain sufficient information to show that the proposed generic drug has the same 
active ingredient(s), previously approved conditions of use, route of administration, dosage form, 
strength, and (with certain exceptions) labeling as the RLD, and has adequate information to 
assure and preserve the identity, strength, quality, and purity of the drug.38  BE studies are 
conducted with the goal of demonstrating that the generic drug has the same rate and extent of 
absorption at the site of action as the RLD (21 CFR 314.3, 320.21(b)(1)).   
 
Nanomaterials range from simple nanocrystals, organic nanomaterials (e.g., liposome, polymeric 
nanoparticle), and inorganic nanomaterials (e.g., gold nanoparticles), to complex-structure 
integrated nanoparticles (e.g., core-shell, surface modified nanoparticles).  In general, an ANDA 
applicant is responsible for providing sufficient scientific evidence based on a comprehensive in 
vivo PK evaluation and in vitro physicochemical characterization to demonstrate bioequivalence 
between a proposed generic drug and its nanomaterial-containing RLD.  In addition, for an active 
ingredient that is a nanomaterial, comprehensive characterization of the RLD and understanding 
of the fundamental chemistry used to form the active ingredient may be needed to demonstrate 
active ingredient sameness.  Current thinking is that any critical structural change in the multiple 
components of nanomaterial-based products may influence the BE, pharmacology, and 
toxicology profiles.   
 
Therefore, there are additional challenges that should be considered for demonstrating BE for a 
drug product containing nanomaterials.  First, the active ingredients of some nanomaterials are 
generally heterogeneous mixtures which may require considerable characterization to 
demonstrate active ingredient sameness.  Second, some excipients in drug products containing 
nanomaterials are complex and available from different sources (e.g., naturally sourced, semi-
synthetic, or synthetic).  These excipients should be sufficiently controlled to ensure their 
intended properties.  Third, the properties of nanomaterials can be dependent on the 
manufacturing processes, which can be complicated and involve lengthy steps.  Fourth, after 
administration, the therapeutic moiety often exists in multiple forms, e.g., free drug39 or 
nanomaterial-associated drug, both in systemic circulation and at the site of action.  Therefore, 
it is critical to identify the most therapeutically relevant moiety for establishing BE.   
 
 
37 Under the FD&C Act, [a] drug shall be considered to be bioequivalent to a listed drug if . . . the rate and extent of 
absorption of the drug do not show a significant difference from the rate and extent of absorption of the listed drug 
when administered at the same molar dose of the therapeutic ingredient under similar experimental conditions in 
either a single dose or multiple doses.  See section 505(j)(8)(B)(i); see also implementing regulations at 21 CFR 
part 320. 
38 See, e.g., sections 505(j)(2)(A) and (j)(4) of the FD&C Act; see also 21 CFR 314.94 and 21 CFR 314.127. 
39 As used in this guidance, free drug is drug not associated with a nanomaterial or carrier.  Free drug may have been 
released from a carrier or never associated with a nanomaterial or carrier.  Although not used in this sense in this 
guidance, in other contexts, free drug may refer to non-protein bound drug in the blood (PK). 
  22  Contains Nonbinding Recommendations 
 
Due to the diversity of nanomaterial formulations, drug release mechanisms, and unique bio-
distribution, evidence of comparable PK parameters in blood/plasma in conventional BE studies 
alone may or may not be sufficient to establish BE of the proposed generic drug product and the 
RLD.  Drug levels in systemic circulation may not always reflect drug concentration at the site of 
action.  However, the type of BE studies sufficient to satisfy the requirements for generic drug 
approval depend on the route of administration and nanomaterials employed. 
 
For orally-administered drug products containing nanomaterials that have relatively low risk, PK 
studies in blood/plasma and BE criteria generally are considered sufficient to demonstrate BE 
between the generic and the RLD.  ANDA applicants can refer to FDAs draft guidance for 
industry on Bioequivalence Studies with Pharmacokinetic Endpoints for Drugs Submitted Under 
an ANDA (December 2013)40 for recommendations on BE study design.  Generally, both fasted 
and fed BE studies are recommended to demonstrate BE of orally administered drug products. 
 
ANDAs referencing oral drug products using nanomaterials to improve BA for poorly water-
soluble drugs need not use that particular nanomaterial or any nanomaterial, but may use 
alternative strategies to achieve the same BA enhancement.  There are a number of effective 
technologies that exist to improve drug BA, including the use of amorphous solid dispersions, 
introduction of surfactants or co-solvents, and others.  If the ANDA applicant uses a different 
type of nanomaterial than the RLD (e.g., nanocrystal versus nanomaterials other than 
nanocrystals) that may potentially affect nanoparticle distribution in the GI tract, additional 
characterization and evidence supporting non-specific drug uptake by Peyers patch or other GI 
tissues, should be provided. 
 
For drug products containing nanomaterials adminstered non-orally, it is generally recommended 
that the generic applicant conduct appropriate in vitro tests as part of demonstrating BE and 
conduct in vivo BE studies when necessary.  In addition, for certain non-oral drug products the 
applicant should, or in some cases must, demonstrate that the generic product contains the same 
inactive ingredients (i.e., is qualitatively the same (Q1)) in the same concentration (i.e., is 
quantitatively the same (Q2)) as the RLD.41  The inclusion of additional measures, such as 
comparative physicochemical testing (i.e., as in vitro elements of a BE study), may be needed as 
a scientific matter to ensure similar bioavailability, since comparable PK parameters in 
blood/plasma alone may not be sufficient to do so.  Examples of such physicochemical 
characterizations include particle morphology, particle size and distribution, surface charge, in 
vitro drug release, free and nanomaterial-associated drug, and others.  These in vitro 
characterizations should be conducted on at least three different batches of each of the generic 
and reference drug products and compared using appropriate methods. For example, it might be 
appropriate to demonstrate comparable size and distribution of nanomaterials using a statistical 
equivalence approach, such as population BE.42 As for the most therapeutically relevant moiety 
 
40 When final, this guidance will represent the FDAs current thinking on this topic. 
41 See 21 CFR 314.94(a)(9)(iii)(v). Certain differences, as described in these regulations, may be permitted 
provided that the applicant identifies and characterizes these differences and provides information demonstrating 
that the differences do not affect the safety or efficacy of the proposed generic drug product. 
42 See, e.g., FDAs guidance for industry Statistical Approaches to Establishing Bioequivalence (January 2001) and 
FDAs product-specific Guidance on Budesonide inhalation suspension (September 2012) at  
 
  23  Contains Nonbinding Recommendations 
 
for in vivo BE studies, the ANDA applicant should provide concentration-time curves for all 
clinically relevant entities (e.g., free drug and/or nanomaterial-associated drug) relating to the 
drug release from nanoparticles, in order to enable an accurate assessment of the PK of the 
generic product.  Generally, the PK of both the free drug and nanomaterial-associated drug in the 
blood/plasma should be comparable between the generic and the RLD, based on adequate and 
validated bioanalytical methods.43 
 
The potential multi-component structure of drug products containing nanomaterials allows great 
flexibility of drug delivery designs.  Due to the complexity and diversity of materials, structures, 
and functionalities of nanomaterials in drug products, FDA currently examines these drug 
products and develops product-specific guidances on a product-by-product basis.44  A number of 
product-specific guidances for generic drug development, including draft product-specific 
guidances with BE recommendations for doxorubicin hydrochloride liposomal injection, sodium 
ferric gluconate colloidal complex, and others have been published. 
 
C.  351(k) Submissions 
 
The development of a biosimilar to a biological reference product containing nanomaterials 
should generally follow current guidance on biosimilars.45  The contribution of the nanomaterial 
to product safety, purity, and potency should be assessed as part of the product development and 
the demonstration of biosimilarity or interchangeability.  Applicants are encouraged to contact 
FDA early during the development of biosimilars containing nanomaterials. 
 
D.  Bioanalytical Methods 
 
All clinically relevant entities, i.e., parent drug and major active metabolites, if possible, should 
be measured in the appropriate biologic matrices after administration of products containing 
nanomaterials.  In general, total, free, and nanomaterial-associated drug should be measured 
separately or indirectly derived.  This may require separation of free and nanomaterial-associated 
drug prior to detection or simultaneous analysis.  The concentrations of free parent drug and 
major active metabolite(s) may be low.  The use of validated, specific, and highly sensitive 
methods is recommended. 
 
   
 
https://www.fda.gov/regulatory-information/search-fda-guidance-documents/statistical-approaches-establishing-
bioequivalence;  
https://www.accessdata.fda.gov/drugsatfda_docs/psg/Budesonide_Inhalation_Sus_20929_RC_09-12.pdf for 
additional information regarding a population BE statistical method.  When final, this guidance will represent the 
FDAs current thinking on the topic addressed by that guidance.  
43 See FDAs guidance for industry Bioanalytical Method Validation (May 2018). 
44 See Product-Specific Recommendations for Generic Drug Development at https://www.fda.gov/drugs/guidances-
drugs/product-specific-guidances-generic-drug-development.  
45 See a sortable listing of Biosimilarity guidances at https://www.fda.gov/drugs/guidances-drugs/all-guidances-
drugs, using biosimilarity for category. 
  24  Contains Nonbinding Recommendations 
 
E.  In Vitro Tests With Human Biomaterials 
 
Stability and Biocompatibility:  The impact of human plasma and blood on the stability of 
nanomaterials intended for systemic activity and the biocompatibility of nanomaterial with blood 
and serum should be examined. 
 
Because of significant differences between products containing nanomaterials and other 
products, the methods for the test procedures listed below may have to be appropriately adapted 
to provide reliable results with products containing nanomaterials. 
   
Plasma Protein Binding:  Nanomaterials entering the blood circulation interact with multiple 
plasma proteins in a process lasting over several hours, which ultimately results in the formation 
of a protein corona.  The goal of this study, therefore, is to determine the major binding proteins 
involved in the formation of the corona over time and the percentage of bound nanomaterial over 
the incubation time. 
 
In Vitro Clearance and Metabolism:  Phagocytes play a major role in the clearance of 
systemically administered nanomaterials.  The uptake of nanomaterials may expose phagocytes 
to high concentrations of the active component.  Therefore, in vitro exposure of cultured human 
phagocytes to nanomaterials may be useful in evaluating potential cytotoxicity.  Small molecule 
active ingredients released from carriers are metabolized primarily by Phase 1 and Phase 2 
enzymes or eliminated unchanged in the urine.  The interaction of active ingredients that are 
nanomaterials and intact nanomaterial carriers with enzymes is thought to be limited, but some 
dissociated monomers, such as block copolymers, PEG, and lipids, may affect the function of 
cytochrome P450 enzymes and gastrointestinal transporters.  Therefore, experimental evidence 
supporting or rejecting this notion should be provided. 
 
F.  Immunogenicity 
 
There is a potential for nanomaterials to exert an immunogenic effect depending on a patients 
immunologic status, prior history, route/dose/frequency of drug administration, and unique 
characteristics of the administered nanomaterial.46  It is recommended that applicants use a risk-
based approach to evaluate and mitigate adverse immune responses that may be associated with 
administration of products containing nanomaterials that could affect safety and efficacy.  
Applicants should assess the risks for immunogenicity on a case-by-case basis and considered at 
the earliest stage of product development as well as throughout the remainder of the product life 
cycle depending on the potential severity of immune responses and the likelihood of their 
occurrence.  Immunogenicity risks should similarly be assessed prior to implementing changes to 
the process and/or product (e.g., product and/or process optimization) depending on the extent of 
such changes and the level of risk for invoking immune responses.  For general 
recommendations regarding how to evaluate and mitigate risks associated with adverse immune 
responses, the applicants should consult FDA guidance for industry Immunogenicity Assessment 
for Therapeutic Protein Products (August 2014) and the ICH guidance S8 Immunotoxicity 
 
46 See footnote 34. 
  25  Contains Nonbinding Recommendations 
 
Studies for Human Pharmaceuticals (April 2006) for sample approaches.47  Immunogenicity risk 
assessments of biological products that have a non-biologic nanomaterial component should 
consider that the nanomaterial component may possess adjuvant properties.  Consequently, 
biological products with a nanomaterial component may have different immunogenic 
characteristics compared to the biologic alone that may warrant specific examination. 
 
VII.  ENVIRONMENTAL IMPACT CONSIDERATIONS 
 
The National Environmental Policy Act (NEPA) requires Federal agencies to assess the 
environmental impact of Agency actions and to ensure that the interested and affected public is 
informed of environmental analyses.  FDA requires applicants to submit an Environmental 
Assessment (EA) or a claim of categorical exclusion when requesting Agency action on a drug 
or biologic premarket application (21 CFR 25.15(a); see also FDAs guidance for industry 
Environmental Assessment of Human Drug and Biologics Applications (July 1998)). 
 
In light of the current, evolving state of scientific knowledge regarding the impact of 
nanomaterials in the environment, CDER and CBER intend to use a case-by-case approach at 
this time to determine whether drug products that contain nanomaterials qualify for an existing 
categorical exclusion or whether an EA is required.  In accordance with FDA regulations, if an 
EA is submitted, CDER or CBER will evaluate the information contained in the EA to determine 
whether it is accurate and objective, whether the proposed action may significantly affect the 
quality of the human environment, and whether an Environmental Impact Statement (EIS) will 
be prepared.  If significant effects requiring the preparation of an EIS are identified, FDA will 
prepare an EIS for the action pursuant to its procedures (21 CFR 25.15(b)).  If significant effects 
requiring the preparation of an EIS are not identified, resulting in a decision not to prepare an 
EIS, FDA will prepare a Finding of No Significant Impact, in accordance with 21 CFR 25.41. 
 
To assist the Agency in our decision-making and to help avoid late cycle information requests, 
we advise industry to notify the FDA early in the development process of their intent to either 
claim a categorical exclusion or submit an EA.  If a categorical exclusion is claimed, the 
applicant should provide information supporting the criteria for the selected categorical 
exclusion and the accompanying statement of no extraordinary circumstances48 required by 21 
CFR 25.15(a).  For example, the applicant could provide information demonstrating negligible 
release of the nanomaterial into the environment (e.g., dosing, ADME, partitioning and 
biodegradation data) or information demonstrating that the nanomaterial would not be expected 
to produce toxicity in aquatic and terrestrial organisms at expected levels of exposure.  As 
needed, the Agency may request additional information to support a conclusion that approval of 
the premarket application would not significantly affect the quality of the human environment.  
If FDA determines that extraordinary circumstances exist, the applicant will be required to 
submit at least an EA, see 21 CFR 25.21, which should assess the biopersistence, exposure, 
route, fate, effects and risk of the nanomaterial(s) in the environment.  If FDA determines that 
the proposed action may significantly affect the quality of the human environment and, therefore, 
prepares an EIS, FDA may request additional information from the applicant to assist in 
 
47 See also FDAs guidance for industry Immunogenicity Testing of Therapeutic Proteins  Developing and 
Validating Assays for Anti-drug Antibody Detection (January 2019). 
48 See also 21 CFR 25.21 for an explanation of extraordinary circumstances.  
  26  Contains Nonbinding Recommendations 
 
preparation of such an analysis.  Impacts on the environment may occur at various stages of the 
product life cycle including manufacture, storage, patient use, and disposal. 
 
FDA may provide additional guidance, as needed, as our knowledge of and experience with 
nanomaterials increases. 
 
GLOSSARY 
 
The following terms are described for the purposes of this guidance only:  
 
Agglomerate:  Collection of weakly bound particles or aggregates or mixtures of the two where 
the resulting external surface area is similar to the sum of the surface areas of the individual 
components. 
 
Aggregate:  A particle composed of strongly bonded or fused particles where the resulting 
external surface area may be significantly smaller than the sum of calculated surface areas of the 
individual components. 
 
Bioavailability:  The rate and extent to which the active ingredient or active moiety is absorbed 
from a drug product and becomes available at the site of action. 
 
Bioequivalence:  The absence of a significant difference in the rate and extent to which the 
active ingredient or active moiety in pharmaceutical equivalents or pharmaceutical alternatives 
becomes available at the site of drug action when administered at the same molar dose under 
similar conditions in an appropriately designed study. 
 
Biological Products:  Refers to those drug products that are biological products under 42 USC 
262(i) and subject to licensure under section 351(a) or (k) of the PHS Act (42 U.S.C. 262(a) or 
(k)).  According to 42 USC 262(i), the term biological product means a virus, therapeutic 
serum, toxin, antitoxin, vaccine, blood, blood component or derivative, allergenic product, 
protein, or analogous product, or arsphenamine or derivative of arsphenamine (or any other 
trivalent organic arsenic compound), applicable to the prevention, treatment, or cure of a disease 
or condition of human beings. 
 
Carrier:  A material in which the drug is trapped, bound, encapsulated, or associated, and from 
which the drug is released. 
 
Core-shell:  A type of nanoparticle structure which has a particle core (inner material) 
surrounded by a shell (outer material). 
 
Colloids:  Dispersed systems with one phase (dispersed phase) distributed throughout another 
phase (continuous phase), where linear dimension of the dispersed phase falls within 1 to 1,000 
nm range. 
 
Critical Quality Attribute:  A physical, chemical, biological, or microbiological property or 
characteristic that should be within an appropriate limit, range, or distribution to ensure the 
  27  Contains Nonbinding Recommendations 
 
desired product quality.  CQAs are generally associated with the drug substance (and its 
intermediates), drug product (and its in-process materials), and excipients. 
 
Dendrimer:  A repetitively branched molecule radiating out from a common core creating a 
structure typically symmetric around the core, and often with spherical three-dimensional 
morphology. 
 
Drug Product:  Refers to any human drug product or products in finished dosage form, 
including those that are also biological products, unless otherwise specified.   
 
Emulsion:  A dosage form consisting of a two-phase system composed of at least two 
immiscible liquids, one of which is dispersed as droplets (internal or dispersed phase) within the 
other liquid (external or continuous phase), generally stabilized with one or more emulsifying 
agents. 
 
Excipient:  Any inactive ingredient that is intentionally included in a drug product, but that is 
not intended to exert therapeutic, prophylactic, or diagnostic effect(s) at the intended dosage, 
although it may act to improve product delivery (e.g., enhance absorption or control release of 
the drug substance). 
 
Free Drug:  As used in this guidance, drug not associated with a nanomaterial or carrier.  Free 
drug may have been released from a carrier or never associated with a nanomaterial or carrier. 
 
Immunogenicity:  The propensity of a material to generate immune responses. 
 
Inactive Ingredient:  Any component other than an active ingredient. 
 
Liposomes:  Microvesicles composed of a bilayer and/or a concentric series of multiple bilayers 
separated by aqueous compartments formed by amphipathic molecules such as phospholipids 
that enclose a central aqueous compartment.  In a liposome drug product, the drug substance is 
contained in liposomes. 
 
Micelles:  Particle of colloidal dimensions that exists in equilibrium with the molecules or ions 
in solution from which it is formed. 
 
Nanocrystals:  Nanomaterials that are solids formed with a periodic lattice of atoms, ions, or 
molecules, usually achieved by either direct crystallization (bottom-up) or milling of bulk 
material (top-down). 
 
Nanoemulsion:  A nanomaterial kinetically stabilized emulsion system, with at least one feature 
that falls into the size range of 1-1,000 nm. 
 
Nanomaterial:  We use the term nanomaterial generally to refer to materials falling within 
either Point 1 or Point 2, as described in section II - Scope of this document. 
 
  28  Contains Nonbinding Recommendations 
 
Nanomaterial-associated Drug:  Drug that is trapped, bound, encapsulated, or associated with a 
nanomaterial. 
 
Nanoparticle:  A particle with all three dimensions in the nanoscale range. 
 
Nanoscale:  Typically within the size range of approximately 1 to 100 nm. 
 
Premarket application:  Refers to Investigational New Drug (INDs) applications, New Drug 
Applications (NDAs), Biologics License Applications (BLAs), and Abbreviated New Drug 
Applications (ANDAs), including any referenced Drug Master File (DMF), unless noted 
otherwise. 
 
Therapeutic moiety:  For the purposes of this guidance, the functional or clinically significant 
part of the active ingredient(s) / drug substance(s) that can be used in obtaining pharmacokinetic 
data.  This can constitute the entire active ingredient / drug substance.  
  29