Guidance 

 
 
 
Media Fills for Validation of Aseptic 

Preparations for Positron Emission 

Tomography (PET) Drugs 

 
 
 
 
    
 
 
 
 
 
 
 
 
 
 
U.S. Department of Health and Human Services 

Food and Drug Administration 

Center for Drug Evaluation and Research (CDER) 

 
April 2012 

Current Good Manufacturing Practices (CGMP) 

 
 
   
Guidance 

 
 
Media Fills for Validation of Aseptic 

Preparations for Positron Emission 

Tomography (PET) Drugs 

 
 
 
 
Additional copies are available from: 
 
Office of Communications  
Division of  Drug Information, WO51, Room  2201  
Center for Drug Evaluation  and Research  
Food and  Drug Administration 
10903 New Hampshire Ave. 
Silver Spring, MD   20993-0003  
Phone: 301-796-3400;  Fax: 301-847-8714  
druginfo@fda.hhs.gov 
 http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/default.htm  
 
 
 
 
 
U.S. Department of Health and Human Services 

Food and Drug Administration 

Center for Drug Evaluation and Research (CDER) 

 
April 2012 

Current Good Manufacturing Practices (CGMP) 

   
TABLE OF CONTENTS 

 
 
 
 
I.   INTRODUCTION..............................................................................................................................................1
  
II.   BACKGROUND ................................................................................................................................................1
  
III.   QUESTIONS AND ANSWERS ...................................................................................................................2
  
A.   WHAT IS A MEDIA FILL? ...................................................................................................................................2
  
B.   WHAT IS THE MEDIA FILL DESIGNED TO EVALUATE?........................................................................................2
  
C.   WHAT ARE THE STEPS INVOLVED IN A MEDIA FILL? .........................................................................................3
  
D.   HOW DO  I CHOOSE  THE GROWTH  MEDIUM? ......................................................................................................4
  
E.   HOW OFTEN SHOULD A MEDIA  FILL BE PERFORMED?........................................................................................5
  
F.   A MEDIA VENDOR IS TYPICALLY QUALIFIED BY TESTING THREE BATCHES OF MEDIUM.   HOW DO  I DO THAT?..5
  
G.   WHAT IS GROWTH PROMOTION TESTING?   HOW IS IT USED IN  PET  PRODUCTION?...........................................5
  
H.   WHAT IS THE DIFFERENCE BETWEEN A GROWTH PROMOTION TEST AND A POSITIVE CONTROL?.......................6
  
I.   WHEN DO I USE A POSITIVE CONTROL?.............................................................................................................6
  
 
 
 
 
 
 
  Contains Nonbinding Recommendations 
 
 
1 
Guidance  
 
Media Fills for Validation of Aseptic Preparations for Positron Emission 

Tomography (PET) Drugs 

 
This guidance represents the Food and Drug Administration's (FDA's) current thinking on this topic.  It 
does not create or confer any rights for or on any  person and does not operate to bind FDA or the public.  
You can use an alternative approach if the approach satisfies the requirements of the applicable statutes 
and regulations.  If you want to discuss an alternative approach, contact the FDA staff responsible for 
implementing this guidance.  If you cannot identify the appropriate FDA staff, call the appropriate 
number listed on the title page of this guidance.  
 
 
I.   INTRODUCTION 
 
This guidance is intended to help manufacturers of positron emission tomography (PET) drugs 
meet the requirements for the Agencys current good manufacturing practice (CGMP) 
regulations for PET drugs (21 CFR part 212).  Most PET drugs are designed for parenteral 
administration and are produced by aseptic processing.  The goal of aseptic processing is to make 
a product that is free of microorganisms and toxic microbial byproducts, such as bacterial 
endotoxins. A media fill is the performance of an aseptic manufacturing procedure using a 
sterile microbiological growth medium, in place of the drug solution, to test whether the aseptic 
procedures are adequate to prevent contamination during actual drug production.  Media fill 
procedures recommended in this guidance apply only to sterile PET drugs manufactured by 
aseptic processes under 21 CFR part 212. 
 
FDA's guidance documents, including this guidance, do not establish legally enforceable 
responsibilities. Instead, guidances describe the Agency's current thinking on a topic and should 
be viewed only as recommendations, unless specific regulatory or statutory requirements are 
cited. The use of the word should in Agency guidances means that something is suggested or 
recommended, but not required.  
 
II.   BACKGROUND 
 
In 1997, Congress passed the Food and Drug Administration Modernization Act (Public Law 
105-115) (the Modernization Act). Section 121 of the Modernization Act directed FDA to 
establish appropriate approval procedures and Current Good Manufacturing Practices (CGMP) 
for PET drugs.  The procedures were finalized and an implementation timeline was instituted on 
December 10, 2009, when FDA published regulations that described the minimum CGMP 
standards that each PET drug manufacturer is to follow during the production of a PET drug.2 
   
                                                 
1  This guidance has been prepared  by  the PET  Drugs Working Group in  the Center for Drug  Evaluation and 
 
Research (CDER) at FDA.  

2 The regulations, CGMP guidance, and supportive information,  including historical documents, are available at 

http://www.fda.gov/Drugs/DevelopmentApprovalProcess/Manufacturing/ucm085783.htm. 
 
  Contains Nonbinding Recommendations 
 
Under the requirements of section 121, within 2 years following that publication date, a new 
drug application (NDA) or abbreviated new drug application (ANDA) must be submitted for any 
PET drug marketed for clinical use in the United States.  Accordingly, PET drug application 
submissions should have been received by the Agency on or before December 12, 2011.  In early 
December 2011, FDA decided that it would exercise enforcement discretion with regard to the 
submission of applications until June 12, 2012.  Until June 12, 2012, FDA does not intend to 
take enforcement action against a PET facility currently producing PET drugs for clinical use for 
a failure to submit a new drug application by December 12, 2011, provided that the facility 
complies with all other FDA requirements, including current good manufacturing practices 
(CGMPs). FDA will not exercise enforcement discretion after June 12, 2012.  Therefore, if a 
facility wishes to continue to produce PET drugs for clinical use after June 12, 2012, they must 
have submitted a new drug application (NDA) or an abbreviated new drug application (ANDA) 
by that date, or be producing the drugs under an investigational new drug application (IND). PET 
producers who are unable to submit an NDA or ANDA by June 12, 2012 or operate under an 
IND must find a new supplier who has submitted an NDA or ANDA. All PET producers must be 
operating under an approved NDA or ANDA, or effective IND, by December 12, 2015.  
 
Recognizing that many PET drug producers are unfamiliar with the drug approval process, FDA 
issued the guidance PET Drug Applications  Content and Format for NDAs and ANDAs,3 and 
held a public meeting in March 2011 to assist applicants in preparing NDAs and ANDAs for the 
three most commonly used PET drugs.  In comments to the guidance and in questions raised at 
the public meeting, stakeholders requested that FDA provide guidance on media fills for 
validation of aseptic preparation for PET drugs.  This guidance is being issued in response to 
these requests and is designed to help manufacturers of PET drugs comply with FDA 
regulations. 
 
III.   QUESTIONS AND ANSWERS 
 
A.   What is a media fill? 
 
A media fill (sometimes known as a process simulation) is the performance of an aseptic 
manufacturing procedure using a sterile microbiological growth medium in place of the drug 
solution. Microbiological growth medium is used in place of the drug solution during media fills 
to test whether the aseptic procedures are adequate to prevent contamination during actual drug 
production. A media fill is one part of the validation of an aseptic manufacturing process.   
 
B.   What is the media fill designed to evaluate? 
 
The media fill should evaluate the aseptic assembly and operation of the critical (sterile) 
equipment, qualify the operators and assess their technique, and demonstrate that the 
environmental controls are adequate to meet the basic requirements necessary to produce a 
sterile drug by aseptic processing.  The media fill does not validate the ability of the filter to 
sterilize growth media.   
                                                 
3  We  update  guidances periodically.  To make sure you  have the most recent version of a guidance, check the FDA  
Drugs guidance Web page  at  
http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/default.htm. 
 
 
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  Contains Nonbinding Recommendations 
 
 
C.   What are the steps involved in a media fill? 
 
1.   Design 
 
A media fill should be carefully designed to ensure that the simulation is representative of 
all the aseptic manipulations performed during production.  These include preparation 
and assembly of the product containers, transfer of the product containers to the fill area, 
and all process steps downstream from the sterilizing filter up to product release, 
including packaging into finished product containers.  Finished product containers with 
medium should then be incubated to permit the growth of microbial contamination in any 
containers.  Microbiologically contaminated containers are expected to exhibit observable 
evidence of microbiological contamination after suitable incubation.  The same type and 
source of containers should be used for media fills as are used in routine production.  
Media fills should be conducted in the same locations where the production occurs and 
employ the broadest scope of possible manipulations that could occur during production.  
Every aseptic manipulation during production up to the point of finished product release 
should be included in the media fill.  Because each PET finished product container is to 
be sampled aseptically prior to release, sample withdrawal and any adjustments should be 
simulated as well.   
 
The media fill is an experiment and therefore should include controls.  These controls are 
independent of the quality audit of the growth medium (i.e., growth promotion testing).  
A positive control for a media fill is a sealed product container of medium that is 
inoculated with a small number (i.e., less than 102) of microorganisms.  Inoculation of the 
positive control container should be done in an area separate from the critical 
manufacturing area.  Consult United States Pharmacopeia (USP) Chapter 71>, Sterility 
Tests, for appropriate organism selection (one species is enough).  To ensure the absence 
of false positive results, a negative control should be included to demonstrate that the  
medium was sterile to begin with.  A negative control may be prepared by preincubating 
the medium, or by aseptically transferring medium into a separate suitable sterile 
container and incubating the control simultaneously with the media fill test containers.  
The controls should be incubated under the same conditions as the media fill containers.  
These controls may not need to be repeated when multiple media fills are being done 
within a week and use the same lot of growth medium.   
 
All steps intended for aseptic manufacturing should be reproduced in the media fill, 
including sampling and dilution of the final product.  All personnel involved in the 
aseptic manufacture of the drug product should participate in at least one media fill per 
year. All processing steps that the operator normally performs during aseptic 
manufacturing should be simulated. 
 
The simulation process should duplicate the actual production process where the aseptic 
steps are conducted, from the set-up of the vial assemblies to the transfer of the bulk drug 
from the sterilizing filter into the final containers that are ready for release.  A connection 
to the container of sterile medium may be substituted in place of the filter.  Alternatively, 
 
 
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  Contains Nonbinding Recommendations 
 
a filter may be included during media fills, but the filter should not be used to sterilize the 
growth medium.  If the process is expected to include the addition of sterile diluent to 
adjust the strength following radionuclidic assay, sterile medium should be added in the 
same manner during the media fill.  The temperature of the medium should be the same  
temperature as the drug solution would be during manufacture (e.g., ambient).  If 
multiple vials are assembled, stored, and used over a period of days, the simulation 
should use vials that have been assembled in advance and stored as they would be during 
actual production. 
 
After the final product container is filled and ready for release, it should be incubated in a 
temperature-controlled incubator.  Although USP <71> recommends incubation at 20o 
25oC for the aerobic growth medium, as a practical matter any controlled temperature 
between 20o and 35oC would work for media fills.  However, the controlled 
temperature should be specified in your procedures and be maintained within a range 
that does not exceed 2.5oC. The incubation period of a media fill should be no less than 
14 days and the containers should be examined every 2 or 3 days.  
 
All steps in a media fill should be done in the same locations as the drug production 
steps. If the product container is filled within the hot cell, then the media fill should also 
be performed in the hot cell.  If it is not filled in the hot cell, then the media fill does not 
need to be performed there either. 
 
The synthesis box is generally located upstream from the sterilizing filter and is not 
considered a sterile component or part of the aseptic operations.  In such cases, do not 
include the synthesis unit in the simulations. 
 
2.   Preparation for the Test  
 
Once the media fill procedures are established, all of the components necessary for the 
simulation should be assembled, including all of the equipment used in the aseptic part of 
the process. Media to be used in the simulation may be obtained commercially or 
prepared on site, and should be sterile. 
 
When media are prepared on site, sterilization should be conducted using a validated 
process such as steam autoclave.  Filtration is not recommended to sterilize the growth  
medium.   
 
D.   How do I choose the growth medium? 
 
The most commonly used growth medium is soybean casein digest medium (SCDM), which is 
commercially available under various names such as Trypticase Soy Broth.  A recipe for this 
medium is found in USP <71>.  Recipes for SCDM in other pharmacopeia may have slight 
variations from the USP, but are acceptable.  Other general growth media are available, but their 
use may not be as practical and may require justification.  
 
 
 
4
  Contains Nonbinding Recommendations 
 
Medium from a qualified commercial vendor may be used by multiple PET facilities for media 
fills. Shipping, storage, preparation, and handling procedures should be carefully designed, 
documented, and followed to ensure media integrity and stability.  Commercially prepared media 
should be used within the labels shelf life and stored according to the labels recommendations.   
 
E.  	 How often should a media fill be performed? 
 
To initially qualify an aseptic process at a specific facility, three media fills should be conducted 
on three separate days at that facility using the specific production process that is being qualified.  
Additionally, media fills should be conducted whenever significant changes are made to the 
aseptic process (e.g., changes in personnel, components, or equipment) and whenever there is 
evidence of a failure to maintain product sterility.  Media fills performed to validate an aseptic 
process at a specific facility should be done by an operator who previously has been trained and 
qualified in aseptic techniques (e.g., proper gowning, disinfection practices, handling sterile 
materials).  
 
Media fills are an important element of operator qualification.  To become a qualified operator 
for PET drug product production, an operator should perform three media fills on three separate 
days. A qualified operator should perform a media fill at least annually.    
 
F.  	 A media vendor is typically qualified by testing three batches of medium.  How do I 
do that? 
 
Three commercially available batches/lots of medium from a single supplier should be subject to 
quality control tests. These tests should include visible inspection, pH, sterility, and growth 
promotion.  Results of this testing should conform to the results reported in the certificate of 
analysis (CoA). You can refer to USP <71> for conduct of growth promotion tests. 
 
Many vendors will have samples of different batches available for purchase and testing.  If three 
different batches are not available initially, then it may be necessary to test each of the first three 
incoming batches for conformance to the CoA.   
 
According to USP <71>, SCDM should be sterile (confirmed by incubating samples for 7 days at 
a defined controlled temperature), pH 7.3 (0.2), and able to permit growth of selected aerobic 
species (e.g., Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa). For media 
fills, use of only one species of bacteria is necessary once a media vendor is qualified.  Media 
qualification programs should periodically verify the full CoA and growth promotion capability 
to ensure continuing vendor reliability. 
 
G. 	  What is growth promotion testing?  How is it used in PET production? 
 
A growth promotion test ensures that the medium used in the media fill will support the growth 
of contaminating microorganisms.  This is an essential control for media fills because the desired 
test result is no growth and only by demonstrating the mediums ability to support microbial 
growth can the negative result be relied upon.  Growth promotion testing should be performed on 
the growth medium used in media fills.  This may be performed by inoculating a portion of the 
 
 
5
  Contains Nonbinding Recommendations 
 
batch with a small number (102) of microorganisms to confirm that the medium supports 
growth. 
 
When the medium is prepared in-house (at the site of the PET drug manufacture), a growth 
promotion test should be performed for each batch of medium prepared.  Medium should be 
prepared using autoclave sterilization processing and not by sterilizing filtration.   
 
A ready to use liquid medium supplied from  a commercial vendor should be confirmed as 
suitable by growth promotion and other testing to confirm that it meets specifications and 
conforms to its CoA.  Once a supplier has been demonstrated to provide consistently suitable 
medium, the CoA and positive control will suffice to establish the mediums suitability for use in 
media fills (the positive control will be used in lieu of demonstrating growth promotion 
potential). 
 
H.   What is the difference between a growth promotion test and a positive control? 
 
Growth promotion testing confirms the mediums ability to support growth.  Growth promotion 
testing is commonly done before using the medium  in an experiment.  A positive control tests the  
ability of the test method to result in a positive outcome and is commonly done concurrently with 
an experiment.   
 
Media fill positive control shows that the medium in the drug product container will support 
growth after exposure to the filling process.  The positive control should be a container filled as 
part of a media fill.  The positive control test  may serve as the growth promotion test for the 
medium, as long as a qualified vendor is being used.  
 
I.   When do I use a positive control? 
 
A positive control is needed for each media fill that is performed using a single batch of medium.  
As stated previously, a positive control in the media fill may also serve as the growth promotion 
test of the medium (from qualified vendor) employed for the media fill.  When performing a 
media fill, the positive control test may be done simultaneously with the media fill by inoculating 
a vial of medium from the same batch used for the media fill.  It is also permissible to perform a 
positive control at the end (after incubation) of a media fill by inoculating an uncontaminated 
media fill test container and returning it for additional incubation.  Inoculation of the positive 
control container should be done in an area separate from the critical manufacturing area.   
 
 
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