PDA Technical Glossary

PDA Technical Glossary

PDA Technical Reports are highly valued membership benefits because they offer expert guidance and opinions on important scientific and regulatory topics and are used as essential references by industry and regulatory authorities around the world. These reports include terms which explain the material and enhance the reader’s understanding.

The database presented here includes the glossary terms from all current technical reports. The database is searchable by keyword, topic, or by technical report. Each definition provided includes a link to the source technical report within the  PDA Technical Report Portal.

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Adverse Event (AE) Report
An AE report is a communication to the U.S. FDA of an undesirable sign or symptom associated with use of a drug as required and detailed by 21 CFR 314.80. These reports are logged into the U.S. FDA’s Adverse Event Reporting System (AERS). Drug manufacturers are required to report adverse event information to FDA. These reports may also may be voluntarily submitted to the FDA directly by healthcare professionals or the general public at Med Watch. The reports are reviewed, safety issues are monitored, and data are periodically analyzed and assessed by the Center for Drug Evaluation and Research (CDER). (TR55)
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Adverse Trend
A series of alert-level or action-level excursions that indicates the system or areas are not in control and have the potential to affect the product quality. (TR 70) An increase in the frequency of alert- and action-level excursions or repeated recovery of low levels of microorganisms below the alert level during microbial monitoring or of pharmaceutical ingredient or finished product failure that is indicative of a loss of process control. (TR88)
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Aggregation
Clumping of proteins, viruses, or bacteria that may arise from several mechanisms and may be classified in numerous ways, including soluble/insoluble, covalent/noncovalent, reversible/irreversible, and native/denatured. (TR47)
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Animal-Derived Raw Materials (Primary)
Contains in the final raw material or uses in the manufacturing process of the final raw material, any raw material derived directly from bovine or other animal tissues, for example, bovine serum, porcine-derived trypsin, and animal-tissue-de­rived hydrolysates. (TR83)
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Animal-Derived Raw Materials (Secondary)
Non-animal in origin but may be derived from processes that include materials from animal components that come in direct contact with the raw material, for example, a recombinant protein produced in an E. coli fermentation that uses fermentation medium containing tryptone, or a recombinant protein expressed in plants that are exposed to bovine manure fertilizer. (TR83)
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Biomethylation
The enzyme chlorophenol o-methyltransferase responsible for fungal methylation has been isolated in cell-free extracts. Biomethylation, in this context, may be seen as a detoxification mechanism, although it plays a role in the production of mycotoxins by secondary metabolism. Slightly xerophilic fungi frequently associated halophenol biomethylation include Trichoderma longibrachiatum, Trichoderma virgatum, Aspergillus sydowii, and Penicillium islandicum. (TR55)
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Closed System
An isolated system that has no interaction with its external environment, preventing contamination and release of the material contained.(TR28) (TR 66)
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Cytopathic Effect (CPe)
Morphological changes induced by viruses in infected cells in invitro culture. They are usually localized around a site of initial infection and vary in appearance based on the virus and the cultured cell. (TR47)
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Cytopathic Virus
Viruses where infection of cells results in microscopically visible degeneration of the cells or other morphological changes. (TR47)
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Endogenous Virus
Endogenous Virus-Like Particles – (e.g., Type C endogenous retroviruses)
Virus-like entity whose genetic material is stably integrated into the germ line of an organism or cell line. Cell lines (notably CHO) may constitutively produce virus-like particles, which are typically noninfectious but still of safety concern. Model retroviruses are generally used as surrogates to measure virus-like particle clearance. (TR41)
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Frank (Canonical) Pathogens
Microorganisms responsible for infection in healthy individuals (i.e., individuals with normal operative and functional host defense mechanisms) that may be acquired from exposure to other infected people or animals, environmental reservoirs (exogenous) or the individual’s normal (endogenous) microbial flora. (TR67)
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Genome Copy (GC)
An amount of nucleic acid equivalent to the genetic complement present in the genome of a single microorganism. (TR50)
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Genotypic
Relating to those characters that reside in the genetic complement of a specific strain of a specific organism. (TR51)
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Indicator Cells
Cell lines that are used in in vitro assays to detect the presence of viral agents. (TR71)
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Infectious Unit
A measure of quantity of infectious virus. An infectious unit does not necessarily reflect the number of virus particles, as virus preparations also contain noninfectious virus particles and, depending on the cellular host, more than one virus particle may be necessary to infect a cell. (TR47)
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Inoculated Carrier
A carrier upon which a defined number of test organisms have been deposited. (TR51)
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Lenticular Filters
A filter made up of a series of biconvex cells that are stacked on top of one another with rings between them to prevent bypass between the cells. End-caps are then placed at the top and bottom of the assembly and are held in place with a central core. [Synonyms: Lenticular Cartridge, Modules, Filter Elements, Filter Devices] (TR45)
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Log Reduction
Log reduction is defined as the first log being 90%, the second log being 9% and the third log being 0.09% of the original inoculums. (TR70)
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Master Cell Bank (mCb)/Master Virus Bank (mVb)
A stock of cells or virus used to produce the Working Cell Bank or the Working Virus Bank. Cell/virus banking is used to enhance biological consistency. (TR47)
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Monodispersed particles
Particles of uniform size in a dispersed phase. In the case of viruses, this term refers to free virus particles not agglomerated to other viruses or proteins in solution. (TR41)
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Most Probable Number (MPN) Method
A statistical method of estimating the number of viable organisms suspended in a liquid. (TR51)
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Nonspecific Model Virus
A virus used for characterization of viral clearance of the process when the purpose is to characterize the capacity of the manufacturing process to remove and/or inactivate viruses in general (i.e., to characterize the general viral clearance capacity of the purification process.) (TR41)
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Process Characterization of Viral Clearance
Viral clearance studies in which nonspecific model viruses are used to assess the general virus clearance capacity of the manufacturing process to remove and/or inactivate viruses. (TR41)
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Process Evaluation Studies of Viral Clearance
Viral clearance studies in which relevant and/or specific “model” viruses are used to determine the ability of the manufacturing process to remove and/or inactivate these viruses. (TR41)
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Pyrogen
Any substance capable of eliciting a febrile (or fever) response upon injection or infection (as in endotoxin released in vivo by Gram-negative bacteria. (TR3) Fever-producing substance (TR69) A material that elicits a pyrogenic response (fever). (TR70)
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Q-PCR Probe
A synthetic, chemically-labeled single-stranded nucleic acid complementary to a selected sequence within a DNA sequence to be amplified using forward and reverse primers in a Q-PCR reaction. A probe is typically labeled with both a fluorophor and quencher. The latter inhibits fluorescence until the quencher and fluorophore are separated by the exonuclease activity of DNA polymerase. (TR50)
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Stirred-Cell Filtration
A surrogate for tangential flow filtration where shear is achieved by rapidly stirring the solution immediately adjacent to the membrane. Typically the stirring is accomplished by mechanical means, such as through the use of a stir bar or impeller. (TR15)
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