
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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- TR 45: Depth Filtration (5)
- TR 15: Validation: TFF in Biopharmaceuticals (3)
- TR 41: Virus Filtration (3)
- TR 47: Virus Spikes/Virus Clearance (1)
- TR 49: Validation: Cleaning Biotech (1)
- TR 57: Analytical Method Validation (1)
- TR 61: Steam in Place (1)
- TR 1: Validation: Moist Heat (1)
- TR 14: Validation: Protein Purification Chromatography (1)
- TR 26: Sterilizing Filtration of Liquids (1)
- TR 29: Validation: Cleaning (1)
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Bacteriophage
A bacteriophage is any one of a number of viruses that infect bacteria. The term is commonly used in its shortened form, “phage”. (TR41) (TR 47)
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Batch Filtration Process
In a batch filtration process, the entire volume to be filtered is held in a single feed tank. The retentate stream is recycled back to that single feed tank. (TR15)
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Bracketing
A demonstration of unit operation performance at two different values of a given parameter (e.g., ionic strength, dwell time or temperature), allowing the use any values of that parameter falling within this range. (TR41)
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Bracketing Approach
A scientific approach for defining product/load characteristics (e.g., viscosity, container sizes, container fill volumes, item sizes, loading configurations) that are tested (in a qualification study or validation study) at upper and/or lower limits. (TR1) (TR61) A validation method that tests the extremes of a process or product. The method assumes the extremes will be representative of all the samples between the extremes. (TR26)
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Fed-Batch Filtration Process
A modification of the batch filtration process in which a separate (typically larger) reservoir feeds a smaller recycle tank. The retentate stream is returned to the recycle tank. (TR15)
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Pressure Shock
An unanticipated rapid increase in fluid flow. [Synonym: Hydraulic Shock] (TR45)
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Pressure Shock (Backward Pressure Shock)
Rapid backward fluid flow that may result in filter rupture. (TR45)
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Pressure Shock (Forward Pressure Shock)
Rapid increase in forward fluid flow that may dislodge particulates. (TR45)
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Recovery
The mass of desired solute in the final product solution (either permeate or retentate, depending on the process), divided by the mass of the desired solute in the initial feed solution, expressed as a percentage. [Synonym: yield] (TR15) (TR45) A measure of the amount of analyte carried through the entire sample preparation and assay procedure and expressed as a percentage of the nominal concentration. (TR57)
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Recovery Study
A laboratory study combining the sampling method and analytical method to determine the quantitative recovery of a specific residue for a defined surface. (TR29) A laboratory study combining the sampling method and analytical method to determine the quantitative recovery of a specific residue for a defined surface. (TR49)
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Screening Studies
Studies used to select a particular type and grade of filter media. (TR45)
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Surrogate Fluid
A model process fluid used in a small-scale validation study. The fluid is intended to either match or resemble an actual process fluid as closely as is feasible. (TR41)
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Transition Analysis
Mathematical evaluation of the chromatogram tracing as the mobile phase changes from one solution to another. An alternative to HETP and peak asymmetry for evaluating column packing and performance. (TR14)