
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 22: Aseptic Process Simulation (6)
- TR 62: Manual Aseptic Processes (5)
- TR 69: Bioburden/Biofilm Management (4)
- TR 45: Depth Filtration (4)
- TR 14: Validation: Protein Purification Chromatography (3)
- TR 60: Process Validation (2)
- TR 66: Single-Use Systems (2)
- TR 73: Prefilled Syringe User Requirements for Biotech Applications (2)
- TR 13: Environmental Monitoring (2)
- TR 26: Sterilizing Filtration of Liquids (2)
- TR 28: Process Simulation for Bulk API (2)
- TR 54-4: QRM: Biotech Drug Substance (1)
- TR 55: TBA/TCA Detection Mitigation (1)
- TR 67: Objectionable Microorganisms (1)
- TR 70: Cleaning/Disinfection Programs (1)
- TR 74: Reprocessing of Biopharmaceuticals (1)
- TR 88: Microbial Data Deviation Investigations in the Pharmaceutical Industry (1)
- TR 76: Identification and Classification of Visible Nonconformities in Elastomeric Components and Aluminum Seals for Parenteral Packaging (1)
- TR 41: Virus Filtration (1)
- TR 42: Validation: Protein Manufacturing (1)
- TR 43: Glass Defects (1)
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Action Level (environmental monitoring)
An established microbial or non-viable particle level that, when exceeded, should trigger appropriate investigation and corrective action based on the investigation. (TR22)
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Action Limit
An internal (in-house) value used to assess the consistency of the process. The cause of the excursion should be investigated and documented and corrective action is generally required. Action limits are not specifications. (TR42)
An established internal (in-house) data-based value which is part of the control strategy and used to assess the consistency of the manufacturing process. An action limit excursion result in an investigation, identification of recovered isolates, root-cause analysis, assessment of a systemic failure and impact on product quality and patient safety. (TR69)
An established internal (in-house) data-based value that is part of the control strategy and used to assess the consistency of the manufacturing process. An action limit excursion result in an investigation, identification of recovered isolates, root-cause analysis, assessment of a systemic failure and impact on product quality and patient safety. (TR74)
A limit that, when exceeded, indicates a process is outside of its normal operating range. A response to such an excursion should involve a documented investigation and corrective actions based on the results of that investigation. (TR60)
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Aerobic Microorganism
A microorganism that utilizes oxygen as the final electron acceptor during metabolism; a microorganism that will grow primarily in the presence of oxygen. For the purpose of this report, this definition encompasses facultative anaerobes. (TR22) (TR62)
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Alert Level
An established microbial or nonviable particle level giving early warning of potential drift from normal operating conditions; not necessarily grounds for definitive corrective action but typically requires follow-up investigation. (TR13) (TR22) (TR69)
An established level that, when exceeded, is giving an early warning of a potential drift from normal operating conditions; while not necessarily grounds for definitive corrective action, it typically requires follow-up review. (TR 60)
An established microbial or nonviable particle level giving early warning of potential drift from normal operating conditions; not necessarily grounds for definitive corrective action, but typically requires follow-up investigation (3, 4, 7). (TR88)
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Anaerobic Microorganism
A microorganism that does not utilize oxygen as the final electron acceptor during metabolism; microorganism that will grow only in the absence of oxygen. (TR62)(TR22)
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Aseptic Processing
Handling sterile materials in a controlled environment, in which the air supply, facility, materials, equipment and personnel are regulated to control microbial and particulate contamination to acceptable levels. (TR28) (TR62) (TR69) Handling of sterile product, containers, and/ or devices in a controlled environment in which the air supply, materials, equipment, and personnel are regulated to maintain (product) sterility. (TR13)
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Aseptic Processing Area (APA)
Controlled environment, consisting of several zones, in which the air supply, facility, materials, equipment and personnel are regulated to control microbial and particulate contamination to acceptable levels. (TR22) (TR28) (TR62) (TR70)
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Aseptic Processing Simulation (APS)
A means for establishing the capability of an aseptic process as performed using a growth medium. (TR22) (TR62)
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Attachment (Adhesion)
Discrete association of a microorganism with an animate or inanimate surface. (TR69)
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Autoclave
A chamber for steam sterilization. (TR45)
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Back Pressure
Residual pressure opposing the free flow of liquid or gas at the outlet side of the filter. (TR45) Pressure applied downstream of a filter or other piece of equipment. (TR26)
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Breakthrough Limited
A filtration operation resulting in a significant rise in filtrate turbidity accompanied by a small increase in differential pressure. This occurs when the adsorptive capacity of the filter is reached, resulting in the passage of particles smaller than the pore size of the filter that would normally be removed by adsorption. (TR45)
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Brevundimonas Diminuta (B. diminuta)
Small bacteria (0.3–0.4 &mum in diameter by 0.6–0.1 &mum long) used to challenge a sterilizing grade filter during validation testing. [Formerly Pseudomonas diminuta](TR45)
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Column Load
The solute that is passed through the column for separation. (TR14)
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Column Packing
Preparation of a column that includes the addition of resin slurry into a column to create a bed suitable for its intended use. Characteristics of a packed column bed include bed height and diameter, backpressure, and number of theoretical plates. (TR14)
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Compatibility (Filter)
The ability of a filter to be used with a particular process fluid without a change in the inherent properties of the filter. (TR41)
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Consumables
This refers to items (e.g., SUS, storage bags, tubing, filters, diaphragms, flasks, etc.) that form or are a part of process equipment and are used on a per batch basis. (TR66)
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Dimensional Product Quality
The product conforms to the required drawing dimensions. (TR43)(TR76)
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Elastomer
Thermoplastic material formulation (that may or may not contain rubber/natural latex) derived from elastic polymer; often used interchangeably with the term “rubber.” (TR73)
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Leachable
A chemical component that migrates from a contact surface into a drug product or process fluid during storage or normal use conditions. The term leachable is often erroneously used to describe an extractable. (TR14) (TR26) Leachables are organic and inorganic chemical entities that migrate from a packaging/delivery system, packaging component, or packaging material of construction into an associated drug product under normal conditions of storage and use or during accelerated drug product stability studies. Leachables are typically a subset of extractables or are derived from extractables. (TR54-4) Chemical substances that are leached, from product-contact or non-product-contact materials, under typical process conditions and detected in final dosage. Leachables may be a subset of extractables, and can include their reaction or breakdown products. (TR66) Organic or inorganic chemical entity that migrates from pharmaceutical container closure system components into a drug product formulation. (TR73)
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Water Activity (Aw)
Water Activity, Aw is the ratio of the vapor pressure of water in a product (P) to the vapor pressure of water in a product (P) to the vapor pressure of pure water (Po) at the same temperature. It is numerically equal to 1/100 of the RH generated by the product in a closed system. It is a measure of the free or available moisture in the material. Note: Water activity ≠ water content. RH can be calculated from direct measurements partial vapor pressure or dew point, or from indirect measurements by sensors whose physical or electric characteristics are altered by the RH to which they are exposed. Microorganisms need available water within a pharmaceutical product, as well as nutrients and minerals, to proliferate. Water activity, and not water content, is a better measure of the free water, in contrast to bound water that microbial cells require for metabolic activity and osmotic regulation. Effects of reduced Aw on microbial growth include a longer lag phase, slower growth rate, lower numbers of organisms in the stationary phase, and reduced microbial toxin production; below a specified Aw for an organism, microbial growth will not occur. (TR55) (TR67)