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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Viable
Alive and able to be cultured in the laboratory. (TR69)

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Turbulent Flow
Movement of a fluid in which its velocity at any point varies in a random or erratic (nonlaminar) manner. (TR69)

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Specification
A list of tests, references to analytical procedures, and appropriate acceptance criteria that are numerical limits, ranges, or other criteria for the test described. It establishes the set of criteria to which a material should conform to be considered acceptable for its intended use. (TR14) A list of tests, references to analytical procedures, and appropriate acceptance criteria that are numerical limits, ranges, or other criteria for the test described. It establishes the set of criteria to which a material should conform to be considered acceptable for its intended use. Drug product and drug substance specifications are critical quality standards that are proposed and justified by the manufacturer and approved by regulatory authorities (TR38) (TR57) A list of tests, references to analytical procedures, and appropriate acceptance criteria that are numerical limits, ranges, or other criteria for the test described. It establishes the set of criteria to which a material should conform to be considered acceptable for its intended use. Drug product and drug substance specifications are critical quality standards that are proposed and justified by the manufacturer and approved by regulatory authorities (TR69) A list of tests, references to analytical procedures, and appropriate acceptance criteria, which are numerical limits, ranges, or other criteria for the tests described. It establishes the set of criteria to which a drug substance, drug product, or materials at other stages of its manufacture should conform to be considered acceptable for its intended use. “Conformance to specification” means that the drug substance and drug product, when tested according to the listed analytical procedures, will meet the acceptance criteria. Specifications are critical quality standards that are proposed and justified by the manufacturer and approved by regulatory authorities as conditions of approval. (TR56) (TR74) A list of tests, references to analytical procedures, and appropriate acceptance criteria that are numerical limits, ranges, or other criteria for the test described. It establishes the set of criteria to which a material should conform to be considered acceptable for its intended use (17). (TR60-3)(TR88)

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Shear
Relative motion between adjacent layers of a moving liquid. (TR69)

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Sanitization
Reduction of microbial contaminants to safe levels as judged by public health requirements for the specific country. (TR13) A significant reduction in bioburden, achieved in chromatography by the use of bactericidal agents, such as sodium hydroxide (NaOH), hydrochloric acid (HCl), ethanol (EtOH), and isopropanol (IPA). (TR14) The process of reducing microbial levels by treatment at less than defined sterilizing conditions. Typically water at 80 °C or a chemical treatment is used to perform sanitization of process components. (TR45) A process that reduces the number of viable microorganisms to a defined level. (TR61) (TR69)

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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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Rapid Microbiological Methods (RMMs; Alternative Microbiological Methods)
Technologies that allow users to obtain microbiology test results more quickly than traditional microbiological methods, which are usually culture/ growth based. (TR69)

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Lipopolysaccharide
A component of the cell wall of Gram-negative bacteria.(TR3) Component of the outer cell wall of Gram-negative bacteria that is pyrogenic. (TR69)(TR82)

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Laminar Flow
Type of fluid (gas or liquid) movement in which the fluid travels smoothly (in a nonturbulent way) or in regular paths. The velocity, pressure, and other flow properties at each point in the fluid remain constant. (TR69)

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Excursion
A temperature or humidity deviation from conditions such as those specified by product labeling or shipping specifications. (TR53) Measurement that exceeds an alert, concern, or action level/limit by either a discreet value or an increasing/decreasing trend. (TR69)

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Extracellular Polymeric Substance (EPS)
Product of microbial growth, particularly in biofilms, composed of polysaccharides, lipids, proteins, and nucleic acids; produced by bacteria and fungi; is an important mediator of microbial attachment to surfaces and biofilm formation. (TR69)

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Endotoxin
Lipopolysaccharides from the cell walls of bacteria, the most potent of which derive from Gram-negative organisms. When injected, they are known to cause a febrile, or fever-producing reaction that can cause severe patient reactions, and on occasion, can be fatal. (TR26) (TR44) Pyrogenic lipopolysaccharide component of Gram-negative bacterial cell walls. (TR69)

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Disinfection
The destruction of pathogenic and other kinds of microorganisms by thermal or chemical means. (TR51) (TR70) Process of eliminating nearly all recognized pathogenic microorganisms but not necessarily all microbial forms (e.g., bacterial spores) on inanimate objects. (TR69) The chemical or physical inactivation of a bioburden on inanimate surfaces. Typically this requires a minimum three-log (3-log) reduction of vegetative microorganisms and two-log (2-log) reduction for bacterial spore be achieved in validation. (TR13)

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Dead Leg
Area of entrapment in a vessel or piping run that could lead to contamination of the product. (TR69)

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Contaminant
Any adventitiously or externally introduced material(s) (e.g., chemical, biochemical, or microbial species) not intended to be part of the process. (TR14) (TR15) (TR70) An undesired impurity of a chemical or microbiological nature that is introduced into a raw material, intermediate, or API (drug substance) during manufacture. (TR14) (TR15) Any adventitiously introduced materials (e.g., chemical, biochemical, or microbial species) not intended to be part of the manufacturing process of the drug substance or drug product. (TR69) (TR74) Any adventitiously introduced material (e.g., chemi­cal, biochemical) or microorganisms including viruses not intended to be included in the manufacturing process of the drug substance or drug product. (TR83)

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Biofouling (or Biological Fouling)
Accumulation and subsequent deleterious effects of biological contaminants on engineered products or processes (TR 69)

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Bioburden
The total number of microorganisms per unit of material prior to sterilization. (TR13) Total number of viable microorganisms on or in a health care product prior to sterilization. (TR22)(TR61)(TR62) A population of viable microorganisms in a fluid prior to sterilizing filtration. (TR26) A measure of the contaminating organisms found in or on a given amount of material before it undergoes a sterilization process. (TR45) (TR70) The number of detectable microorganisms (bacteria and fungi) with which an object is contaminated. It is measured in CFU (colony forming units). (TR47) The number of viable, contaminating microorganisms present on a product immediately prior to decontamination. (TR51) Viable microbial contaminants associated with personnel manufacturing environments (air and surfaces), equipment, product packaging, raw materials (including water), in-process materials, and finished products. (TR 67) (TR 69)

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Alert Limit
An established internal (in-house) data-based value giving early warning of potential drift of manufacturing process from normal operating conditions and triggers appropriate follow-up investigations. Alert limits are always lower than action limits. (TR69)

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Attachment (Adhesion)
Discrete association of a microorganism with an animate or inanimate surface. (TR69)

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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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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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Adventitious Agents
A foreign material that is introduced inadvertently; not natural or hereditary (as in microbial, chemical, or biochemical contamination of a purified substance). (TR 69)

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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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Action Level
An established microbial or airborne particle level 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. (TR13) An established microbial or non-viable particle level that, when exceeded, should trigger appropriate investigation and corrective action based on the investigation. (TR22) An established microbial or airborne particle level for environmental, water or gas monitoring that, when exceeded, indicates that a facility process is outside of its normal operating range. The response to such an excursion involves a documented investigation and corrective actions based on the results of that investigation. The prescribed action level is often specified in guidance or standards relating to environmental monitoring and water quality. (TR69) An established microbial or nonviable particle level for environmental, water, or gas monitoring that, when exceeded, indicates a facility or process is outside of its normal operating range. The response to such an excursion may involve a documented investigation and corrective actions based on the results. The prescribed action level is often specified in guidances or standards relating to environmental monitoring and water quality (3-6). (TR88)

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Acceptance Criteria
Numerical limits, ranges, or other suitable measures for acceptance of test results. (TR 14) (TR 29) (TR 38) (TR 64) Numerical limits, ranges, or other suitable measures for acceptance of test results. Exceeding the acceptable range for a critical parameter during subsequent validation studies may result in questionable product quality that would require initiation of an investigation. Exceeding the operating range should be documented and explained in the validation report and evaluated for validation study impact. (TR 42) The pre-defined specifications, standards or ranges that must be met under stated test conditions. (TR 48) Numerical limits, ranges, or other suitable measures for acceptance of the results of analytical method validation that is satisfied to determine suitability of test method performance.(TR 57) (TR 69) (TR 72) (TR 74) The criteria that a system or component must satisfy in order to be accepted by a user or other authorized entity. (TR 54-5) Numerical limits, ranges, or other suitable measures for acceptance of the results of analytical procedures which the drug substance or drug product or materials at other stages of their manufacture should meet (16). Exceeding the acceptable range for a critical parameter during subsequent validation studies may result in questionable product quality that would require initiation of an investigation and possible batch rejection. (TR60)

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