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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Z-Value
The number of degrees of temperature change necessary to change the D-value by a factor of 10. The z-value allows integration of the lethal effects of heat as the temperature changes during the heating and cooling phases of a sterilization cycle. (TR01) (TR3) The number of degrees of temperature change necessary to change the D-value by a factor of 10. The z-value allows integration of the lethal effects of heat over time (i.e., calculation of F0) as the temperature changes in a cycle. (TR61)

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Steam in Place Cycle
A sequence of defined steps and operating parameters (e.g., time, temperature, and pressure) performed in situ on equipment and/or systems to provide a given sterility assurance level (SAL) or defined sanitization level. (TR61)

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Spore Log Reduction (SLR)
The number of log reductions (10-fold changes) of spores from the initial population. For the overkill sterilization method, one targets a spore log reduction of 12 to achieve 1 x 10-6 probability of a survivor when using a biological indicator having a population of 1 x 106. (TR61)

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Steam: Pure Steam
Collected condensate that complies with the Compendial requirements for Water for Injecton (WFI). [Synonyms: clean steam, high quality steam] (TR01) (TR61) (TR48)

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Superheated Steam
Steam that is at a higher temperature than that indicated by the equilibration curve for the vaporization of water (at a given pressure).(TR01) (TR61)

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Survivor Curve
Graphical representation of the inactivation of a population of microorganisms with increasing exposure to a microbicidal agent under stated conditions. (TR01) (TR3) (TR51) (TR61)

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System Integrity Test
Any test designed to detect leaks or other breaches in system integrity that might compromise operator safety or system sterility (or sanitary status). [Synonym: leak test.] (TR61)

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System Integrity Test (System Pressure Hold Test)
A system integrity test in which the system is pressurized to a predetermined level with filter sterilized compressed air or other compressed gas, after which the system is isolated and the amount of pressure loss over time is measured. (TR61)

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Saturated Steam
Steam that is at a temperature and pressure that corresponds to the vaporization curve of water. It is in a state of equilibrium between being a liquid and a gas, with no entrained liquid water. [Synonym: Dry Saturated Steam] (TR01) (TR48) (TR61)

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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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Overkill Design Approach
A sterilization design approach where minimal information is required about the product bioburden. A worst-case bioburden assumption is used to determine the delivered lethality needed to achieve a PNSU of 10-6 on or in the items being sterilized. When using this approach, the qualification program must demonstrate that both the FBIO and FPHYS are greater than 12 minutes. The required lethality may vary regionally. (Note: For typical SIP systems, the FPHYS will need to be greater than the FBIO.) (TR01) (TR3) (TR30) (TR61)

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Operational Qualification (OQ)
Documented verification that the equipment or systems, as installed or modified, perform as intended throughout the anticipated operating ranges. (TR14) (TR61) (TR64) (TR72) The documented verification that the facilities, systems and equipment, as installed or modified, perform as intended throughout the anticipated operating ranges. (TR54-5) Documented verification that the equipment or systems, as installed or modified, perform as intended throughout the anticipated operating ranges (17). (TR60-3)

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Operating Parameters (Key Parameters)
Values that are controlled and/or measured and are used to assure the ongoing “state of control” and consistency of runs. Failure to meet a key process parameter should result in an investigation with a documented rationale for the disposition of the load. (TR01) (TR3) (TR51) (TR48) Values that are controlled and/or measured and are used to assure the ongoing “state of control” of steam in place cycles. Failure to meet a key process parameter should result in an investigation. (TR61)

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Performance Qualification (PQ)
Documented verification that the equipment and ancillary systems, as connected together, can perform effectively and reproducibly based on the approved process method and specifications. (TR3) (TR14) (TR45) (TR42) (TR48) (TR61) (TR64) Transport tests of product or representative product that is conducted during actual transportation or distribution. (TR39) Documented evidence that provides a high de­gree of assurance that the equipment and/or system functions accurately and consistently according to predetermined specifications in its operating environment. (TR54-5) Documented verification that the equipment and ancillary systems, as connected together, can perform effectively and reproducibly based on the approved process method and specifications (17). (TR60-3)

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Minimum Acceptable Cycle (MAC)
The minimum cycle conditions (in terms of delivered minimum lethality or minimum time and temperature) that would be considered acceptable. (TR01) (TR61)

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Leak Test
See System Integrity Test. (TR61)

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Installation Qualification (IQ)
Documented verification that the equipment or systems, as installed or modified, comply with the approved design, the manufacturer’s recommendations, and/or user requirements. (TR14) (TR42) (TR48) (TR61) (TR64) The documented verification that the facilities, systems and equipment, as installed or modified, comply with the approved design and the manu­facturer’s recommendations. (TR54-5) Documented verification that the equipment or systems, as installed or modified, comply with the approved design, the manufacturer’s recommendations, and/or user requirements (17). (TR60)

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Hazard
The potential source of harm. (TR44) (TR54) (TR54-2) (TR58) (TR61)

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Heat-up Phase
The phase of a sterilization cycle that occurs prior to the exposure phase. Process parameters are developed for this phase in order to meet applicable user requirements for load conditioning (e.g., air removal and preheating.) (TR01) (TR3) (TR48) (TR61)

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Gravity Displacement
A sterilization process based on the principle that cold air within the chamber is heavier than the steam entering and will sink to the bottom of the chamber. As steam enters the chamber, air is pushed out the bottom drain and exits, with the condensate, through a steam trap. (TR01) (TR48) (TR61)

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F-Value (Lethality Factor)
A measurement of sterilization effectiveness, the F-value is the calculated equivalent lethality (using a specified z-value), in terms of minutes at a reference temperature (Tref), delivered by a sterilization cycle. (TR1) (TR3) (TR30) (TR48) (TR61)

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DT Value
The time in minutes required for a onelogarithm, or 90%, reduction of the population of microorganisms used as a biological indicator under specified lethal conditions. For steam sterilization, the D-value should always be specified with a reference temperature, DT . For example, a BI system with a D121°C = 1.4 minutes requires 1.4 minutes at 121°C to reduce the population by one logarithm.(TR1) (TR61)

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Deadlegs
An area of entrapment in the vessel or piping run that could lead to contamination of the product due to insufficient exposure to moist heat. (TR61)

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Cycle Development
A series of activities performed for the purpose of defining or confirming the cycle parameters (e.g., time, temperature, pressure) necessary to ensure sanitization or sterilization. (TR61)

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Cool-Down Phase
The phase of a sterilization cycle that occurs after completion of the exposure phase. Parameters of a cool-down phase are typically defined in order to meet applicable user requirements for load cooling and drying. (TR01) The phase of a sterilization cycle that occurs after completion of the exposure phase. [Synonym: post-conditioning phase, slow exhaust phase, drying phase, equalization phase] (TR48) The phase of an SIP cycle that occurs after completion of the exposure phase. Parameters (e.g., time, temperature, pressure) of a cool-down phase are typically defined in order to meet applicable user requirements for system cooling and drying. (TR61)

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Critical Control Point
A step at which control can be applied and that is essential to prevent or eliminate a pharmaceutical quality hazard or reduce it to an acceptable level. (TR54-4) (TR61)

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Biological Qualification
A component of performance qualification that demonstrates, by use of biological indicators, that the required lethality (FBIO) is achieved consistently throughout the load. (TR1) (TR3) (TR30) A component of performance qualification that demonstrates, by use of biological indicators, that the required lethality (FBIO) or spore log reduction (SLR) is achieved consistently throughout the sterilized or sanitized portion of the SIP system. (TR61)

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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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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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