Pressure
Force applied per unit area, usually expressed as psi, mbar, kPa or kg/cm2. (TR45) (TR26)
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Pre-Filter
Any filter placed upstream of the final filter. (TR26)
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Volatile
Evaporates easily; converts easily from a liquid form to gas. (TR45) (TR26)
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Throughput
The amount of solution that passes through a filter, described as volume per membrane area. [Synonym: capacity.] (TR15) The amount of solution that passes through a filter. It is described as volume through the membrane area. [Synonym: capacity] (TR26)
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Validation
A documented program that provides a high level of scientific assurance that a manufacturing process will reliably produce acceptable product. The proof of validation is obtained through rational experimental design and the evaluation of data, preferably beginning from the process development phase and continuing through the commercial production phase. (TR01)
A documented program that provides a high degree of assurance that a specific process, method, or system will consistently produce a result meeting predetermined acceptance criteria. (TR26) (TR57) (TR70) (TR74)
Documented testing, performed under highly controlled conditions, which demonstrates that a process consistently produces a result that meets predetermined acceptance a result that meets predetermined acceptance criteria. Used to test processes, methods, and systems for which conditions can be controlled in the real world (i.e., after completion of testing, when the process is in use). Transportation processes can be qualified but not validated; in the real world, it is not possible to exert control over all parameters that could affect the transportation process (e.g., weather, customs, traffic delays, mechanical failures, etc.). (TR58)
A documented program that provides a high degree of assurance that a specific process, method, or system will consistently produce a result meeting predetermined acceptance criteria. (Note: Validation is a lifecycle program which may include development and qualification activities for one or more elements/systems that form a process.) (TR54-5)
A documented program that provides a high degree of assurance that a specific process, method, or system will consistently produce a result meeting pre-determined acceptance criteria (17). (TR60-3)
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Upstream
The influent side of the filter. (TR45) (TR26)
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Surfactant
A soluble compound that reduces the surface tension of a liquid or reduces interfacial tension between two liquids (causing formation or micelles) or between a liquid and a solid. [Synonym:Wetting Agent] (TR45) (TR26)
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Surface Tension
The tendency of the surface of a liquid to contract to the smallest area possible under defined conditions. It is expressed as dynes per centimeter. (TR26)
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Redundant Filtration
A type of serial filtration in which a second sterilizing-grade filter is used as a backup in the event of an integrity failure of the primary sterilizing filter. (TR26)
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Serial Filtration
Filtration through two or more filters of the same or decreasing pore size, one after the other. (TR26)
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Porosity
The ratio of void volume to bulk volume of the filter media. (TR26)
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Pore
The channel(s)/path(s) in a membrane through which a fluid or a gas may pass. (TR41) (TR26)
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Outlet Pressure
The pressure exiting the downstream side of the filter. [Synonym: effluent or downstream pressure] (TR26)
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Particulate
Relating to, or occurring in the form of particles. (TR45) (TR26)
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Particle
Any discrete unit of material structure; a discernible mass having an observable length, width, thickness, size and shape. (TR45) (TR26)
Foreign material which is unintended and either removable from the surface of a primary packaging component or freely moving within a filled and sealed pharmaceutical dosage form. The term particle is used interchangeably with “particulate” and “particulate matter” without any intended difference in meaning. (TR85)
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Permeability
The degree to which a fluid will pass through a permeable substance under specified pressure and temperature conditions. (TR41) (TR26)
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Microorganism
A microbe; a free-living organism too small to be seen by the naked eye. (TR45) (TR26)
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Non-fiber Releasing
Refers to a filter that does not shed fibers into the filtrate. (TR26)
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Membrane
A thin, microporous medium used to remove particles and microorganisms from a fluid stream under pressure. (TR26)
Analytical technique to collect particles from a liquid sample on a membrane filter followed by manual examination (sizing and counting) with a microscope. (TR85)
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Medium
In filtration, the porous material which retains particles as a fluid passes through during the process of filtration (TR26)
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Materials of Construction
Polymers or other materials that make up the components of the filter. (TR26)
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Mass Spectroscopy
An analytical test method for identifying the chemical composition of a sample by separating its gaseous component ions according to their mass and charge. (TR26)
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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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Integrity Test
Test to determine the functional performance of a membrane filter or container/closure system. (TR22) A nondestructive test used to predict the functional performance of a filter. (TR45) A nondestructive physical test that can be correlated to the bacterial retention capability of a filter/filter assembly. (TR26)
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Hydrophilic
Literally “water loving.” A filter that will wet with aqueous solutions to allow flow at a low pressure differential. (TR26)
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Influent
Fluid that flows into a process step. [Synonym: feed.] (TR26)
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Inlet Pressure
The applied pressure entering the upstream side of the filter. [Synonym: influent, upstream or line pressure] (TR26)
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Gamma Irradiation
The process by which a material is rendered sterile by exposing the material to a radioactive source, such as Cobalt 60. (TR70) Ionizing radiation that can be used to sterilize a material. (TR26)
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Gauge Pressure
The pressure measured by a pressure gauge. Typically expressed in units of psig, bar or kilopascal. (TR45) Gauge pressure is the difference between a given fluid pressure and that of the atmosphere. (TR26)
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Filterability Test
A test to determine the suitability and sizing of a filter with a given fluid. (TR26)
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Filter Efficiency
A measurement of how well a filter retains particles. It is usually expressed as the percentage, or ratio, of the retention of particles of a specific size by a filter. (TR26)
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Fouling (or Clogging)
Adsorption or interaction with components in the feed stream resulting in a decrease in membrane performance. Generally, fouling can be reversed by cleaning the membrane. (TR15) The result of solutes blinding or blocking membrane pores. It is observed as a decrease in the flux (at constant pressure) or an increase in the filtration differential pressure (at constant flux). (TR26)
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Filtrate
Fluid that has been passed through a process step (filter). [Synonym: Permeate] (TR15) (TR26)
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Flow Rate
The volumetric rate of flow of a solution, expressed in units of volume per time (e.g., L/min or gal/day). (TR15) (TR26)
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Filter (verb)
To pass a fluid through a porous medium whereby bacteria or other particles are removed from the fluid. (TR26)
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Filtration
A process of removing particles from a fluid by passing it through a permeable material, such as a membrane film. (TR41) The process by which particles are removed from a fluid by passing the fluid through a porous material. (TR26)
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Extractable
A chemical component that is removed from a material by application of an artificial or exaggerated force (e.g., solvent, temperature, time). The term extractable is often erroneously used to describe a leachable. (TR14) (TR15) (TR26) (TR41) (TR45) Chemical substances that can be extracted from components of material process fluid contact surfaces by exertion of an exaggerated force (e.g., organic solvent, extreme elevated temperature, ionic strength, pH, contact time, etc.) Extractables may represent most but not all of the potential leachables that may be seen in process fluids. (TR66) Extractables are organic and inorganic chemical entities that can be released from a pharmaceutical packaging/delivery system, packaging component, or packaging material of construction under laboratory conditions. (TR54-4) Organic or inorganic chemical entity that is forced out of container closure system materials and components under laboratory experimental conditions. (TR73)
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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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Effective Filtration Area
The total surface area of the filter available to the process fluid. (TR26)
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Downstream Side (of Filter)
The effluent side of the process step (filter). (TR45) The filtrate or outlet side of the filter. (TR26)
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Diffusive/Forward Flow Test
A test to determine the integrity of a filter. [Synonym: diffusive flow test, forward flow test.] (TR26)
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Diffusive Flow
The movement of a dissolved gas across a liquidwetted membrane based on the concentration (e.g., gas pressure) differential. (TR26)
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Differential Pressure
The difference in pressure between the upstream (feed or influent) and downstream (effluent) sides of the filter. (May be modified with the terms: applied, available differential pressure, clean differential pressure, dirty differential pressure, initial differential pressure, or maximum differential pressure). [Synonym: Delta P (Δ P), PSID, Pressure Drop] (TR45) (TR26)
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Compatibility
Proof that no adverse interaction between the filter and the process fluid has occurred. (TR26) A term used in relation to the non-reactivity of filter materials with the substance to be filtered. (TR45)
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Bubble Point Test
A test to indicate the maximum pore size of a filter. The differential gas pressure at which a liquid (usually water) is pushed out of the largest pores and a steady stream of gas bubbles is detected from a previously wetted filter under specific test conditions. Used to test filter integrity with specific, validated, pressure values, wetting liquids and temperatures for specific pore-size (and type of ) filters. (TR26)
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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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Cartridge Filter
Filter elements encased in a housing. Generally, the filter elements are disposable while the housing units are multi-use. In a few cases, both filter and housings are disposable. (TR26) (TR41)
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Bubble Point
The measured differential gas pressure at which a wetting liquid (e.g., water, alcohol, product) is pushed out of the largest pores of a wetted porous membrane, and a steady stream of gas bubbles or bulk gas flow is detected.(TR15) (TR26) The minimum pressure at which a wetting liquid is pressed out of the pore system of a membrane while forming a steady bubble chain. (TR41)
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Cake
Solids deposited on the upstream side of filter media. (TR15) (TR45) (TR26)
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Capsule Filter
Compact, self-contained filter assembly. Generally, the whole assembly is disposable. (TR26) (TR41)
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