Parison
The “tube” of polymer extruded by the BFS machine from which the containers are formed. (TR77)
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Mandrel
Specialized filling needles on certain BFS machines which also act to form the container. (TR77)
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Dynamic (in operation)
BFS machine line fully operational and filling, with the number of allowed operating personnel present as during normal running conditions. (TR77)
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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
An unanticipated rapid increase in fluid flow. [Synonym: Hydraulic Shock] (TR45)
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Pre-Filter
Any filter placed upstream of the final filter. (TR26)
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Pressure Shock (Forward Pressure Shock)
Rapid increase in forward fluid flow that may dislodge particulates. (TR45)
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Wash
Step in a chromatography cycle designed to flush the column to remove substances acquired during a previous step (often used between the load and elution steps). (TR14)
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Volatile
Evaporates easily; converts easily from a liquid form to gas. (TR45) (TR26)
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Volumetric Throughput (Vmax)
The maximum volume that can be processed through a filter area. It is the volumetric capacity of the filter for a given process fluid and generally expressed in L/m2. (TR41) (TR47)
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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)
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Void Volume
See Porosity. (TR45)
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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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Velocity
The average linear rate of fluid flow equal to the volumetric flow rate divided by the cross-sectional area of the flow channel. (TR15)
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Titer Reduction (TR)
A measure of the degree to which a particular filter removes a microorganism under specified test conditions. Calculated as the ratio of the total number of microorganisms used to challenge the filter divided by the total number of microorganisms that passed through the filter. (TR75)
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Ultrafiltration Membranes
Membranes that retain particles whose sizes are measured by molecular weight, with retention ranges from 1,000 to 1,000,000 (Daltons). (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)
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Upstream
The influent side of the filter. (TR45) (TR26)
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Turbidity
Finely dispersed particles causing cloudiness or haziness in water or other fluid. Turbidity may be measured using a nephelometer. (TR45)
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Viral Removal
Physical separation of virus particles from the intended product. (TR47) (TR83)
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Transmembrane Pressure (TMP)
The pressure difference equal to the average feed-stream pressure minus the average filtrate-stream pressure. TMP = (Pfeed + Pretentate)/2 - Pfiltrate (TR15)
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Tangential Flow Filtration
Filtration in which the product stream is introduced parallel to the membrane surface and flows in a direction perpendicular to the filtrate flow. (Synonym:cross-flow filtration) (TR15)
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Tangential or Cross Flow Filtration (TFF or CFF)
Filtration in which a fluid (feed) stream runs tangential to a membrane. A pressure differential causes some fluid to pass through the membrane. (TR41)
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Size Exclusion
A technique which separates particles based on diameter. (TR41)
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Slurry (verb)
To mix resin particles in a liquid to achieve a homogenous liquid suspension. (TR14)
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Slurry (noun)
A homogenous distribution of resin particles in a liquid. (TR14)
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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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Stirred-Cell Filtration
A surrogate for tangential flow filtration where shear is achieved by rapidly stirring the solution immediately adjacent to the membrane. Typically the stirring is accomplished by mechanical means, such as through the use of a stir bar or impeller. (TR15)
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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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Sieving Coefficient (S0)
The ratio of the filtrate concentration of component i (Ci,f) to the bulk or feed concentration of component i (Ci,b) as in the following equation: S = Ci,f/Ci,b Where S = 1 for a freely passing solute, typically a low molecular weight solute S = 0 for a solute that is fully retained by the membrane [Synonym: transmission; product transmission] (TR15)
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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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Rejection
The ability of a filter to exclude solutes or particulate matter from passing through. (TR45)
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Retention Factor
One minus the ratio of filtrate concentration of component i (Ci,f) to the bulk or feed concentration of component i (Ci,b) as in the following equation:R = 1 - [Ci,f/Ci,b]Where R=0 for a freely passing solute R=1 for a solute that is fully retained by the membrane[Synonym: rejection coefficient, rejection factor] (TR15)
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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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Retentate
The concentrated feed solution after removal of filtered liquid through the membrane and into the filtrate. [Synonym: concentrate] (TR15)
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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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Retention Efficiency
The percentage of particles of a specific size that are removed by a filter. (TR45)
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Retention Rating
The means by which a filter manufacturer defines the ability of a filter to retain specific-sized particles. (TR45)
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Screening Studies
Studies used to select a particular type and grade of filter media. (TR45)
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Shear Rate
The velocity gradient in a flowing fluid. This value is proportional to the average linear velocity and is inversely proportional to the channel height or diameter when the recirculation is in the laminar flow regime (most TFF applications). (TR15)
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Sieving
Size-exclusion filtration occurs when a particle is too large to pass through the filter medium and is retained on the surface or within the depth of the filter. (TR45)
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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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Psid
Pound-force per square-inch differential is the difference in pressure; for example, the pressure differential between the upstream (influent) and downstream (effluent) sides of a filter. (TR75)
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Positive Control Filter Membrane (Penetration Control)
A control filter membrane with a larger pore size rating than the test filter and used to demonstrate the penetrative ability of the test microorganism. Penetration of this filter by at least one CFU is required to validate a test. (TR75)
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Porosity (Synonym:Void volume)
The percentage of a membrane’s volume that is occupied by pores. (TR15)
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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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Porosimetry (Gas-Liquid and Liquid-Liquid)
An analytical technique used to determine various quantifiable aspects of a material’s porous nature, such as pore diameter, total pore volume, surface area, and bulk and absolute densities. (TR41)
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Pore-Size Distribution
The range of pore sizes in a filter used to determine the filter’s average pore size. (TR15)
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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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