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PDA Glossary

PDA Glossary of Pharmaceutical and Biotechnology Terminology

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.

Browse Terms by Title


Browse Terms by TR #

  • Magnetic Capture Hybridization (MCH)

    A purification method based on sequence-specific hybridization of labeled nucleic acid probes with targeted regions of test article nucleic acids, followed by magnetic bead capture. (TR50)

  • Mandrel

    Specialized filling needles on certain BFS machines which also act to form the container. (TR77)
  • Manual Baseline

    Data generated from visual inspection of a blind­ed set of seeded test containers that demonstrates the detection capability of human inspection. The test set is sometimes referred to as a “particle size threshold set,” where various foreign particu­late types in a gradation of sizes are examined to yield a statistically significant probability of de­tection percentage for each unit. This allows the determination of what types and sizes of particu­lates can be reproducibly detected in a specific product/container system. (TR79)

  • Manual Cleaning

    A cleaning procedure requiring operator-performed critical steps (e.g., scrubbing with a brush or rinsing with a hose). (TR70)

  • Manual Inspection

    Consists of manual handling and presentation of filled containers under controlled conditions of lighting and background to allow for human visual inspection. (TR79)

  • Manual Integration

    Process used by a person to modify the integration of peak area by modifying the baseline, splitting peaks, or dropping a baseline as assigned by the chromatography software to overrule the pre-established integration parameters within the chromatographic software.(TR80)

  • Manufacturing

    The production, packing, testing, storage, release and distribution of drugs or medical devices for use in humans or animals where the manufacturing is indented to produce doses, typically in significant numbers, for an undefined population of future patients or clinical trial subjects. (TR63)

    All operations including purchasing and receipt of materials to production, packaging, labelling, quality control, release, storage, distribution of components and the related controls. (TR 76)

  • Manufacturing System

    The term system or systems represents equipment, facility, critical utilities, instruments, and other entities which perform the process or provide the conditions under which the process is performed. (TR54-5)

  • Manufacturing System Lifecycle

    All phases in the life of a manufacturing system from the initial development until the manufac­turing system retirement, including specification design, fabrication, installation, commissioning, qualification, operation, maintenance, change, decommissioning and retirement. (TR54-5)

  • Marker

    Component of a product or a cleaning agent used as an analyte to quantitate the total amount of product or cleaning agent present. (TR29)

  • Market Action

    Voluntary withdrawal, recall or notification to patients, consumers or physicians of marketed pharmaceutical or consumer healthcare products for compliance or safety reasons. (TR55)

  • Market Package

    The package presentation intended for the end user (e.g., bottle + cap liner + screw cap + label + dose cup + carton; may contain multiple units of product), but not including packaging used solely for transportation (e.g., corrugated boxes or insulated containers). (TR39)

  • Marketing Authorization Application (MAA)

    An application submitted by a sponsor to the European Medicines Agency (EMA) for approval to market a new drug for human use in Europe. The MAA is similar in purpose to the Biologic License Application (BLA) or New Drug Application (NDA) in the United States. (TR56)

  • Masking

    A type of interference that may result in low endotoxin recovery.(TR82)

  • 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)

  • Master Cell Bank (MCB)

    The MCB represents a collection of cells of uniform composition derived from a single source prepared under defined culture conditions. (TR 54-4)

    The MCB represents a collection of cells of uni­form composition derived from a single source pre­pared under defined culture conditions, aliquoted into multiple vials, cryopreserved and stored in the vapor phase of liquid nitrogen. (TR 83)

  • Master Cell Bank (mCb)/Master Virus Bank (mVb)

    A stock of cells or virus used to produce the Working Cell Bank or the Working Virus Bank. Cell/virus banking is used to enhance biological consistency. (TR47)

  • Master Seed Stock

    Reference culture of a microorganism derived from an authenticated source such as American Type Culture Collection (ATCC) and used to produce working seed lots. (TR51)

  • Material Safety Data Sheet (MSDS)

    Information provided with chemicals and other materials intended to provide workers and emergency personnel with procedures for handling or working with that substance in a safe manner. Includes information such as physical data (melting point, boiling point, flash point, etc.), toxicity, health effects, first aid, reactivity, storage, disposal, protective equipment, and spill-handling procedures. (TR65)

  • Materials of Construction

    Polymers or other materials that make up the components of the filter. (TR26)

  • Matrix

    The combination of materials (e.g., excipients, stabilizer components, etc.) which are components together with the measured analyte. (TR57)

  • Matrix Effect

    The direct or indirect alteration or interference in response due to the presence of additional sample components due to sample preparation (for analysis) or other interfering substances in the sample (product related excipients or residuals). (TR57) (TR57-2)

  • Matrix Spike Control

    An internal control in which an amplifiable amount of nucleic acid is added to a test article to determine inhibition of the PCR. This addition is usually performed pre-extraction and should provide a weak signal 100% of the time. Also known as “interference control”. (TR50)

  • Maximum Allowable Leak Limit (MALL)

    The greatest gap or leak rate that does not put product quality at risk (2). (TR86)

  • Maximum Load

    The maximum quantity or mass of items permitted in a sterilizer load. (TR01) The maximum quantity or mass of items permitted in a depyrogenation or sterilization load. (TR3) The maximum quantity or mass of products permitted in a validated sterilizer load. (TR30)The maximum quantity or mass of items permitted in a sterilizer load. (TR48)

  • Maximum Tolerated Dose (MTD)

    The highest dose of an agent that can be administered without unacceptable toxicity. (TR55)

  • Mean Kinetic Temperature (MKT)

    The single calculated temperature at which the total amount of degradation over a particular period is equal to the sum of the individual degradations that would occur at various temperatures. Thus, MKT may be considered as an isothermal storage temperature that simulates the nonisothermal effects of storage temperature variation. It is not a simple arithmetic mean. (TR46) (TR58)

  • Meaningful Disruption

    A meaningful disruption is a change in production that is reasonably likely to lead to a reduction in the supply of a drug by a manufacturer that is more than negligible and affects the ability of the manufacturer to fill orders or meet expected demand for its product. A meaningful disruption is not an interruption in manufacturing due to matters such as routine maintenance and does not include insignificant changes in manufacturing so long as the manufacturer expects to resume operations in a short period of time. (TR68)

  • Measured Values

    Those values where activity is confirmed by interpolation from a reference standard curve.(TR82)

  • Media

    The part of the filter through which fluid passes that retains particles during filtration. (TR45)

  • Media Fill

    See Aseptic Processing Simulation. (TR22)

  • Medically Necessary Drug

    Any drug product used to diagnose, treat, or prevent a serious disease or medical condition for which no other drug is judged to be an appropriate substitute or there is an inadequate supply of an acceptable alternative as determined by the relevant health authority. (TR68)

  • Medicinal Product

    Any product intended for the diagnosis, treatment, or prevention of disease. (TR39)

  • Medium

    In filtration, the porous material which retains particles as a fluid passes through during the process of filtration (TR26)

  • Melting Temperature (Tm)

    The calculated or observed temperature for a primer/nucleic acid mixture at which 50% of primer-binding sites are in single strand form. (TR50)

  • 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)

  • Membrane (Synthetic)

    A finely porous structure having lateral dimensions much greater than its thickness, through which mass transfer may occur by the application of driving forces like pressure or electro-osmotic. (TR15)

  • Membrane Area

    The effective surface area of a membrane device that is available for filtration. (TR15)

  • Metabolite

    A substance that is either the result of metabolism or a requirement for a metabolic process. (TR70)

  • Metadata (FDA)

    The contextual information required to understand data. A data value is by itself meaningless without additional information about the data. Metadata is often described as data about data. Metadata is structured information that describes, explains, or otherwise makes it easier to retrieve, use, or manage data.(TR80)

  • Metadata (MHRA)

    Metadata is data that describe the attributes of other data and provide context and meaning. Typically, these are data that describe the structure, data elements, inter-relationships and other characteristics of data. It also permits data to be attributable to an individual (or if automatically generated, to the original data source).(TR80)

  • Metadata (WHO)

    Metadata are data about data that provide the contextual information required to understand those data. These include structural and descriptive metadata. Such data describe the structure, data elements, interrelationships and other characteristics of data. They also permit data to be attributable to an individual.(TR80)

  • Method Capability

    The resulting acceptable uncertainty of results to achieve the required capability to detect, quantify, and/or discriminate the analyte at levels that is relevant to the intended use. (TR57)

  • Method Comparability

    The demonstration of analytical method comparability (AMC) for method replacements. A study to demonstrate that a modification to an existing method either improves or does not significantly change the analytical procedure’s characteristics relative to the methods’ validation and intended use. (TR57)

  • Method Development

    A process that involves the selection, optimization, and qualification of a physical/chemical, biological, molecular, or microbiological test procedure. (TR57)

  • Method Lifecycle

    All stages in the life of a method, from the initial development through marketing, until the method’s discontinuation. (TR57-2)

  • Method Operating Space

    Proven acceptable ranges of a method based on knowledge of the effects of critical instrument and procedural parameters on method performance within the design space. (TR57-2)

  • Method Parameter

    Any factor or method operational step that can be varied continuously (e.g., flow rate) or specified at controllable unique levels (e.g., Gas Chromatograph liner type).

  • Method Qualification

    Formal or informal study performed to assess initial method performance prior to full ICH Q2 (R1) validation; assessment activity that cul­minates in a scientifically sound method that has an acceptable level of performance and is docu­mented to be suitable for its intended use. (TR56)

    Experimental studies performed to confirm the inherent performance capabilities of a test method for the material being analyzed and the intended use of the method. Method qualification can be performed during early development phases, prior to method validation. Specific method qualification characteristics (e.g., accuracy, specificity) should be confirmed based on the intended use of the analytical method and the relevant risk(s). (TR57)

  • Method Validation

    A formal, archived demonstration of the analyti­cal capacity of an assay that provides justification for use of the assay for an intended purpose. (TR56)

    A formal, archived demonstration of the analytical capacity of an assay that provides justification for use of the assay for an intended purpose. Validations are conducted prospectively according to a written, approved plan that states acceptance criteria. (TR57) (TR57-2)

  • Method, Qualitative

    An analytical procedure, based on the characteristics of a material that yields results that are not amenable to reliable enumeration. (TR57)

  • Method, Quantitative

    An analytical procedure that yields numerical results compared to quantitative specification(s). (TR57)

  • Microbial By-Products

    An analytical procedure that yields numerical results compared to quantitative specification(s). (TR57)

    Organic compounds produced by microorganisms during metabolism and released into the bulk-phase environment. (TR69)

  • Microbial Characterization

    The description of microorganisms based on their cellular morphology, Gram reaction, and key diagnostic tests (e.g., Gram-positive coagulase-negative cocci). (TR13)

  • Microbial Classification

    The arrangement of microorganisms into taxonomic groups based on their similarities and relationships. (TR13)

  • Microbial Count Determination

    A test performed to quantify the number of microorganisms present in a sample of material. Standard microbial methods are utilized to estimate the number of colony forming units (CFU) per unit mass or volume. (TR28)

  • Microbial Data Deviation

    A microbial test result that deviates from approved specifications or in-process limits. (TR88)
  • Microbial Enumeration

    Compendial test for microbial counts using the plate-count, membrane-filtration or most probable number methods described in USP <61> Microbiological Examination of Nonsterile Products: Microbial Enumerations Tests. (TR67)

  • Microbial Identification

    The determination of the genus, and species when possible, to which a laboratory or manufacturing isolate belongs. (TR13)

  • Microbiological Examination Tests

    The compendial tests for microbial enumeration and absence of specified microorganisms as found in USP <61> Microbiological Examination of Nonsterile Products: Microbial Enumerations Tests and USP <62> Microbiological Examination of Nonsterile Products: Tests for Specified Microorganisms. (TR67)

  • Microbiological Identification

    Biochemical characterization of isolated colonies to determine the isolate genus and, where feasible and appropriate, the species. (TR22)

  • Micro-condensation

    The formation of very fine layers of condensation often invisible to the naked eye. (TR51)

  • Microdosing Studies

    Studies designed to speed up the development of promising drugs by establishing early on whether the drug or agent behaves in human subjects as was expected from preclinical studies. May in­clude the administration of single subtherapeutic doses of the study drug to a small number of sub­jects (10 to 15) to gather preliminary data on the agent’s pharmacokinetics and pharmacodynam­ics. A Microdosing study gives no data on safety or efficacy, being by definition a dose too low to cause any therapeutic effect. (TR56)

  • Microfiltration (MF)

    Pressure-driven, membrane-based separation process in which particles and dissolved macromolecules (typically 0.1 &;mum or larger) are retained. (TR15)

  • Microorganism

    A microbe; a free-living organism too small to be seen by the naked eye. (TR45) (TR26)

  • Microorganism of Concern

    A bacterium, yeast, or mold that, due to it prominence in product recalls, infection outbreaks, nosocomial infections, and the clinical literature, results in a multifactor risk assessment to determine whether the microorganism is objectionable if it is present in a specific nonsterile product. (TR67)

  • Microprocessor

    One of the five major components of a TCU, the unit interfaces with temperature sensors in the discharge and return air and adjusts the output rate of active cooling or heating to achieve the setpoint temperature. (TR64)

  • 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)

  • Minimum Load

    The minimum quantity or mass of items permitted in a validated depyrogenation or sterilization load. (TR01) (TR3) (TR30) (TR48)

  • Mitigation

    Systematic steps taken or in place to reduce or limit the identified risk. (TR84)

  • Mixed Load

    A load that contains multiple item item types representing various sterilization challenges. For example, some load items may have air removal challenges, while others pose a challenge due to their mass. (TR01)

  • Mock Soil

    A soil which is used in place of the manufactured product during a cleaning validation protocol (also called a “surrogate” soil). (TR29)

  • Mock Soiling

    A process of soiling the equipment for a cleaning validation protocol in which soil is applied to the equipment surfaces to simulate the condition of the soil on those surfaces following typical product manufacturing. (TR29)

  • Module

    An individual unit consisting of multiple membranes in any format within a frame structure containing integral channels and ports for feed, retentate, filtrate and air connections. (TR15)

    Filter element that is incorporated into a cartridge or capsule. (TR26)

  • Moist Heat

    Steam, steam-air mixtures, and superheated water used for sterilization. (TR01)

  • Moist Heat Sterilizer

    Equipment (e.g., a pressure-rated vessel and associated controls) used to achieve sterilization through time, temperature and pressure. [Synonym: Autoclave, Steam Sterilizer] (TR48)

  • Moisture Content of Wood

    The moisture content of wood is calculated by the following formula: Moisture content = (Mg-Mod)/Mod. Where Mg is the green mass of the wood and Mod is its oven-dry mass (the attainment of constant mass generally after drying in an oven set at 103 ± 2 °C for 24h). The equation can also be expressed as a fraction of the mass of the water and the mass of the oven-dry wood rather than a percentage. For example, 0.59 kg/kg (oven-dry basis) expresses the same moisture content as 59% (oven-dry basis). (TR55)

  • Mollicutes

    A class of bacteria which lack a cell wall. Mollicutes are small, typically about 0.1-0.5 &;mum in size, and vary in form (trivial name: mycoplasma) (TR50)

  • Monodispersed particles

    Particles of uniform size in a dispersed phase. In the case of viruses, this term refers to free virus particles not agglomerated to other viruses or proteins in solution. (TR41)

  • Most Probable Number (MPN) Method

    A statistical method of estimating the number of viable organisms suspended in a liquid. (TR51)

  • Multiplicity of Infection (MOI)

    The average number of infectious units added per cell in an infection. (TR41)

  • Multi-Use System (MUS)

    An engineered process equipment solution for process management and unit operations designed for repeated use. (TR66)

  • Mycoplasma

    Small, flexible bacteria that lack a cell wall. Mycoplasma can pass through 0.2 μm and some 0.1 μm rated filters and are unaffected by some antibiotics, such as penicillin. (TR70) (TR47)

  • Mycoplasma Reduction Filter

    A sterilizing grade filter that also provides a log reduction value (or a titer reduction value) for a specified test mycoplasma according to the PDA Mycoplasma Consensus Method. (TR75)