Quality Control Definitions and Terms are useful and essential for every pharmaceutical scientist or employee.
Quality Control Definitions and Terms
Herein the list of Terminology and Definitions Used in Quality Control is provided as Guidance.
Amorphous
A term used to describe a solid which does not exhibit crystalline structure. While there may be a local ordering of the atoms or molecules in an amorphous solid, no long-term ordering is present. Examples: window glass, polystyrene.
Atomic mass unit
An atomic mass unit or AMU is one-twelfth of the mass of an unbound atom of carbon-12. It is a unit of mass used to express atomic masses and molecular masses. Also Known As a unified atomic mass unit (u), Dalton (Da), or universal mass unit.
Boiling point
The boiling point is the temperature at which the vapor pressure of a liquid equals the external pressure surrounding the liquid. Therefore, the boiling point of a liquid depends on atmospheric pressure. The boiling point becomes lower as the external pressure is reduces.
Buffer
A buffer is a solution containing either a weak acid and its salt or a weak base and its salt, which is resistant to changes in pH. Examples are blood, TRIS buffer, and phosphate buffer.
Quality Control Definitions – Calibration
Process of determining the relation between the output or response of a measuring instrument and the value of the input. Calibration typically involves the use of a measuring standard.
Concentration
The amount of a substance per defined space. Concentration usually express in terms of mass per unit volume. Examples: g/cm3, kg/l.
Colloid
A type of homogenous mixture in which the dispersed particles do not settle out. Examples: Butter, milk, smoke, fog, ink, paint
Quality Control Definitions – Density
Mass per unit volume. Examples: The density of pure water is defined to be 1 gram per milliliter.
Element
A chemical element is a substance that cannot brake-down by chemical means. Elements are defined by the number of protons they possess.
Proton
A component of an atomic nucleus with a mass defined as 1 and a charge of +1. The nucleus of a hydrogen atom. The H+ ion.
Neutron
The neutron is the particle in the atomic nucleus with a mass=1 and charge =0.
Electron
An electron is a negatively charged component of an atom. Electrons exist outside of and surrounding the atom nucleus. Each electron carries one unit of negative charge and has a very small mass as compared with that of a neutron or proton.
Freezing point depression
The phenomenon occurs when the freezing point of a liquid (a solvent) is lowered by adding another compound to it, such that the solution has a lower freezing point than the pure solvent. Examples: The freezing point of seawater or even ordinary salt water is lower than the freezing point of pure water.
Quality Control Definitions – Glass
An amorphous solid. The term is usually applied to inorganic solids and not to plastics or other organics. Glasses do not have a crystalline internal structure. They usually are hard and brittle solids. Examples: borosilicate glass, soda lime glass, isinglass
Gram
A unit of mass in the metric system is equal to the mass of one cubic centimeter of water at 4oC.
Gram molecular mass
The mass in grams of one molecule of a molecular substance. Examples: The molecular mass of N2 is 28, so the gram molecular mass of N2 is 28 g.
Litmus paper
Filter paper has been treated with a natural water-soluble dye obtained from lichens. The resulting piece of paper, called ‘litmus paper can be used as a pH indicator. Blue litmus paper turns red under acidic conditions (pH below 4.5) while red litmus paper turns blue under basic conditions (pH above 8.3). Neutral litmus paper is purplish in color.
Quality Control Definitions – Mass
Mass is the property that reflects the quantity of matter within a sample. Examples: 10 grams, 55.4 kg
Measurement
Measurement is the collection of quantitative data. A measurement is made by comparing a quantity with a standard unit. Since this comparison cannot be perfect, measurements inherently include error.
Mole
A chemical mass unit, is defined to be 6.022×1023 molecules, atoms, or some other unit. The mass of a mole is the gram formula mass of a substance. Examples: 1 mole of NH3 has 6.022× 1023 molecules and weighs about 17 grams. 1 mole of copper has 6.022×1023 atoms and weighs about 63.54grams.
Molecule
A molecule refers to two or more atoms that have chemically combined to form a single species. Examples: Examples of molecules include water H2O, oxygen, gas, and O2.
Quality Control Definitions for Molecular weight
Molecular weight is a measure of the sum of the atomic weights of the atoms in a molecule. However, Molecular weight is often used interchangeably with molecular mass in chemistry, but there is a difference between the two. Molecular mass is a measure of mass and molecular weight is a measure of force acting on the molecular mass.
Quality Control Definitions – Mixture
Two or more substances have been combined such that each substance retains its own chemical identity.
Molarity
A concentration unit is defined to be the number of moles of solute divided by the number of liters of solution. Examples: There are 6 moles of HCl in 6 molar HCl or 6M HCl
Molality
A unit of concentration is defined to be equal to the number of moles of solute divided by the number of kilograms of solvent. Examples: The solution made by dissolving 0.10 mol of KNO3 into 200g of H2O would be 0.50 molal in KNO3 (0.50 m KNO3).
Quality Control Definitions – PPM
PPM stands for parts per million. It is commonly used to express concentration and temperature coefficients. Also Known As parts per million Examples: 100 ppm is identical to 0.01%.
Reference standards
USP’s official Reference standards are highly characterized specimens of drug substances, excipients, impurities, degradation products, dietary supplements, compendial reagents, and performance calibrators. They are specified for use in conducting official USP-NF tests and assays.
Solution
A solution is a homogenous mixture of two or more substances. A solution may exist in any phase. Solution Examples: An example of a solid solution is brass. An example of a liquid solution is aqueous hydrochloric acid (HCl in water).
Solvent
The component of a solution that is present in the greatest amount. It is the substance in which the solute is dissolved. Examples: the solvent for seawater is water. The solvent for air is nitrogen.
Specific weight
Weight per unit volume of a material. Also Known As unit weight.
Quality Control Definitions – Solubility
The maximum quantity of a substance that may be dissolved in another. The maximum amount of solute that may dissolve in a solvent.
QC definitions – Sol
Sol is a type of colloid in which solid particles are suspended in a liquid. Examples: protoplasm, gel, starch in water.
Standard Solution
Any solution which has a precisely known concentration. Similarly, a solution of known concentration has been standardized.
Stock Solution
A stock solution is a concentrated solution that will be diluted to some lower concentration for actual use. Stock solutions are useful to save preparation time, conserve materials, and reduce storage space. However, Stock solutions will improve the accuracy of the working solutions which are intended to prepare.
Water
Water is a chemical compound consisting of two hydrogen atoms and one oxygen atom. The name water typically refers to the liquid state of the compound. The solid phase is named ice and the gas is called steam. Also Known As Dihydrogen monoxide, H2O.
Working solution
The working solution is a name given to a chemical solution made for actual use in the lab, usually made from diluting or combining stock or standard solutions.
Viscosity
Viscosity is a measure of the resistance of a fluid that is being deformed by either shear stress or tensile stress. In everyday terms (and for fluids only), viscosity is “thickness” or “internal friction”. Thus, water is “thin”, having a lower viscosity, while honey is “thick”, having a higher viscosity. The cgs physical unit for the dynamic viscosity is the poise (P), named after Jean Louis Marie Poiseuille. It is more commonly expressed, particularly in ASTM standards, as centipoise (cP). Water at 20 °C has a viscosity of 1.0020 cP.
- 1 P = 0.1 Pa·s
- 1 cP = 1 mPa·s = 0.001 Pa·s.
Freezing Point
The temperature at which a liquid of specified composition solidifies under a specified pressure.
Quality Control Definitions – Flash Point
The flash point of a volatile material is the lowest temperature at which it can vaporize to form an ignitable mixture in air. Measuring a flash point requires an ignition source. At the flash point, the vapor may cease to burn when the source of ignition is removed.
Hygroscopic
Hygroscopy is the ability of a substance to attract and hold water molecules from the surrounding environment. This will achieve through either absorption or adsorption with the absorbing or adsorbing material becoming physically ‘changed’. This is somewhat, by an increase in volume, stickiness, or another physical characteristic of the material, as water molecules become ‘suspended’ between the material’s molecules in the process.
Accuracy
The closeness of agreement between the value which is accepted either as a conventional true value or an accepted reference value and the value found.
Precision
The closeness of agreement (degree of scattering) between a series of measurements obtained from multiple sampling of the same homogeneous sample under the prescribed conditions.
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Quality Control Glossary – Microbiology Definitions
Absorption
A process by which a substance is taken up chemically or physically in bulk by a material (absorbent) and held in pores or interstices in the interior.
Activated Carbon
A highly porous form of carbon is used for the sorption of organics and removal of free chlorine and chloramine.
Adsorption
Adherence of molecules, atoms, and ionized species of gas or liquid to the surface of another substance (solid or liquid) is the result of a variety of weak attractions.
Microbiology Definitions – Bactericide
A chemical or physical agent that kills bacteria.
Biocide
A chemical or physical agent that kills microorganisms.
Biofilm
A layer of microorganisms enclosed in a glycoprotein polysaccharide matrix that are adherent to each other and/or to surfaces.
Calibration
A comparison of a measurement instrument to detect, correlate or eliminate by adjustment of any variation.
Microbiology Definitions – CFU/ mL
Colony Forming Units per milliliter. A measure of viable microbial populations.
Endotoxin Units (IU/mL or EU/mL)
A quantification of endotoxin levels relative to a specific quantity of reference endotoxin. 1 IU/mL is approximately equal to 0.1 ng/mL.
Feedwater
The water is introduced into a purification process.
Filtration
A purification process in which the passage of fluid through porous material results in the removal of impurities.
Fines
Particulates are released from a bed of material such as ion exchange resins.
Quality Control Definitions – GAMP
Good Automated Manufacturing Practice.
Microbiology Definitions – Gram-negative
Refers to bacteria that do not absorb a violet stain originally described by Gram.
Microbiology Definitions – Gram-positive
Refers to bacteria that absorb a violet stain originally described by Gram.
Hardness
The scale–forming and lather–inhibiting qualities of some water supplies, are caused by high concentrations of calcium and magnesium. Temporary hardness, caused by the presence of magnesium or calcium bicarbonate, is so-called because it may be removed by boiling the water to convert the bicarbonates to insoluble carbonates. Calcium and magnesium sulfates and chlorides cause permanent hardness.
LAL
Limulus Amoebocyte Lysate is an extract from the horseshoe crab which forms a gel in the presence of sufficient endotoxin. Used as the basis for the LAL test for endotoxins.
Offline Water monitoring systems
Water monitoring systems, refer to measurement devices that are not directly coupled to the water stream.
Online Water monitoring systems
Water monitoring systems, refer to measurement devices directly coupled to the water stream.
Ozone
Ozone is used in the pharmaceutical industry as a sanitizing agent. O3 is a very strong oxidizing agent, kills bacteria and reduces TOC in water.
Permeate
The purified solution has been produced by passage through a semi-permeable reverse osmosis membrane.
pH
A measure of the acidity or alkalinity of a solution equal to –log (H+).
Ph. Eur.
European Pharmacopoeia.
Potable Water
Water that meets regulations is suitable for ingestion by humans.
PPB
Parts per billion is a unit equal to a micro gram per kilogram of water. Numerically ppb is equivalent to microgramme per liter in dilute aqueous solutions.
PPM
Parts per million is a unit equal to milligrams per kilogram of water. Numerically ppm is equivalent to milligrams per liter in dilute aqueous solutions.
PPT
Parts per trillion is a unit equal to a nano gram per kilogram of water.
PSG
Pure Steam Generator.
Pyrogen
A category of substances, including bacterial endotoxins, may cause fever when injected or infused.
Qualification
The act of establishing with documented evidence that the process, equipment, and/or materials are designed, installed, operated, and perform according to the pre-determined specifications.
Regeneration
The method by which exhausted ion exchange resins are reactivated by treatment with strong acid or alkali.
Reverse Osmosis (RO)
A process in which water is forced under pressure through a semi-permeable membrane leaving behind dissolved organic, dissolved ionic, and suspended impurities.
Sanitization
Chemical and/or physical processes are used to kill microorganisms and reduce contamination from microorganisms.
Sterilization
Destruction or removal of all living microorganisms.
Total organic carbon (TOC)
The total concentration of carbon present in organic compounds.
Turbidity
The degree of cloudiness of water is caused by the presence of suspended particles or colloidal material. Turbidity reduces the transmission of light and is measured in Nephelometric Turbidity Units (NTU).
Oxidation
A process using short wavelength light to kill microorganisms and cleave or oxidize organic molecules.
Condenser
The stage of the distillation system removes sufficient heat from a vaporized liquid to cause the vapor to change to a liquid phase.
Conductivity
Conductivity is the reciprocal of resistivity. For water purification systems, conductivity is usually reported as micro siemens per centimeter (μS/cm).
De–gassing
The removal of O2 and CO2 from water, usually by transfer across a hydrophobic membrane. CO2 is removed to increase ion exchange capacity and improve electro-deionization efficiency.
Deionization (DI)
Removal of impurity ions from water. Usually used to refer to ion exchange – see Ion Exchange.
Distillation
A purification process that takes advantage of changing the phase of a substance from liquid to vapor and back to liquid usually at the boiling temperature of the substance, in order to separate it from other substances with higher or lower boiling points.
Microbiology Definitions – Endotoxin
A thermally stable lipopolysaccharide component from the cell wall of viable or nonviable Gram-negative microorganisms can act as a pyrogen.
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