Chemistry terms, explained
ANDA
An Abbreviated New Drug Application is the route for approval of a generic medicine in the United States. Rather than repeat…
API (Active Pharmaceutical Ingredient)
An Active Pharmaceutical Ingredient is the substance in a medicine that produces its therapeutic effect. APIs are made by ch…
AR Grade
Analytical Reagent grade, a purity grade for chemicals intended for quantitative analysis. Its specification sets a minimum…
Assay
The measured content of the named substance in a sample, normally expressed as a percentage by weight. It may be determined…
Batch or Lot Number
A unique code that identifies material produced in one manufacturing run or filled from one homogeneous lot. It links the co…
BP (British Pharmacopoeia)
The British Pharmacopoeia, the United Kingdom's official collection of standards for medicinal substances and products. It i…
Buffer
A solution that resists changes in pH when small amounts of acid or base are added. It usually contains a weak acid with its…
Building Block
A relatively small, functionalised molecule used as a starting point to assemble larger structures. Medicinal chemists combi…
CAS Registry Number
A unique numeric identifier assigned by the Chemical Abstracts Service to a specific substance, written as up to ten digits…
Catalyst
A substance that increases the rate of a chemical reaction without being consumed overall, by providing a lower-energy pathw…
Certificate of Analysis (COA)
A document issued for a specific lot that lists each specification test, its acceptance limit and the result obtained. A use…
Certificate of Suitability (CEP)
A Certificate of Suitability issued by EDQM confirming that the quality of a substance, typically an API or excipient, is su…
Chelating Agent
A molecule that binds a metal ion through two or more donor atoms, forming a stable ring-shaped complex. EDTA, citric acid a…
Chiral Purity
The extent to which a sample of a chiral compound consists of a single enantiomer, usually expressed as enantiomeric excess…
CIF (Cost, Insurance and Freight)
Cost, Insurance and Freight, an Incoterm for sea transport. The seller pays freight to the named destination port and buys m…
Coagulant
A chemical that destabilises suspended colloidal particles in water by neutralising their surface charge, allowing them to c…
Custom Synthesis
The preparation of a compound to a customer's specification when it is not available commercially, or not at the required pu…
DAP (Delivered at Place)
Delivered at Place, an Incoterm under which the seller bears the cost and risk of transporting goods to a named place in the…
Deuterated Compound
A compound in which one or more hydrogen atoms have been replaced by deuterium, the stable hydrogen isotope with one neutron…
Drug Master File (DMF)
A Drug Master File is a confidential submission to a regulator, most often the US FDA, that describes how a substance such a…
Enantiomer
One of a pair of molecules that are non-superimposable mirror images of each other, like left and right hands. Enantiomers h…
EP / Ph. Eur. (European Pharmacopoeia)
The European Pharmacopoeia, published by EDQM of the Council of Europe and legally binding in the states that have signed it…
Excipient
Any component of a medicine other than the active ingredient. Excipients act as fillers, binders, disintegrants, lubricants,…
EXW (Ex Works)
Ex Works, the Incoterm that places the least obligation on the seller. Goods are made available at the seller's premises, no…
FCC (Food Chemicals Codex)
The Food Chemicals Codex, a compendium of standards for the identity, purity and quality of food ingredients, published by t…
Flash Point
The lowest temperature at which a liquid gives off enough vapour to form an ignitable mixture with air near its surface, mea…
Flocculant
A substance, often a high molecular weight polymer such as polyacrylamide, that gathers destabilised particles into larger,…
FOB (Free On Board)
Free On Board, an Incoterm for sea and inland waterway transport. The seller clears the goods for export and loads them on t…
Gas Chromatography (GC)
Gas chromatography separates volatile compounds carried by an inert gas through a heated column coated with a stationary pha…
Genotoxic Impurity
An impurity that can damage DNA and potentially cause mutations or cancer, even at very low levels. Such impurities often co…
GHS (Globally Harmonized System)
The Globally Harmonized System of Classification and Labelling of Chemicals, developed by the United Nations. It sets common…
GLP (Good Laboratory Practice)
Good Laboratory Practice is a quality system governing how non-clinical safety studies are planned, performed, recorded and…
GMP (Good Manufacturing Practice)
Good Manufacturing Practice is the set of quality rules that ensures medicines and their ingredients are consistently produc…
Heavy Metals
Metallic impurities such as lead, mercury, cadmium and arsenic that are toxic at low levels. Older pharmacopoeial tests meas…
Hill Notation
A convention for writing molecular formulas. For organic compounds, carbon is written first, then hydrogen, then all other e…
HPLC
High-performance liquid chromatography separates compounds dissolved in a liquid mobile phase as they pass through a column…
HPLC Grade
A grade of solvent made for use as an HPLC mobile phase. Besides a high assay, it is tested for UV absorbance at specified w…
HSN Code
The Harmonized System of Nomenclature code used in India to classify goods for customs duty and GST. It extends the six-digi…
Hygroscopic
Describes a substance that readily absorbs moisture from the air. Hygroscopic materials can gain weight, cake, hydrolyse or…
IATA DGR
The Dangerous Goods Regulations published by the International Air Transport Association, based on ICAO Technical Instructio…
ICH M7
The ICH guideline on assessment and control of DNA-reactive, potentially mutagenic impurities in pharmaceuticals. It uses st…
ICH Q3A and Q3B
Two International Council for Harmonisation guidelines on impurities in new drug substances (Q3A) and new drug products (Q3B…
IMDG Code
The International Maritime Dangerous Goods Code, adopted by the International Maritime Organization, which governs how dange…
InChIKey
A fixed-length, 27-character hashed version of the IUPAC International Chemical Identifier (InChI). Its first block encodes…
Incoterms
A set of eleven trade terms published by the International Chamber of Commerce that define the responsibilities of seller an…
Intermediate
A material produced during the steps of a synthesis that undergoes further chemical change before it becomes the final produ…
IP (Indian Pharmacopoeia)
The Indian Pharmacopoeia, published by the Indian Pharmacopoeia Commission under the Ministry of Health and Family Welfare.…
ISO 17034
The international standard that sets general requirements for the competence of reference material producers. Accreditation…
IUPAC Name
The systematic name of a compound built according to rules set by the International Union of Pure and Applied Chemistry. It…
Lead Time
The time between confirming an order and dispatching the goods, or sometimes delivering them. It includes sourcing, producti…
Letter of Credit (LC)
A bank's written undertaking to pay the seller a stated amount once documents that comply exactly with the credit's terms ar…
LOD and LOQ
The limit of detection (LOD) is the lowest amount of analyte that a method can reliably distinguish from background, often t…
Loss on Drying (LOD)
A test that measures the percentage of weight a sample loses when heated under defined conditions of temperature, time and p…
LR Grade
Laboratory Reagent grade, a practical purity grade for general laboratory work, synthesis and teaching. The assay is typical…
Molarity
The concentration of a solution expressed as moles of solute per litre of solution, written with the unit mol/L or the symbo…
Molecular Weight
The mass of one molecule of a substance relative to one twelfth of a carbon-12 atom, or equivalently the mass of one mole in…
MOQ (Minimum Order Quantity)
The minimum order quantity is the smallest amount a supplier will sell in one order, set for reasons such as batch size, pac…
Packing Group
A transport classification that indicates the degree of danger within most dangerous goods classes. Packing group I means hi…
pH
A logarithmic measure of the acidity or basicity of an aqueous solution, defined as the negative base-ten logarithm of the h…
Pharmacopoeia
An official book of quality standards for medicines and their ingredients, with legal status in the countries that adopt it.…
Polymorph
One of two or more crystalline forms of the same chemical compound that differ in the arrangement of molecules in the crysta…
Proforma Invoice (PI)
A preliminary invoice sent before shipment that sets out the goods, quantities, prices, Incoterm, payment terms and bank det…
Pyrophoric
Describes a material that ignites spontaneously on contact with air, usually within minutes or at once. Examples include alk…
REACH
The European Union regulation on the Registration, Evaluation, Authorisation and Restriction of Chemicals. Manufacturers and…
Reference Standard
A highly characterised material used as a benchmark to confirm identity, measure assay or quantify impurities. Its value com…
Residue on Ignition (Sulfated Ash)
A pharmacopoeial test in which a sample is moistened with sulfuric acid and burned at high temperature, usually around 600 °…
Retest Date
The date after which a material should be re-examined to confirm it still meets its specification before use. It is set from…
Safety Data Sheet (SDS)
A standardised hazard document, arranged in 16 sections under the GHS, that describes a substance's hazards, safe handling,…
Scale-Up
The process of moving a chemical reaction from laboratory scale to larger batches. It is not simply a matter of multiplying…
Secondary Standard
A working reference standard whose identity and potency have been established by comparison with an official primary standar…
SMILES
The Simplified Molecular Input Line Entry System, a way of writing a chemical structure as a line of text. Atoms are written…
Surfactant
A surface-active agent whose molecules contain a water-loving head and an oil-loving tail. Surfactants lower surface and int…
UN Number
A four-digit number assigned by the United Nations Committee of Experts on the Transport of Dangerous Goods to identify a ha…
USP (United States Pharmacopeia)
The United States Pharmacopeia, published together with the National Formulary by the United States Pharmacopeial Convention…
UV Cutoff
The wavelength below which a solvent absorbs ultraviolet light too strongly to be useful, conventionally where absorbance re…
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