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Medicines By Design



ADME Abbreviation for the four steps in a medicine's journey through the body: absorption, distribution, metabolism, and excretion.

Agonist A molecule that triggers a cellular response by interacting with a receptor.

Analgesic A medicine's ability to relieve pain, or a drug that alleviates pain; the term comes from the Greek word algos, which means pain.

Antagonist A molecule that prevents the action of other molecules, often by competing for a cellular receptor; opposite of agonist.

Antibiotic A substance that can kill or inhibit the growth of certain microorganisms.

Antibody A protein of the immune system, produced in response to an antigen (a foreign, often disease-causing, substance).

Anti-inflammatory A drug's ability to reduce inflammation, which can cause soreness and swelling.

Antipyretic Fever-reducing; the term comes from the Greek word pyresis, which means fire.

Arachidonic acid A molecule that synthesizes regulatory molecules such as prostaglandins; it is found in fatty animal tissue and foods such as egg yolk and liver.

Bacterium One-celled organism without a nucleus that reproduces by cell division; can infect humans, plants, or animals.

Bioavailability The ability of a drug or other chemical to be taken up by the body and made available in the tissue where it is needed.

Bioinformatics A field of research that relies on computers to store and analyze large amounts of biological data.

Biotechnology The industrial use of living organisms or biological methods derived through basic research.

Biotransformation The conversion of a substance from one form to another by the actions of organisms or enzymes.

Blood-brain barrier A blockade consisting of cells and small blood vessels that limits the movement of substances from the bloodstream into the brain.

Carcinogen Any substance that, when exposed to living tissue, may cause cancer.


Central nervous system The brain and spinal cord.

Chemical bond Physical force holding atoms together to form a molecule.

Chemical genetics A research approach resembling genetics in which scientists custom-produce synthetic, protein-binding small molecules to explore biology.

Cholesterol A lipid unique to animal cells that is used in the construction of cell membranes and as a building block for some hormones.

Chromosome A structure in the cell nucleus that contains hereditary material (genes); humans have 23 pairs of chromosomes in each body cell, one of each pair from the mother and the other from the father.

Clinical trial A scientific study to determine the effects of potential medicines in people; usually conducted in three phases (I, II, III), to determine whether the drug is safe, effective, and better than current therapies, respectively.

Combinatorial genetics A research process in which scientists remove the genetic instructions for entire metabolic pathways from certain microorganisms, alter the instructions, and then put them back.

Cyclooxygenase An enzyme, also known as COX, that makes prostaglandins from a molecule called arachidonic acid; the molecular target of nonsteroidal anti-inflammatory drugs.

Cytochrome P450 A family of enzymes found in animals, plants, and bacteria that have an important role in drug metabolism.

DNA (deoxyribonucleic acid) A double-stranded molecule that encodes genetic information.

Dose The amount of medicine to be taken at one time.

Dose-response curve A graph drawn to show the relationship between the dose of a drug or other chemical and the effect it produces.

Enzyme A molecule (usually a protein) that speeds up, or catalyzes, a chemical reaction without being permanently altered or consumed.

Essential fatty acid A long, fat-containing molecule involved in human body processes that is synthesized by plants but not by the human body and is therefore a dietary requirement.

First-pass effect The breakdown of orally administered drugs in the liver and intestines.

G protein One of a group of switch proteins involved in a signaling system that passes incoming messages across cell membranes and within cells.

Gene A unit of heredity; a segment of a DNA molecule containing the code for making a protein or, sometimes, an RNA molecule.

Genetics The scientific study of genes and heredity, of how particular qualities or traits are transmitted from parents to offspring.

Genomics The study of all of an organism's genetic material.

Hormone A messenger molecule that helps coordinate the actions of various tissues; made in one part of the body and transported, via the bloodstream, to tissues and organs elsewhere in the body.

Immunotherapy A medical treatment to stimulate a patient's immune system to attack and destroy disease-causing cells.

Inflammation The body's characteristic reaction to infection or injury, resulting in redness, swelling, heat, and pain.

Informed consent The agreement of a person (or his or her legally authorized representative) to serve as a research subject, with full knowledge of all anticipated risks and benefits of the experiment.

Kinase An enzyme that adds phosphate groups to proteins.

Lipid A fatty, waxy, or oily molecule that will not dissolve in water; it contains hydrogen, carbon, and oxygen.

Liposome Oily, microscopic capsules designed to package and deliver biological cargo, such as drugs, to cells in the body.

Membrane A thin covering surrounding a cell and separating it from the environment; consists of a double layer of molecules called phospholipids and has proteins embedded in it.

Metabolism All enzyme-catalyzed reactions in a living organism that builds and breaks down organic molecules, producing or consuming energy in the process.

Metabolite A chemical intermediate in metabolic reactions; a product of metabolism.

Model organism A bacterium, animal, or plant used by scientists to study basic research questions; common model organisms include yeast, flies, worms, frogs, and fish.

Monoclonal antibody An antibody that recognizes only one type of antigen; sometimes used as immunotherapy to treat diseases such as cancer.

NSAID (nonsteroidal anti-inflammatory drug) Any of a class of drugs that reduces pain, fever, or inflammation by interfering with the synthesis of prostaglandins.

Neurotransmitter A chemical messenger that allows neurons (nerve cells) to communicate with each other and with other cells.

Nucleus The membrane-bound structure within a cell that contains most of the cell's genetic material.

Organelle A specialized, membrane-bound structure that has a defined cellular function; for example, the nucleus.

Peptide A small protein fragment.

Pharmacodynamics The study of how drugs act at target sites of action in the body.

Pharmacogenetics The study of how people's genes affect their response to medicines.

Pharmacokinetics The study of how the body absorbs, distributes, breaks down, and eliminates drugs.

Pharmacologist A scientist focusing on pharmacology.

Pharmacology The study of how drugs interact with living systems.

Pharmacy An area in the health sciences that deals with the preparation, dispensing, and appropriate use of medicines.

Physiology The study of how living organisms function.

Prostaglandins Any of a class of hormone-like, fat-soluble, regulatory molecules made from fatty acids such as arachidonic acid; prostaglandins participate in diverse body functions, and their production is blocked by NSAIDs.

Protein A large molecule composed of one or more chains of amino acids (the building blocks of proteins) in a specific order and a folded shape determined by the sequence of nucleotides in the gene encoding the protein; essential for all life processes.

Proteomics The systematic, large-scale study of all proteins in an organism.

Receptor A specialized molecule that receives information from the environment and conveys it to other parts of the cell; the information is transmitted by a specific chemical that must fit the receptor, like a key in a lock.

Recombinant DNA technology Modern techniques in molecular biology to manipulate an organism's genes by introducing, eliminating, or changing genes.

RNA (ribonucleic acid) A molecule that serves as an intermediate step in the synthesis of proteins from instructions coded in DNA; some RNA molecules also perform regulatory functions in cells and viruses.

Sepsis A clinical condition in which infectious agents (bacteria, fungi) or products of infection (bacterial toxins) enter the blood and profoundly affect body systems.

Side effect The effect of a drug, other than the desired effect, sometimes in an organ other than the target organ.

Signal transduction The process by which a hormone or growth factor outside the cell transmits a message into the cell.

Site of action The place in the body where a drug exerts its effects.

Steroid A type of molecule that has a multiple ring structure, with the rings sharing molecules of carbon.

Structural biology A field of study dedicated to determining the three-dimensional structures of biological molecules to better understand the function of these molecules.

Therapeutic drug A drug used to treat a disease or condition; contrast with drug of abuse.

Toxicology The study of how poisonous substances interact with living organisms.

Virus An infectious agent composed of a protein coat around a DNA or RNA core; to reproduce, viruses depend on living cells.

X-ray crystallography A technique used to determine the detailed, three-dimensional structure of molecules based on the scattering of X rays through a crystal of the molecule.

This page last reviewed on October 27, 2011