DOE Design of experiments; a term for experiments that are planned and analyzed using statistical design tools. A structured, organized method for determining the relationship between factors affecting a process and the output of that process. [From ICH Q8]

dosage group A group of subjects in a clinical trial receiving the same dosage of a drug being tested.

downstream processing Bioprocessing steps following fermentation and/or cell culture, a sequence of separation and purification activities needed to obtain the required drug product at the necessary level of purity.

drift time The drift time of an ion is a measure of how long it takes to move through a mobility region in a mass spectrometer. For a travelling wave, this is measured in low hundreds of milliseconds (see also TWIG).

drug discovery Methods for identifying new therapeutic molecules. High-throughput techniques include combinatorial chemistry, genomics, and proteomics analysis as the starting point. Low-throughput methods include traditional disease research.

drug product The final dosage form of a pharmaceutical medicine containing drug substance formulated with selected excipients and packaged for the end user.

drug substance The active drug chemical or biological substance in purified bulk form. The drug substance is further processed to derive a drug product. Also known as active pharmaceutical ingredient (API).

E

EBA Expanded-bed adsorption; a chromatography method that uses an upward flow of liquid in a column of suspended, dense chromatography beads to allow passage of crude, unclarified raw materials without clogging the chromatography medium.

efficacy The ability of a substance (such as a protein therapeutic) to produce a desired clinical effect; its strength and effectiveness; usefulness; the power to produce an effect.

efficiency of delivery The relative effectiveness of a drug delivery system.

EHSS exact hard sphere scattering; An ion is modeled by a collection of overlapping hard spheres with radii equal to hard sphere collision distances (see also PA). The orientationally averaged momentum transfer cross section is calculated by determining the scattering angles between the incoming buffer gas atom trajectory and the departing buffer gas atom trajectory.

elastomeric closure A rubber or rubber-like closure or stopper; a packaging component that may come into direct contact with the enclosed drug, which is usually an injectable.

electrolytes Ionized salts in body fluids; electrolyte solutions are solutions containing charged atoms or molecules.

electroosmotic The movement of a liquid out of or through a porous material or a biological membrane under the influence of an electric field.

electrophoresis Analytical method in which an electric field is applied to a medium (paper, thin-layer plates, polyacryl-amide or agarose gel), causing charged molecules to move through it. In capillary electrophoresis, samples move through a buffer-filled tube (capillary). In gel electrophoresis, samples move through a thin agarose or polyacrylamide gel. Bigger biomolecules (and those carrying few electrically charged chemical groups) move slower through the medium than smaller molecules (and those with many electrically charge chemical groups).

electrospray ionization Technique for generation of charged ions for mass spectrometry. Analyte containing solution is dispersed as a fine charged aerosol into the MS by passage of the liquid through a electrically charged capillary emitter.

electrostatic binding A chemical bond of two atoms or molecules by an electrostatic force (like static electricity) caused by one or more electrons moving from one atom to the other.

ELISA Enzyme linked immunosorbent assay; a test to measure the concentration of antigens or antibodies.

eluate Also called elution fractions; the separated components of a mixture that wash out from a chromatography column during elution.