Live vaccine

A vaccine in which live virus is weakened (attenuated) through chemical or physical processes in order to produce an immune response without causing the severe effects of the disease. Live vaccines currently licensed in the United States include measles, mumps, rubella, varicella, rotavirus, yellow fever, smallpox, and some formulations of influenza, shingles, and typhoid vaccines. Also known as an attenuated vaccine.

Live attenuated vaccine

A vaccine created by reducing the virulence of a pathogen, but still keeping it viable. Attenuation takes an infectious agent and alters it so that it becomes harmless or less virulent.


A specific, fixed position on a chromosome where a particular gene or genetic marker is located.

Logistic Regression

Estimating the parameters of a logistic model, which models the log-odds of an event as a linear combination of one or more independent variables, predicting the probability of a binary outcome.


A low temperature dehydration process, also known as freeze drying, that involves freezing the product and lowering pressure, thereby removing the ice by sublimation.

Loop Testing

A type of software testing that examines the loop constructs for accuracy.

Lot Number

An identification number assigned to a particular quantity or lot of material from a single manufacturer.

Lot Release

The process of evaluating each individual lot of a licensed product before giving approval for its release onto the market.


Small white blood cells that help the body defend itself against infection.


The ability to provide laboratory test results that are directly proportional to the concentration of the measured in a test sample.


A mathematical process of finding the linear approximation to a function at a given point.

Lipid Nanoparticles

Nanoparticles composed of lipids. They are a novel pharmaceutical drug delivery system, and a novel pharmaceutical formulation.


Tending to combine with or dissolve in lipids or fats.

Laminar flow

The property of fluid particles in fluid dynamics to follow smooth paths in layers, with each layer moving smoothly past the adjacent layers with little or no mixing.


A minute spherical sac of phospholipid molecules enclosing a water droplet, especially as formed artificially to carry drugs or other substances into the tissues.

Large biologics

Large-sized biologics, such as antibodies that are typically composed of 5000 to 50,000 atoms.

Large-volume parenterals

Sterile solutions intended for parenteral application with a volume of 100mL or more in one container of the finished dosage form.

Legally Acceptable Representative

An individual or judicial or other body authorized under applicable law to make decisions on participation in clinical trials on behalf of another individual.


An abnormal change in the structure of an organ due to injury or disease.

Lethal Dose 50 (LD50)

Dose of a medication that kills 50% of the population that has been administered that dose.


The granting of licenses especially to practice a profession.