Preclinical Research Glossary

A comprehensive guide to terminology used in contract research organizations and preclinical drug development.

A

A

AAALAC (Association for Assessment and Accreditation of Laboratory Animal Care)

A private, nonprofit organization that promotes the humane treatment of animals in science through voluntary accreditation and assessment programs. AAALAC accreditation is considered the gold standard for animal care programs.

Absorption

The process by which a drug moves from its site of administration into the bloodstream. One of the key components of ADME studies in pharmacokinetics.

ADME

Acronym for Absorption, Distribution, Metabolism, and Excretion. These four processes determine the pharmacokinetics of a drug and how it moves through the body.

Acute Toxicity Study

A study designed to evaluate the adverse effects that occur within a short time (usually 24-48 hours) after a single dose or multiple doses of a test substance given within 24 hours.

B

B

Bioanalytical Method

A validated analytical technique used to measure the concentration of drugs, metabolites, or biomarkers in biological samples such as blood, plasma, urine, or tissue.

Bioavailability

The fraction of an administered dose of a drug that reaches systemic circulation in unchanged form. Intravenous administration is considered 100% bioavailable.

Biodistribution

The study of how a drug or compound distributes throughout the body's tissues and organs after administration.

C

C

Chronic Toxicity Study

Long-term toxicity studies (typically 6-12 months) designed to assess the adverse effects of repeated exposure to a test substance over a significant portion of the animal's lifespan.

Clinical Pathology

The analysis of blood, urine, and other body fluids to assess organ function and detect toxicity. Includes hematology, clinical chemistry, coagulation, and urinalysis.

CNS (Central Nervous System)

The brain and spinal cord. CNS drug delivery is a specialized field focused on delivering therapeutics across the blood-brain barrier to treat neurological conditions.

Contract Research Organization (CRO)

A company that provides support to the pharmaceutical, biotechnology, and medical device industries in the form of research services outsourced on a contract basis.

D

D

Distribution

The process by which a drug reversibly leaves the bloodstream and enters the tissues and organs of the body. Part of ADME studies.

Dose-Response Relationship

The relationship between the dose of a drug and its pharmacological effect. Understanding this relationship is critical for determining safe and effective dosing.

Dose Range-Finding Study

A preliminary study conducted to determine the appropriate dose levels to be used in subsequent toxicology studies.

E

E

Efficacy Study

A study designed to evaluate whether a drug produces the desired therapeutic effect in an appropriate animal model of disease.

Excretion

The process by which drugs and their metabolites are eliminated from the body, primarily through urine (renal) or feces (biliary). Part of ADME studies.

F

F

FDA (Food and Drug Administration)

The U.S. federal agency responsible for protecting public health by regulating food, drugs, medical devices, and other products.

Formulation Development

The process of combining active pharmaceutical ingredients with excipients to create a stable, effective, and manufacturable drug product.

G

G

GLP (Good Laboratory Practice)

A quality system of management controls for research laboratories and organizations to ensure the uniformity, consistency, reliability, reproducibility, quality, and integrity of non-clinical safety studies.

Genotoxicity

The property of a chemical agent to damage genetic information within a cell, potentially causing mutations that may lead to cancer.

H

H

Half-Life (t½)

The time required for the concentration of a drug in the body to decrease by half. An important pharmacokinetic parameter for determining dosing frequency.

Histopathology

The microscopic examination of tissue samples to identify signs of disease or drug-induced changes. A critical component of toxicology studies.

I

I

IACUC (Institutional Animal Care and Use Committee)

A committee mandated by federal regulations to oversee and evaluate all aspects of an institution's animal care and use program.

ICM (Intracisterna Magna)

A route of drug administration involving injection into the cisterna magna, a cerebrospinal fluid-filled space at the base of the skull. Used for CNS drug delivery.

ICV (Intracerebroventricular)

A route of drug administration involving injection directly into the cerebral ventricles of the brain. Used to bypass the blood-brain barrier for CNS drug delivery.

IND (Investigational New Drug)

An application submitted to the FDA before clinical trials can begin. The IND includes preclinical data, manufacturing information, and proposed clinical protocols.

Intrathecal

A route of drug administration involving injection into the spinal canal or subarachnoid space, allowing drugs to reach the cerebrospinal fluid directly.

In Vivo

Latin for "within the living." Refers to studies conducted in living organisms, as opposed to in vitro (in glass/laboratory) studies.

In Vitro

Latin for "in glass." Refers to studies performed outside a living organism, typically in cell cultures or test tubes.

L

L

LD50 (Lethal Dose 50)

The dose of a substance that causes death in 50% of a test population. While historically used, modern toxicology often employs alternative methods.

Large Animal Model

Animal species such as dogs, pigs, sheep, or non-human primates used in preclinical research when their physiology more closely resembles humans.

M

M

Maximum Tolerated Dose (MTD)

The highest dose of a drug that does not cause unacceptable toxicity. An important endpoint in dose-finding toxicology studies.

Metabolism

The chemical transformation of drugs in the body, primarily by liver enzymes. Part of ADME studies. Metabolites may be active, inactive, or toxic.

N

N

NHP (Non-Human Primate)

Primates other than humans, such as cynomolgus macaques or rhesus monkeys, used in preclinical research due to their physiological similarity to humans.

NOAEL (No Observed Adverse Effect Level)

The highest dose at which no adverse effects are observed in a toxicology study. Critical for determining safe starting doses in human clinical trials.

Non-Clinical Studies

Studies conducted before human clinical trials, including pharmacology, pharmacokinetics, and toxicology studies in animals or in vitro systems.

P

P

Pharmacodynamics (PD)

The study of how drugs affect the body, including their mechanism of action and the relationship between drug concentration and effect.

Pharmacokinetics (PK)

The study of how the body affects a drug, including absorption, distribution, metabolism, and excretion (ADME).

Pilot Study

A small-scale preliminary study conducted to evaluate feasibility, time, cost, and other parameters before a full-scale study.

Preclinical Research

Research conducted before clinical trials in humans. Includes laboratory studies and animal studies to evaluate safety and efficacy of drug candidates.

Proof of Concept (PoC)

Studies designed to demonstrate that a drug candidate has the desired pharmacological effect in an appropriate model system.

R

R

Regulatory Submission

Documentation submitted to regulatory agencies (FDA, EMA, etc.) containing all data required for drug approval, including preclinical and clinical study results.

Reproductive Toxicology

Studies evaluating the effects of drugs on fertility, pregnancy, fetal development, and postnatal development.

Route of Administration

The path by which a drug enters the body (e.g., oral, intravenous, subcutaneous, intrathecal, intramuscular).

S

S

Safety Pharmacology

Studies designed to evaluate the potential undesirable pharmacodynamic effects of a drug on physiological functions, particularly cardiovascular, respiratory, and central nervous systems.

Small Animal Model

Animal species such as mice, rats, hamsters, or guinea pigs commonly used in early preclinical research.

Sponsor

A company, institution, or organization that initiates and finances a preclinical or clinical study.

Stereotactic Surgery

A minimally invasive surgical technique that uses a three-dimensional coordinate system to locate precise targets within the brain or spine for drug delivery or device placement.

Subchronic Toxicity Study

A toxicity study with repeated dosing over an intermediate duration (typically 14-90 days) to assess cumulative toxic effects.

T

T

Target Organ

An organ that is specifically affected by a particular drug or toxin, either as the intended site of therapeutic action or as a site of toxicity.

Toxicokinetics

The study of pharmacokinetics in the context of toxicology studies, focusing on the systemic exposure to test substances at toxic dose levels.

Toxicology

The study of the adverse effects of chemical, physical, or biological agents on living organisms and the environment.

V

V

Validation

The process of establishing documented evidence that a procedure, process, or method consistently produces a result meeting predetermined specifications.

Vehicle

An inactive substance used as a carrier or solvent for the active drug substance in formulation. Control groups often receive vehicle alone.

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