The degree to which overt adverse effects can be tolerated by the subject or patient.

Type I error

A false positive, is the rejection of the null hypothesis when it is actually true.

Toxic Hepatitis

Impairment of liver function caused by taking various drugs.

Type II error

A false negative, is the failure to reject a null hypothesis that is actually false.


The degree to which a chemical substance or a particular mixture of substances can damage an organism.


A disease caused by Salmonella enterica serotype Typhi bacteria, also called Salmonella typhi. Symptoms vary from mild to severe, and often there is a gradual onset of a high fever over several days. This is commonly accompanied by weakness, abdominal pain, constipation, headaches, and mild vomiting.


The scientific study of the characteristics and effects of poisons.

Typhoid Fever

Typhoid fever is a life-threatening illness caused by the bacterium Salmonella Typhi. Persons with typhoid fever carry the bacteria in their bloodstream and intestinal tract.


A poisonous substance, especially one produced by bacteria, that causes disease.


An inactivated toxin (usually an exotoxin) whose toxicity has been suppressed either by chemical (formalin) or heat treatment, while other properties, typically immunogenicity, are maintained.

Transverse Myelitis

Sudden-onset inflammation of the spinal cord. Symptoms include general back pain followed by weakness in the feet and legs that moves upward. There is no cure, and many patients are left with permanent disabilities or paralysis. Transverse Myelitis is a demyelinating disorder that may be associated with Multiple Sclerosis (MS). See demyelinating disorders.


The process by which a cell makes an RNA copy of a piece of DNA.


The process by which a virus transfers genetic material from one bacterium to another.


A process by which foreign nucleic acids are delivered into a eukaryotic cell to modify the host cell’s genetic makeup.

Transgenic mouse

Mice that have been artificially modified at a genetic level to include a foreign sequence.

Transitional Provision

A statutory provision that regulates a process that starts before an amendment or enactment of the statute comes into force , and ends after the amendment or enactment of the statute has come into force.

Transmission Electron Microscopy (TEM)

Microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. An image is formed from the interaction of the electrons with the sample as the beam is transmitted through the specimen.

Trial Statistician

A statistician with adequate education on clinical trials, substantial experience in conducting clinical trials, and practical responsibility for all statistical tasks related to clinical trials.


The fact of living things turning towards or away from something, for example light.


A person or organization that has been given responsibility for managing someone else’s property or money through a trust.


Infectious disease usually caused by Mycobacterium tuberculosis. Tuberculosis generally affects the lungs, but it can also affect other parts of the body, including pleura, meninges, bones, etc.

Td vaccine

A vaccine against tetanus (T), diphtheria (d). Lower-case “d” means this vaccine use smaller doses.

Tdap vaccine

A vaccine against tetanus (T), diphtheria (d), and pertussis (ap). Lower-case “d” and “p” means this vaccine use smaller doses. ‘a’ stands for ‘acellular’, meaning it contains only part of the pertussis bacteria instead of the whole bacteria.

Temporal association

Two or more events that occur around the same time whether causally related or not, chance occurrences.


Of, relating to, or causing developmental malformations in a fetus or unborn baby.

Tertiary structure

The folding of the secondary structure into distinct arrangements known as domains.

Test Method Validation

Establishing by objective, evidence that the test method consistently produces a desired result required to satisfy the intended use.


A bacterial infection caused by Clostridium tetani. The bacteria generally enter through a break in the skin, such as a cut or puncture wound caused by a contaminated object. They produce toxins that interfere with normal muscle contractions, causing characteristic muscle spasm in those who are infected.

T cell

A type of white blood cells of the immune system that plays a central role in the adaptive immune response. T cells are born from hematopoietic stem cells, and then migrate to the thymus gland to mature. T cell has two major subtypes: CD8+ cytotoxic T cells and CD4+ helper T cells. Cytotoxic T cells mainly function by directly killing virus-infected cells, as well as cancer cells. Helper T cells mainly function by further activating memory B cells and cytotoxic T cells, which leads to a larger immune response.

Theoretical yield

Theoretical yield calculated based on the stoichiometry of the chemical equation.

T helper cell

A type of T cell that plays an important role in the adaptive immune system. They aid the activity of other immune cells by releasing cytokines. They are considered essential in B cell antibody class switching, breaking cross-tolerance in dendritic cells, in the activation and growth of cytotoxic T cells, and in maximizing bactericidal activity of phagocytes such as macrophages and neutrophils.


Of or relating to the treatment of illness.


The production of a disk-shaped solid by compaction or agglomeration of a powder.

Therapeutic Index (TI)

Range of doses at which a medication is effective without unacceptable adverse events.

Tangential flow filtration (TFF)

A type of filtration used in biochemical engineering that biomolecules are separated and purified while feed flow travels tangentially across the surface of the filter.

Tap water

Water, obtained directly from a faucet or tap, that has not been purified, distilled, or otherwise treated.


The ability of a substance to resist irreversible change in its chemical or physical structure.

Target Market Profile (TMP)

The set of attributes that relate to a target population. It typically includes demographic, psychographic, and geographic factors.


A mercury-containing preservative used in some vaccines and other products since the 1930s.

Target Product Profile (TPP)

Strategic guidance which outlines the desired ‘profile’ or characteristics of a target product that is aimed at a particular disease or diseases.

Thin Layer Chromatography (TLC)

A chromatographic technique used to separate the components of a mixture using a thin stationary phase supported by an inert backing.

Targeted Protein Degradation (TPD)

The use of heterobifunctional small molecule “Degraders”, such as PROTAC® Degraders, to achieve knockdown of target proteins within cells.


The detection of antibodies in blood through a laboratory test, the concentration of antibodies detected in such a test.

Targeted Release

A formulation designed to release the drug after it has reached the target site.


A method of finding exactly how much of a substance there is in a solution by gradually adding measured amounts of another substance that reacts to it.