A
ACE
Angiotensin Converting Enzyme. Inhibitors of this enzyme are
used in drugs to lower blood pressure.
Acetyl choline
One of the naturally occurring chemicals that transmits
impulses from one nerve to another. Particularly important in the brain.
Adrenal glands
A pair of small glands, one located on top of each kidney.
The adrenal glands produce hormones (epinephrine, norepinephrine, and steroid
hormones) that help control heart rate, blood pressure, the way the body uses
food, and other vital functions.
AIDS
Acquired Immune Deficiency Syndrome. An infection due to HIV
(Human Immunodeficiency Virus) that severely damages the immune system.
Allergens
Any substance that can trigger an inappropriate immune
response, or allergy, in susceptible people. Common allergens include animal
fur, dust, pollen and certain foods or medications.
Allergic reaction
A response, such as rash, hives, itching, asthma, hay fever,
etc., to an allergen.
Alzheimer's disease
A form of senile dementia, caused by the build-up of
abnormal proteins in the brain.
Ambulatory
Able to walk.
Ameliorate
Make better.
Anaemia
The condition of having less than the normal number of red
blood cells or haemoglobin in the blood. Patients can feel tired, fatigue
easily, appear pale, develop palpitations, and become short of breath.
Anaesthetic
A substance that causes lack of feeling or awareness. A
local anaesthetic causes loss of feeling in a part of the body. A general
anesthetic puts the person to sleep.
Antibiotics
Prescription drugs which inhibit growth of bacteria or kill
bacteria.
Antibodies
Protein produced by white blood cells which neutralise or
destroy foreign proteins in the body (antigens). When infected with virus or
bacteria, the body produces antibodies which destroy the invading
micro-organisms.
Anticoagulant
Medicine that delays or prevents blood from clotting.
Antifolate
A substance that opposes the action of folic acid or folates
in the body.
Antigens
Substances that cause an immune response in the body. The
body "sees" the antigens as harmful or foreign. To fight them, the
body produces antibodies, which attack and try to eliminate the
antigens.Antigens include foreign proteins, bacteria, viruses, pollen and other
materials.
Antihypertensive
Medicine used to reduce high blood pressure (hypertension).
Antiseptic
Prevents or retards growth of germs when applied externally;
an agent that kills bacteria. Alcohol is a common antiseptic.
Antiserum
Serum containing antibodies.
Antitoxin
A substance that neutralises toxin formed in the body.
Artery
A large blood vessel that carries blood high in oxygen
content away from the heart to other parts of the body. Arteries are thicker
and have walls that are stronger and more elastic than the walls of veins.
Asthma
An allergic reaction of the airways leading to the lungs.
Atherosclerosis
Hardening and narrowing of the arteries. Aujesky's disease
Inflammation of the brain affecting many species and caused by a herpes virus.
The disease is widespread and notifiable, but can be controlled by vaccination
or slaughter.
B
Bacillus
A rod shaped bacterium. Also commonly used to mean any
disease-causing bacterium.
Bacteria
One-celled organisms; microscopic germs. Some bacteria
contribute to health, others cause disease.
Barbiturate
Compounds, derived from barbitric acid, commonly used as
hypnosedatives, or sleeping pills.
Blackleg
Acute infection of cattle or sheep caused by the bacterium
Clostridium chauvoei, leading to fever and swelling of infected muscles.
Controlled by vaccination.
Bone marrow
The inner, spongy tissue of large bones where red blood
cells, white blood cells, and platelets and made.
Bronchiolitis
Inflammation, usually due to infection by the Respiratory
Syncytial Virus, of the smallest airways of an infant, when severe leading to
failure of oxygen and carbon dioxide exchange and potentially fatal.
BSE
Bovine Spongiform Encephalopathy. A progressive brain
disease of cattle thought to be due to a transmissible form of prion protein.
C
CAPD
Continuous ambulatory peritoneal dialysis.
Cardioplegia
Paralysis of the heart.
Cardiovascular
Of the heart and blood vessels.
Chemotherapy
Treatment of (usually malignant) disease with chemicals or
drugs, specifically those which are selectively toxic to the diseased cells.
Cholinergic cells
Nerve cells activated by acetyl choline.
Chromatograph
A machine that can chemically separate or analyse gases,
liquids or solutions.
Citrated
The addition of citrate.
CJD
Creutzfeldt Jacob Disease. Progressive dementia thought to
be due to a transmissible form of prion protein.
Clostridial toxoids
Toxins from any of a group of bacteria called Clostridium,
which can cause botulism, gangrene or tetanus, and blackleg in cattle and
sheep.
Collagen
Protein found in connective tissues such as skin, bone
ligaments and cartilage.
Compound
A chemical made up of more than one element bonded together
so they cannot be physically separated.
Congenital
Diseases or deformities dating from birth.
Cornea
The clear covering of the eye.
Cystic fibrosis
A fatal genetic disorder, caused by a defect in the cftr
gene, affecting many body systems but principally the respiratory and digestive
systems.
D
Dendrite
Dendrites are the part of the neuron (nerve cell) which
communicates with other neurons. Each nerve cell usually has many dendrites, a
fine network of branched extensions extending out of the nerve cell body (like
long fingers) that receive signals ('impulses') from other nerve cells.
Dendritic cells
Immune cells commonly found in parts of the body that have
frequent contact with the environment such as the skin, nose, lungs and
stomach.
Dendritic spine
A dendritic spine is a tiny extrusion that protrudes from a
dendrite and forms one half of a synapse. Dendritic spines are found on the
dendrites of most principal neurons in the brain.
Diabetes
A condition where the pancreas produces insufficient or no
insulin, a hormone which controls sugar levels in the blood. Without insulin,
the blood cannot absorb sugar into cells for energy and into liver and fat
cells for storage.
Diagnosis
Identification of a disease or disorder. Dialysis Technique
of removing waste and toxins from the blood, used primarily when the kidneys
malfunction or in cases of overdose of a drug.
Diphtheria
A serious bacterial infection which causes a sore throat and
fever and may lead to further complications or fatal diseases. Diphtheria is
extremely rare in developed countries where there is high uptake of
immunisation.
Disease
Malfunctioning of the body or any part of the body resulting
from any number of influences, including genetic errors, toxins, infections,
nutritional deficiencies, and environmental factors
DNA methylation
A chemical modification where a methyl group is added to a
stretch of DNA that codes for a gene. This can 'silence' that gene, ie prevent
it being expressed. Methylation is important in regulating cell growth and
differentiation.
Dopamine
A naturally occurring chemical in the brain that transmits
nerve impulses.
Draize test
A safety test using rabbits to test the irritation of
substances to the eye or skin.
Dystrophin
A protein in muscle absent in muscular dystrophy.
E
Egg drop disease
Infection affecting laying and breeding poultry. Causes a
severe decrease in egg production and poor shell quality. Eggs may have reduced
pigmentation, soft shells or irregular shapes.
Shell-less eggs may also be
seen.
Encephalomyelitis
Inflammation of the brain and spinal cord.
Endotracheal tube
Tube inserted into the trachea (windpipe) to allow breathing
with a ventilator.
Epithelial cells/ epithelium
Cells that line the inner and outer surfaces of the body.
Ethical
Judgement that an action is socially and morally acceptable.
F
FDP
Fixed Dose Procedure. An acute toxicity test carried out on
animals in regulatory toxicology to assess the safety of medicines and other
substances. Developed as a more humane test to replace the LD50.
Foot and mouth disease
An acute infectious disease of cattle caused by an
aire-borne virus. Characterised by blistering of the mucous membranes,
particularly in the mouth and clefts of the feet. Causes abortion and affects
milk yields. Controlled by slaughter or vaccination.
G
GAD
Glutamic acid decarboxylase. Ganglionic blockers Compound
that block nerve-to-nerve junctions at swellings called ganglia.
GDNF
A nerve growth factor - glial-cell-line-derived neurotrophic
factor.
Gene
The biological units made of DNA that are passed from both
parents to a child. Genes determine all of the child's characteristics - for
example, hair, eye, and skin color, foot size, height - and whether the child
will have an inherited disease.
Gene expression
The process by which the information in a gene is used to
create proteins: the gene is a sequence of DNA. It is 'copied' (transcribed
into mRNA) and 'read' (translated into a protein) and proteins are made or
altered based on the information. If a gene is highly expressed, then a large
amount of that protein is made.
Gene therapy
Treatment that alters genes (the basic units of heredity
found in all cells in the body). In early studies of gene therapy for cancer,
researchers are trying to improve the body's natural ability to fight the
disease or to make the tumour more sensitive to other kinds of therapy.
Glutamate
A salt of glutamic acid. Large quantities of glutamate are
generated in the brain following a stroke, causing brain damage.
GM foods
Genetically modified foods.
H
Heart bypass
(or coronary artery bypass graft) Surgical replacement of
blocked sections of the coronary arteries that supply blood to the heart. They
are replaced with vessels from elsewhere in the body, usually the leg or chest.
Heart lung machine
Machine that oxygenates and circulates blood during
open-heart surgery.
Hib meningitis
A bacterial form of meningitis caused by Haemophilus
influenzae.
HIV
Human Immunodeficiency Virus which can destroy the immune
system and lead to AIDS.
Hormone
Chemical substance produced by endocrine glands (thymus,
pituitary, thyroid, parathyroid, adrenal, ovaries, testicles, pancreas) that
regulates many body functions to maintain homeostasis (a steady state).
Hormones travel throughout the body and regulate the activities of systems,
tissues, organs, and glands. They play an important role in regulating
functions such as growth, reproduction, digestion, and fighting infection.
Huntington's disease
A rare fatal genetic disease affecting the nervous system,
which does not appear until middle age. There is no cure, but the gene was
discovered in 1993.
Hypertension
Condition in which the blood is pumped through the body
under abnormally high pressure; also known as high blood pressure.
I
Immune system
A complex network of organs, cells and specialised
substances distributed throughout the body and defending it from foreign invaders
such as bacteria, viruses, parasites and fungi that cause infection or disease.
Immunity
State of being resistant to a disease, particularly an
infectious one.
Immunosuppression
Drugs that block the body's ability to fight infection or
foreign substances that enter the body. A person receiving a kidney or heart
transplant is given these drugs to stop the body from rejecting the new organ
or tissue.
In vitro
Literally = "in glass" ie in a test-tube. A
non-animal method of medical research.
In vivo
Literally = "in life" ie in a living animal or
human.
Infectious bursal disease
A disease of young chickens causing suppression of the
immune system.
Inhaler
A device used to deliver measured doses of inhaled
medicines, eg for asthma.
Insulin
A hormone that helps glucose leave the blood and enter the
muscles and other tissues of the body. The beta cells of the pancreas (in areas
called the islets of Langerhans) produce insulin. When the body cannot make
enough insulin on its own, a person with diabetes must use insulin from human
(recombinant DNA origin) or animal (pigs/cows) origin.
Intravenous : Into a vein.
Islet cells
Cells in the islet of Langerhans in the pancreas, known as
beta cells, that produce insulin.
Laughing gas
A common name for nitrous oxide.
LD50
Lethal Dose 50. An acute toxicity test carried out on
animals, developed in the 1920s. Although superseded by the more humane FDP, it
is still required by some regulatory authorities.
Leishmaniasis
A group of diseases caused by infection by Leishmania
parasites.
Leptospirosis
Disease of humans or animals caused by infection with
Leptospira bacteria, common in sewage and water. In humans known as Weil's
disease.
Leukaemia
A malignant disease of the blood-forming organs that results
in the uncontrolled production of abnormal white blood cells.
Levodopa
A precursor of dopamine, used as a medicine to improve
mobility in Parkinson's disease.
Louping ill
A disease transmitted by a tick-borne virus, mainly
affecting sheep and cattle. Inflammation of the brain and spinal cord affects
the nervous system and leads to acute fever. Controlled by vaccination.
Lungworm
Infection of cattle caused by Dictyocaulus viviparus.
Affects young stock. Adult worms infest the airways leading to respiratory
disease. Also known as husk or parasitic bronchitis.
Lymphoma
A type of cancer that begins in lymphatic tissue and may
spread to other areas of the body.
M
Macular degeneration
Deterioration of the macular region of the eye leading to
loss of vision.
Malaria
A tropical disease caused by the parasite Plasmodium
falciparum, passed on by the mosquito.
Malignant
Harmful, tending to become worse, as in cancerous tissue
that can grow uncontrollably and spread (metastasise).
Marek's disease
A common fatal disease of chickens caused by herpes virus.
Affects the nervous system, can cause paralysis before death. Controlled by
vaccination.
Medicine
Substance intended to treat, cure or prevent disease.
Meningitis
Inflammation of the membranes that cover the brain or spinal
cord, usually caused by infection.
Meningococcal
Types of bacteria that cause meningitis.
Mesenchymal cells/ mesenchyme
Cells which can become a variety of cells types that make up
connective tissue including bone, fat, cartilage, and blood vessels that are
derived from embryonic mesoderm.
Metabolite
Any substance produced by physical or chemical processes in
the body.
Metastasis
(me-TASS-tah-sis) The migration of cancer cells from the
original tumor site through the blood and lymph vessels to establish new tumor
sites in other tissues. Metastasis also is the term used for a secondary cancer
growing at a distant site. The plural is metastases.
Microarray
A tool for studying how large numbers of genes interact with
each other and how a cell's regulatory networks control vast batteries of genes
simultaneously. A microarray allows you to see the difference in expression
levels of hundreds or thousands of genes at once, so you can see which genes
act together.
MicroRNA
miRNAs are short RNA genes which are transcribed from DNA,
but are not translated into protein. The function of miRNAs appears to be in
gene regulation.
Mortality Rate
The death rate; the number of people who die of a certain
disease compared with the total number of people. Mortality is most often
stated as deaths per 1,000, per 10,000, or per 100,000 persons.
Motor neurone disease
Also called amyotrophic lateral sclerosis or Lou Gehrig's
disease in the USA. A chronic disease in which there is progressive
degeneration of the nerve cells which instigate movement, leading to weakness,
wasting, and loss of muscle function and death usually within two to three
years of onset. Motor neurone disease occurs in both hereditary and sporadic forms
but its causes remain unclear.
MPTP
A neurotoxin - 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.
MRC
Medical Research Council.
Mucous membrane
Membranes lining the body cavities, such as the mouth, nose,
throat, vagina and rectum.
Multiple sclerosis
A chronic, usually progressive disease of the nervous
system, in which the insulating myelin sheath surrounding nerves in the brain
and spinal cord breaks down. Occurs in young or middle adulthood, affects more
women than men. Typical symptoms are unsteadiness, loss of muscular
coordination, weakness, speech difficulties, and rapid involuntary movements of
the eye. Its cause is unknown.
Muscular dystrophy
Any group of inherited chronic muscle disorders marked by
weakening and wasting of muscle. Muscle fibres degenerate, to be replaced by
fatty tissue, although the nerve supply remains unimpaired. Death occurs in
early adult life. The commonest form, Duchenne muscular dystrophy, is inherited
and strikes boys.
Myelin
The white fatty substance that forms an insulating sheath
around nerves.
Myxomatosis
A highly contagious and fatal disease of rabbits, in which
tumour-like tissue grows beneath the skin of the head and body. Controlled by
vaccination.
N
Neuromuscular
Pertaining to nerve and muscle.
Neuron (nerve cell)
A unique type of cell found in the brain and body that is
specialised to process and transmit information. Each neuron is composed of a
cell body containing the nucleus; an axon which conveys electrical signals to
other neurons; and dendrites which deliver incoming signals.
Newcastle disease
Acute highly contagious viral disease of chickens, other
domestic fowl and wild birds. Affects the digestive system leading to loss of
appetite and diarrhoea, breathing and the nervous system. Controlled by
vaccination.
Nucleus (pl nuclei)
An organelle found in cells, which contains the cell's
chromosomes (genetic material).
Oestrogen
A female hormone produced by the ovaries, also applied to
synthetic versions.
Orf
Infectious viral disease of sheep and goats characterised by
vesicle and pustule formation on the skin and mucous membranes, particularly
lips, nose and feet. Controlled by vaccination.
Organelle
A structure inside the cell, which has specialised
function(s) eg the nucleus.
P
Pancreas
A small organ that lies behind the lower part of the
stomach. The pancreas makes insulin needed to convert glucose to energy. The
pancreas also makes enzymes that help the body digest food.
Paramyxovirus
A group of viruses causing measles, mumps, croup or viral
pneumonia, and including respiratory syncytial virus, the leading cause of
hospitalisation of children under two. Other paramyxoviruses cause devastating
diseases of wildlife and livestock, such as canine distemper - normally a virus
of dogs, but which also ravaged the lion population of the Serengeti Plain -
and Newcastle disease of chickens.
Parkinson's disease
A degenerative disease of the brain characterised by a
progressive loss of mobility, muscular rigidity, tremor, and speech
difficulties, mainly seen in people over 50. Parkinson's disease destroys a
group of cells in the brain stem that produce dopamine, essential to control of
voluntary movement.
Pasteurella
The name of a group of bacteria causing blood poisoning and
lung infections in several species of animals. Pasteurella multocida causes
haemorrhagic septicaemia in cattle, characterised by high fever, pneumonia and
swelling of the skin. A similar disease affects sheep.
Penicillin
An antibiotic derived from the penicillium mould.
Peptide
Two or more amino acids chained together by a chemical bond
called a 'peptide bond'. A protein is a long chain of amino acids joined
together in this way, and is sometimes referred to as a 'polypeptide'. Some
proteins contain more than one polypeptide chain.
Pertussis
Whooping cough.
Pigeon pox
A mosquito borne viral disease of pigeons and poultry.
Damages the skin and mucous membranes.
Plasma
Protein-rich, cell-free blood.
Pneumococcal vaccine
A vaccine which protects against S. Pneumoniae (bacteria
that cause pneumonia).
Polio (Poliomyelitis)
A disease caused by virus infection of the central nervous
system, leading to muscle paralysis. It used to be known as infantile
paralysis. Now largely eradicated by vaccination.
Prion proteins
Proteins which, in a certain form, are thought to transmit
brain diseases such as BSE, CJD, scrapie and kuru.
Procedure
An experiment or scientific technique.
Progesterone
A hormone involved in the preparation for, and maintenance
of, pregnancy. Progesterone is also used to treat some gynaecological
conditions.
Prostate gland
A chestnut shaped organ in males which resides below the
bladder and in front of the rectum. The prostate gland produces most of the
seminal fluid (the fluid that carries the semen during ejaculation).
Proteasome
A large complex of cell proteins that degrade damaged or
unwanted cellular proteins when they are no longer needed.
Protein
Any of numerous complex molecules that are made of amino
acids, the building blocks of cells. Proteins are the fundamental components of
the body and are essential to all biological processes. Proteins are needed in
the diet; they are broken down into amino acids which are absorbed, and rebuilt
to form new proteins in the body.
PRP
A type of protein.
Pyrogen
Bacterial contamination that causes fever.
R
Rabies
An acute viral infection of dogs, wolves and other
carnivores, transmitted to humans by the bite of an infected animal.
Radiotherapy
The use of electromagnetic or particulate radiation in the
treatment of disease.
Red blood cell
A haemoglobin-containing blood cell, carrying oxygen in the
blood from the lungs and supplying it to tissues throughout the body. They are
also called red corpuscles.
Remission
A period or state during which the symptoms of a disease
subside or decrease.
Renal
Pertaining to the kidneys.
Retina
Light-sensitive layer of tissue located at the back of the
eye that transmits visual images to the brain.
Rheumatoid arthritis
Inflammation of the joints; a chronic progressive disease,
it begins with pain and stiffness in the small joints of the hands and feet and
spreads to involve other joints, often with severe disability and
disfigurement. There may also be damage to the eyes, nervous system and other
organs.
Rinderpest
Acute, highly contagious and often fatal disease of cattle,
characterised by fever and ulceration of the mucous membranes, causing severe
diarrhoea and discharges from the mouth, nose and eyes. Also known as cattle
plague. Notifiable in the UK and controlled by vaccination.
S
Safety testing
Testing of a substance to protect the safety of humans,
animals or the environment.
Schistosomiasis
Infestation by Schistosome parasitic worms, transmitted via
water by a complex cycle involving snails as intermediate hosts. Common in the
tropics and affecting mostly the bladder and rectum.
Serotonin
Serotonin or 5-hydroxytryptamine (5-HT) is a chemical widely
distributed in the body tissues - in the blood platelets, the wall of the
intestine and the central nervous system. Believed to be implicated in the
inflammatory process and, in the nervous system, it acts as a neurotransmitter,
controlling sleep.
Serum
Clear fluid that separates out from clotted blood. Blood
plasma with the anticoagulant proteins removed, containing antibodies and other
proteins, as well as the fats and sugars of the blood. It can be produced
synthetically, and is used to protect against disease.
Sickle-cell anaemia
A hereditary chronic blood disorder common among people of
black African descent, characterised by distortion and fragility of the red
blood cells (sickling) which contain abnormal haemoglobin.
Stem cell
An immature cell capable of both indefinite proliferation
and specialisation into all cell types found in the body, eg in the blood or in
the brain.
Streptococcal bacteria
Bacteria that have a tendency to form pairs or chains.
Widely distributed in nature living mainly as parasites in the bodies of
animals and humans. Some are harmless, but most are implicated in a number of
infections, including scarlet fever.
Stroke
A haemorrhage or clot in the brain causing symptoms ranging
from transient weakness and numbness to deep coma and death. Damage to the
brain is permanent, though some recovery can be made.
Swine erysipelas
Also known as diamond skin disease. Causes blood poisoning,
fever, skin rash, arthritis and lameness. Widely controlled by vaccination.
Synapse
The functional connection between a nerve cell axon and
target cells, which may be other nerve cells, muscle cells, or gland cells.
T
T cells
T cells are white blood cells, derived from the thymus
gland, that participate in a variety of cell-mediated immune reactions and are
involved in acquired immunity (the ability to fight off something that the body
was previously exposed to). Three fundamentally different types of T cells are
recognised.
Thalidomide
Sedative developed in the 1950s for use in morning sickness.
When taken in early pregnancy, it caused malformation of the foetus (such as
abnormalities in the limbs). It was then withdrawn.
Thrombosis
Formation of a blood clot in a vein or artery, causing loss
of circulation to the area served by the vessel. Thrombosis increases the risk
of heart attack and stroke. It is treated by surgery and/or anticoagulant
drugs.
Toxin
Any poison produced by another living organism (usually a
bacterium) that can damage the living body.
Transcriptome
The transcriptome is the set of all messenger RNA (mRNA)
molecules, or 'transcripts', produced in one or a population of cells. Because
it includes all mRNA transcripts in the cell(s), the transcriptome reflects the
genes that are being actively expressed at any given time.
Transgenic
A plant or animal containing a gene or genes from another
species. Also refers to plants or animals that have altered genes.
TSE
Transmissible Spongiform Encephalopathy. A group of diseases
including BSE, CJD, scrapie and kuru, caused by an infectious form of prion
protein.
Tumourigenesis
The formation, growth and development of a tumour, or
accumulation of rapidly proliferating cells.
V
Vaccination
Introduction of modified pathogens (viruses or bacteria)
into the body, usually either orally or by a hypodermic syringe, to induce the
specific antibody reaction that produces immunity against a particular disease.
Vaccine
Weakened or killed micro-organisms, or parts of
micro-organisms, of a specific disease that are introduced into the body to
stimulate immunity.
Vein
Blood vessel that returns blood to the heart.
Virulent
Capacity of a harmful organism to cause disease.
Virus
Infectious organism that reproduces in the cells of an
infected host. A virus is a microbe which cannot grow or reproduce apart from a
living cell. It is smaller in size than a bacterium. Viruses cause most of the
common human infections, but are also responsible for causing many rare
illnesses. Examples of viral illnesses include the common cold and acquired
immunodeficiency disease syndrome (AIDS).
Vivisection
Literally, cutting into living flesh, ie surgery. Commonly
used today to mean any experimental use of animals.
W
Warfarin
A drug that prevents circulating blood from clotting by
inhibiting the action of vitamin K. It can be taken orally and begins to act
several days after the initial dose. It is often given as a preventive measure,
to reduce the risk of thrombosis or embolism after major surgery.
White blood cells
Any of a group of blood cells that have no haemoglobin and
migrate into tissues to fight infection and digest cell debris. White blood
cells circulate in the blood and lymphatic system and are pooled in the lymph
glands and spleen. They are part of the immune system responsible for both
directly (T cells and macrophages) and indirectly (B cells producing
antibodies) attacking foreign invaders of the body.
X
Xenotransplantation
Transplantation of organs and tissues from animals to humans
C
increase in temperature. This relationship has been observed for nearly all
drug hydrolysis and some drug oxidation reactions. The actual factor of rate
increase depends on the activation energy of the particular reaction. The
activation energy is a function of the specific reactive bond and the drug
formulation (e.g., solvent, pH, additives). As an example, consider a
hydrolyzable drug that is exposed to a 20