Experimentation

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‘Dose Routes’ as offered by Labcorp

‘Dose routes’ means parts of the body into which chemicals can be injected, pumped or placed.

The homepage for Labcorp’s Harrogate (UK) site boasts a comprehensive list of ‘dose routes’ which can be specified by the client. They use medical terms which are less familiar to the non medically trained, so here’s a translation table.

Medical termWhat it means
BladderBladder
CannulaTube shaped needle which remains attached for repeated or prolonged injection into the body, usually directly into the bloodstream
DermalSkin
ImplantInserted into the body
IntraarticularInto an artery
IntracecalInto the space around the spinal cord
IntracisternalInto the ventricles of the brain
IntradermalInto the skin
IntrajejunalInto the small intestine
IntramuscularInto muscle
IntranasalUp the nose
IntraperitonealInto the space around the intestines
IntrauterineInto the uterus
IntravesicularInto the bladder
IntravenousInto a vein
Ocular: intervitreal, intracameral, subretinal, topicalInto an eyeball, in front of the lens, under the inside wall of the eyeball, onto the outer surface of the eyeball.
Oral: capsule, diet, gavageBy mouth, either pills, with food or by tube down the throat into stomach
OticInto an ear
SubcutaneousUnder the skin
SublingualUnder the tongue

Types of Animal Test

Here are just some of the types of test performed on beagle puppies and other animals.

The UK legislation stipulates that all new drugs have to be tested in two different species of animal: a rodent (usually mice or rats) and on a larger non-rodent mammal (usually a dog, pig or monkey)

Acute Toxicity

A chemical is forcedly given to animals by tube feeding, gas masks, and/or applied to their skin. Different acute doses of the chemical are given to the animals, in an attempt to determine what dose is required to achieve a prescribed level of poisoning or other damaging effect. Animals used on these tests experience excruciating pain, convulsion, seizures, loss of motor and body functions, diarrhoea and vomiting. At the end of the experiments, the animals are killed to study the internal damage it has been caused.

Every animal species, including humans, have widely different chemicals responses, varied degrees of sensitivity, diverse metabolism and absorption capacities. Exposure test on two different species of animals generates two different results, therefore extrapolation of results to humans is vastly inaccurate.

Chronic toxicity

They are just like the acute toxicity test but the chemical or substance is given to the animals for longer period of time.  Subacute doses are repeatedly given to the animals for periods of up to 90 days in an attempt to evaluate chronic toxic effects. Toxicity effects on the animals are observed during the long exposure and then the animals are killed to study organ and body system damage.

Animals used in these experiments have a much shorter life span than humans, therefore they are not reliable predictors of the chronic effect on humans. Also, as with acute toxicity, there is great variation in how chemicals are absorbed, metabolised and excreted by different species, including humans.

Eye Irritancy

A substance is placed in one of the animal eyes, while the other eye serves as a control. The eye irritation is evaluated at different intervals and at different doses levels. Animals must be restrained at all times to stop them from naturally responding to the eye irritation. Animals in these tests experience swelling, redness, ulcerations, blindness.

These tests do not only cause immense animal suffering but also produces unreliable results as animals’ eyes structure and pH is significantly different from human eye.

Skin Irritation, Skin Corrosivity, and Skin Sensitisation

In these experiments, a chemical or substance is applied to a shaved patch of the skin to evaluate levels of irritation, or to assess levels of potential irreversible damage, or to observe allergic reactions. These animals suffer itchiness, rashes, inflammation, ulcers, bleeding and scabs, and most of them will be euthanised at the end of the experiment.

It is most apparent that the skin of fur animals is different to the skin of humans both in structure and composition, therefore the data obtained from these test is not accurate or relevant to humans.

Mutagenicity

The genetic information of an animal is permanently changed to create mutations in the animal. These changes are sometimes transmissible so genetically altered animals are then bred to produce further mutated individuals. This mutation causes the development of cancerous tumour or other debilitating diseases. The animals in these experiments are often kept alive for long time for observation, and they have to endure a life of disease and pain. When they die or are killed they are examined at a cellular level.

Carcinogenicity

These are long-term experiments in which the animals are exposed to various doses of a test substance to observe whether the exposure causes them to develop cancerous tumours. The test substance is administered to the animals orally, topically or via inhalation. Some observations are conducted while the animals are alive, but the key assessment is performed once the animal is killed or have died due to the induced cancer.

The animal species frequently used in experiments are much more prone to cancer than humans, therefore they are not appropriate models to study carcinogenicity. Also, it has been observed that test results vary widely depending on the animal species, and even the breed of animal used, therefore, the results are unreliable and unpredictable.

Reproductive and Developmental toxicity

Pregnant female animals are administered different doses of test chemical or substance, then, before birth, they are killed to assess toxicity effects on the foetuses. On longer term experiments, both males and females are given test substance before mating, then the female is given other doses while pregnant, and finally the test substance is also given to their offspring.

These experiments are aimed to assess the effects on their reproductive system and on their offspring development. At the end, the whole family is killed and their bodies examined.

Different species have different reproductive cycles as well as different life spans to those of human beings, therefore it is inaccurate to assume that the results are applicable to humans.