Administration & Extraction Methodology Flashcards
What is covered regarding Experimental procedures
In laboratory animal science?
Administration of drugs
Collection of blood
Collection of urine and feces
In what two broad ways can a drug be administered (application & effect)
Systemic & Local
What is meant by systemic?
Reaches the circulatory system so the entire body is affected
What is the entry route for local application?
‘Topical’
What two entry routes are associated with systemic application?
Enteral administration
- Via the Gastrointestinal tract
Parenteral administration
- Everything that is not enteral
Give two examples of topical application
- Cutaneous (on the skin)
- Mucous membrane
Give 5 examples of mucous membranes that can be used to topical application
eyes
ears
nose
lungs
vagina
Give 3 examples of enteral application
Injection
Respiratory
Cutaneous (?)
Give two examples of parenteral application
Oral
Rectal
Give three stages to consider for deciding on a specific drug delivery method
Administration/ Absorption
Distribution/ metabolism
Elimination
Describe the route when a drug is administered intravenously
Intravenous administration -> blood
Eliminated via kidney (urine) and skin (sweat)
Describe the route when a drug is administered orally
Oral administration-> gut -> liver via portal system -> blood
Eliminated via gut (feces), kidney (urine) and skin (sweat)
Describe the route when a drug is administered subcutaneously
Subcutaneous administration -> blood
Eliminated via kidney (urine) and skin (sweat)
Describe the route when a drug is administered transdermally
Transdermal administration -> blood
Eliminated via kidney (urine) and skin (sweat)
Describe the route when a drug is administered transdermally
Inhalation -> Lungs -> Exhaled air
Give 8 things to consider when deciding a specific drug method
- Local or systemic action
- Site of desired action
- Physical and chemical properties of the drug
- Rapidity of response desired
- Extend of drug absorption
- Effect of digestion and first pass metabolism
- Accuracy of dosage required
- Condition of patient/animal
Is an aseptic technique required for:
Enteral administration?
Parenteral administration?
Enteral administration: Not required
Parenteral administration: Required
What is meant by the first pass effect?
Hepatic metabolism of a pharmacological agent; Metabolic process of the liver will mean that some of it will be dissolved and passed through the urine, some are deactivated by the liver, some are activated. Generally the greater the first pass effect, the less will reach the systemic
circulation.
Is there a first pass effect in enteral administration?
Oral: Yes
Rectal: No
How is rectal administrated carried out in small lab animals?
It is not
How may a drug be orally administered?
● Drinking water
● Oral cavage
What are the benefits of placing it in food or drinking water?
- Easy to do
- No disturbance of the animal
What are four attention points of placing it in food or drinking water?
- Variation in consumption
- Substance solubility
- Substance stability
- Substance smell/taste
Why is there a variation in consumption with oral adminitration?
Lack of control over how much animal takes in; can weigh a bottle as an indication but no exact way of telling.
Why should you be concerned with the taste or smell of a solution with oral administration?
If a substance has a very sour taste for example they will not want it, can be used as a water restriction technique.
What is oral cavage/ stomach tube?
Passage of a gavage needle into the esophagus, and this technique often involves the animal swallowing the gavage needle as it approaches the pharynx.
What is the benefit of using a oral cavage/ stomach tube?
Direct accurate individual dose, no variation in
consumption
What are the attention points of using an oral cavage technique?
- Disturbance of the animal
- Still first pass effect
- Practice is required for restraining the animal and introducing the needle into the oesophagus and not the trachea
What points of attention does the oral cavage neutralise?
– Substance stability
– Substance smell/taste
– Variation in consumption
How can the stress during an oral cavage be attenuated?
Habituation
Describe the steps involved in the oral cavage technique
- fill the syringe and attach the cannula
- Flexible cannula are preferred as they are less likely to cause damage to the oesophagus
- Excess agent should be wiped from the cannula to avoid introducing unpalatable material into the mouth
- The length of cannula required to reach the stomach is measured on the outside of the animal
- Mouse should be restrained by the scruff sufficiently firmly so that it is not able to move its head during the procedure
- If restraint is too firm, this can result in vocalisation and other signs of distress
- Tube is passed down animals mouth an into stomach, should be no or minimal resistance encountered when passing the tube.
- Important that the head and oesophagus are straight so you have clear passage through - Resistance could indicate insertion into the trachea, then the tube should be withdrawn and re-inserted
- Tube should be administered slowly to minimise reflux from the stomach
- After dosing is complete, tube should be gently withdrawn, animal carefully returned to cage and observed to ensure no immediate adverse effects. If signs of respiratory distress are seen, animal should immediately be humanely killed.
How is rectal administrated carried out in small lab animals?
It is not
How is rectal administrated carried out in small lab animals?
It is not
Why is length an important factor for the cannula used in an oral cavage?
Too short might not reach stomach, too long and it can be dangerous for the animal
How is rectal administrated carried out in small lab animals?
It is not
Why may a flexible cannula not be preferred?
The flexible tube carries risk that if the animal is not well restrained they can bite through it in one bite and the tube may become stuck.
Why is aseptic adminitration required in parenteral administration?
No degredation by GI tract; most materials will not survive acidity of stomach
How is rectal administrated carried out in small lab animals?
It is not
Name four forms of injection
Subcutaneous
Intra-muscular
Intra-peritoneal
Intra-venous
Give 9 basic rules of injections
- Pick correct needle size
- Use a clean, sharp, sterile needle
- Fill syringe free of air bubbles
- Fluids should be room or body temperature
- Restrain the animal
- Inject with beveled (open) side of the needle upward
- Aspirate to validate the injection site
- Fluid entering your syringe means you have to reposition!
- Vein/bladder/intestine
- Inject slowly
- Don’t inject more fluid than the recommended maximum volume
What does the size of the needle depend on?
Size depends on animal and location
How many times is it safe to use a single needle?
Once
What should you do if taking a solution from a fridge?
Warm it first
What does it mean to aspirate for verification?
Can check if you are in a vacuum to verify, although some say you can create a vacuum with the needle and taking up tissue can be dangerous.
Why should you inject slowly?
Injecting too fast can exert force and do damage, although too slowly can be stressful for you & animal.
What is the recommended maximum volume?
Depends on species and injection method
For a mouse give:
The recommended dose (when the animal displays discomfort) in ml/kg
for:
oral
s.c
i.p.
i.m.
i.v. (bolus)
i.v. (slow inj.)
oral: 10 (50)
s.c: 10 (40)
i.p.: 20 (80)
i.m.: 0.05 (0.1)
i.v. (bolus): 5
i.v. (slow inj.): 25
For a rat give:
The recommended dose (when the animal displays discomfort) in ml/kg
for:
oral
s.c
i.p.
i.m.
i.v. (bolus)
i.v. (slow inj.)
oral: 10 (40)
s.c: 5 (10)
i.p.: 10 (20)
i.m.: 0.1 (0.2)
i.v. (bolus): 5
i.v. (slow inj.): 20
For a macaque give:
The recommended dose (when the animal displays discomfort) in ml/kg
for:
oral
s.c
i.p.
i.m.
i.v. (bolus)
i.v. (slow inj.)
oral: 5 (15)
s.c: 2 (5)
i.p.: * (10)
i.m.: 0.25 (0.5)
i.v. (bolus): 2
i.v. (slow inj.): *
- Data not available
What should be taken into account for multiple injections?
Take maximum fluid dose per
minimum time past into account. Approximately 10 ml/kg per 30min.
How should you interpret these injection volume values?
This is a high value and you would not want to reach it. New study shows new lower maximum volumes; Talk to animal staff or relevant people for the max volume in your institution.
Describe a subcutaneous injection
Subcutaneous injection is used to deliver a liquid substance under
the skin.
Describe an intramuscular injection
Intramuscular injection is used to deliver small amounts of liquid substances to the animal via the muscle
Describe an intraperitoneal injection
IP injection is used to deliver larger amounts of liquid substances to the animal