Routes of drug administration

1. TO STUDY OF DIFFERENT ROUTES
OF DRUG ADMINISTRATION IN
RAT/MICE
Dr. Nitin Kumar Sen
Assistant professor
Department of pharmacology
SJIPR, Palghar

2. ANIMAL HANDLING
• Animals should be approached in a confident and relaxed
manner.
• Animals should be handled regularly to help reduce stress and to
calm them down when restraining them for procedures to be
performed on them.
• Most animals have sharp claws and prefer not to be placed on
slippery surfaces, so, where possible, use a cage top (for
rodents) or a nonslip cover/liner for benches.
• With practice, most species of animals are easily restrained and
handled.
• There is no one correct method of handling or restraining
animals, but the general principle is that it should not cause pain
or discomfort to the animal. It should also be comfortable for
the handler, especially when the animal is being restrained for
an injection, so that the handler is able to concentrate on the
injection procedure.

3. • The methods shown in the species-specific sections are
recommended,
• although some people may feel more comfortable using
slightly different ways to restrain the animals, which is also
acceptable.
• It may be obvious, but one basic tip to remember is to keep
your fingers away from the mouth of the animal, especially
when performing a procedure such as an injection. Many
people, while busy concentrating on positioning the needle,
forget that their fingers are within easy reach of the mouth of
a mouse or rat and hence get bitten.

4. HANDLING OF MICE & RATS

5. • The path taken by the drug to get into the body is known as
the route of drug administration. A drug may be in ionized or
unionized form.
Classification:
1. Oral route
2. Parenteral route
3. Inhalation
4. Topical
1. ORAL ROUTE:
Oral route is the most common route of drug
administration. It is mostly used for the neutral drug. It
may be in the form of tablets, capsules, syrup, emulsions
or powders.
ROUTES OF DRUG ADMINISTRATION

6. Disadvantages:
Advantages:
▪ It is convenient
▪ It is the cheapest available route
▪ It is easy to use
▪ It is safe and acceptable.
▪ Less amount of drug reaches the target tissue.
▪ Some of the drug is destroyed by gastric juices
e.g. adrenaline, insulin, oxytocin
▪ Absorption has to take place which is slow, so
is not preferred during emergency.
▪ It might cause gastric irritation
▪ It might be objectionable in taste.
▪ It might cause discoloration of teeth e.g. iron causes
staining, tetracyclines below 14 cause brown discoloration
so are not advisable during pregnancy.

9. 2. PARENTERAL ROUTE:
Parenteral route includes:
Injections:
a. Intra muscular
b. Intra venous
c. Intraperitoneal
d. Intradermal (Intracutaneous)
e. Subcutaneous route (Hypodermic)
Advantages:
• Parenteral route is rapid.
• It is useful for uncooperative patients
• It is useful for unconscious patients
• Inactivation by GIT enzymes is avoided
• First pass effect is avoided
• Bioavailability is 100%
Disadvantages:
• Skill is required
• It is painful
• This method is
expensive
• It is less safe.

10. A. INTRAMUSCULAR ROUTE:
Intramuscular route might be
applied to the buttock, thigh and
deltoid. The volume used is 3 ml.
Advantages:
• Absorption is rapid than
subcutaneous route.
• Oily preparations can be used.
• Irritative substances might be
given
• Slow releasing drugs can be
given by this route.
Disadvantages
• Using this route might cause
nerve or vein damage.
Large muscle mass
Site of injection
Needle Insertion in to the thigh at 45°

11. B. INTRAVENOUS INJECTIONS:
• Intravenous injections might be applied to
the lateral tail veins
Advantages:
• Immediate action takes place
• This route is preferred in emergency
situations
• This route is preferred for unconscious
patients.
• Titration of dose is possible.
• Large volume of fluids might be injected
by this route
• Diluted irritant might be injected
• Absorption is not required
• No first pass effect takes place.
• Blood plasma or fluids might be injected.
Transverse section of rat tail

12. C. INTRAPERITONEAL ROUTE:
Intraperitoneal route may be used for peritoneal dialysis.
Two persons - (Rat & other species)
The hindquarters and tail should restrained by the assistant and
the operator should extend one of the animals hind legs. The
injection should be made in to the lower left quadrant of the
abdomen. In this area there are no organs except small intestine.
Prepare by wiping the area with 70% ethanol. The tip of the
needle should insert in to the intraperitoneal cavity without
puncturing the small intestine. The plunger of the syringe should
be pulled back to confirm that the needle is not in intestine or any
other organ.

13. Assistant holding the animal for
Intraperitoneal injection
needle insertion at 30° angle in to
the intraperitoneal cavity.

14. D. INTRADERMAL ROUTE:
The site of injection should be clipped/depilated before the
injection.
• The test item is injected in to the dermis layer of skin and not
below the dermis.
• Animal holding should be done by assistant and the person
performing the injection should hold the fold of skin and insert
the needle nearly flat on the skin, so that the needle is in the
dermis layer.
• Inject the test item slowly in the dermis layer.
• The intradermal injection is proper if there is bleb formation at
the site of injection.

15. Site of injection Bleb formation at the site of
injection

16. E. SUBCUTANEOUS:
• Subcutaneous route might be used for the arm, forearm, thigh
and subscapular space.
• Hypodermic needle (25G–30G)
Advantages:
• Absorption is slow and constant
• It is hygienic
Disadvantages:
• It might lead to abscess formation
• Absorption is limited by blood flow
• Examples of drugs given by subcutaneous route include insulin,
adrenaline and norplant.

18. 3.
INHALATION:
• Inhalation may be the route of
choice to avoid the systemic
effects. In this way drugs can
pass directly to the lungs.
• Drugs used involve volatile
drugs and gases.
• Examples include aerosols like
salbutamol;
steam inhalations include
tincture and Benzoin

19. • Advantages:
• Rapid absorptions takes place.
• Rapid onset of action takes place.
• This route has minimum side
effects.
• No first pass effect takes place.
• This method is easy.
• Fewer doses is required.
• Disadvantages:
• Special apparatus is required.
• Irritation of the respiratory tract may
take place.
• Cooperation of the patient is
required.

20. 4. TOPICAL
ROUTE:
• Drugs may be applied to the external surfaces, the skin and the
mucous membranes.
Topical route includes:
a. Enepidermic route
• When the drug is applied to the outer skin, it is called
enepidermic route of drug administration. Examples include
poultices, plasters, creams and ointments.
b. Epidermic route (Innunition):
• When the drug is rubbed into the skin, it is known as epidermic
route. Examples include different oils.
c. Insufflations:
• When drug in finely powdered form is blown into the body
cavities or spaces with special nebulizer, the method is known
as insufflations.

21. d. Instillation
• Liquids may be poured into the body by a dropper into the
conjunctival sac, ear, nose and wounds. Solids may also be
administered.
e. Irrigation or Douching
• This method is used for washing a cavity e.g. urinary bladder,
uterus, vagina and urethra. It is also used for application of
antiseptic drugs.
f. Painting/Swabbing
• Drugs are simply applied in the form of lotion on cutaneous or
mucosal surfaces of buccal, nasal cavity and other internal
organs.