1. By
Dr. Muhammad Adil Rasheed
Assistant Professor
Pharmacology and Toxicology
UVAS, Lahore
ROUTES OF DRUG
ADMINISTRATION

2. Drug Absorption
 Absorption is the process by which a drug
enters the bloodstream without being
chemically altered
or
 The movement of a drug from its site of
application into the blood or lymphatic
system

3. Factors affecting route of drug
administration
 Physicochemical properties of the drug
 Onset of action required
 Type of response required
 Site of desired action
 Nature and Formulation of drug
 Circulation at the site of absorption
 Biotransformation
 Condition of patient

4.  The possible routes for drug entry into the
body may be divided into two classes:
 ENTERAL
 PARENTERAL
Routes of Drug Administration

5. ENTERAL ROUTES
 ENTERAL Drug placed directly in the GI
tract:
 Oral swallowing (p.o., per os)
 Sublingual placed under the tongue
 Rectum Absorption through the rectum

6. Oral
 Administration of drug by ingestion.
 Not very much preferred in animals because of
restraining of animals is difficult.
 Given in the form of drench or mixed with feed or
water.
 Applied with the help of stomach tube, or
Nasogastric tube.
 If rapid effect is required drug may be
administered before meal if drug causes irritation
may be administered after meal.

7. Advantages of oral route
 Can be self- administered, pain free, easy to
take.
 Absorption takes place along the whole length
of the GI tract.
 The drugs preparations needs no sterilization.
 Both solid and liquid dosage forms can be
given through this route.
 Most suitable route for GIT Infections and GI
parasites
 Cheap as compared to most other parenteral
routes.

8. Disadvantages of oral route
 Drug action has slower onset son not suitable
in case of emergency.
 Drug absorption is irregular and unpredictable
due to presence of ingesta.
 First-pass effect - drugs absorbed orally are
initially transported to the liver via the portal
vein.
 Irritation to gastric mucosa - nausea and
vomiting.

9. First-pass Effect
 The first-pass effect is the term used for the
hepatic metabolism of a pharmacological
agent when it is absorbed from the gut and
delivered to the liver via the portal circulation.
The greater the first-pass effect, the less the
agent will reach the systemic circulation when
the agent is administered orally

10. Disadvantages of oral route
 Destruction of drugs by gastric acid and
digestive juices.
 Unpleasant taste of some drugs.
 Unable to use in unconscious patient.
 Poor administration techniques may lead to
intratracheal delivery and subsequent
aspiratory bronchopneumonia

11. Sublingual/Buccal
Drugs are taken as solutions or smaller tablets
which are held in the mouth or under the tongue.
Advantages
Rapid absorption
Drug stability
Avoid first-pass effect
Disadvantages
 Inconvenient
 Small doses
 Unpleasant taste of drugs

12. 1. Unconscious patients and children.
2. If patient is nauseous or vomiting.
3. Easy to terminate exposure.
4. Absorption may be variable.
5. Good for drugs affecting the bowel
such as laxatives.
Rectal route of drug administration

13. Parenteral
 Intravascular
Intravenous
Intra-arterial
 Extravascular
Intramuscular
Subcutaneous
Intra-articular
Intraperitoneal
Intracardial
Intrapleural
Epidural
Intradermal
Intrathecal
Intraoosseous
 Other Extravascular
Inhalation
Topical Application
Other Mucous Membranes
(Vagina, Nose…)

14. Intravascular
Intravenous
Intra-arterial
Absorption phase is bypassed
(100% bioavailability)
1.Precise, accurate and almost immediate
onset of action,
2. Large quantities can be given, fairly pain
free
3. Greater risk of adverse effects
a. high concentration attained rapidly
b. risk of embolism

15. Intravenous route of drug
administration
Drug solution is injected directly in one of
superficial vein either as bolus or infusion.
In cattle and Horses vein is jugular, In sheep and
goat jugular, Caphaneous and cephalic, vein is
and in dog vein is Caphaneous and cephalic.
Identify the vein to be used in some animals this
is straightforward, others may have to palpate
(feel for) veins. Always inject with the blood flow.
Clean the site with soap and water, or an alcohol
swab.
Introduce the needle into the vein at a shallow
angle.

17.  Pull back the plunger to identify that the needle
is in a vein a small amount of dark red venous
blood should trickle into the syringe.
 Inject slowly to reduce the likelihood of damage
to the vein and to lower the overdose risk.
 Remove the needle slowly if the needle is
removed too quickly, the vein may collapse.
 Immediately apply pressure to the site bruising
is caused by bleeding into the surrounding
tissues. Immediate firm pressure will limit the
amount of bruising caused.
Intravenous route of administration

18. Advantages of Intravenous route
 Quick onset of action.
 This route is used when precise control of the
drug effect is required.
 Highly irritating and non isotonic solutions can
be given by slow IV because dilution provided
by circulating blood.
 Large volume of fluids can be administered
through this route.

19. Disadvantages of Intravenous route
 This route required special technique.
 Air embolism may put life of animal in danger.
 Extra vascular accumulation of irritant drugs
may cause necrosis of peripheral tissues and
phlebitis.
 Not suitable for insoluble drugs like oils and
suspensions.

20. Intramuscular route of administration
 Drug is injected deep
between the layers of
one of large skeletal
muscle because
these are richly
supplied with blood
and less with nerves.
 This route is used for
providing systemic
effects of drugs.

21. Advantages of Intramuscular route
Route of choice in animals.
Very rapid absorption of drugs in aqueous solution and
oleaginous suspensions.
Absorption of drug is rapid except for oily and depot
preparations.
The duration of action is longer than for IV injection, but
usually a little shorter than for subcutaneous
administration.
Mostly suitable route for fractious, wild and zoo animals,
which may be difficult to restraint.

22.  Large volume of fluids cannot be injected.
 There is possibility of improper deposition of
drug in nerve, blood vessels, fat or connective
tissues.
 It is not suitable for emergency situations
because conditions like cardiovascular
collapse or shock may impede absorption of
drugs.
Disadvantages of Intramuscular route

24. Subcutaneous route of administration
The drug preparation is deposited in the loose
subcutaneous tissue (Under skin).It is richly supplied with
nerve but less blood supply.
Advantages
Large volume of non irritating drugs may be administered.
Absorption of drugs is slower than
IM and IV.
It is suitable for depot preparations.
Disadvantages
Not suitable for irritant drugs

25. Intradermal route of administration
The drug preparation is injected in the dermis of skin.
Injection is applied on the skin of most sensitive part of
body.
Advantages
Used for diagnostic purposes, like tuberculin test, Malein
test, Antibiotic sensitivity test.
Disadvantage
Painful condition.

27. Intra articular Injection
 Inject the drug in Joints
For the treatment of arthritis
More skill is required
Painful application
Damage the cartilage

28. Intraperitoneal drug administration
 Injection into Peritoneum (body
cavity).
 IP injection is more often applied to
animals than humans.
 It is generally preferred when large
amounts of blood replacement fluids
are needed, or when low blood
pressure or other problems prevent
the use of a suitable blood vessel
for Intravenous Injection.

29. Advantages
 Rapid absorption
 Large volume of drug may be injected.
 Used frequently in lab animals.
Disadvantages
 Not suitable for irritating compounds because it
causes chemical peritonitis.
 There is possibility of puncturing of intestine or
other abdominal organs.

30. Intra Cardiac Injection
 Drug is injected directly in to the
heart

31. Epidural Injection
 An injection in the epidural space.
 It is a space located in the spine between
the vertebrae and the dural sac, which
surrounds the spinal cord.

33. Intrathecal Injection
 Drugs which
cannot cross BBB
are administered
through this route

34. Intraoosseous Injection
 Injection in Bone marrow

35. 1.Gaseous and volatile agents and aerosols
2.Rapid onset of action due to rapid access to
circulation
a. Large surface area
b. Thin membranes separates alveoli from
circulation
c. High blood flow
Other Extravascular
Inhalation

36. Topical route of drug administration
SKIN
Absorption is directly proportional to the lipid solubility of drugs.
Absorption through skin can be enhanced by use of dressing,
inunctions or special drug delivery devices like ear tags and
transdermal patches.
BATH
It is immersion of the body in medicated water. Baths are given
generally for their local effects upon the skin in cutaneous
disorders.
DIPS
It is type of bath in which body is dipped in medicated fluid for a
certain time. In vet. Dips are used in small animals to kill
ectoparasites.

37. Topical route of drug administration
INUNCTIONS
It is the application of semisolid or liquid drug on the body by
rubbing.
DUSTING
It is application of fine particles of solid on surface of body.
APPLICATION ON MUCOUS MEMBRANES
Intramammary Administration.
Intra ocular Administration.
Intra aural Administration.
Intranasal Route.
Intravaginal
Intrauterine
Intra Prepucial

38. Specialized drug delivery systems
Transdermal Drug delivery system
Transdermal drug delivery system are topically
administered medicaments in the form of patches that
deliver drugs for systemic effects at a predetermined and
controlled rate.

39. Liposomes.
Liposomes are minute vesicles of lipid bilayers
enclosing and aqueous compartment. They are utilized
for the transportation of drugs to areas not normally
accessible to free form of drug.
Specialized drug delivery systems

40. Dermojet/Hypospray
It is a special form of subcutaneous administration in
which needle is not used. A high velocity jet of drug
solution is projected from a micro fine orifice using a
gun like device. It is painless method for insertion of
drug in the body.
Specialized drug delivery systems

41.  Intravenous 30-60 seconds
 Intraosseous 30-60 seconds
 Inhalation 2-3 minutes
 Sublingual 3-5 minutes
 Intramuscular 10-20 minutes
 Subcutaneous 15-30 minutes
 Rectal 5-30 minutes
 Ingestion 30-90 minutes
 Transdermal (topical) variable (minutes to
hours)
Route for administration
-Time until effect-

42. Thanks!!