This document discusses various routes of drug administration. It begins by defining key terms like pharmacology and first-pass effect. It then identifies the appropriate routes for different drug formulations like ear drops, injections, insulin etc. The various routes covered are oral, sublingual, rectal, parenteral routes like intravenous, intramuscular, subcutaneous etc. Factors influencing route selection and new advanced drug delivery systems are also discussed. The document is authored by Dr Lokendra Sharma and aims to provide an overview of different routes of drug administration.

1. Disquisition on Routes of Drug
Administration
Dr Lokendra Sharma
Professor Pharmacology
SMS Medical College
Jaipur

2. 1. Identify the term used for the study of drugs and their effect on the
body :
A Pharmacy
B Pharmaceutical
C Pharmacology
D Physiotherapy
(C)

3. 2.What is the first-pass effect?
first-pass metabolism or presystemic metabolism
Metabolism of drug in the gut wall or portal circulation before reaching
systemic circulation so the amount reaching system circulation is less
than the amount absorbed.

4. 3. Identify the route of administration for ear drops :
A Oral administration
B Parenteral administration
C Topical administration
D Subcutaneous
(C)

5. 4. Identify the term used to describe an injection
that is given just under the skin :
A Subcutaneous
B Intramuscular
C Intravenous
D Epidural
A.

6. 5 .Which of the following is the appropriate route
of administration for insulin?
A) Intramuscular
B) Intradermal
C) Subcutaneous
D) Intravenous
(C)

7. 6.The nurse is to administer an iron injection to an
adult. How should this be administered?
A) Subcutaneous in the arm
B) Intradermal in the forearm
C) Intramuscular in the deltoid
D) Z track intramuscular in the gluteal
(D)

8. 7.The permeation of drugs across cellular
membranes is dependent on what drug
properties and (local) circumstances?
• Drug solubility; drug concentration gradient; drug ionization; surface
area; vascularity

9. 8. The nurse prepares IM injection that is irritating to the
subcutaneous tissue. Which of the following is the best action in
order to prevent tracking of the medication:
A) Use a small gauge needle
B) Apply ice on the injection site
C) Administer at a 45° angle
D) Use the Z-track technique
(D)

10. The route of administration (ROA) that is chosen may have a
profound effect upon the speed and efficiency with which the drug
acts.

14. Dr L K Sharma

15. Q…Ion Trapping cont:
Dr L K Sharma
Body fluids where a pH difference from blood pH
will favor trapping or reabsorption: stomach contents
small intestine
breast milk
aqueous humor (eye)
vaginal secretions
prostatic secretions

16. Ion Trapping:
Dr L K Sharma
Kidney:
Nearly all drugs filtered at the glomerulus:
Most drugs in a lipid-soluble form will be absorbed by passive
diffusion.
To increase excretion: change the urinary pH to favor the charged form
of the drug:
Q..Weak acids: excreted faster in alkaline pH (anion form favored)
Q.. Weak bases: excreted faster in acidic pH (cation form favored)

17. Systemic
Enteral Parenteral
• Oral Inhalational
• Sublingual Injections (Intravenous,Intramuscular
Subcutaneous Intraarterial,Intraarticular
Intrathecal ,Intradermal)
• Rectal Transdermal

18. Local
Skin topical
Intranasal
Ocular drops
Mucosal-throat,
vagina, mouth, ear
Inhalational
Transdermal

19. Factors governing choice
of route
1. Characteristics of the drug.
2. Emergency/routine use.
3. Site of action of the drug—local or systemic.
4. Condition of the patient (unconscious, vomiting, diarrhoea).
5. Age of the patient.
6. Effect of gastric pH, digestive enzymes and fi rst-pass metabolism.
7. Patient’s/doctor’s choice (sometimes).

20. Systemic route
Enteral Routes
In this route the drug through Gastrointestinal Tract is absorbed into
the blood.
This route is further classified into three classes:
Oral
Sublingual - placed under the tongue
Rectum - Absorption through the rectum

21. (1) Oral Route:
In this route the drug is placed in the mouth and Swallowed. It is
also called per oral (p.o.)
Advantages of Oral Route
• Convenient - Can be self administered, pain free, easy to take
• Absorption - Takes place along the whole length of the gastro
intestinal tract
• Cheap - Compared to most other parenteral routes

22. Disadvantages of Oral Route
• drug not absorbed in GIT e.g. aminoglycosides
• First-pass effect e.g. lignocaine.
• Irritation to gastric mucosa – nausea and vomiting
• Destruction of drugs by gastric acid and digestive juices.g. insulin
• Effect too slow for emergencies
• Unpleasant taste of some drugs
• Unable to use in unconscious patient

23. First-pass effect
Where ?
Liver
Gut wall
Gut Lumen
Result ?
Low bioavailability.
Short duration of action (t
½)..

25. Examples of drugs which undergo marked First Pass Effect:-
• Imipramine,
• Propranolol,
• Lidocaine

26. The example of dosage forms which are used by oral route include
1. Tablet
2. Capsules
3. Syrups etc

27. 2.Sublingual/Buccal
Some drugs are taken as smaller tablets which are held in the mouth
or under the tongue.
Example : Nitroglycerine tablets
Advantages
rapid absorption
drug stability
avoid first-pass effect
Can be used in emergencies

28. Disadvantages
Inconvenient
Small Doses
Unpleasant taste of some drugs

29. 3.Rectal Route:
given as a suppository.
Rectum's wall is thin with rich blood supply, so drug is readily
absorbed.

30. Vaginal Route
As solution, tablet, cream, gel, suppository, or ring.
 Drug is slowly absorbed through the vaginal wall.
 Used to give estrogen to women at menopause, because the drug
helps prevent thinning of the vaginal wall, an effect of menopause

31. Urethral Route
Drugs are given through the urethra
Advantages of rectal/urethral/vaginal routes:-
1. Unconscious patients and children
2. If patient is having nausea or vomiting

32. Disadvantages rectal/urethral/vaginal routes
1. May cause irritation
2. Absorption may be variable
Examples:-
1. Suppositories
2. Vaginal Bogies
3. Urethral Bogies

33. II Parenteral Routes:-
In this route of administration the drug does not pass through the
gastrointestinal tract. It directly reaches to the blood.

34. It can further be classified into two classes:-
1. With injections:-
eg. Intravascular,
Intramuscular,
Subcutaneous
2. Without injections/Inhalationals: -.
e.g. Inhalations.

37. Direct delivery of drug in to systemic circulation without
intestinal mucosa
Intradermal (I.D.) (into skin)
Subcutaneous (S.C.) (into subcutaneous tissue)
Intramuscular (I.M.) (into skeletal muscle)
Intravenous (I.V.) (into veins)
Intra-arterial (I.A.) (into arteries)
Intrathecal (I.T.) (cerebrospinal fluids )
Intraperitoneal (I.P.) (peritoneal cavity)
Intra - articular (Synovial fluids)

38. Advantages of Parenteral route
high bioavailability
• Rapid action (emergency)
• No first pass metabolism
Disadvantages
 Infection
 Sterilization.
Invasive assistance require
 Pain
 Needs skill
 Anaphylaxis
Expensive

39. Suitable for
–Vomiting &unconsciousness
– Irritant & Bad taste drugs.
– No gastric irritation
– No food-drug interaction
Dosage form:
Vial or ampoule

40. • Ampoule iv infusion Vial

41. 1. Intravascular
Advantages:-
1. Precise, accurate and almost immediate onset of action
2. Large quantities can be given, fairly pain free
3. Can be given to unconscious patients.
4. Quick action
5. Drugs having unpleasant taste can be given.

42. Disadvantages:-
1. Pain at the site of injection.
2. Greater risk of adverse effects
a. High concentration attained rapidly
b. Risk of embolism

43. 2. Intramuscular:-
drug is given into the muscles , absorbs into the blood.
1. Very rapid absorption of drugs in aqueous solution
2. Depot and slow release preparations
3. Pain at injection sites for certain drugs

44. Subcutaneous:-
• Drug is deposited in loose subcutaneous tissue – rich nerve
supply- irritant drugs cannot be given.
• Less vascular- slow absorption than im route
• Avoid in shock pt – vasoconstriction
• Only Small volume can be injected
• minimizes the risks associated with intravascular injection
• Depot preparation can be injected- Dermojet, Pellet
implantation, Sialistic and biodegradable implants.

46. Intradermal Route
Inj into skin raising bleb – BCG Vaccine, Sensitivity test
Intrathecal/intraventricular
It is sometimes necessary to introduce drugs directly into
the cerebrospinal fluid. For example, amphotericin B is used
in treating Cryptococcal meningitis

50. Without injection/Inhalational route

51.  for gases or aerosol drugs
provides the rapid delivery of a drug across the large surface
area of the mucous membranes
almost as rapidly as with IV injection.

52. effective and convenient for patients with respiratory
complaints ( asthma, or COPD) because the drug is delivered
directly to the site of action and systemic side effects are
minimized
Examples : albuterol, corticosteroids, such as fluticasone

53. Advantages of Inhalational
1. Rapid onset of action due to rapid access to circulation.
2. Pain not occurs because injection is not used.
3.Provide local action
4 Minor systemic effect
5. Low bioavailability
6. Less side effects.
7. No first pass effect
Examples:-
1. Inhalers
2. Aerosols

54. Disadvantages
• Only few drugs can be used Nebulizer
Inhaler

55. Local/Topical Route of Drug
Administration in this route the drug is applied on the skin
and mucous membrane for the local action.
• Mucosal membranes (eye drops, antiseptic, sunscreen, callous
removal,nasal, etc.)

56. • Skin
Dermal - Rubbing in of oil or ointment (local action).
Transdermal - Absorption of drug through skin (systemic
action)
i. Stable blood levels
ii. No first pass metabolism
iii. Drug must be potent
Examples
1. Creams
2. Lotions
3. Gels etc

57. Intranasal
• Involves administration of drugs directly into the nose. Agents include
nasal decongestants such as the anti-inflammatory corticosteroid
• Eg: Desmopressin for diabetes insipidus; salmon calcitonin for
osteoporosis
• The abused drug, cocaine, is generally taken by intranasal
sniffing.

58. Onset of action of different routes is as follows:-
• 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
• Oral 30-90 minutes
• Topical/transdermal (topical)
variable (minutes to hours)

59. New Drug delivery system
• Definition :
NDDS Therapeutic systems that incorporate drugs in
a dosage form that releases the medication at
a predetermined site at a predetermined rate over
an extended period of time from a single application

60. Advantages
Delivery of the drug
a) controlled rate
b) slow delivery
c) targeted delivery
2. Longer duration of action
3. ↑ bioavailability
4. ↓ Adverse Effects
5. ↑ compliance

61. Types
1) Prolong release
• Oral preparations
• Parenteral preparation
2) Targeted drug delivery system
3) Local delivery system

62. Prolonged release Oral preparations
Prodrugs
Inactive form of the drug which undergoes biotransformation inside
the body to pharmacologically active drug .
They increase Absorption, distribution and duration of action.

63. ENTERIC COATED TABLETS & CAPSULES
Drug coated with acid resistant substance
1. Prevent gastric irritation
2. Prevent alteration of drug in the stomach
3. To get desired conc. of drug in small intestine
4. Retards rate of absorption and prolongs duration of action

65. Controlled release / extended release / sustained release
PREPARATIONS
Release medication in a predetermined manner over extended period
of time
1. Medicines incorporated in different layers
2. Granules of the drug
3. Medication can be covered with a gel which can swell and act like a
semipermeable membrane

66. Prolonged Release Parenteral preparations
Pumps
 Osmotic pumps
 Portable pumps
 Computerised pumps
Implantable pumps
Pens
Pellets
Transdermal delivery system

67. PUMPS
Deliver drugs at a predetermined rate for a specific period following a
single application.
MECHANICAL PUMPS
Insulin infusion devices: -CSII-Continuous subcutaneous insulin
infusion device
Advantages: • More physiological & better control
• Less variations in absorption

70. Insulin jet Delivers insulin subcutaneously without
using needle. Achieved by pressurizing the liquid
through a small orifice which creates high speed jet
that can penetrate the skin and underlying tissue

72. Dermojet It is a sub-cutaneous needleless injection used for
mass inoculation

73. Pellet implantation
Drug as a solid pellet is implanted
under the skin to provide
uniform systemic effect.
• Eg: testosterone

74. Pens

75. Transdermal
Advantages
• Slow effect (prolonged drug action)
• First pass effect avoided
Site – Upper arm, chest,abdomen, mastoid region

76. • This route is most often used for the sustained delivery
of drugs, such
as the antianginal drug nitroglycerin, the antiemetic
scopolamine.
the nicotine patches.
• Absorption- increase by oily base, occlusive
dressing,rubbing preparation

78. • Transdermal patch
• Scopolamine : Motion sickness Lasts 72hr,
Applied 4hrs before journey
Oral dose - action : 4-6hrs
• Nitroglycerine : Angina – 1d
• Clonidine : Hypertension – 7d
• Nicotine : Smokers - 1 d
• Fentanyl : Pain - 3 d

79. Local controlled delivery systems
OCULAR SYSTEMS
Ocusert: Eg: Pilocarpine ocusert - Treatment of glaucoma Lasts 7 days
Less side effects Dose also ↓

80. VAGINAL & UTERINE SYSTEMS
• Progestasert: Hormone releasing IUCD Release 60µg/d of
progesterone for 1 year
• Dinoprostone vaginal insert: Inserted vaginally Absorbs water swells
and release drug - cervical ripening

81. IONTOPHORESIS Mild electric current applied for the
transport of drug across the skin Eg: Vasopressin,
Dexamethasone

82. • Drug eluting stents:
Stents can be coated with drugs embedded in a surface
polymer

83. Targeted drug delivery systems
• LIPOSOMES Bilayered vesicles made of amphipathic phospholipids E
g: Liposomal Amphotericin B

85. • Monoclonal antibodies • mAbs act directly when
binding to a cancer specific antigen and induce
immunological response to cancer cells

88. Future Opportunities
•Gene Therapy
•Nanoparticles

89. •No single method of drug
administration is ideal for all
drugs in all circumstances

90. Thanks to all Participants in Teaching Learning
Module
PhD Scholar
Dr Deepshika Yadav
Dr Kopal Nimawat
Dr Meenu Saharan
PG Students
Dr Shivankan
Dr Retesh
Dr Jaya Dadhich
Faculty
Dr Monica Jain
Dr Alka Bansal
Dr Uma advani
Dr Charu Jain

91. THANKS