This document discusses various routes of drug administration and factors affecting their selection. It describes both enteral and parenteral routes, including oral, sublingual, rectal, intravenous, intramuscular, subcutaneous, inhalation, intranasal, topical, and others. For each route, it outlines advantages and disadvantages related to onset of action, absorption, convenience, cost, and other considerations. The optimal route depends on the drug's properties, desired effects, and patient condition.

1. Presented by-
Miss R. S. Dhole (Assistant Professor)

3. Factors Affecting Choice Of Route
• Physical & chemical properties of drug
• Site of desired action-
a. Local, b. Generalized
• Rate & extent of absorption from various routes
• Effect of digestive juices & first pass metabolism
• Rapidity of the desired response- emergency/routine
• Condition of the patient
• Accuracy of dosage

4. SYSTEMIC
Enteral Parenteral
Oral Inhalational
Sublingual Transdermal
Enema Injections
LOCAL
Skin topical
Intranasal
Inhalational
Transdermal
CLASSIFICATION
Intravenous
Intramuscular
Subcutaneous
Intra-arterial
Intra-articular
Intrathecal
Intradermal
Intraperitoneal

5. ORAL ROUTE
 The most common and oldest route
 Liquid or solid preparations are given
 Drug is given through oral cavity.
ADVANTAGES
 Safe
 More Convenient- self-administered
 Painless
 Economical- compared to other parenteral routes
 Usually good absorption
 No need for sterilization

6. DISADVANTAGES
1. Slow action of drug - can not used in emergency
2. Irritable and unpalatable drugs- Difficult to administer
3. Cannot be used uncooperative, unconscious and vomiting patients
4. Causes- Nausea and vomiting
5. Some drugs destroyed- Digestive juice (Eg- Insulin, streptomycin)
6. First-pass effect (Liver)- Due to Biotransformation (Eg-
Testosterone, Lidocaine)
7. Food–Drug interactions and Drug-Drug interactions

7. Dosage forms
Capsules, powders
Tablets, spansules
Syrup, emulsion
Suspension, elixirs
Tablets
Hard- gelatin capsule
Spansule
Soft- gelatin capsule
Syrup

8. SUBLINGUAL / BUCCAL ROUTE
Advantages
•Drug absorption is quick
•Rapid onset of action
•Quick termination
•First-pass avoided
•Can be self administered
•Overdose can be avoided
Disadvantages
•Unpalatable & bitter drugs
•Irritation of oral mucosa
•Large quantities not given
 Tab or pellet containing the drug - under tongue
 Crushed in mouth and
 Absorbed by- Buccal mucous membrane
 Ex- GTN, Isoprenaline

9. Advantages
Irritant or unpleasant drug can be given
Little or no first pass effect
Used in vomiting or unconscious
patients
Higher concentrations rapidly achieved
Disadvantages
Inconvenient
Absorption is slower, irregular,
unpredictable
Rectal inflammation can occur
RECTAL ROUTE
Administration of liquid or semisolid medicament- Suppositories or
Enema

10. Evacuant Enema Retention Enema
 Used to remove fecal matter
 Max.qty.- 600 ml
 Used before
a. surgical operation
b. Delivery
c. GIT investigation by X ray
• Eg- Soap water enema
 Used to retain drugs in rectum
 Max.qty.- 120 ml
 Used for producing anasthesia
 Eg- Paraldehyde enema
Predinisolone enema

11. PARENTERAL ROUTES
 Par= beyond, enteral= intestinal
 Routes of drug administration other than oral/ alimentary tract
 Administering drug directly into blood or tissue fluid
Ampoule iv infusion Vial

12. 1. Intradermal (I.D.) (into skin)
2. Subcutaneous (S.C.) (into subcutaneous tissue)
3. Intramuscular (I.M.) (into skeletal muscle)
4. Intravenous (I.V.) (into veins)
5. Intra-arterial (I.A.) (into arteries)
6. Intrathecal (I.T.) (cerebrospinal fluids )
7. Intraperitoneal (I.P.) (peritoneal cavity)
8. Intra - articular (Synovial fluids)

13. ADVANTAGES
1. Rapid onset of action
2. Useful in unconscious, unco-operative patients
3. Useful in patient suffering from vomiting, nausea
4. 100% drug absorption
5. No destruction or degradation of drug- Gastric juice
6. No gastric irritation
7. Accurate dosage of drug
8. No first pass metabolism (Liver is bypassed)

14. DISADVANTAGES
1. Costly route
2. Technique is invasive and painful
3. Inconvenient- assistance of other person is needed
4. Self medication is not possible
5. Skilled person- necessary- to avoid injury to nerves, blood vessels
6. Difficult to control or reverse effect of drug- RISKY

15.  Introduced directly into Lumen of Vein
 Drug is injected IV
1. As Bolus- Eg- Furosemide
2. Over 5-10 min- diluted in 10-20 ml of isotonic glucose or saline
3. In an infusion- Eg- NS, DNS
ADVANTAGES
1. Very rapid onset of action- Most effective in Emergency condition
2. Large qty of drug can be administered- Eg- Fluids in dehydration
3. Irritant and hypertonic solutions can be given
4. Required drug concentration in blood- obtained accurately
5. 100 % bioavailability
INTRAVENOUS ROUTE

16. DISADVANTAGES
1. Care should be taken- Inserting needle into vein
2. Drug should not leak out- site of administration
3. Speed of drug entering into vein- Must be controlled and
maintained
4. Chances of causing air embolism is risky
5. Local irritation – Phlebitis
6. Once drug administered- no retreat
7. Side effects are more quicker than any other route

17. ADVANTAGES
Uniform and slow absorption
of drug
Rapid onset of action
Mild irritants can be given
First pass avoided
Gastric factors can be avoided
DISADVANTAGES
Only up to 10ml drug given
Local pain and abscess
Expensive
Nerve damage
INTRAMUSULAR ROUTE
Large skeletal muscle- Deltoid, triceps, laterofemoral, gluteus maximus
Suitable for administration- soluble substances, Mild irritants,
suspensions and colloids
Eg- Sex hormones, Corticosteroids, Penicillin G

18.  Drug injected- loose connective tissue- Subcutaneous tissue under
skin
 Only soluble, non-irritant drugs are injected
 Small vol.of drug injected- up to 2 ml
 Slow absorption of drug as compared to I.V. and I.M. route
 Self injection is possible
 Eg -Insulin, Testosterone, Morphine
SUBCUTANEOUS ROUTE

19. SITES OF
SUBCUTANEOUS
INJECTION
 Gluteal
 Thigh
 Shoulder
 Back…

20. Subcutaneous injections
Drug can be administered subcutaneously as ;
1. Dermojet- Needleless method, drug is injected
by means of high velocity jet produced through
micro fine orifice
2. Pellet implantation- a tablet or porous capsule
is inserted into the loose tissues by incision of
the skin, which is then stiched up.

21. Type of
Injection
Needle Dia. Needle length Needle Angle
Subcutaneous 25 to 30 guaze 3/8 to 5/8 inch 45 to 90
I.M. 18 to 25 guaze 5/8 to 1 ½ inch 90
0
0
0

22. Intradermal Route
Injected into skin raising bleb
Only small qty is injected (1ml)
Used for detecting allergy to drugs
Eg- Penicillin
Vaccines are also administered
Eg- BCG Vaccine, Small pox vaccine,
Local anaesthetic
Intrathecal
Injected into subarachnoid space
Useful for local and rapid effect- Spinal anaesthetics, antibiotics
Eg- Amphotericin B is used in treating Cryptococcal meningitis

24. Rapid delivery of a drug across the large surface area of alveoli
Producing an effect almost as rapidly as with IV injection.
Used for drugs- Volatile liquids and gases
Effective and convenient - patients with respiratory problems
No first pass effect
Eg- Salbutamol,Albuterol
DISADVANTAGE-
Require special apparatus
Irritation of respiratory tract may takes place
INHALATION

25. Nebulizer Atomizer

26. INTRANASAL
 Drug administered directly into the nose.
Digestive juice and liver is bypassed
Eg-
1. Nasal decongestants- anti-inflammatory corticosteroid.
2. Desmopressin - diabetes insipidus
3. Salmon calcitonin - osteoporosis

27. Route for administration
-Time until effect-
Route Time
Intravenous 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 min
Transdermal (topical) Variable (minutes to hours)

28.  External application of drug
 Dusting powders, lotions, paste, ointments, drops, spray
 Site of drug action-
Skin, Eye, Ear, Nose, Rectum, Vagina, Throat
 Simplest route
 Useful - Prolonged effect of drug is required
 Drug absorption- depends on lipid solubility of drug
 Watery solution of drug- absorbed in blood- undesirable
toxic effect
Topical Route

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