Know About Your Drug ,,, Part - II ( Route of Drug Administration) for study purpose pharmaceutical professional such as students and other specialized field. Presentation for "LEARN & EARN KNOWLEDGE" based. Thanks all of you for your support...Part-I success and your comments.

1. KNOW ABOUT YOUR DRUGS
PART - II
PRESENTED BY
SANI SINGH
M. PHARM (PHARMACEUTICS)
Route of Drug
Administration

2.  Drugs can be administered by different routes for their suitability, efficacy,
rapid action, and patient condition. When making decision on the route of
administration, two major factors come to mind: therapeutic concerns and
drug properties.
 Therapeutic Concerns include questions relating to the desired onset rate
and duration of drug action, where the drug target site is (readily accessible or
not) and whether or not patient compliance is an issue.
 Drug Properties to be taken into account include its physicochemical
characteristics (e.g., lipid solubility, molecular size, ionization status) and
plasma concentration-time profile.
Selection of Route for Administration

3. Factors
Characteristics of
the drug
Emergency/routine
use
Effect of gastric
pH, digestive
enzymes and first-
pass metabolism
Age of patient
Site of action of the
drug (local or
systemic)
Condition of the
patient (unconscious,
vomiting, diarrhea).
Factors Consider for Route of Administration

4. Condition of Patient (Acute or Chronic)
 In an acute or emergency situation, the route used must allow sufficiently fast
absorption to ensure a prompt onset of action.
Route of Choice in
Acute Condition
Parenteral Injection
(I.V., I.M., S.C.)
Intrathecal route
(for amphotericin B
in cryptococcal
meningitis)
Inhalation Route (for
bronchodilators [by
nebulizer] in acute
bronchial asthma attack)
Sublingual Route (for
nitroglycerin in acute
angina attack)
 With young children, the rectal route (as enema or suppository) may also be used,
especially when the patient is unconscious or when vomiting occurs.

5.  For the treatment of chronic illnesses, the onset rate is not so much of a concern,
whereas a more convenient route (e.g., oral, transdermal or topical) and simple
dosing regimen (e.g., once-daily or once weekly dosing) would ensure better patient
compliance.
 Formulation that can provide controlled release of the drug would be an added
advantage especially in situation of poor patient compliance (e.g., severe
depression). That is notwithstanding the need to take into account the cost factor.
Route of Choice in
Chronic Condition
Oral Route
Topical RouteTransdermal Route

6. Different Route of Administration
Route for
administration
Time until effect
Intravenous 30-60 seconds
Intraosseous 30-60 seconds
Intramuscular 10-20 minutes
Endotracheal 2-3 minutes
Subcutaneous 15-30 minutes
Inhalation 2-3 minutes
Sublingual 3-5 minutes
Transdermal
(topical)
Variable (minutes to
hours)
Rectal 5-30 minutes
Ingestion 30-90 minutes

7. Routes of Administration
Local Systemic
• Intra-arterial route
• Deeper Tissues
• Topical
EnteralParenteral
• Oral
• Sublingual/Buccal
• RectalInjections
• Intradermal
• Subcutaneous
• Intramuscular
• Intravenous
• Intraperitoneal
• Intramedullary
TransdermalInhalation

8. Local Routes
 It is the simplest mode of administration of a drug at the site where the desired action
is required. Systemic side effects are minimal.
1. Intra-arterial route
• This route is rarely employed. It is mainly used during diagnostic studies
such as coronary angiography and for the administration of some anticancer
drugs, e.g. for treatment of malignancy involving limbs.

9. Intra-articular
Injection
Intrathecal
Injection
Retrobulbar
Injection
2. Administration of the Drug into Deep Tissues
 Deep areas can be approached by using a syringe and needle, but the drug should be
such that systemic absorption is slow.
 Intra-articular injection - Drug is injected into the subarachnoid space (spinal
anaesthetics, e.g. lignocaine; antibiotics, e.g. amphotericin B, etc.).
 Intrathecal Injection - Drug is injected directly into the joint space, e.g. hydrocortisone
injection for rheumatoid arthritis. Strict aseptic precautions should be taken. Repeated
administration may cause damage to the articular cartilage.

10. 3. Topical
• Suspension (Nystatin)
• Troche (Clotrimazole - for oral candidiasis)
• Cream (Acyclovir - for herpes labialis)
• Ointment and Jelly (5% Lignocaine hydrochloride - for topical anaesthesia)
• Spray (10% Lignocaine hydrochloride - for topical anaesthesia)
Oral Cavity
• Tablet that is not absorbed (neomycin – for sterilization of gut before surgery)
GI Tract
• An enema (administration of drug into the rectum in liquid form) e.g. soap water
• Suppository (administration of the drug in a solid form into the rectum) e.g.
bisacodyl
Rectal and Anal
• Drops, ointments and sprays (for infection, allergic conditions, etc.) e.g.
gentamicin eye/ear drops.
Eye, Ear and
Nose
• Inhalation, e.g. salbutamol, ipratropium bromide, etc. (for bronchial asthma and
chronic obstructive pulmonary disease).Bronchi
• Ointment, cream, lotion or powder, e.g. clotrimazole (antifungal) for cutaneous
candidiasis.Skin

11. Systemic Routes
 Drugs administered by this route enter blood and produce systemic
effects.
 Medication, nutrition or other substances into the circulatory system so
that the entire body is affected.
 It classify 2 broad categories like Enteral (oral, sublingual, and rectal)
and Parenteral (inhalation, injection, transdermal) routes.

12. 1. Oral Route
 It is the most common and acceptable route for drug administration. Dosage forms are
tablet, capsule, syrup, mixture, etc., e.g., paracetamol tablet for fever, omeprazole
capsule for peptic ulcer are given orally.
Advantages
Shafer Cheaper Painless
Convenient for repeated
and prolonged use
Can be self-
administered
Disadvantages
Not suitable for emergency
as onset of action of orally
administered drugs is slow
It is not suitable for/in:
Unpalatable and highly irritant drugs
Unabsorbable drugs (e.g. aminoglycosides)
Drugs that are destroyed by digestive juices
(e.g. insulin)
Drugs with extensive first-pass metabolism
(e.g. lignocaine)
Unconscious patients
Uncooperative and unreliable patients
Patients with severe vomiting and diarrhoea

13. 2. Sublingual/Buccal Route
 The preparation is kept under the tongue. The drug is absorbed through the buccal
mucous membrane and enters the systemic circulation directly, e.g. nitroglycerin for
acute anginal attack and buprenorphine for myocardial infarction.
Advantages
Quick onset of action.
Action can be terminated by spitting
out the tablet.
Bypasses first-pass metabolism
Self-administration is possible.
Disadvantages
It is not suitable for:
Irritant and lipid-insoluble drugs.
Drugs with bad smell and taste.

14. 3. Rectal Route
 Drugs can be given in the form of solid or liquid.
a. Suppository: It can be used for local (topical) effect as well as systemic effect, e.g.
indomethacin for rheumatoid arthritis.
b. Enema: Retention enema can be used for local effect as well as systemic effect. The
drug is absorbed through rectal mucous membrane and produces systemic effect, e.g.
diazepam for status epilepticus in children.
• Useful in the patient ishaving recurrent vomiting or
unconscious stage.
• Potential of long term drug absorption with various
intrauterinedevices (IUDs).
• Some irritant and unpleasant drugs can be introduced
into rectum as suppositories.
Advantages
• This is rather inconvenient and embarrassing.
• Absorption is slower, irregular and unpredictable.
• Bleeding problems such as discomfort to real pathologies.
Disadvantages

15. Parenteral Routes
 Routes of administration other than enteral route are called parenteral routes.
• Onset of action of drugs is faster; hence it is
suitable for emergency.
• Useful in: Unconscious, Uncooperative and
unreliable patients.
• It is suitable for: Irritant drugs, Drugs with high
first-pass metabolism, Drugs not absorbed orally,
Drugs destroyed by digestive juices.
Advantages
• Preparations should be sterile and is expensive.
• Requires invasive techniques that are painful.
• Cannot be usually self-administered.
• Can cause local tissue injury to nerves, vessels etc.
• Require aseptic conditions.
Disadvantages

16. 1. Inhalation
Drugs which are gaseous (e.g., nitrous oxide) or readily vaporized (e.g., isoflurane) may
be inhaled.
 Solid drugs may also be given by inhalation route in the form of aerosols or suspended
powder (e.g., salbutamol and beclomethasone). The inhalation route may be used for
producing both local (e.g., bronchodilatation in asthma) as well as systemic effects
(anesthesia).
Advantages
• Quick onset of action.
• Dose required is very
less, so systemic
toxicity is minimized.
• Amount of drug
administered can be
regulated.
Disadvantages
• Local irritation may
cause increased
respiratory secretions
and bronchospasm.
Advancements
Nebulizer
Metered Dose
Inhaler (MDI)
Powder
Inhaler
(DPI)

17. 2. Injections
Injectable Routes of Drug Administration

18.  The drug is injected into the layers of the skin, e.g. Bacillus Calmette–Guerin (BCG)
vaccination and drug sensitivity tests. It is painful and only a small amount of the drug
can be administered.
 Intradermal injectionalso known as the mantoux method.
Purpose : Injects medication below the epidermis drugs are absorbed slowly. Typically
used for diagnosis of tuberculosis and allergens.
a. Intradermal Route
Methods of
Intradermal
Injections
Normal Size
Needle
Shorter
Needle
Without
Needle

19. b. Subcutaneous Route (s.c.)
 The drug is injected into the subcutaneous tissues of the thigh, abdomen and arm,
e.g. adrenaline, insulin, etc.
 Only small amount can be injected S.C self injection is possible because deep
penetration in not needed
Advantages
• Self-administration is possible
(e.g. insulin).
• Depot preparations can be
inserted into the subcutaneous
tissue, e.g. norplant for
contraception.
Disadvantages
• It is suitable only for nonirritant
drugs.
• Drug absorption is slow; hence it
is not suitable for emergency.

20. Advancement in Subcutaneous Route
Dermojet
• A high velocity jet of drug solution is projected from a microfine orifice
using a gun like implement.
• The solution passes through the superficial layers and gets deposited in the
subcutaneous tissue.
Pellet implantation
• The drug in the form of a solid pellet is introduced with a trochar and
cannula.
• This provides sustained release of the drug over weeks and months e.g.
DOCA, testosterone.
Sialistic (nonbiodegradable) and biodegradable implants
• Crystalline drug is packed in tubes or capsules made of suitable materials
and implanted under the skin.
• Slow and uniform leaching of the drug occurs over months providing
constant blood levels.
• The nonbiodegradable implant has to be removed later on but not the
biodegradable one.
• Examples - for hormones and contraceptives (e.g. NoRPLANT).

21. c. Intramuscular Route (I.M.)
 Drugs are injected into large muscles such as deltoid,
gluteus maximus and vastus lateralis, e.g. paracetamol,
diclofenac, etc.
 A volume of 5–10 mL can be given at a time.
Advantages
Disadvantages
• Absorption is more rapid as
compared to oral route.
• Mild irritants, depot injections,
soluble substances and suspensions
can be given by this route.
• Aseptic conditions are needed.
• Intramuscular injections are painful
and may cause abscess.
• Self-administration is not possible.
• There may be injury to the nerves.

22. d. Intravenous Route (i.v.)
 Injection into a peripheral vein over 1 to 2 minutes (bolus) or longer as an infusion.
 Drugs are injected directly into the blood stream through a vein. Drugs are
administered as:
1. Bolus: Single, relatively large dose of a drug injected rapidly or slowly as a single unit
into a vein. For example, i.v. ranitidine in bleeding peptic ulcer.
2. Intravenous infusion: For example, dopamine infusion in cardiogenic shock;
mannitol infusion in cerebral oedema; fluids infused intravenously in dehydration.
3. Slow intravenous injection: For example, i.v. morphine in myocardial infarction.

23. Advantages
• Bioavailability is 100%.
• Quick onset of action; therefore, it is the
route of choice in emergency.
• Large volume of fluid can be
administered, e.g. intravenous fluids in
patients with severe dehydration.
• Highly irritant drugs, e.g. anticancer
drugs can be given because they get
diluted in blood.
• Hypertonic solution can be infused by
intravenous route, e.g. 20% mannitol in
cerebral oedema.
Disadvantages
• Local irritation may cause phlebitis.
• Self-medication is not possible.
• Once the drug is injected, its action
cannot be halted.
• Strict aseptic conditions are needed.
• Extravasation of some drugs can cause
injury, necrosis and sloughing of
tissues.
• Depot preparations cannot be given by
i.v. route.
Precautions - Drug injected slowly and before injecting, make sure that the tip of the
needle is in the vein.

24. 3. Transdermal Route
 The drug is administered in the form of a patch or ointment that delivers the drug into
the circulation for systemic effect .
 For example, scopolamine patch for sialorrhoea and motion sickness, nitroglycerin
patch/ointment for angina, oestrogen patch for hormone replacement therapy (HRT).

25. Advantages
• Self-administration is possible
• Prolonged duration of action
• Minimize systemic side effects
• Provide a constant plasma
concentration of the drug
• Patient compliance is better
Disadvantages
• Expensive
• Local irritation may cause
itching and dermatitis
• Patch may fall-off unnoticed
• Drug must be lipophilic in
nature

26. Absorption Pattern, Advantages and Disadvantages of the Most
Common Routes of Administration
Route of
Administration
Absorption Pattern Advantages Disadvantages
Oral Variable; affected by
many factors
• Safest, economic and most
common route
• Food may affect
absorption
• Drug may be
metabolized before
systemic absorption
Intravenous Absorption not required • Suitable for irritating
substances and complex
mixtures
• Dosage titration
permissible
• Ideal for high molecular
weight proteins and peptide
drugs
• Unsuitable for oily
substances
• Bolus injection may
result in adverse effects
• Strict aseptic
techniques needed
Subcutaneous • Depends on drug
diluents:
Aqueous solution:
prompt
Depot preparations:
slow and sustained
• Suitable for slow-release
drugs
• Ideal for some poorly
soluble suspensions
• Pain or necrosis if
drug is irritating
• Unsuitable for drugs
administered in large
volumes

27. Route of
Administration
Absorption Pattern Advantages Disadvantages
Intramuscular • Depends on drug
diluents:
Aqueous solution:
prompt
Depot preparations:
slow and sustained
• Suitable for oily vehicles
and certain irritating
substances
• Preferable to intravenous
if patient must self administer
• Affects certain lab
tests (creatine kinase)
• Can cause
intramuscular
hemorrhage
(precluded during
anticoagulation
therapy)
Transdermal
(Patch)
Slow and sustained • Ideal for drugs that are
lipophilic and have poor oral
bioavailability
• Ideal for drugs that are
quickly eliminated from the
body
• May cause delayed
delivery of drug
to pharmacological site
of action
• Limited to drugs
that can be taken in
small daily doses
Rectal Erratic and variable • Bypasses destruction by
stomach acid
• Ideal if drug causes
vomiting
• Ideal in patients who are
vomiting, or comatose
• Drugs may irritate the
rectal mucosa
• Not a well-accepted
route

28. Route of
Administration
Absorption Pattern Advantages Disadvantages
Inhalation Systemic absorption
may occur; this is not
always desirable
• Ideal for gases
• Effective for patients with
respiratory problems
• Localized effect to target
lungs: lower doses used
compared to that with oral
or parenteral administration
• Most addictive
route (drug can enter
the brain quickly)
• Patient may have
difficulty regulating
dose
Sublingual Depends on the drug:
Few drugs (example,
nitroglycerin) have
rapid, direct
systemic absorption
Most drugs erratically
or incompletely
absorbed
• Bypasses destruction by
stomach acid
• Drug stability
maintained because the pH
of saliva relatively neutral
• May cause immediate
pharmacological
effects
• Limited to drugs that
can be taken in small
doses
• May lose part of the
drug dose if
swallowed

29. Route of
Administration
Dosage Form
Oral Solution, Syrups. Suspensions, Emulsions, Gels, Powders,
Granules, Capsules, Tablets
Parenteral Injections (solutions, suspensions, Emusions forms)
implants, irrigation & dialysis solutions
Topical Ointment, Creams, Pastes, Lotions, Gels, Topical Aerosols,
Transdermal patches
Rectal Suppositories, Ointments, Creams, Powders, Solutions
Respiratory Aerosol (solustions suspensions, emulsions, powders
forms) inhalations, sprays, gases
Nasal Solutions, inhalations
Ear Solutions, Suspensions, ointments, creams
Eye Solutions, ointments, creams

30. • For a drug to be clinically useful, it must also have an appropriate
pharmacokinetic profile besides having the desired pharmacodynamic action.
• The choice of the route of drug administration depends mainly on two major
factors: therapeutic concerns and drug properties.
• Parenteral injection routes are often the routes of choice in acute care while oral
route is the most common route used in chronic illnesses.
• The physical and chemical properties of a drug can influence both the dosage
form as well as the route(s) by which it may be administered.
Key Concepts

31. References
 Physical Pharmacy: Physical Chemical Principles in the Pharmaceutical Sciences, 4th
edn. (1993) Martin A.N. and Bustamanta, P. Lea and Febiger, Philadelphia.
 Physicochemical Principles of Pharmacy, 3rd edn. (1998) Florence, A.T. and Attwood,
D., Macmillan, Basingstoke.
 Martindale, W. (1999) The Extra Pharmacopoeia, Royal Pharmaceutical Society of
Great Britain, London.
 Modern Pharmaceutics, 3rd edn. (1999), Eds Banker, G.S., Rhodes, C.T., Marcel
Dekker.
 Lachman, L., Liebermann, H.A. & Konig, J.L. 1986. The theory and practice of
industrial pharmacy, 3rd ed., Chapter 5 to 21.
 Y.K. Chan et al. (eds.), Pharmacological Basis of Acute Care, Springer International
Publishing Switzerland 2015 , DOI 10.1007/978-3-319-10386-0_2 OR
http://www.springer.com/978-3-319-10385-3
 www.wikipedia.com. Assessed on February 2019.
 For detail study refer reference books and journal mention in reference.

32. Thanks You