This document defines dosage forms and discusses various routes of drug administration. It provides details on: 1) The need for dosage forms such as accurate dosing, protection, taste masking, and controlled release. 2) Classification of dosage forms by route of administration (oral, topical, rectal, parenteral), physical form (solid, semisolid, liquid, gaseous) and type. 3) Advantages and disadvantages of different routes including oral, sublingual, buccal, rectal, parenteral, topical and others. Time of onset of effect for different routes is also compared.

2. Definition: Dosage forms are the means by which drug
molecules are delivered to sites of action within the body.
The need for dosage forms:
1 Accurate dose.
2 Protection e.g. coated tablets, sealed ampules.
3 Protection from gastric juice.
4 Masking taste and odour.
5- Controlled release medication.
6- Optimal drug action.
7- Insertion of drugs into body cavities (rectal, vaginal)
Dosage Forms

3. Medicine
API (Active
Pharmaceutical
Ingredients)
Excipients
3
Pabitra

4. They are classified according to:
Route of administration
I) Oral
II) Topical
III) Rectal
IV) Parenteral
V) Vaginal
VI) Inhaled
VII) Ophthalmic
VIII) Otic
Physical form
I) Solid
II) Semisolid
III) liquid
IV) Gaseous
Types of dosage
forms:
4
Pabitra

5. ROUTE OF DRUG
ADMINISTRATION
ENTERAL PARENTERAL TOPICAL

6. ENTERAL
ORAL
RECTAL
BUCCAL
SUBLINGUAL

7. 1. ORAL ROUTE
 Oral refers to
two methods of administration:
applying topically to the mouth
swallowing for absorption along the gastrointestinal
(GI) tract into systemic circulation
 po (from the Latin per os) is the abbreviation used
to indicate oral route of medication administration

8. 1. ORAL Route
 Advantages
Convenient - can be self- administered, pain free, easy to
take, portable, multi-dose bottles
Absorption - takes place along the whole length ofthe GI tract
Cheap - compared to most other parenteral routes as
sterilization of drug products is not essential

9. 1. ORAL ROUTE
 Disadvantages
Sometimes inefficient - only part of the drug may be
absorbed
First-pass effect - drugs absorbed orally are
initially transported to the liver via the portal
vein
irritation to gastric mucosa - nausea and vomiting .
Polar drugs can't be given as they are not absorbed
(eg: Streptomycin)

10. 1. ORAL ROUTE
 Disadvantages cont.
destruction of drugs by gastric acid and
digestive juices (Eg: Penicillin-G, Insulin,
Oxytocin)
effect too slow for emergencies
unpleasant taste of some drugs
unable to use in unconscious patient,
Uncooperative patient
Drug can’t be given during emesis

11. Disadvantages-Oral Route
Food - Food and G-I motility can effect drug absorption. Often
patient instructions include a direction to take with food or
take on an empty stomach.
Absorption is slower with food for tetracyclines and
penicillins, etc. However, for propranolol bioavailability is
higher after food, and for griseofulvin absorption is higher
after a fatty meal.

12. 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

13. First-pass Effect

14. Oral Dosage Forms
 Common dose forms for oral administration
tablets
capsules
liquids
solutions
suspensions
syrups
elixirs

15. 2. SUBLINGUAL ROUTE
 Sublingual administration is
where the dosage form is placed
under the tongue
rapidly absorbed by
sublingual mucosa
Nitroglycerin, as a softer sublingual tablet [2 min disintegration
time], may be used for the rapid relief of angina.
This ROA is also used for some steroids such as testosterone and
oxytocin. Nicotine containing chewing gum may be used for
cigarette smoking replacement.

16. 2. SUBLINGUAL ROUTE
ADVANTAGES
 ECONOMICAL
 Quick onset of action because of rapid
absorption due to more blood supply in
that region
 FIRST-PASSAVOIDED
 Drug stability - pH in mouth relatively
neutral (cf. stomach - acidic). Thus a drug
may be more stable
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17. DISADVANTAGES
 Distasteful, irritant drugs can't be given, Drug taste may
need to be masked
 Holding the dose in the mouth is inconvenient. If any part of
the dose is swallowed that portion must be treated as an
oral dose and subject to first pass metabolism.
 LARGE QUANTITIES CANNOT BE GIVEN. Usually
more suitable for drugs with small doses.
 FEW DRUGS AREABSORBED

18. 2. SUBLINGUAL eg.
Examples
Isosorbide dinitrate tablets & Nitroglycerin tablets
(for Angina), Isopranline sulfate tablets (for
Bronchial Asthma), Nifedipine in powder form (in
Hypertension)

19. 3. BUCCAL ROUTE
 Buccal
administration is
where the dosage
form is placed
between gums and
inner lining of the
cheek (buccal
pouch)
absorbed by
buccal mucosa

20. 2. BUCCAL ROUTE
ADVANTAGES
– Avoid first pass effect
– Rapid absorption
– Drug stability
DISADVANTAGES
– Inconvenience
– advantages lost if
swallowed
– Small dose limit

21. 3. RECTAL ROUTE
ADVANTAGES
DISADVANTAGES
Useful for Children
Little or no first pass effect. Some (but not all) of the veins
draining the rectum lead directly to the general circulation thus
bypassing the liver. Therefore there may be a reduced first-pass
effect.
Useful for vomiting or unconscious patient, gastric irritant drugs
 INCONVENIENT
 ABSORPTION IS SLOW AND ERRATIC
 IRRITATION OR INFLAMMATION OF RECTAL MUCOSA CAN OCCUR
 INCONVENIENT AND EMBARRASSING TO THE PATIENT
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22. Examples
Dulcolax & Glycerine suppositories, enemas,
ointments for Local action
Aminophylline (Bronchodillator) &
Indomethacin (Anti-inflammatory agent)
Suppositories for Systemic action

23. SYSTEMIC-PARENTERAL
 Parenteral administration is
injection or infusion by means of
a needle or catheter inserted into
the body
 The term parenteral comes from
Greek words
para, meaning outside
enteron, meaning the intestine
 This route of administration
bypasses the alimentary canal

24. SYSTEMIC-PARENTERAL
17
I.
III.
 INJECTABLES
INTRAVENOUS
II. INTRAMUSCULAR
SUBCUTANEOUS
IV. INTRA-ARTERIAL
V. INTRA-ARTICULAR
VI. INTRATHECAL
VII. INTRADERMAL
 INHALATION - Absorption through the lungs

25. INTRAVENOUS
ADVANTAGES
 BIOAVAILABILITY 100%
 DESIRED BLOOD
CONCENTRATIONSACHIEVED
 LARGE QUANTITIES
 VOMITING & DIARRHEA
 EMERGENCY SITUATIONS
 FIRST PASSAVOIDED
 GASTRIC MANUPALATION
AVOIDED
Valuable in emergency
Can be given evening unconscious,
uncooperative patients those are
having nausea, vomiting & diarrhea
DISADVANTAGES
 IRRITATION & CELLULITIS
 THROMBOPHELEBITIS
 REPEATED INJECTIONS NOT
ALWAYS FEASIBLE
 LESS SAFE
 TECHNICALASSISTANCE
REQUIRED
 DANGER OF INFECTION
 EXPENSIVE
 LESS CONVENIENTAND
PAINFUL
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26. INTRAMUSULAR ROUTE
ADVANTAGES
 ABSORPTION
REASONABLY UNIFORM
 RAPID ONSET OF
ACTION
 MILD IRRITANTS CAN BE
GIVEN
 FIRST PASSAVOIDED
 GASTRIC FACTORS CAN
BEAVOIDED
DISADVANTAGES
 ONLY UPTO 10MLDRUG
GIVEN
 LOCAL PAIN ANDABCESS
 EXPENSIVE
 INFECTION
 NERVE DAMAGE
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27. SUBCUTANEOUS
 Injected under the skin.
 Absorption is slow, so action is prolonged.
IMPLANT :a tablet or porous capsule is inserted into
the loose tissues by incision of the skin, which is
then stiched up.
example : certain hormonal drugs

28. INTRA-ARTERIAL
 Rarely used
 Anticancer drugs are given for localized effects
 Drugs used for diagnosis of peripheral vascular
diseases

29. INTRA-ARTICULAR
 injections of antibiotics
and corticosteroids are
administered in
inflammed joined
cavities by experts.
example: hydrocortisone
in rheumatoid arthritis

30. INTRADERMAL
 drug is given within skin layers
(dermis)
 Painful
 Mainly used for testing sensitivity
to drugs.
e.g. penicillin, ATS (anti tetanus
serum)
INOCULATION :administration of
vaccine (like small pox vaccine )

31. Topical Routes of Administration
 Topical administration is the application of a drug
directly to the surface of the skin
 Includes administration of drugs to any mucous
membrane
– vagina
– urethra
– colon
eye
nose
ears
lungs

32. Topical Dosage Forms
Dose forms for topical administration include:
 Skin:
creams
ointments
lotions
gels
transdermal patches
disks
• Eye or ear:
– solutions
– suspensions
– ointments
• Nose and lungs:
– sprays and powders

33. Advantages and Disadvantages of the
Topical Route
 Local therapeutic effects
 Not well absorbed into the deeper layers of the
skin or mucous membrane
lower risk of side effects
 Transdermal route offers steady level of drug in
the system
sprays for inhalation through the
nose may be for local or systemic
effects

34. Transdermal
absorption of drug through skin (systemic action)
i. stable blood levels
ii. no first pass metabolism
iii. drug must be potent or patch
becomes too large

35.  intravenous
 intraosseous
 endotracheal
 inhalation
 sublingual
 intramuscular
 subcutaneous
 rectal
 ingestion
 transdermal (topical)
30-60 seconds
30-60 seconds
2-3 minutes
2-3 minutes
3-5 minutes
10-20 minutes
15-30 minutes
5-30 minutes
30-90 minutes
variable (minutes to hours)
Route for administration
-Time until effect-

36. SELECTION OF ROUTE
The ROA is determined by :
 the physical characteristics of the drug
 the speed which the drug is absorbed and/
or released
 the need to bypass hepatic metabolism
 to achieve high conc. at particular sites
 Accuracy of dosage
 Condition of the patient