Various routes are used not only for the therapeutic purpose but also for the diagnosis purpose. The various routes can be classified as follows into: Enteral Parenteral Topical The following dosage forms are commonly used for oral route of administration of a drug. Solid oral dosage forms Tablets, Capsules, Powders, Granules Liquid dosage forms Suspensions, Aqueous solutions Both solid and liquid dosage forms can be administered via oral route. Oral route or enteral route of drug administration is the most commonly employed route for drug administration They provide a correct compact dosage, are portable, usually bland to taste and are convenient to market, store and administer Solid oral dosage forms Advantages Available in correct compact dosage Portable Usually bland to taste Convenient to market, store and administer Disadvantages Onset of action is tardy Irritant and unpalatable drugs cannot be administered by oral route Absorption of certain drugs can be irregular or negligible e.g. aminoglycoside. This route may not be useful in presence of vomiting and diarrhea This route cannot be employed in unconscious or uncooperative patients nor in emergency Drugs destroyed by digestive juices cannot be administered orally. E.g. insulin Liquid dosage forms Advantages Easy to administer in children and elderly. Better absorbed and quickly effective. Certain drugs may cause gastric pain when given in the dry form and hence are safer when administered as solution e.g. salts of potassium iodide and bromide. Disadvantages They are less stable. They have unpleasant taste. They are bulky and inconvenient to store and transport. Accidental breakage causes loss of drug. Dose administered may not be accurate, especially when household measures are used. Liquid dosage forms may contain one or more of the following: Vehicle It is used to dissolve or suspend the drugs. Commonly used vehicles are water, syrups and elixirs. An ideal vehicle should have the following properties: Solvent action: A maximum number of substances should be dissolved to an optimum degree. Chemically and pharmacologically inert. Flavoring property: e.g. aromatic waters, rose water, menthol. Sweetening property: e.g. syrup, glycerin. Preservative property: e.g. syrup, chlorobutanol. Should be economical Many of these requirements are fulfilled by water. Hence, it is called an ideal vehicle . Coloring agents They are harmless substances used for lending color to the preparation to make them more acceptable to the patient e.g. amaranth-red, caramel-brown, cochineal-bright red, tartrazinegreen, titanium dioxide-white, indigo carmin-blue. Sweetening agents They are added to mask the bitter or unpleasant taste of the drug and make it more palatable e.g. sugar, saccharin, aspartame, sorbitol, sucrose. Flavoring agents They mask the bad taste of medicines e.g. raspberry syrup, orange syrup.

1. ORAL ROUTE OF
DRUG
ADMINISTRATION

2. Route of administration
• Various routes are used not only for the
therapeutic purpose but also for the
diagnosis purpose.
• The various routes can be classified as
follows into:
Enteral
Parenteral
Topical

3. • The following dosage forms are commonly
used for oral route of administration of a
drug.
Solid oral dosage forms
•Tablets, Capsules, Powders, Granules
Liquid dosage forms
•Suspensions, Aqueous solutions
• Both solid and liquid dosage forms can be
administered via oral route.

4. • Oral route or enteral route of drug administration
is the most commonly employed route for drug
administration
• They provide a correct compact dosage, are
portable, usually bland to taste and are
convenient to market, store and administer.
A. Solid oral dosage forms
 Advantages
• Available in correct compact dosage
• Portable
• Usually bland to taste
• Convenient to market, store and administer

5. Disadvantages
• Onset of action is tardy
• Irritant and unpalatable drugs cannot be
administered by oral route
• Absorption of certain drugs can be irregular or
negligible e.g. aminoglycoside.
• This route may not be useful in presence of
vomiting and diarrhea
• This route cannot be employed in unconscious or
uncooperative patients nor in emergency
• Drugs destroyed by digestive juices cannot be
administered orally. E.g. insulin

6. Solid oral dosage forms

7. Tablets
• These are solid dosage forms containing unit dose of one or
more powdered or granulated drugs that are compressed or
moulded into round or discoid shapes. They are prepared with
or without a diluent.
• Contents of a tablet
In addition to active ingredients, a tablet may contain one or more
of the following substances (excipients):
• Diluent: It is used when the amount of the drug(s) in the tablet
is small.
• Lubricant: It helps keep the tablet from sticking to the
manufacturing machine.
• Disintegrator: It helps the tablet to disintegrate in the GIT.
• Binder: It binds the drug particles together in the tablet form.
• Sweetener, preservative, coloring agent etc.

8. Different types of tablets
i. Compressed tablets
The solid drugs are subjected to great mechanical
pressure and pressed into tablets (e.g.
erythromycin).

9. ii. Coated tablets
The tablets are coated with a film like sugar to enhance
palatability or enteric coated to protect the drug from
effect of gastric secretions or film coated to protect the
drug from effects of atmospheric oxygen or moisture.
Enteric coated tablets are provided with one or more layers
of coating intended to resist the gastric fluid but permit
their disintegration in the intestinal fluid e.g. aspirin.
They should be taken as a whole unbroken form.

10. iii. Scored tablets
These tablets contain break marks or other
markings on their surface so that they can be
easily divided into smaller doses, if required e.g.
septran DS, paracetamol

11. iv. Slow or sustained release (SR), Modified
Release, Controlled Release (CR), Timed
Release tablets
• SR preparations release the drug slowly over a
long period of time.
• Peak plasma concentration of the drug will be
lower, but the action will continue for longer
period of time.
• Hence these preparations require less frequent
drug administration and favour patient
compliance (e.g. isosorbide dinitrate, nifedipine).
• However, they are not useful in emergency,
where a quick onset of drug action is necessary.

12. v. Chewable tablets
• These are large tablets, usually pleasant tasting, that
are meant to be chewed well before swallowing.
They disintegrate poorly in the GIT e.g. antacid
tablets.

13. vi. Effervescent tablets
• These uncoated tablets contain acidic substances,
carbonates or bicarbonates.
• They are dissolved or dispersed in water before
administration.
• They mask bad taste of the drug and may have a
psychological effect on the patient.

14. vii. Dispersible tablets
• These disintegrate rapidly in water and are
intended to be dispersed in water before
administration.
viii. Kid tablets
• These contains pediatric dose of the drug.
• They are easy to administer in children and
ensure accuracy of dosing.
• They are easier to preserve as compared to
syrups e.g. amoxycillin kid tablet.

15. ix. Lozenges or troches
• These are flat, rounded or rectangular
preparations kept in mouth till they dissolve.
• They temporarily produce high concentration of
the drug in the oral cavity and are used to treat
local conditions of the mouth or throat e.g. cough
lozenges like strepsil.
x. Mouth dissolving (MD) Tablets/ orally
• These are designed to dissolve on the tongue
rather than to swallow as a traditional tablet.
• These are alternative dosage form for patients
having dysphagia e.g. levocetrizine MD,
voglibose MD.

16. Capsules
• These are small containers, usually made of gelatin.
• They may be hard or soft.
• They are available in different colors and are usually
bland to taste.
• Powders, oils and liquids can be administered as
capsules.
• They dissolve readily in the GIT and hence make
drug absorption quicker (e.g. cod liver oil capsules,
ampicillin capsules).

17.  Spansules are delayed action capsules prepared by
variably coating drug particles with materials that
permit the gradual release of the drug in the gut.
• Thus long term and uniform medication is provided.
• These allow less frequent administration of the drug
and hence favor patient compliance e.g. Fefol
spansule.
• Capsules and tablets are packed in the plastic-coated
paper or aluminium strips or in blister packing

18. Powders
• Powders are solid dosage form of drugs in a finely
divided form and intimately mixed.
• They are meant for internal use.
• These are easy to dispense, can be weighed
accurately and administered to children with great
ease (with few exceptions).
• Simple powder contains one ingredient while
compound powder may contain more than one
ingredient, granular effervescent powders are also
available.
• They are dispensed in powder papers or if the dose
can be measured, with spoon, in bulk containers.
Nauseating or unpalatable powders can be
dispensed in capsules or caplets.

19. Granules
• These are small aggregates of powder held
together by a binding agent e.g. Vitamin D3
granules.

20.  Advantages of oral route
• Convenient
• Safe
• Economical
• Complications of parenteral route like infection, damage
to surrounding structures can be avoided
 Disadvantages of oral route
• Onset of action is slow
• Irritant and unpalatable drugs cannot be administered
by oral route
• Absorption of certain drugs can be irregular or negligible
e.g. aminoglycoside.
• This route may not be useful in presence of vomiting
and diarrhea
• This route cannot be employed in unconscious or
uncooperative patients nor in emergency
• Drugs likely to be destroyed by digestive juices cannot
be administered orally. E.g. insulin

21. B. Liquid dosage forms
Advantages
• Easy to administer in children and elderly.
• Better absorbed and quickly effective.
• Certain drugs may cause gastric pain when
given in the dry form and hence are safer when
administered as solution e.g. salts of potassium
iodide and bromide.

22.  Disadvantages
• They are less stable.
• They have unpleasant taste.
• They are bulky and inconvenient to store and
transport. Accidental breakage causes loss of drug.
• Dose administered may not be accurate, especially
when household measures are used.

23. Liquid dosage forms may contain one or more of the
following:
1. Vehicle
It is used to dissolve or suspend the drugs. Commonly
used vehicles are water, syrups and elixirs. An ideal
vehicle should have the following properties:
• Solvent action: A maximum number of substances
should be dissolved to an optimum degree.
• Chemically and pharmacologically inert.
• Flavoring property: e.g. aromatic waters, rose water,
menthol.
• Sweetening property: e.g. syrup, glycerin.
• Preservative property: e.g. syrup, chlorobutanol.
• Should be economical
 Many of these requirements are fulfilled by water.
Hence, it is called an ideal vehicle.

24. 2. Coloring agents
They are harmless substances used for lending
color to the preparation to make them more
acceptable to the patient e.g. amaranth-red,
caramel-brown, cochineal-bright red,
tartrazinegreen, titanium dioxide-white, indigo
carmin-blue.
3. Sweetening agents
They are added to mask the bitter or unpleasant
taste of the drug and make it more palatable e.g.
sugar, saccharin, aspartame, sorbitol, sucrose.
4. Flavoring agents
They mask the bad taste of medicines e.g.
raspberry syrup, orange syrup.

25. Liquid oral dosage forms

26. Aqueous solutions
These contain one or more drugs dissolved in water
along with sugar solution, flavoring and coloring
agents:
• Mixture: It is a liquid preparation containing one or
more soluble ingredients meant for internal use e.g.
alkaline mixture.
• Syrup: These are simple, medicated, aromatic or
flavored for making drug more palatable e.g.
chloroquine syrup.
• Linctus: These are viscous liquids containing the
drug with some demulcents like menthol e.g. linctus
codeine.
• Drops: They are for pediatric use, dispensed in
dropper bottles e.g. multivitamin drops, iron drops.
They facilitate accurate dosing in infants.

27. • Elixirs: These are pleasantly flavored solutions of
a drug in sugar syrup along with high proportion of
alcohol e.g. vitamin B-complex elixirs etc.
2. Suspensions
These contain one or more drugs dispersed in water
by means of suspending or emulsifying agents.
The preparation should be shaken well before use.
They are available as:
Emulsions: These are suspension of fats or oils
dispersed in water by means of an emulsifying
agent. They are more palatable and easily
absorbed than the undispersed oils e.g. cod liver
oil emulsion, liquid paraffin emulsion.

28. • Gels: These are colloidal aqueous
suspension of hydrated inorganic
substances e.g. aluminum hydroxide gel
• Magmas: These are bulky suspensions of
poorly soluble substances in water. Since
they are white liquids, they are also known
as milks e.g. milk of magnesia.