DOSAGE FORMS AND ROUTES OF ADMINISTRATION

Introduction to routes of administration: Drug substances are rarely

administered in their natural or pure state. They are usually administered

in combination with one or more nonrnedicinal agents that serve different

and specialized pharmaceutical functions. The selective use of these

nonrnedicinal agents, called as pharmaceutical ingredients

(components /parts), helps, adjuncts (supports), or necessities different

pharmaceutical preparations. The pharmaceutical ingredients are used to

solubilize (dissolve), suspend, thicken (harden), dilute, emulsify, stabilize,

and preserve the pharmaceutical preparations. Some pharmaceutical

ingredients are also used as coloring agents and flavoring agents

(flavoring agents are used to hide or mask the bitter test of drugs). Every

intention to use pharmaceutical ingredients is to improve the quality

(efficacy) and also to make the pharmaceutical preparations attractive for

the consumer (user). The pharmaceutical preparations with particular

characteristics presented (given) to the patients are called as dosage forms.

[Pharmaceutics: The general area of study related with the physical, chemical

and biological factors influencing the formulation, manufacturing, stability and

effectiveness of pharmaceutical dosage forms is called as pharmaceutics].

Importance or need for dosage form: Most of the drugs are highly

biologically active and hence exact dosage (quantity) of every drug is to

be administered. Further, age of patients, condition of patients, general

liking (choice) of patients, site of application etc. are different factors that

made the pharmacists to design (plan to prepare) dosage forms. The

importance or need to prepare dosage forms may be summarized as

follows-

1) To provide safe and convenient administration of drug substance in

accurate dosage (quantity).

2) For protection of drug substances from destructive influence of

atmospheric oxygen and moisture (e.g. coated tablets, sealed

ampules etc.).

3) For protection of drug substances from destructive influence of

gastric acid after oral administration (e.g. enteric coated tablets).

4) To conceal (hide or mask) the bitter, salty, or obnoxious (hateful)

taste or (smell) of a drug substance (e.g. capsules, coated tablets,

flavored syrups etc.).

5) To provide liquid preparations of substances that are insoluble or

unstable in the desired vehicle (medium), (e.g. suspensions).

6) To provide liquid dosage forms of substances that are soluble in the

desired vehicle (medium), (e.g. solutions).

7) To provide extended drug action through controlled release

mechanism (e.g. various controlled release tablets, capsules

andsuspensions).

8) To provide optimal drug action from topical administration sites

(e.g. ointments, creams, ophthalmic (related to eye), ear and nasal

preparations).

9) To provide for the insertion of a drug substance into one of the

body's orifices (opening/ aperture/ outlet) (e.g. rectal or

vaginal suppositories).

10) To provide for the placement of drugs within body tissue

(e.g.injections).

11) To provide optimal drug action through inhalation therapy

[e.g.inhalants (vicks) and inhalation aerosols (used by

asthmatic patients).

Routes of administration: There are different routes of

administration, (i.e. The route by which the drug is placed

(regulated/given or taken).

The list term (name/designation) and the site of routes of

administration of drugs are given as :-

Variety of Dosage Forms: There are different forms into which a drug

may be placed (regulated/given or taken) for convenient and effective

treatment of disease. Drugs can be prepared for administration by very

conceivable (convincing) route and the suitable preparation is formulated

to insure maximum therapeutic (curative) response. These may be

tablets, capsules, solutions, syrups, elixirs, suspensions, gels, powders,

troches or lozenge, ointments, creams, pastes, aerosol, lotions, sprays,

inhalants, emulsions and suppositories. The preferred dosage forms in

different routes of administration is listed as:-

S. No.

Term Site

S. No. Term Site

1) Oral Mouth

2) Per-oral Gastro intestinal tract (via mouth)

3) Sublingual Under the tongue

4) Parenteral Other than gastro intestinal tract (by injection)

4) a) Intramuscular Muscle4) b) Intravenous Vein

4) c) Intraarterial Artery

4) d) Intracardiac Heart

4) e) Intra synovial Joint-fluid area

4) f) Intraatrticular Joints

4) g) Intracutaneous or intradermal

Skin

4) h) Subcutaneous Beneath the skin

5) Epicutaneous (topical)

Skin surface

6) Conjunctival Conjunctiva

7) Intraocular Eye8) Intranasal Nose

9) Aural Ear

10) Intrarespiratory Lung

11) Rectal Rectum

12) Vaginal Vagina

13) Urethra! Urethra

1) Oral

TabletsCapsulesSolutionsSyrupsElixersSuspensionsGelsPowders

2) SublingualTabletsTroches or Lozenge

3) ParenteralSolutionsandSuspensions

4) Epicutaneous (topical)

SolutionsSuspensionsGelsPowdersOintmentsCreamsPastesAerosolLotionsSprays

5)Conjunctival

Ointments andSolutions

6)Intraocular/Intraaural Solutions and

Suspensions

7) Intranasal

SolutionsOintmentsAerosolSprays Inhalents

8) Intrarespiratory Aerosol

9) RectalSolutions,Ointments and Suppositories

10)

Vaginal TabletsSolutionsOintments Emulsions andSuppositories

11) Urethra! Solutions andSuppositories

Advantages and Disadvantages of oral rout of administration: Drugs are usually

taken by oral route of administration. The Advantages and disadvantage

of oral route of administration are discussed below

Advantages of oral route of administration:

1) It is most natural route of administration.

2) It is most easy route for administration of drug for patients.

3) It is safest route of administration.

4) It is most convenient for patients.

5) This route can take large variety of dosage forms.

6) Nursing for administration is not required.

7) An allergic reaction of the drug (toxicity) is delayed and hence safe.

8) It is economical to the patients.

Disadvantages of oral route of administration:

1) The onset of action of drug is late and hence recovery is not fast.

Therefore oral route of administration not preferred in emergency.

2) As it is absorbed from gastrointestinal tract the quantity of doses of

drug required is more.

3) It is difficult route of administration of drug for non-

cooperative patients like babies and children.

4) It is also difficult route of administration of drug for unconscious

patients.

5) The absorption of drug from gastrointestinal tract is not assured by

patients suffering from gastrointestinal disorder.

6) Oral route of administration may cause gastrointestinal disorders

like acidity, loss of appetite, etc.

7) The uncertainty of maintenance of the prescribed dosage of

drug is possible in oral route of administration.

8) Drug may be destroyed or inactivated by the

enzyme in gastrointestinal tract.

Advantages and Disadvantages of parenteral rout of administration: Taken by

parenteral route of administration, The Advantages and Disadvantages

of parenteral rout of administration are discussed below-

Advantages of parenteral route of administration:

1) The onset of action of drug is fast and hence recovery is fast.

Therefore parenteral route of administration preferred in

emergency.

2) As it is administered directly on the site or nearer to the site, the

quantity of doses of drug required is less.

3) It is easy route of administration of drug for those patients like

babies and children who normally resist to oral route of

administration.

4) It is the only possible route of administration of drug for unconscious

patients.

5) The absorption of drug from gastrointestinal tract is not assured by

patients suffering from gastrointestinal disorder and hence

parenteral route of administration is preferred.

6) Parenteral route of administration is preferred for those suffering

from gastrointestinal disorders like acidity, loss of appetite, etc.

7) The certainty of maintenance of the prescribed dosage of drug is

possible in parenteral! route of administration.

8) There is no chance of drug getting destroyed or inactivated as

by the enzyme in gastrointestinal tract.

Disadvantages of parenteral route of administration:

1) It is not natural route of administration.

2) It is riot easy route for administration of drug for patients and self-

administration is not possible.

3) It is painful route of administration.

4) Preparation of dosage form for parenteral route of administration

requires highly sophisticated instrumentation and condition.

5) The verity of dosage form by which the drugs, an be taken by this

route is restricted and are in liquids, solutions and suspensions

form.

6) Nursing for administration is required.

7) An allergic reaction of the drug (toxicity) is fast and hence is not

safe.

8) It is not economical to the patients.