Understanding Drug Dosage Forms and Their Applications

What is a Dosage Form?

A dosage form may be defined as a blend of drugs and additives, produced in a definite physical form, size, and shape suitable for administration by a particular route.

Key Properties of Dosage Forms

• Economical
• Provides protection to the drug substance.
• Provides a better therapeutic effect.
• Easy to identify.
• Conceals bitter taste or odor.
• Easy to use and handle.
• Easy to store.
• Stable during use.

Importance and Need for Dosage Forms

The need for dosage forms, or their importance, is outlined below:

1. To protect the drug substance from oxidation, reduction, and hydrolysis (e.g., coated tablets, sealed ampules).
2. To provide a safe and convenient delivery of accurate dosage.
3. To mask the bitter, salty, or obnoxious taste or odor of a drug substance (e.g., capsules, coated tablets, flavored syrups).
4. To provide for optimum drug action through inhalation therapy (e.g., inhalation aerosols).
5. To provide for the insertion of drugs into body cavities (e.g., rectal and vaginal suppositories).
6. To provide maximum drug action from topical administration sites (e.g., creams, ointments, ophthalmic preparations, and ENT preparations).
7. To provide sustained-release action through controlled-release mechanisms (e.g., sustained-release tablets, capsules).
8. To provide liquid dosage forms for drugs soluble in a suitable vehicle (e.g., solutions).
9. To provide liquid preparations for drugs which are insoluble in different vehicles (e.g., suspensions).
10. To provide drugs within body tissues (e.g., injections).

Classification of Dosage Forms

Dosage forms are classified based on physical state, administration route, application site, and use.

By Route of Administration

• Oral: Powders, tablets, capsules, solutions, emulsions, syrups, elixirs, magmas, gels, pills, cachets.
• Parenteral: Solutions, suspensions, emulsions.
• Transdermal: Ointments, creams, powders, pastes, lotions.
• Vaginal: Suppositories, ointments, creams, tablets.
• Urethral: Suppositories.
• Sublingual: Lozenges, tablets.
• Intranasal: Solutions, sprays, inhalations.
• Conjunctival: Ointments.
• Intraocular: Solutions, suspensions, ointments.
• Intrarespiratory: Aerosols.

By Site of Application

• Foot: Foot creams.
• Hair: Oil, gels.
• Nose: Nasal sprays.
• Skin: Ointments, lotions, creams.
• Eye: Drops, creams.
• Tooth: Dentifrices, fillers.

Defining a Drug

A drug may be defined as an agent intended for use in the diagnosis, mitigation, treatment, cure, or prevention of disease in humans or other animals.