Dosage forms are the means by which the drug molecules are delivered to the site of action within the body to produce the desired effects with the minimum adverse effects. The dosage consists of both APIs and excipients.

Need for Dosage Forms:

1. To provide safe and convenient delivery of an accurate dose, for example, tablets, capsules, and syrups

2. To protect the drug substance from atmospheric oxygen or moisture, for example. Coated capsules and sealed ampoules

3. Protection of the drug substance from gastric acid after oral administration, for example, with enteric-coated tablets.

4. Conceal a drug substance’s bitter taste or odour, for example, in capsules or flavouring syrups.

5. Provide the optional drug action at topical administration sites, for example, ointments, creams, ear, and nasal preparations.

6. Provide the optimal drug action through inhalation therapy, for example, with inhalants.

Classification of Dosage Form:

A.  Based on the route of administration:

◾ Oral: tablets, capsules, syrups, suspensions

◾ Parenteral: intravenous, intramuscular, intradermal, intracardiac, intraperitoneal, intrathecal

◾ Topical: ointment, paste, cream, lotion

◾ Transdermal: transdermal patch

◾ Ophthalmic: Eye drops

◾ Respiratory: nebulizer, metered-dose inhaler

◾ Rectal: suppository, enema

B.  Based on physical form: solids, semi-solids, liquids, and gases.