Dosage Form

Key facts

Standard vocabulary

FDA Structured Product Labeling (SPL) dosage form terms

Shown in the Orange Book as

Dosage form and route pair, such as TABLET; ORAL

Generic requirement

Same dosage form as the reference listed drug

RxNorm usage

Dose form is part of every clinical drug concept name

What is a dosage form?

The dosage form is how a drug is presented to the body: a solid such as a tablet or capsule, a liquid such as a solution or suspension, a semisolid such as a cream or ointment, or a sterile form such as an injectable solution or a powder for reconstitution. The same active ingredient often comes in several dosage forms.

Release characteristics are part of the dosage form. An extended-release tablet and an immediate-release tablet of the same drug are different dosage forms, with different labeling, pricing and generic equivalents.

How dosage forms are classified

FDA vocabularies used in drug labels and the NDC Directory write dosage forms in uppercase with qualifiers after a comma, such as TABLET, FILM COATED or CAPSULE, EXTENDED RELEASE. Common groups include:

• Oral solids: tablets, film-coated and extended-release tablets, capsules, delayed-release capsules and orally disintegrating tablets.
• Oral liquids: solutions, suspensions, syrups and powders for oral suspension.
• Injectables: injectable solutions and suspensions, powders for injection and emulsions.
• Topical and local forms: creams, ointments, gels, transdermal patches, suppositories and ophthalmic solutions.
• Inhaled and nasal forms: metered-dose aerosols, inhalation powders and nasal sprays.

Why dosage form matters

Dosage form is a dividing line in equivalence, pricing and lifecycle strategy:

• Equivalence: the Orange Book rates therapeutic equivalence only among products with the same dosage form, so an extended-release product is not substitutable for an immediate-release one.
• Pricing units: NADAC reports cost per unit, and the unit depends on the dosage form, such as each for tablets, milliliters for liquids and grams for creams, so compare prices within a form.
• Lifecycle management: a new dosage form supported by new clinical investigations can earn 3-year exclusivity and can move patients to a protected product before generic entry.
• Data normalization: sources spell the same form differently, so mapping to a standard vocabulary such as RxNorm dose forms comes before joining NDC, label and pricing data.