Drugs are rarely administered as pure chemical entity, Almost always given as formulated preparations i.e Dosage form. They are administered in the different dosage forms after converting them into a suitable dosage formulation.

Drug substances are seldom administered alone; rather they are given as part of a formulation in combination with one or more nonmedicinal agents (referred to as pharmaceutical ingredients or excipients) produce dosage forms of various types. The pharmaceutical ingredients solubilize, suspend, thicken, dilute, emulsify, stabilize, preserve, color, flavor, and fashion medicinal agents into efficacious and appealing dosage forms.

The potent nature of most active drug substances and their low dose requirement which may not be convenient to weigh on routine bases as required by patients has prevented their use in the treatment and management of disease conditions. In other to obtain a stable, elegant, safe and therapeutic active drug product, drug substances are formulated into appropriate dosage forms; each designed to contain a given quantity of active drug substances for ease and accuracy of dosage administration.

What is A Drug

The word “drug” is derived from the old French word “drogue” which means a “dry herb”; and has often been used interchangeably with “medicine”,.

“Pharmaceutical product” and “pharmaceuticals” to refer to chemical substances intended for use in the diagnosis, prevention, treatment and management of disease(s) in man and in other animals. Traditionally, drugs were obtained naturally from minerals, plants or animals, but more recently, as by-products of microbial growth, through chemical/ organic synthesis, molecular modification, or biotechnology.

Dosage form & need for the Dosage form

Drugs are rarely administered as pure chemical entity, Almost always given as formulated preparations. They are administered in the different dosage form after converting then into a suitable dosage formulation.

Dosage forms are the means by which strong molecules/drugs are delivered to desired site of action within the body.

or

The term “dosage forms” refers to pharmaceutical preparations or formulations in which a specific mixture of drug substances (active pharmaceutical ingredients) and inactive components (excipients) are presented in a particular configuration to facilitate easy and accurate administration and delivery of active drug substances.

Or You can say

The manner in which drug substance are presented in the market. (Solid, Liquid or Gaseous)

Desirable properties of dosage form should:

• Convenient to handle, use and store
• Stable during storage and use
• Withstand mechanical shock during transport
• Flexibility in different drug strength
• Provide expected therapeutic effect
• Extent, drug release, onset, intensity, duration of action predictable
• Economical and elegant

Needed for Dosage Forms

• To protect the drug substance from the destructive influences of atmospheric oxygen or humidity (coated tablets, sealed ampuls).
• To protect the drug substance from the destructive influence of gastric acid after oral administration (enteric-coated tablets)
• To conceal the bitter, salty, or offensive taste or odor of a drug substance (capsules, coated tablets, flavored syrups)
• To provide liquid preparations  of substances that are either insoluble or unstable in the desired vehicle (suspensions)
• To provide clear liquid dosage forms of substances (syrups, solutions)
• To provide rate-controlled  drug action (various controlled-release tablets, capsules, and suspensions)
• To provide optimal drug action from topical administration sites (ointments, creams, transdermal  patches,  and  ophthalmic,  ear,  and nasal preparations)
• To provide for insertion of a drug into one of the body’s orifices (rectal, urethral or vaginal suppositories)
• To provide for placement of drugs directly in the bloodstream or body tissues (Parenteral injections)
• To provide for optimal drug action through inhalation therapy (inhalants and inhalation aerosols)
• To provide drug products that bind to a specific physiological site of action/ targeted-release

Classifications of Dosage Forms

Pharmaceutical dosage forms are classified mainly either based on the route of drug administration or based on the physical form of the dosage form.

1. Based on the route of the Drug Administration
2. Based on Physical state
3. Others

1. Based on the route of the Drug Administration

2. Based on Physical state

1) Classification of Solid dosage forms

• Powders: Solid dosage forms containing finely divided particles in micron size
• Tablets: Solid dosage form containing medicaments with or without excipients
• Granules: Aggregate of particles
• Capsules: Drug enclosed with a gelatin capsule
• Cachets: Drugs enclosed with wafer sheet of rice
• Pills: Small tablet containing excipients
• Lozenges: Solid preparations containing sugar and gum used to medicate mouth and throat
• Suppositories: Solid dosage containing medicaments with suitable suppository base that inserted into the body cavities other than the mouth, like rectum, nose, ear
• Poultices: Solid dosage form converted to paste-like preparation used externally in the skin to reduce inflammation

2) Classification of Liquid dosage forms

• Collodions: Liquid preparations for external use having nitrocellulose used to protect the skin 2. Droughts: Liquid preparations for oral containing medicaments available in a single dose or multiple doses
• Elixirs: Liquid preparation for oral containing medicaments with suitable excipients
• Emulsions: Biphasic liquid dosage form for oral containing medicaments in which fine oil globules dispersed in the continuous phase
• Suspensions: Biphasic liquid dosage form for oral containing medicaments in which fine solid particles suspended in the continuous phase
• Enemas: Liquid preparation for rectal containing medicaments
• Gargles: Concentrated aqueous solutions for external use used to treat throat infections
• Gels: Aqueous colloidal suspensions containing medicaments used as antacids
• Linctuses: Viscous, liquid oral preparations used to relief cough
• Lotions: Liquid preparations for external application usually applied without friction
• Liniments: Liquid preparations for external application usually applied with friction
• Mixtures: Liquid oral preparations containing one or more medicaments
• Mouthwashes: Concentrated aqueous solutions for external use used to treat mouth infections and oral hygienic
• Nasal drops: Liquid preparations containing medicaments that are instilled into the nose with a dropper used to treat nose infections and blockage of the nose
• Paints: Liquid preparations for external application to the skin or mucous membrane with a soft brush
• Solutions: Clear liquid preparation containing with or without medicaments used for internal or external preparations
• Syrups: Sweet, viscous, concentrated liquid preparations containing with or without sugar and medicaments

3) Classification of Semisolid dosage forms

• Ointments: Semisolid dosage forms for external use containing with or without medicaments with a suitable ointment base
• Creams: Semisolid dosage forms for external use containing with or without medicaments with a suitable fatty base
• Paste: Semisolid dosage forms for external use containing a high proportion of finely powdered medicaments with a suitable fatty base
• Gels: Transparent semisolid dosage forms for external use containing hydrophilic or hydrophobic base with gelling agents
• Poultices: Semisolid dosage forms for external use containing medicaments applied to the skin to hold the dressing and protective

4) Classification of Gaseous dosage forms

• Aerosols: Suspension of fine solid or liquid particles with gas used to apply the drug to the respiratory tract having atomizer within the device
• Inhalations: Internal liquid preparations containing medicaments dissolved in a suitable solvent or if insoluble suspended in the propellant
• Sprays: Gaseous preparations of drugs containing alcohol applied to mucous membrane of nose or throat with atomizer or nebulizer

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