Pharmaceutical Dosage Forms

Drug substances and crude drugs are developed into drug dosage forms in order to optimize stability, safety and effectiveness of drug substances and to make them suitable for administration. According to the consistence, they are classified as:

1. Solid dosage forms

2. Liquid dosage forms

3. Semisolid dosage forms

4. Aerosols

I. SOLIDE DOSAGE FORMS

         Solid dosages, such as tablets, capsules,
have many advantages over other types: greater stability, less risk of chemical interaction between different medicaments, smaller bulk, accurate dosage, and ease of production. 

   1. Tablet

                      - Uncoated tablet
                      - Sugar coated tablet

                      - Film coated tablet

                      - Modified release tablet: sustained release and delay release

                      - Effervescent tablet

                      - Chewable tablet

                      - Lozenge tablet

                      - Sublingual tablet

   2. Capsule

            

                     - Hard gelatin capsule

                    - Soft gelatin capsule

                    - Modified release capsule: sustained release and delay release

   3. Pill

   4. Oral Powder

   5. Granule

II. LIQUID DOSAGE FORMS

             Liquid dosage forms are prepared by dissolving the active ingredient(s) in an aqueous or nonaqueous solvent, by suspending the drug in appropriate medium or by incorporating the drug substance into one or two phases of an oil and water system. These forms can be formulated for different routes of administration: oral use, introduction into body cavities, or applied externally. Liquid drugs may also be administered systemically by mouth or by injection throughout the body.

The oral liquid forms can be readily administered to children or people unable to swallow tablets or capsules.

   1. Syrup

   2. Suspension

   3. Emulsion

   4. Elixir

   5. Tincture

   6. Eye, Ear, Nose Drops

   7. Mouthwash solution

   8. Enema

   9. Douche solution

   10. Liniment

   11. Medications for injection

III. SEMISOLID DOSAGE FORMS

             Semisolid dosage forms are normally presented in the form of creams, gels, ointments, pastes, suppository or patch. They contain one or more active ingredients dissolved or uniformly dispersed in a suitable base and any suitable excipients such as emulsifiers, viscosity-increasing agents, antimicrobial agents, antioxidants, or stabilizing agents. The choice of a base for semi-solid dosage forms depends on many factors: the therapeutic effect desired, the nature of the active ingredient(s) to be incorporated, the availability of the active ingredient(s) at the site of action, the shelf-life of the finished product, and the environmental conditions in which the product is intended to be administered. In many cases, a compromise has to be made in order to achieve the required stability. For example, drugs that hydrolyze rapidly are more stable in hydrophobic bases than in water-containing bases, even though they may be more effective in the latter.

The base should neither irritate nor sensitize the skin, nor should it delay wound healing. It should be smooth, inert, odorless, physically and chemically stable, and compatible with both the skin and the active ingredient(s) to be incorporated. It should normally be of such a consistency that it spreads and softens easily when stress is applied.

It may be necessary for a topical semi-solid dosage form to be sterile, for example, when it is intended for use on large open wounds or severely injured skin.

   1. Cream

   2. Ointment 

   3. Gel

   4. Paste 

   5. Patch/Plaster

   6. Suppository 

IV. AEROSOLS/GASES FORMS

                 Are heterogeneous systems consisting of very finely subdivided liquid or solid particles dispersed in a gas medium. The pressurized aerosol packages contain different propellants (compressed gases) driving the drug in the form of mist or foam.   They can be inhaled nasally or orally or applied topically to dispense a variety of agents for systemic or topical treatment.

Example: Salbutamol inhaler, Nasonex nasal spray, Coplaster spray, Burnaid spray, etc

             

References: Essential Pharmacology for Health Occupations, 5TH EDITION,  RUTH WOODRAW