Introduction to dosage forms

Introduction to Dosage Forms, Classification, and Definition.

Dosage forms are carriers to carry drug molecules to be delivered at the site of action within the body.

Needs for the dosage forms

1. Protection

   1. a. Protection of drug molecules from the external environment. Such as Coating of tablets,

   2. b. Protection of drug molecules from the acidic environment in the stomach, such as gastric juice.

   3. c. Improvement in physical properties of drugs.

   4. d. Use of the desired vehicle for insoluble drugs.

2. Improvement in therapeutic efficacy

   1. a. Maintain drug dose accuracy,

   2. b. Placement of drugs in the body,

   3. c. Drug insertion in the body cavities such as in rectum, vagina, urethra,

   4. d. Maintenance of optimal drug action,

   5. e. Controlled release of medication,

   6. f. Sustained release of medication,

   7. g. Improve the bioavailability of drugs,

3. Patient compliance

   1. a. Ease of handling of drugs,

   2. b. Masking of taste and odors.

   3. c. Reduction in frequency of drug administration,

   4. d. Insertion of drugs in the body cavities,

Desirable properties of the dosage forms

1. Easy to handle, use, and store.

2. Stable during the storage period and use

3. Withstand mechanical shock during transportation and handling,

4. Easy to formulate dosage form of the required dose

5. Able to produce a required therapeutic effect,

6. Predictable drug release rate, onset of action, intensity of action, duration of action,

7. Economical

8. Elegant.

Classification

The dosage form can be classified on the basis of the following

1. Physical form,

2. Route of administration,

3. Site of application

Classification on the basis of physical form

1.  Solid dosage form:

   1. i. Unit Dosage form: Tablet, Capsule

   2. ii. Bulk Dosage form: Powder

2. Semi-solid dosage form: Cream, Paste, Gel, Jelly, Ointment, Suppository,

3. Liquid dosage form: These are Monophasic dosage form and Biphasic dosage form

   1. a. Monophasic liquid dosage form: It is further subdivided into the following two classes

      1. i. Liquid dosage form meant for internal applications: Syrup, Elexir, mixture, linctuses

      2. ii. Liquid dosage form meant for external use:

         1. Applied on skin: Lotion, Liniment, Paints, Collodions.

         2. Applied in the mouth: Gargle, throat paint, mouth-wash

         3. Instilled into body cavities: Douches, Ear drops, Nasal drops, Eye drops, Enemas.

   2. b. Biphasic liquid dosage form: Emulsion suspension,

4. 4. Gaseous dosage form: Inhaler, Aerosol.

Classification on the basis of Route of Administration

1. On the Basis of the Oral Route of Drug Administration: Tablet, Capsule, Pills, Powder, Cachets, Solution, Suspension, Emulsion, Syrup, Elexir, Gel, and Magmas.

2. On the Basis of the Parenteral Route of drug Administration: Powder, Solution, Suspension, Emulsion.

3. On the Basis of the Dermal Route of Drug Administration: Ointment, cream, pessaries, paint, Lotion, Plaster.

4. On the Basis of the Respiratory Route of Drug Administration: Inhalation, Aerosol,

5. On the Basis of the Body cavities Route of drug Administration:

   1. Rectal: Rectal Suppository, Enemas, Ointment.

   2. Vaginal: Vaginal suppository, Ointment, cream, Douches, Tablet suppository,

   3. Urethral: Urethral suppository

   4. Sublingual: Tablets, Lozenges.

   5. Intranasal: Solution, Sprays, Inhalation.

   6. Intra-ocular: Solution, ointment

   7. Conjuctival: Ointment.

Classification on the basis of the Site of the Application

1. Skin: Ointment, cream, lotion, liniment, powder

2. Eye: Solution, ointment, cream.

3. Hair: Ointment, cream, gel, lotion, shampoo,

4. Nasal: Solution, spray, inhalation.

5. Tooth: Toothpaste, tooth-powder.

6. Foot: Cream ointment, dusting powder.

7. Hand: Hand cream, lotion, Hand wash

Classification on the basis of their uses

1. Internal uses: All preparation except preparations for external application.

2. External use: Powder, Ointment, cream, paste, lotion, liniment, hair dyes, hair color, solution.

Definitions

1. Drug: A Drug is a natural or synthetic substance to prevent, cure, or diagnose disease or disorders of the body. They work by interacting with the biological system to produce specific effects.