Dosage forms: Introduction to dosage forms, classification and definitions

 Introduction

Dosage forms are pharmaceutical formulations that are designed to deliver drugs to the body in a safe and effective manner. They are available in various forms such as tablets, capsules, liquids, injectables, and many more. In this post, we will discuss the basics of dosage forms, their classification, and definitions.

Basics of Dosage Forms

A dosage form is a pharmaceutical product that contains a specific dose of a drug. It is designed to be administered by a specific route of administration, such as oral, topical, or injectable. The main objectives of dosage forms are to deliver the drug to the desired site of action, to ensure safety and efficacy, and to improve patient compliance.

Classification of Dosage Forms

Dosage forms can be classified into several categories based on various criteria such as route of administration, physical state, and release characteristics. Some of the commonly used classification systems are discussed below.

1. Based on Route of Administration

Dosage forms can be classified based on the route of administration, such as oral, topical, parenteral, inhalational, and rectal. This classification is based on the intended site of drug delivery and includes the following dosage forms:

• Oral dosage forms: Tablets, capsules, liquids, suspensions, and powders for oral use.
• Topical dosage forms: Creams, ointments, lotions, gels, and transdermal patches.
• Parenteral dosage forms: Injectables, infusions, and implants.
• Inhalational dosage forms: Aerosols and nebulizers.
• Rectal dosage forms: Suppositories and enemas.

2. Based on Physical State

Dosage forms can also be classified based on their physical state, such as solid, liquid, and semi-solid. This classification is based on the physical form of the dosage form and includes the following dosage forms:

• Solid dosage forms: Tablets, capsules, and powders.
• Liquid dosage forms: Solutions, suspensions, emulsions, and syrups.
• Semi-solid dosage forms: Ointments, creams, and gels.

3. Based on Release Characteristics

Dosage forms can also be classified based on their release characteristics, such as immediate release, delayed release, and sustained release. This classification is based on the rate of drug release and includes the following dosage forms:

• Immediate release dosage forms: Tablets and capsules that release the drug immediately after administration.
• Delayed release dosage forms: Tablets and capsules that release the drug after a specific period of time or at a specific site in the body.
• Sustained release dosage forms: Tablets and capsules that release the drug over a prolonged period of time.

Definitions of Dosage Forms

1. Tablets

Tablets are solid dosage forms that are prepared by compressing a mixture of active ingredients and excipients. They are designed to be swallowed whole and are available in various shapes, sizes, and colors. Tablets can be coated to mask the taste, to protect the drug from degradation, or to control the release of the drug.

2. Capsules

Capsules are solid dosage forms that are prepared by filling a shell with a mixture of active ingredients and excipients. They are designed to be swallowed whole and are available in two types: hard gelatin capsules and soft gelatin capsules. Capsules can be used to mask the taste of the drug, to improve stability, or to control the release of the drug.

3. Liquids

Liquids are dosage forms that are prepared by dissolving or suspending the drug in a liquid medium. They are designed to be administered orally or parenterally and are available in various types such as solutions, suspensions, emulsions, and syrups. Liquids can be used to improve patient compliance, to mask the taste of the