Capsule: Definition, Size Chart, Filling method & Difference between Hard and Soft Gelatin Capsule
Introduction:
Capsules is a widely used pharmaceutical dosage form which encapsulate drugs within a gelatinous shell, providing a convenient and effective means of administration. This exploration into capsules will cover their types, formation methods, and the diiference between soft and hard gelatin capsules.
Definition:
Capsules are dosage forms in which the drug is enclosed within a gelatinous shell. Hard capsules consist of gelatin and water, suitable for solid or powdered drugs, while soft capsules incorporate gelatin, plasticizers, and water, accommodating liquid or semisolid drug formulations.
Size Chart of Capsules:
Types of Capsules:
1. Hard Gelatin Capsules
A hard gelatin capsule is a solid oral dosage form consisting of two parts, the body and the cap, made from a suitable form of gelatin. It encloses medication and facilitates easy ingestion while ensuring protection and controlled release of the drug.
Advantages:
- Quick dissolution
- Versatile for various drug formulations.
Disadvantages:
- Brittleness
- Limited to non-aqueous formulations
Methods of Filling Hard Gelatin Capsules:
The capsules can be filled either by hand or Semi–automatic device or by an automatic filling machine.
- Load empty capsules into tray on bed.
- Fill powder tray accurately, collecting excess on platform.
- Lower pin plate, press filled powder downward.
- Raise pin plate, fill remaining powder.
- Remove powder tray after filling.
- Reposition cap holding tray, lower rubber top plate to lock caps and bodies.
- Collect filled capsules after removing loading tray.
- 200-hole machine fills about 5000 capsules/hour; 300-hole machine fills about 7500 capsules/hour.
Cleaning of Capsules:
- Wipe small quantities individually; rotate or shake large quantities with crystalline sodium chloride.
- Roll capsules on cloth-covered surfaces.
Sealing of Capsules:
- Seal capsules to prevent medicament spillage.
- Options: banding with molten gelatin or spot welding using heated metal pin.
2. Soft Gelatin Capsule
Soft gelatin capsules are pharmaceutical dosage forms consisting of a gelatin shell filled with a liquid or semi-solid drug formulation. They are commonly used to encapsulate drugs, vitamins, and dietary supplements. They may be round, oval or oblong in shape.
Advantages:
- Suitable for liquid and semisolid formulations.
- Enhanced bioavailability
- Ease of swallowing due to their smooth, flexible shell
Disadvantages:
- Stability concerns
- Limited drug compatibility
Method of Formation of Soft Gelatin Capsules:
The plate process, also known as the rotary die process, is a method used for the filling of soft gelatin capsules.
Steps involved in this are as follows:
– Mix gelatin, glycerine, water, preservative, and colorants; heat at 70°C for 2 hours to form gelatin mass.
– Pour gelatin mass onto an air-cooled rotating drum to create controlled thickness gelatin ribbons.
– Feed two gelatin ribbons between revolving dies and an injection wedge, cutting them into hollow forms.
– Medicament flows from fill tank through a metering pump; a measured quantity is injected into one half shell of capsules.
– Sealing occurs as the dies move, completing the capsules.
– Ejected capsules have unwanted material which is cut off by knives.
– Thoroughly wash capsules in hexane and then dry.
– Production capacity ranges from 20,000 to 30,000 capsules per hour, depending on machine and capsule size.
Difference between Hard & Soft Gelatin capsule
Feature | Hard Gelatin Capsules | Soft Gelatin Capsules |
Composition | Gelatin and water | Gelatin, plasticizers, and water |
Formulation | Solid or powder drugs | Liquid or semisolid drugs |
Shell Permeability | Impermeable | Permeable, allowing for rapid drug release |
Advantages | – Quick dissolution – Versatile for various drug formulations | – Suitable for liquid and semisolid formulations – Enhanced bioavailability |
Disadvantages | – Brittleness – Limited to non-aqueous formulations | – Stability concerns – Limited drug compatibility |
Flexibility | Rigid shell, less flexibility | Flexible shell, adapting to various drug formulations |
Manufacturing Process | – Requires precise conditions during manufacturing – Generally simpler compared to soft capsules | – Manufacturing process may be more complex – Requires specialized equipment for formulation |
Size Range | Limited range of sizes | Wide range of sizes, accommodating various doses |
Visual Appearance | Typically clear or opaque | Often translucent, allowing visibility of the content |
Use Cases | – Common for dry, powdered medications – Often used for over-the-counter supplements | – Suitable for oily, liquid, or semisolid medications – Frequently used for prescription medications |
A capsule is a solid dosage form consisting of a gelatinous shell that encapsulates a drug. It provides a convenient and effective means of administering medications.
Soft gelatin capsules are frequently used for liquid and semisolid drug formulations, offering enhanced bioavailability.
The size chart for capsules denotes different capsule sizes, with larger numbers representing smaller capsules. It helps in selecting the appropriate size for the desired drug formulation.
Hard gelatin capsules are typically clear or opaque, while soft gelatin capsules are often translucent, allowing visibility of the content.