Capsules

                                   Capsules

•Are solid dosage forms that are more commonly composed of gelatin and are designed to contain a drug containing formulation.

•Types of capsules:

1-Hard gelatin capsules.

2-soft gelatin capsules

•-Hard gelatin capsulesare less flexible and composed of two pieces the cap and the bottom.

•-Soft gelatin capsulesare flexible and are composed of one piece of capsule shell.

•Many formulation type can be added interior of the capsules. For example:

–powders, tablets,semisolids and non aqueous liquids / gels may be filled in the hard capsules.

–Soft gelatin capsules are usually filled with various liquids containing AC either dispersed or dissolved within the carrier.

2 Advantages of capsules formulations:

1) The use of capsules avoids many operations associated with tablet manufacture such as compression, granulation, drying.

2) Capsules may be formulated to increase oral bioavailability of poorly soluble therapeutic agents.

3) It is a convenient method where orally administered liquid in a single dosage forms.

4) The stability of the drug may be improved in capsule formulation.

Disadvantages of capsules formulation:

1. Requirement of specialized manufacturing equipments.

2. Stability problems are associated with capsule containing liquid fills.

3. Problems regarding the homogeneity of fill weight and content may are associated with capsule formulations.
3.Gelatin as the main material in manufacturing capsules Shell:

Gelatin is a mixture from animal collagen extracted from animal skin or bones by either partial acid extraction (type A )or partial alkaline hydrolysis (type B).

The use of gelatin as a capsule material is due excellent physicochemical and biological properties and has the advantages:

1.Non toxic material.

2.Soluble in biological fluids at room temperature.

3.Excellent mechanical properties.

4.Excellent rheological properties at elevated temperature.

5.Undergoes a gel-sol transition at relatively low temperature.