Capsule and Types of Capsule

 

Capsule:

DEFINITION:

A solid pharmaceutical dosage form that contains medicinal agent within either a hard or soft soluble container or shell, usually used for the oral administration of medicine. The shells are made of a suitable form of gelatin or other substance.

OR

Capsule are solid dosage forms in which the active medicament are enclosed in either a hard or soft soluble container or shell of a suitable form of gelatin.

OR

Capsules are solid dosage forms in which drug and/or inert substances are enclosed in a gelatin shell. The gelatin shell may be hard or soft depending on their composition.

The word capsule is derived from the latin capsula, meaning a small box.

Capsules are a common form of dosage for oral administration of pharmaceutical and nutraceutical products. They are produced in various shapes, sizes and materials, each capsule generally containing a single dose of active ingredient. In addition to the active drug ingredient or principal nutrient, other excipients are incorporated into the fill material, including antimicrobial preservatives, fillers, flavouring agents, sweeteners and colouring agent. Branding and dosage information may be printed on the outer surface of the capsule.

 

Medication or ingredients inside the capsule may be in solid, liquid or paste form, depending on the drug component or, in the case of nutraceuticals, on the form of the main nutrient (for example liquid fish oil is encased in the widely available fish oil capsules). The API filled in the capsules may contain solvents or excipients but these do not affect the integrity of the capsule shell. Other than the modified release form, no capsule forms normally contain colouring agents.

 

Type of Capsule:

Hard Gelatin Capsule

Hard gelatine capsules contain solid active ingredients. The capsules are formed by dipping finger-shaped pin forms into liquid gelatine solution and then extracting them and allowing the resulting surface film of gelatine to dry out. Once the film dries, each capsule is trimmed and then removed from the pins. The caps and body pieces of the capsule are supplied unlocked to be filled with the appropriate drug or nutraceutical ingredients.

 

More than one type of drug can be encased in a pharmaceutical capsule. In such a case, it is common to have the drugs in different forms, e.g., one as a tablet and one as a smaller capsule. Both drugs can then be encased in the larger capsule.

Soft Gelatin Capsule

Soft gelatin capsules, also called soft gels, are thicker than hard gelatin capsules and are sometimes the gelatine is plasticized by adding glycerin or sorbitol. The thickness of the gelatin is chosen by the manufacturer according to the requirements of the encased material and the environmental conditions outside the capsule (e.g, air temperature and humidity).

 

The composition of the gelatin used to prepare soft capsules may include preservatives, pigments and dyes. Flavourings and sweeteners may also be added. For example sucrose may be added at a level of about 5% to make the product palatable, and in some cases chewable. Soft gels generally contain between 6% and 13% by weight of water.

 

Soft gels can be filled with liquid or solid materials and solids can be dissolved or suspended in water to form a paste mixture. In other cases the capsule may simply be filled with granules or powder.

Modified Release Capsule

Both hard and soft gel capsules can be chemically modified to control the release of the active ingredient(s). Delivery of the active ingredient is usually effected by dissolution, degradation or disintegration of an excipient in which the active compound is formulated. In the case of capsules, the capsule body may be coated with a material through which the drug diffuses. Or it may be a slowly dissolving coat that slowly releases the drug over time. A more recent innovation is a system utilizing a semipermeable membrane that blocks the drug from diffusing out through the membrane, but where the water on the exterior of the membrane can diffuse into the formulation, allowing the drug to be released through channels within the membrane.

 

Enteric Capsule

Enteric capsules are another form of modified release capsule, and again they maybe in the hard or soft form. The encapsulating material is designed to resist the stomach acid until it reaches the intestinal fluid where at a higher pH it breaks down and releases the active ingredients.

 

It is important to observe during the manufacturing, packaging, storing and distribution of capsules that microbial contamination is possible as the capsules made of gelatine are susceptible to microbial attack and growth.

 

ADVANTAGES:

• They obscure the taste and odour of unpleasant drug.
• They are attractive in appearance.
• They are slippery when moist and hence, easy to swallow with a draught of water.
• If properly stored the shells contain 12-15% of moisture which give flexibility and consequently very considerable resistance to mechanical stresses.
• Less adjuncts are necessary than tablets.
• The contents are usually in fine powder which combined with adjuncts provides rapid and uniform release of medicament in the GIT.
• The shells can be opacified with Tio2 or coloured to give protection from light.
• The shells are physiologically inert and easily and quickly digested in the GIT.
• Presentation of a drug in capsule rather than in tablets, allows quicker submission of a new drug for clinical trial because fewer development problem are involved. Also it is easier to vary the dose.

 

Dis advantage of capsule dosage form:

• Capsule are not suitable for liquids that dissolve gelatin. Such as aqueous or hydroalcoholic solution.
• The concentrated solutions which required previous dilution are unsuitable for capsules because if administered as such lead to irritation into stomach.
• Not useful for efflorescent or deliquescent materials. Efflorescent cause capsules to soften & deliquescent may dry the capsule shell to brittleness.