Capsules of the British Pharmacopoeia

Question 1

Content of active ingredient in capsules

Answer 1

The range for the content of active ingredient stated in the monograph is based on the requirement that 20 capsules, or such other number as may be indicated in the monograph, are used in the Assay. In the circumstances where 20 capsules cannot be obtained, a smaller number, which must not be less than 5, may be used, but to allow for sampling errors the tolerances are widened

Question 2

What are capsules?

Answer 2

The capsule shells are made of gelatin or other substances, the consistency of which may be adjusted by the addition of substances such as glycerol or sorbitol. Excipients such as surface-active agents, opaque fillers, antimicrobial preservatives, sweeteners, colouring matter authorised by the competent authority and flavouring substances may be added. The capsules may bear surface markings.

Question 3

Contents of a capsule

Answer 3

The contents of capsules may be solid, semi-solid or liquid. They consist of one or more active substances with or without excipients such as solvents, diluents, lubricants and disintegrating agents. The contents do not cause deterioration of the shell. The shell, however, is attacked by the digestive fluids and the contents are released.

Question 4

Several categories of capsules may be distinguished:

Answer 4

— hard capsules;
— soft capsules;
— gastro-resistant capsules;
— modified-release capsules;
— cachets

Question 5

Capsule tests

Answer 5

Uniformity of dosage units
Uniformity of content (2.9.6)
Uniformity of mass (2.9.5)
Dissolution
Disintegration

Question 6

Hard capsules are

Answer 6

solid single-dose preparations. They consist of a hard shell, the capacity of which can be varied, containing a solid, semi-solid or liquid preparation. The shell is made of gelatin or other substances, and consists of 2 prefabricated cylindrical sections that are open at one end and rounded and closed at the other. The contents are filled into one of the sections and the capsule is closed by slipping the other section over it.

Question 7

Soft capsules are

Answer 7

solid single-dose preparations. They consist of a soft shell, the capacity and shape of which can be varied, containing a semi-solid or liquid preparation. The shell is made of gelatin or other substances and may have one or more solid active substances incorporated into it. The shell is usually thicker than that of a hard capsule and consists of one part, as soft capsules are generally formed, filled and sealed in a single operation.

Question 8

Modified-release capsules are

Answer 8

hard or soft capsules in which the contents or the shell or both contain special excipients or are prepared by a special process designed to modify the rate, the place or the time at which the active substance(s) are released.

Modified-release capsules include prolonged-release capsules, delayed-release capsules and pulsatile-release capsules.

Question 9

Gastro-resistant capsules are

Answer 9

delayed-release capsules that are intended to resist the gastric fluid and to release their active substance or substances in the intestinal fluid. Usually they are prepared by filling capsule shells with granules or with particles covered with a gastro-resistant coating. In other cases, the shell of the capsule is covered with a gastro-resistant coating or the shell itself has gastro-resistant properties.