The Pharmaceutics and Compounding Laboratory
Capsules

Introduction

Capsules are gelatin shells filled with the ingredients that make up an individual dose. Dry powders, semi-solids, and liquids that do not dissolve gelatin may be encapsulated. Capsules account for about 20% of all prescriptions dispensed.

Capsules have several advantages as pharmaceutical dosage forms:

  1. They may be used to mask the unpleasant tastes, aromas, or appearance of a drug.
  2. They allow powders to be dispensed in an uncompressed form, thus allowing for quicker dissolution and absorption of the drug following oral dosing (as compared with tablets).
  3. They offer the pharmacist versitility to prepare any dose desired for a variety of administration routes (e.g. oral, inhalation, rectal, or to be diluted for vaginal, rectal, oral or topical use).
  4. They may be easier than tablets for some people to swallow.
  5. They can be make to alter the release rate of the drug.

Their disadvantages or limitations include the following:

  • They are easily tampered with (although techniques exist for preventing this).
  • They are subject to the effects of relative humidity and to microbial contamination.
  • They may be difficult for some people to swallow.
  • More expensive (commercially).