Hard Gelatin Capsules
The
hard gelatin capsule consists of a base or body and a shorter cap, which fits
firmly over the base of the capsule. For human use, eight sizes of capsules
are available. The capacity of each size varies according to the combination
of drugs and their apparent densities. Capsules are available as clear gelatin
capsules or in a variety of colors. The pharmacist can use the different colored
capsules to distinguish two capsule formulations for the same patient, or to
encapsulate unattractive ingredients. The pharmacist can add a dye to the powder
before filling a clear capsule to impart a color for identification or esthetics.
Some types of hard gelatin capsules have a locking cap, which makes it more
difficult to reopen the capsule.

To aid in the selection of the appropriate size, a table, with the capacity
of five common drugs for that particular size capsule, is printed on the box
of the capsules. As a guide, the relative sizes and fill capacities of capsules
are given below. By knowing the bulk density of fill material, proper choice
of capsule size is usually made easier; however, trial and error soon develops
the judgment of the beginning pharmacist.
Capsule Size
|
Volume
(ml)
|
Mg of Lactose
|
Mg of Aspirin
|
000
|
1.37
|
1340
|
1000
|
00
|
0.95
|
929
|
600
|
0
|
0.68
|
665
|
500
|
1
|
0.50
|
489
|
300
|
2
|
0.37
|
362
|
250
|
3
|
0.30
|
293
|
200
|
4
|
0.20
|
195
|
125
|
5
|
0.13
|
127
|
60
|