and the medicinal substances combined with it are
always intended to be very fine particles, uniformly
Suppositories are solid bodies intended to
introduce medicinal substances into the various
orifices of the body (rectum, vagina, and urethra). The
ingredients are incorporated in a base that melts at
Capsules are gelatin shells containing solid or
liquid medicinal substances to be taken orally.
common type of capsule contains medicine in the form
of a dry powder that is enclosed in transparent cases
made of gelatin. Capsules are sized by universally
designated numbers: 5, 4, 3, 2, 1, 0, 00, 000. The
number 5 has the capacity of about 65 mg of powder
(such as aspirin) and the number 00 capsule contains
about 975 mg of the same substance. Only sizes 3
through 00 are available through the Federal Stock
commonly used pharmaceutical instruments
and describe the purpose of each.
In the process of preparing some pharmaceutical
preparations, you may need to use specialized
instruments. To acquaint you with some of the more
commonly used pharmaceutical instruments, the
following sections will give you a description of each
instrument and explain its purpose. See figure 6-2 for
an illustration of each instrument discussed.
Two types of pharmaceutical balances are in
common use in the Navy: torsion balances (shown in
figure 6-2) and electronic balances (not shown). These
balances are classified as either Class A or Class
B. Class A balances are used for weighing loads from
120 mg to 120 g.
All dispensing pharmacies are
required to have at least one Class A balance on hand at
all times. Class B balances weigh loads of more than
648 mg, and they must be conspicuously marked
Class B. Class B balances are optional equipment in
Ribbed funnels are utensils used in the filtering
process. They are most commonly made of glass, but
other substances (tin, copper, rubber) are occasionally
used. The funnel is shaped so that the inside surface
tapers at a 60E angle, ending in a tapered delivery
spout. The inside surface is ribbed to allow air to
escape from between the glass and the filtering
medium (improving the filtration process).
The Erlenmeyer flask is a glass container with
metric measurements inscribed on it. It is used for
mixing and measuring various medicinal ingredients.
Mortar and Pestle
These two items always go together, one being
useless without the other. The mortar is basically a
heavy bowl, with one distinct property: the inside
concavity is geometrically hemispheric.
accompanying pestle is primarily a handtool that has a
tip made of identical material as the mortar, and its
convexity forms a perfect hemisphere. The reason for
the two opposing hemispheres is to provide an even
grinding surface. Mortars and pestles are made of
glass, metal, or unglazed pottery called wedgewood.
Glass is used when triturating (reducing substances to
fine particles or powder by rubbing or grinding) very
pure products (such as eye ointments), and when the
preparations contain stains.
Metal mortars and pestles should
never be used when the drugs are likely to react
with the metals.
The spatula is a knifelike utensil with a rounded,
flexible, smoothly ground blade, available in various
The spatula is used to work powders,
ointments, and creams in the process of levigation (the
rubbing, grinding, or reduction to a fine powder with or
without the addition of a liquid) and trituration. It is
also used to transfer quantities of drugs from their
containers to the prescription balance. Spatulas should
not be used to pry open cans or as knives for opening
boxes. Once the surface is scratched or the edges bent,