training and knowledge is required than can be
It is the intent of this section to familiarize you
with the basics of compounding, in order that you
may understand and fully appreciate the complex-
ities involved in bringing the correct medication,
properly prepared, to the patient.
ETHICS OF COMPOUNDING
Since the patient is of prime importance when
compounding medicines, the corpsman must be
a person of integrity, skill, and knowledge. Accu-
racy, both in kind and amount is of utmost impor-
tance, as is cleanliness and orderliness, to ensure
the proper manufacture of medicinal substances.
Pharmaceutical compounding is not an area
for shortcuts or substitution, nor is there room
for dishonest or haphazard attitudes.
In order to understand the principles of com-
pounding, we must first be familiar with some of
the physical processes involved.
Comminution is the process of physical reduc-
tion of a substance to fine particle size, which
makes the substance or drug easier to dissolve and
The processes for comminution are cutting,
grating, grinding, pulverizing, trituration, and lev-
itation. The first four terms are self-explanatory
and are employed primarily on animal and vege-
table drugs from which we wish to extract active
TRITURATIONThis is a process of reduc-
ing a solid to a very fine powder by grinding in
a mortar and pestle, which will be described in
detail later in this chapter.
LEVITATIONSolids can be ground to even
finer subdivision by adding a small amount of liq-
uid to make a paste and triturating further. This
process is ideal for ointments, creams, and lotions.
Processes of Separation
A important phase of compounding medicines
is that of separating solids from liquids by various
means. The main purpose is to purify the liquid,
but the process is also employed to obtain cer-
tain desirable solids from liquids.
DECANTATIONProbably the simplest
method of separating solids from liquids is the
process of recantation, which merely means let-
ting the solids settle to the bottom of the container
and pouring off the liquid by gently tilting the
COLATIONWhen the solids in a liquid are
fairly large, a simple method of separation is pass-
ing the mixture through a strainer, cheesecloth,
or muslin, allowing the fluid to pass through and
retaining the solids.
FILTRATIONThis is the process of sepa-
rating a solid from a liquid with the purpose of
obtaining the liquid in a clear transparent state,
devoid of impurities. The liquid, called the filtrate,
is passed through a porous barrier called the filter.
The filtering medium may be paper, paper pulp,
asbestos, cotton, felt, sand, or other suitable
In pharmacy, we have commercial filter paper
readily available for this purpose, and in large in-
stallation, mechanical filtering machines filter
large quantities in a fraction of the time other-
CENTRIFUGATIONSolids are separated
from liquids by the centrifugal force or rotation.
PRECIPITATIONIn this method, solids are
formed from previously clear solutions by either
physical or chemical means and then separated
by filtration or other previously mentioned means.
Heat is a very important tool in compounding
and must be thoroughly understood.
Heat is a form of energy and is measured in
degrees. Two common scales of temperature are
in use today, Fahrenheit, based on the freezing
point of water as 32° and the boiling point as
212°; and Celsius (centigrade) with the freezing
point of water as 0° and the boiling point as 100°.
The Celsius scale is now used in almost all
temperature determinations, such as scientific
work, the weather, etc. Unless otherwise specified,
all temperatures given in the USP-NF and Rem-
ingtons Pharmaceutical Sciences are Celsius.
Thermometers are instruments for measuring
the intensities of heat. Most of these instruments
are based on the expansion of liquids and vary
only in the purpose for which they were intended.