LESSON 5
MEDICATED APPLICATIONS
Section I. OINTMENTS, PASTES, AND CREAMS
5-1.
INTRODUCTION
Ointments are semisolid preparations intended for external application that
usually contain medicinal substances. Pastes, ointment-like preparations that contain a
greater amount of solids, generally are thicker and do not melt when applied to the
body. Creams are semisolid emulsions very much like ointments in consistency but are
opaque rather than translucent. For purposes of dispensing, because the methods of
preparation and packaging and labeling are so similar, we will discuss these three forms
a. Purpose of Ointments. Ointments have several purposes. They act as
vehicles for medicinal agents for topical application. They may protect, or act as
emollients to, the skin. A few are counterirritants. Ointments are limited only by the
number of medicinals that can be incorporated into them and, to some extent, by their
absorption into the body.
b. Desirable Qualities in Ointments. Ointments, creams, and pastes must be
smooth, never gritty. More trituration is necessary in preparing powders for
incorporation into ointments than powders to be used in tablets or capsules. Since
ointments, creams, and pastes are often applied to broken skin and may be absorbed
into the body, extra measures of cleanliness must be taken in preparing them.
Spatulas, ointment slabs, and all the equipment used to make ointments must be
immaculate. The choice of an ointment base is of the utmost importance, and although
it may be impossible for any single base to be ideal in every respect, the following are
standards for which we strive:
(1)
The base in no way adversely affects a wound to which it is applied.
(2)
It is pharmaceutically elegant.
(3) It does not cause sensitization or irritation, either to unabraded or
traumatized skin.
(4)
It is prepared with relatively little difficulty.
(5)
It is neutral (neither acidic nor basic).
(6)
It does not dehydrate the area to which it is applied.
(7)
It is nongreasy and nonstaining.
MD0809
5-2