April 5, 1873.] 
superior to those in general use, for the following 
A NEW BASIS FOR SUPPOSITORIES AND 
PESSARIES." 
BY WILLIAM MARTINDALE, F.C.S., 
Dispenser and Teacher of Pharmacy to the University 
College Hospital. 
At our evening meeting in February, Dr. Redwood 
stated that “some medical men took exception to the 
present suppositories on account of their greasy 
basis,” f and at our last meeting several vehicles 
were suggested in place of the official one. Among 
others, Dr. Redwood suggested soap—animal soap. 
The use of this substance for the purpose is by no 
means novel, in fact, until comparatively recent 
years, the only suppository in general use was one 
made of the compound pill of soap. The great dis¬ 
advantage in using soap as a basis, from a pharma¬ 
ceutical point of view, is the difficulty in forming the 
suppositories containing it into a proper shape. It 
cannot be melted and poured into moulds in the way 
that we are accustomed to, each suppository would 
require separate manipulation with the hand and 
palette-knife, and this could never be done in the 
quantities in which they are used in our hospitals 
and sold wholesale by some manufacturers. There is 
also a therapeutical disadvantage. Soap, even curd 
soap, is not a pure stearate of soda ; it is apt to con¬ 
tain some free alkali and always contains a little 
chloride of sodium, which has been used to separate 
it from the excess of water and glycerine formed 
during its manufacture. I think, therefore, the use 
of soap ought to be discarded. 
We use some quantity of suppositories at University 
College Hospital; they answer the purpose of both 
pessary and suppository. The pessary weighing one 
or two drachms seems to be going out of use, especially 
if made of a fatty basis,—in liq uefying these are apt 
to discharge and be a source of great inconvenience 
-to the patient. Such is not so much the case, I 
believe, with suppositories where they are firmly 
grasped by the sphincter, and little or no inconveni¬ 
ence, from inquiries I have made, is felt by persons 
who have used those made of oil of theobroma alone, 
<is a basis.. Nevertheless, the use of oil of theobroma 
has its disadvantages. It solidifies very slowly, 
especially in the summer, it is somewhat difficult to 
remove from the mould, and being a fatty substance, 
it impedes the absorption of the medicament the 
suppositories are impregnated with. 
From Professor Marshall’s experiments with oleic 
■acid, I was led to try making suppositories of morphia 
■with pure morphia, and a sufficient quantity of this 
as a solvent, the solution being added to a certain 
quantity of oil of theobroma and moulded into sup¬ 
positories in the usual way. The results were so far 
successful; the suppositories were obtained uniform 
in strength, as the morphia was dissolved in the basis, 
not merely suspended in it. Still, I did not consider 
this was all that was desirable. I, therefore, thought 
ot other fatty acids, the solid ones—stearic acid more 
particularly, and tried it, but the melting point of 
this I found much too high—pure stearic acid melts 
at 69° C. (154° F.). I next tried a mixture of the 
two, equal parts by weight of oleic and stearic acids, 
melted together, and with this I was successful 
beyond my expectations. I have tried it with 
several substances, and find such a mixture very 
* Read at the Evening Meeting of the Pharmaceutical 
Society of Great Britain, April 2, 18/3. 
t Pharmaceutical Journal, 3rd Ser., Vol. III. p. 639. 
Third Series, No. 145. 
reasons:— 
1. This mixture has a very low fusing point , and 
readily melts at the temperature of the body. —It is a 
curious fact—-I quote from Watts’ ‘Dictionary,’*—that 
when stearic acid is melted with more fusible fatty 
acids, the mixture fuses, not at the medium fusing- 
point, but mostly at a temperature, even below that 
of the most fusible acid of the mixture.” Thus equal 
parts of stearic and palmitic acids melt at 56-6° C., 
stearic acid, as 1 have said, fuses at 69° C. Equal 
parts of stearic and oleic acids melt much lower still. 
I have not had the opportunity of testing the melt- 
ing-point of the mixture, but it must be below 100° F., 
the temperature of the blood, as they readily melt 
when placed in their position ; they even do this in 
the warm hand. This low melting point is of ad¬ 
vantage in their manufacture; the heat of a warm 
composition mortar being all that is required to 
liquefy the basis, and also to dissolve the medica¬ 
ment when this is soluble, the suppositories can thus 
be extemporized in a few minutes and prepared for a 
customer while he waits, as such a basis possesses 
the advantage of solidifying almost directly. 
2. The suppositories leave the mould without any 
difficulty. —Pure stearic acid has another peculiar 
property, and one which many of you may have 
noticed in the beautiful crystalline samples of it 
which are sometimes exhibited by candle manufac¬ 
turers. It is, that it expands very strongly when 
heated, especially at the moment of fusion (about 11 
per cent.), and contracts the same on solidifying, so 
much so that cast lumps of it appear porous. This 
porosity does not appear to such an extent in a mix¬ 
ture of stearic and oleic acids, but the contraction which 
takes place is even more than 11 per cent. Care there¬ 
fore must be taken to pour the melted liquid into the 
mould just before it begins to solidify, and also to 
fill up the cavity with more fluid immediately after 
the first contraction has taken place in the mould; it 
is better then to pour in a little excess and scrape 
this off with a knife when the suppositories have be¬ 
come solid. This, as I have said, they do very 
quickly, the mould may then be opened, and owing 
to the contraction that has taken place, the suppo¬ 
sitories are almost quite loose in their cavities, and 
may be removed with a touch of the finger. 
3. This basis has the advantage besides of being a 
solvent of such alkaloids as pure morph ia and atropia , 
and of being itself readily absorbed by the epidermis 
and mucous membrane, at least so far as the oleic 
acid is concerned. This may readiiy be tested by 
rubbing a little oleic acid upon the back of the hand ; 
it is absorbed in a short time, where an oily layer 
would have remained for hours unabsorbed. 
4. On account of the partial crystallization of some 
of the stearic acid, the suppositories are firm and can 
be placed in their position without difficulty , not being 
elastic, brittle, or yielding in any way. This is an 
advantage, especially for a suppository, not so much 
for a pessary. Their elasticity is a disadvantage to 
those made of a solution of gelatine in glycerine for 
use as a suppository. By pounding in a mortar sup¬ 
positories made of the basis I suggest, they soon form 
a soft pasty mass; they cannot, therefore, lie made 
except by liquefying and pouring into moulds in 
which the stearic acid can partially crystallize and 
make a firm mass. 
* Yol. v. p. 414. 
