Suppositories are solid bodies usually intended to be introduced into the rectum with a view either of evacuating the bowels by irritating the mucous membrane of the rectum, or of producing a specific effect on the neighboring parts or on the system at large. Suppositories are also made for vaginal or urethral administration. They fulfill the same indications as enemata, and are sometimes preferable from the facility of their application, and, when the object is to produce the peculiar effect of a medicine, from the smallness of their bulk, which facilitates retention. Their form may be cylindrical, conical, or spherical, the last being preferable when the bulk is small, or they may be in the shape of the modified cone with a tapering base, as recommended by H. S. Wellcome. (Proc. A. Ph. A., 1893, p. 103.) This is the form now generally used when moulded suppositories are supplied. They should be of such a consistence as to retain their shape, but so soft as to incur no risk of wounding the rectum.

Soap is not infrequently employed in this way as a laxative, a piece of pure castile soap being cut to the proper shape and used as a suppository. Cacao Butter, originally recommended by A. B. Taylor (A. J. P., 1852) is the most frequently used base (see Oleum Theobromae). Barely is it necessary to stiffen it but when such a material is employed, wax is usually selected, although cetaceum is preferable. If not more than 10 per cent, of the spermaceti is added, the value of the suppository is not very materially affected, although it melts more slowly, and consequently requires a longer time to act, than, when the butter of cacao is used alone. Suppositories containing a considerable percentage of wax melt so slowly in the rectum as to be comparatively useless, or they may fail altogether to soften down, and be finally passed from the anus unchanged.

A very good method of mixing the oil of theobroma with the hardening material is by grating with an ordinary tin grater, such as used in kitchens, and mixing the coarse powders before melting, and W. G. Ewing has proposed rubbing the powders and the medicinal substance in a mortar together, dividing the plastic mass, and shaping it with the fingers. It is better to shape them with a spatula, and roll them upon a pill tile. This plan, although having its advantages, is, however, not equal to the official one of melting the ingredients and running them into moulds.

The tendency of the hardened suppositories to adhere to the moulds may be overcome more or less perfectly by dusting the moulds with lycopodium powder, or greasing them well with olive oil, but it is far better to rely upon the natural contraction of the mass, caused by thoroughly cooling the moulds as lycopodium is a foreign substance which sometimes produces irritating effects, and oil sometimes makes them too soft, when used too freely. The moulds that open lengthwise, are now used almost exclusively in preference to the archaic individual moulds. The mould must be very cold, so as to chill the melted liquid at once and prevent any separation of its ingredients before cooling. It has also been recommended to form the excipient into the required shape, and then, while it is still soft, make an excavation from the base upward, into which the medicine may be introduced, and afterwards enclosed by a little of the cacao butter. But, as one of the objects of the excipient is an equable diffusion of the medicine, to prevent irritation, this method would be inapplicable to substances in any degree locally irritant.

Hollow rectal suppositories made of pure cacao butter are on the market and have an extensive use; the medicinal ingredients are made into a soft mass rolled out on a slab or cut into pieces on a pill machine, inserted into the hollow chamber of the suppository and the cacao butter plug there fused in place with the use of gentle heat. J. Percy Remington devised a suppository mould made of soft vulcanized rubber; it is used in the same manner as that employed for a metal mould, the advantage being mainly the facility of removal when the suppository is cold; a slight pressure with a twisting motion causes the soft rubber mould to open, and the suppository to drop out easily. (Proc. New Jersey Pharm. Association, 1906.)

The inventive genius of pharmacists has been industriously applied to the construction of suppository moulds, and there are now many varieties; the principle is much the same in all, however, but for convenience they may be classed as follows:

The weight � i.e., the size � of rectal suppositories should vary according to the purposes for which they are employed. When they are to be used for infants and children, they should weigh from five to ten grains. The Br. Pharm. adopts the weight of 1 Gm. (fifteen grains).

Machines for making suppositories by cold compression are now available in a variety of forms, and, while they are more satisfactory for making stock suppositories, made up in large numbers, many retail pharmacists use them to advantage in dispensing suppositories on prescription. (For a discussion of such machines and their relative advantages see Remington, Practice of Pharmacy.) Compression is now recognized as an alternative method in the U. S. P. general article on suppositories. The U. S. P. X directs as follows: " For suppositories made with oil of theobroma the following general processes may be employed: Take of the Medicinal Substance, the prescribed quantity; Oil of Theobroma, grated, a sufficient quantity. Reduce the medicinal substance, if dry, to a very fine powder, or, if an extract, soften it with an appropriate liquid, then mix it thoroughly in a mortar with about an equal weight of grated oil of theobroma, and incorporate the remainder of the oil of theobroma until a homogeneous, plastic mass is obtained, adding, if necessary, a small quantity of expressed oil of almond or wool fat. Roll the mass on a graduated tile until a cylinder of the proper length is formed, divide this into the required number of equal parts, and with a spatula, or other mechanical aid, form them into the desired shape.

If the process of cold compression is preferred, mix the medicinal substance in a suitable mortar with about an equal weight of grated oil of theobroma, as above directed, then thoroughly incorporate it with the remainder of the oil of theobroma, previously finely grated, chilling the mortar, if necessary, to preserve the pulverulent form of the mixture. Transfer the powdered mass to the cylinder of an appropriate suppository compressor and by the use of this apparatus prepare the desired number of compressed suppositories.

If the process of fusion is preferred, mix the medicinal substance with about an equal weight of grated oil of theobroma, as above directed, then thoroughly incorporate it with the remainder of the oil of theobroma, previously melted by a gentle heat on a water bath, in a suitable vessel provided with a lip. Allow it to cool to about 38� C., and, when the mixture begins to congeal, pour it immediately into suitable well-cooled moulds. Keep the moulds at a freezing temperature until the suppositories have hardened and are ready to be removed. For suppositories containing chloral hydrate, phenol, or other substances which soften the vehicle, raise the melting point of the oil of theobroma by the addition of from 10 to 15 per cent, of spermaceti, but the melting point must not be raised above 37� C.

For suppositories made with glycerinated gelatin the following process may be used: Take of: The Medicinal Substance, the prescribed quantity, Glycerinated Gelatin, Glycerin, Water, each, a sufficient quantity. Mix the medicinal substance, if solid and soluble in water or glycerin, or if a miscible liquid, with a little water, and add sufficient glycerin to make the weight of the mixture one-half that of the finished mass. Then thoroughly incorporate it with an equal weight of melted glycerinated gelatin, and pour it at once into suitable moulds which have been greased with a small quantity of petrolatum. Cool the moulds thoroughly before removing the suppositories. Moulds for urethral suppositories should be warmed sufficiently before pouring the mass to facilitate the proper filling of the mould. Suppositories having a firmer consistence may be prepared by substituting mucilage of acacia for a portion of the water or glycerin. If the medicinal substance is insoluble in water or glycerin, thoroughly triturate it in a warm mortar with a sufficient quantity of glycerin to make the weight of the mixture one-half that of the finished mass. Then thoroughly incorporate it with an equal weight of melted glycerinated gelatin, and pour it into suitable moulds as above directed. With bulky powders about one-half of the glycerin may be replaced with water before trituration. Glycerinated gelatin suppositories should be protected against the effects of heat, moisture, and dry air by keeping them in tightly-closed containers in a cool place.

Rectal Suppositories should be cone-shaped, and when made from oil of theobroma should weigh about 2 Gm. If prepared with glycerinated gelatin, they should weigh about 4 Gm.

Urethral Suppositories (Bougies) should be pencil-shaped, pointed at one extremity, and either 7 cm. in length, weighing about 2 Gm., or 14 cm. in length, weighing about 4 Gm., when made with glycerinated gelatin. If prepared with oil of theobroma they should weigh about one-half the above quantities.

Vaginal Suppositories should be globular or oviform in shape, and weigh about 10 Gm. if made with glycerinated gelatin, and about 4 Gm. if made with oil of theobroma." U. S.

The U. S. Pharmacopoeia gives no detailed formulae for suppositories, except in one case, Suppositoria Glycerini.