Acacia Powder by itself is an excipient of very little value for the purpose of giving consistence; but, with the addition of 10 per cent, of powdered althaea-root, or half its weight of finely powdered liquorice-root, it makes a good binder for soft masses. The pills formed are apt to become hard.

Borotartrate Of Potash

Borax (or boric acid) 1, potassium bitartrate 4, water 24; boil until syrupy and scale. An antiquated excipient for salts.

Breadcrumb is regarded by tradition as an excipient for many things. As a matter of fact it is useless, and is never used.

Calcium Phosphate possesses in a remarkable degree the property of giving a greasy substance, such as lard or mercurial ointment, a good pilular consistence, when added in comparatively small quantity. It is also useful for essential oils; mix it, in this case, with half its weight of wheaten flour.

Compound Decoction of Aloes, especially the concentrated kind, is useful where a considerable quantity of oil has to be combined with a rather soft mass. It is an excellent excipient for most pills containing aloes, but is to be avoided where the potassium carbonate contained in it would prove an incompatible.

Confection of Roses and Confection of Hips increase the bulk of pills more than is liked nowadays.

Extract of Malt is a good excipient for general use.

Fullers' Earth is a convenient inorganic and inert powder for massing substances of a fatty nature.

Glucose (Liquid) or Honey is a serviceable excipient in many cases. Glucose syrup is now prescribed by the British Pharmacopoeia for several pills. It is a mixture of 250 grammes of liquid glucose of commerce with 500 grammes of syrup. It is not sufficiently adhesive for some purposes.

Glucanth is an excellent binding excipient. It is a mixture of powdered tragacanth 1/2 ounce, glycerin 1 1/2 ounce, water 1/2 ounce, and liquid glucose 3 1/2 ounces. Glucose mixtures are good for massing vegetable powders alone or mixed with chemical powders.

Remington's General Excipient is somewhat more binding than the foregoing. It is made by mixing benzoic acid 1 grain, powdered acacia 90 grains, glycerin 1 ounce, and liquid glucose 4 ounces.

Glycerin keeps pills soft, and being a very hygroscopic body itself, it cannot be used with other hygroscopic bodies. Glycerin ceases to exhibit this character when it contains half its weight of water. Whenever it is used alone as an excipient, add sufficient powdered tragacanth to bind after the action of the glycerin has taken place, not simultaneously; but it is better to start with glycerin of tragacanth. Careful dispensers are shy about using glycerin alone in pill-making. It is fatal to the silvering or varnishing of pills. Glycerin 1 part, with treacle 3 parts, is an excellent excipient for pil. aloes et myrrhae.

Kaolin, being an inert earth, has come into use for combining with oxidisable or reducible substances, such as potassium permanganate, which cannot be massed with extracts or carbohydrates, but with fats, such as lanoline or vaseline.

Kieselguhr (fossil earth) is a splendid absorbent for liquids, and the mixtures formed may be massed with a fat or glucanth.

Liquorice Powder is largely used as an absorbent and slightly binding excipient. Its fibrous nature plays a part in the internal disintegration of the pills. Powdered extract of liquorice is a favourite American excipient.

Manna is as good an excipient as anything for calomel and similar heavy white compounds.

Martindale's Kaolin Excipient for organic and oxidis-able substances. Melt together vaseline and hard paraffin, of each 1 ounce, and sifted kaolin 1 ounce, and stir until cold.

Mucilage of Acacia as an excipient should be avoided. It makes pills too hard; indeed, with some substances (such as calomel) it forms a perfect cement. Many substances do not require the addition of an adhesive excipient- e.g., the extracts of aloes, pulv. pil. coloc. co., pulv. ext. coloc. co., etc, form a good mass with water (about miv. to 3j.).

Powdered Althaea, if used freely, has a tendency, in consequence of its large proportion of mucilage, to interfere with the solubility of the pills, and to reduce their activity. Besides, it is apt to make a mass too elastic to work well into shape, which hardens too much afterwards. Not more than 1 grain to 5 or 10 grains of the active ingredients should be used. Three parts of powdered althaea require 2 parts of water to form a mass. In German pharmacies the following powders are sometimes kept ready for pills that require a binding excipient:

Another good excipient powder for such things as carbolic acid is a mixture of equal parts of althaea and liquorice. Some prefer flour with 3 per cent, of powdered tragacanth and, if required, a little syrup to moisten.

Resin Ointment makes good pills of ferri et quininae citras and similar articles which cake with aqueous excipients.

Roe's Excipent is one of the best for helping to mass essential oils. It is made thus: Soak gelatin 6 drachms in warm water for a few minutes, then drain, put into a dish with glycerin 2 drachms, heat on a water-bath, stir, and bottle. For each 2 minims ot oil use 1 grain of melted excipient, and add wheaten flour, fullers' earth, soap, or compound tragacanth powder to mass.

Soap-powder makes the best pill-mass with vegetable powders, extracts, and gum resins. In using soap care must be taken not to add too much water. Soap-masses at first appear dry and crumbly, so that the dispenser is tempted to add more water, and finds afterwards that he has too soft a mass. A little spirit has a similar effect to a greater extent, so that it must be used very carefully. Powdered curd soap is better than hard olive-oil soap, especially for creosote and essential oils. As soap is decomposed by acid salts, acids, many metallic salts, and tannin substances, it is not suitable for masses containing these.

Spirit should not be used when there is much resin in the pill, and masses made with it should be rolled off very quickly, or they will crumble. Proof spirit is, on the whole, better than rectified spirit for resinous masses.

Sugar without some mucilaginous addition is not good. Syrup, however, with powdered althaea is very useful. Syrup alone makes an excellent mass with powdered rhubarb.

'Dispensing-syrup' is the best form for using sugar. The formula for it is:

Mix.

This binds (owing to the acacia), keeps the mass from hardening (glycerin) and from oxidation (sugar).

Theriacanth is made thus :Rub 1 drachm of powdered tragacanth with 2 drachms of rectified spirit in a mortar; then add quickly 2 ounces of treacle (previously made more fluid by warming), and thoroughly mix. This soon sets into an adhesive mass which is excellent for such intractable things as reduced iron. Treacle contains a large proportion of salts (including alkaline carbonate). This should be borne in mind in selecting it or its preparations.

Tragacanth gives solidity and elasticity to a mass which is on the soft side, but if too much be added the pills become so elastic that it is almost impossible to round them. Tragacanth is especially to be recommended when the mass is too soft, and when it is desired not to increase the weight too much. If masses crumble, a little tragacanth powder, with a few drops of glycerin, will bind them.

The compound powder of tragacanth is more to be relied on than the pure gum, especially if the starch be replaced by wheaten flour as in the following:

Mix.

This is absorbent, binding, and preservative.