into a rod like a pill mass, cut it into the proper number of pieces, roll these into spheres and then flatten. Pastils. Pastils are troches made from gelatin or chocolate, usually the former. Several formulas are used, but the gelatin may be softened and dissolved in two and one-half parts of water and the same amount of glycerin with the aid of heat. The medicinal matter is incorporated, and the mass poured into molds or pans, allowed to cool, and then cut into pieces. Fumigating pastils are little cone-shaped masses made up of some balsamic substance mixed with charcoal and are intended to be burned to give a pleasant odor, and sometimes to act as a disinfectant. Lamels are very small disks of gelatin with glycerin containing a medicinal agent. They are intended to be dropped into the eye, or used in making hypodermic solutions. Bacills are troches in the form of short rods. COMMENTS Trochisci Carbonis Ligni, N. F. It is a generally recognized fact that charcoal after it has been wet does not absorb much gas, and as these troches are largely used for flatulence they can be of little service. Trochisci Phenolphthaleini, N. F. This is a formula not previously given. Phenolphthalein is colored red by alkalies, even the saliva. The troches are colored with carmine so that those who are not acquainted with this agent will not notice any change in color. Trochisci Quinine Tannatis, N. F. Although quinine is present, these troches are practically free from bitterness because quinine tannate is practically insoluble. It is unquestionably much less active therapeutically than the soluble salts. Chloroform is used to bring the oil and alkaloid into more intimate mixture. Saccharin, vanillin, and cocoa are used to cover up the bitter taste which otherwise might be noticed. Trochisci Santonini, N. F. Santonin turns yellow slowly in diffused light, but quickly in direct sunlight, and any troches containing it which are white should be kept in the dark. In this formula the cocoa gives a color which prevents any change from being noticed. COMPRESSED TABLETS Definition. A compressed tablet is a solid preparation made by compressing one or more medicinal substances. The shape may be round, square, oval, or other form, with a flat or more frequently convex upper and lower surface. They are from to inch in diameter. The medicinal agent may be compressed alone, or it may be diluted or mixed with other agents in order to get it into proper condition for compressing. Some are intended to be held in the mouth until dissolved, while others are to be swallowed whole, and these may be coated with sugar or chocolate. Agents that are likely to change in the air or that are volatile should not, as a rule, be made into compressed tablets. If a volatile oil is to be used as a flavor, one like wintergreen, cloves, or cinnamon, should be chosen which is not very volatile and does not change readily as lemon and orange do. Tinctures and fluidextracts should be evaporated to soft solids and mixed with a drying powder. Alkaloids and other active principles should be mixed with sugar of milk or other inert powder. Granulating. A few chemicals require no treatment, as ammonium chloride or potassium chlorate. Most agents must be granulated, because fine powders do not feed well or evenly into the compressor, and the particles hold air between them so that a perfect tablet cannot be made. Methods of granulating must vary with the material. In case of crystalline salts, they can often be bought in a granulated condition, or if in large crystals they can be coarsely ground and passed through a No. 12-20 sieve. Or they can be granulated by evaporating a solution while stirring, breaking up the larger masses. When several ingredients are to be put into a tablet, it is necessary to powder each separately, mix thoroughly, and granulate. The mixture of powders is dampened with water, alcohol, syrup, glucose, mucilage of tragacanth, or, to the mixture of powders, some sugar, acacia, dextrin, flour, or similar powder is added and then water. The dampened mixture is passed through a No. 12-20 sieve and the granules dried. If left damp the granules will probably not feed well and will stick to the punches. The particular liquid or adhesive agent to be used varies with the medicinal agents. Light bulky powders are usually mixed with quite a percentage of sugar. In compressing some insoluble compounds, as acetanilid or salol, the tablet produced is not dissolved or disintegrated in the body. To overcome this fault, freshly dried starch is added just before compressing, using from 10 to 15 per cent. Dried starch absorbs moisture, swells, and aids the rupture of the tablet. Sodium bicarbonate is sometimes put in, and this with the acid of the gastric juice causes disintegration, or, an acid may be put in with the bicarbonate. In making an effervescing tablet, the acid and bicarbonate are granulated separately and the granules mixed. If two salts are to be used which are capable of reacting and liberating water of crystallization, the water should be driven off first. Some salts or mixtures do not feed well, and stick to the punches or mold. To relieve this trouble a lubricant may be used, such as talc (not over 3 per cent), boric acid (not over 2 per cent), starch, lycopodium, cacao butter, petrolatum, or liquid petrolatum. Talc is most commonly used with insoluble powders and boric acid with soluble ones. In using liquid petrolatum, it is best sprayed on to the granules with an atomizer; some prefer to first dissolve it in ether and then spray, but the ether solution is more liable to penetrate the granules. About 50-60 minims of liquid petrolatum are used for a pound of granules. Machines. Machines for making compressed tablets vary greatly in price as they do in size, but they operate on about the same principle, by pressing the granules between two punches in a mold. The machine is generally equipped with several different sizes of molds. By regulating the lower punch the amount of material or weight of tablet is regulated, and by adjusting the upper punch the amount of pressure is determined. The mold and punches must be kept smooth and polished, and the edges of the punches sharp, otherwise the tablet may be imperfect and stick. After using, the punches and molds should be thoroughly cleaned and oiled. The pressure should be carefully regulated. If it is too great the tablets do not readily disintegrate and are apt to chip. Or if the pressure is not sufficient, the tablets crumble. It should be such that the tablets will not be crushed by ordinary handling, but can be broken in the fingers. In making compressed tablets of potassium chlorate the salt should not be mixed with organic or reducible matter; even dust mixed with it has been known to cause explosion in compressing. COMMENTS fix Toxitabellæ Hydrargyri Chloridi Corrosivi. The preToxi in the Latin name seems unnecessary. The U. S. P. requires these tablets to be angular, stamped with the word poison and design of scull and crossbones, and to be colored blue, all of which is to call attention of the user to the fact that the tablets are poisonous. Sometimes they are made in the shape of a coffin. Blue color is chosen because foods and drinks are not often colored blue, and the uncommon color would catch the eye at once. TABLET TRITURATES As the name implies, tablet triturates are tablets made from triturations. They are made by pressing a properly dampened trituration into holes in a hard rubber plate, the plate containing from 50 to 100 holes. Another plate having pins to fit the holes is used to force out the tablets, after which they are dried. Only enough pressure is used to fill up the holes. These tablets are not as hard as compressed tablets, and dissolve much more quickly. They usually weigh between 1 and 2 grains. In cleaning the mold hot water should not be used because of danger of warping it. Until recently tablet triturates were made by hand, but a machine can now be obtained. The diluent used in making the trituration is sugar of milk, cane sugar, or a mixture of the two. Cane sugar makes a more soluble tablet and also a harder one. For easily reducible substances, as silver nitrate or potassium |