Tabellae; Lozenges; Tablettes, Fr. Cod.; Pastilli, Rotulae, P. G.; Pastillen, Plätzchen, Tabletten, G.; Pastiglie, It.; Tabletas, Sp.
Troches or lozenges are small, dry, solid masses, usually of a flattened shape, consisting for the most part of powders incorporated with sugar and mucilage. They are designed to be held in the mouth and dissolved slowly in the saliva, and are, therefore, adapted for the administration of those medicines only which do not require to be given in large quantities and which are destitute of any very disagreeable flavor.
Lozenges were formerly much more used and more skilfully prepared in Europe than in this country, but at present those manufactured here are fully equal to the imported lozenges. Tragacanth, from the greater tenacity of its mucilage, is better suited for their formation than gum arable. The following directions for preparing them are taken from the Dictionnaire des Drogues. A mucilage of tragacanth is first prepared with cold water and strained. With this the powders, including sugar, are thoroughly mixed by rubbing upon a marble slab, and are thus formed into a paste, which is spread out by means of a roller upon the surface of the marble, previously powdered over with a mixture of sugar and starch. The thickness of the mass is rendered uniform by a frame upon which the ends of the roller rest. The upper surface is now dusted with sugar and starch, and the mass is divided into small cakes by means of a punch. These cakes are placed upon paper, and, having been exposed to the air for twelve hours, are carried into a drying room moderately heated. When perfectly dry, they are thrown upon a sieve to separate the sugar and starch, and are then enclosed in boxes. Lozenges may be prepared from almost any medicine which it is advisable to administer in this form. The following typical formula may be found useful.
Take citric acid, in powder, a drachm; powdered sugar eight ounces; oil of lemon twelve minims; mucilage of tragacanth a sufficient quantity. Form them in the manner above directed into troches of twelve grains each. Lozenges are sometimes made by saturating blank lozenges with aromatic spirits. Currant paste or jelly has come into use of late years largely as a basis for troches. For formulas for lozenges with currant paste basis, see U. S. D., 19th edition, page 1297.
Lozenges of a cylindrical shape are extensively used, having a basis of licorice, gum, and sugar, and the manufacture of these is now an important industry. Franklin C. Hill devised an improved machine for making Licorice and Wistar's Lozenges. (See A. J. P., 1874, 401.) For Slocum's and Harrison's improved forms of lozenge boards, rollers, etc., see A. J. P., 1879, 589; 1880, 255. A. D. Marcy figured an instrument for shaping troches in N. R., Feb., 1882.
The Br. Pharmacopoeia, 1914, adopted four bases for lozenges, as follows: fruit basis, rose basis, simple basis, and tolu basis. It will be noticed that in the British formulas the quantity of active ingredients for each lozenge is stated and the kind of basis indicated. This is done merely to avoid repetition.
Preparation With Fruit Basis.
"Take five hundred times the quantity of the drug ordered for one lozenge. Mix it with 6.5 grammes of Tragacanth and 26 grammes of Refined Sugar, both in fine powder. Add sufficient of the black-currant paste of commerce to produce 650 grammes, beat into a uniform mass, divide into 500 equal lozenges and dry in a hot-air chamber at a moderate temperature." Br.
Preparation With Rose Basis.
"Take five hundred times the quantity of the drug ordered for one lozenge. Treat it as described under 'Preparation with Simple Basis,' previously mixing with the Refined Sugar 0.025 millilitre of Oil of Rose." Br.
Preparation With Simple Basis.
"Take five hundred times the quantity of the drug ordered for one lozenge, mix it with 496 grammes of Refined Sugar and 19.5 grammes of Gum Acacia, both in fine powder. Make the mixture into a paste with 35 millilitres of Mucilage of Gum Acacia and a sufficient quantity of Distilled Water, divide into 500 equal lozenges and dry in a hot-air chamber at a moderate temperature." Br.
Preparation With Tolu Basis.
"Take five hundred times the quantity of the drug ordered for one lozenge; dissolve such salts of alkaloids as may be ordered in 10 millilitres of Distilled Water; mix the solution with 482 grammes of Refined Sugar and 19.5 grammes of Gum Acacia, both in fine powder. Incorporate 10 millilitres of Tincture of Balsam of Tolu, and any other drugs ordered for the lozenges. Make into a paste with 35.5 millilitres of Mucilage of Gum Acacia and a sufficient quantity of Distilled Water; divide into 500 equal lozenges and dry in a hot-air chamber at a moderate temperature." Br.