US3173839A - Method of printing pharmaceutical forms - Google Patents

Description

United States Patent 3,17 3,839 METHOD OF PRlNTlNG PHARMACEUTICAL FORMS Arnold E. Nicholson, Philadelphia, Pa., assignor to Smith Kline 81 French Laboratories, Philadelphia, Pin, a corporation of Pennsylvania No Drawing. Filed Jan. 9, 1962, Ser. No. 165,226 3 Claims. (Cl. 167-82) This invention relates to a novel method of printing pharmaceutical forms such as tablets, pills and the like and to the product of this method. More particularly, this invention provides a versatile, simplified method of printing pharmaceutical forms which greatly reduces the time previously required.

The technique of the prior art involved in the ink monogramming of tablets has been to apply a coat of ink receptive material, preferably shellac, over the coated tablets and printing the desired ink indicia threon. Shellac is used not only because of its ink receptive properties but also because it prevents chipping, smearing and dusting of the tablets during the printing operation.

The present method of applying the shellac to the pharmaceutical forms is very time consuming. The coated tablets, in particular sugar coated tablets, must be thoroughly dried before the application of the shellac coat in order to prevent frosting of the shellac by the presence of moisture. The present method consists of applying the desired tablet coating, removing the tablets from the coating pan after the final color coats have been applied and then drying the tablets overnight. The tablets after being completely dried are then placed in a special shellacking pan and one or more coats of wax free shellac are applied out of a suitable organic solvent, usually isopropyl alcohol. Since this shellac is incompatible with water it is absolutely necessary that the tablets have been thoroughly dried before the application of the shellac. The time required to assure complete drying is approximately 24 hours. The shellac coated tablets are then removed from the coat ing pan, monogrammed and polished.

The novel method of printing tablets and the tablet in accordance with this invention eliminates the above time consuming procedure and makes it possible to print tablets rapidly and inexpensively. The time required to print the tablets has been reduced from days to a matter of hours. The novel process of printing tablets as disclosed by the applicant eliminates the necessity of tablets being dried overnight before the application of the shellac. Another advantage of this novel invention is that less handling of the tablets is required since they do not have to be racked and repanned a second time. A further advantage of this invention is that it permits the shellac coating of the pharmaceutical forms in the same pan in which they are sugar coated following the normal pan drying cycle thus eliminating the necessity of special shellacking pans. The method and tablet of this invention is, therefore, markedly less expensive than those disclosed in the prior art because of the great reduction in operating time and the elimination of special shellac coaing pans discussed above.

The method of printing the solid pharmaceutical forms such as compressed tablets, pills, troches and the like in accordance with this invention comprises preparing a water soluble form of shellac and applying the shellac directly to the tablets immediately after they have been coated and given the usual pan drying period. It is a con- 'ice tinuous operation starting with the coating of the medicinal core to the final shellac coating before the tablets are removed from the pan. Since the shellac is water soluble it does not cause frosting of the coated tablets if they are not thoroughly dried, in fact, it prevents the tablets from frosting. The shellac coated tablets are then removed from the coating pans, printed and polished.

The water soluble shellac is prepared by dissolving wax free shellac in water and ammonia until a solution results. The ratio of water and ammonia to the wax free shellac would be evident to one skilled in the art using just enough necessary to dissolve the shellac. Preferably twice as much water and 28% ammonia solution (U.S.P.) used in a ratio of about 10:1 to about 30:1 is used to dissolve the shellac. If desired, alcohol may be added to hasten the evaporation of the water soluble shellac coating on the tablets.

The printing and polishing of tablets referred to above are very well known conventional steps in the tableting art. For example, the printing can be accomplished simply by biasing the tablets against a printing mechanism such as a stamp or roller having the desired monogram and saturated with any of the well known edible inks. Tablet printing machines are available to perform a continuous operation of printing and conveying the tablets, i.e., mass production.

The polishing operation is well known to the art and the materials used may be, for example, beeswax, carnauba wax, ozokerite or ceresin. Preferably a combination of beeswax and carnauba wax in various proportions is used.

The coated tablets referred to in this invention can have any coating well known to the art, such as for example, sugar coating, enteric coating, film coating or the many difierent forms of sustained release coatings.

The solid pharmaceutical forms which are printed using this novel procedure comprises coated tablets, pills, troches and the like substantially and completely coated with water soluble shellac and having an ink identifying monogram marked upon a portion of the shellac coating. If desired, the tablet can be finished with a polishing coat of wax.

While this invention applies mainly to the phamaceutical industry it is to be understood that this method of printing can be applied to any industry which desires to ink monogram their edible products.

The following is an example which is not limiting but is used specifically to illustrate the water soluble shellac coating composition and method of application. It will make it obvious to one skilled in the art the full practice of the method of this invention.

Example Ingredients: Amounts, gm. Shellac, dry, white, wax free 500 Water, purified 950 Ammonia solution, 28% 50 The shellac, Water and ammonia solution are heated on a steam bath until a thick molasses-like solution results. The solution is then filtered and the final solution is approximately shellac. To 15 grams of this water soluble shellac is added 10 grams of purified water and this solution is then diluted with enough isopropyl alcohol to make 500 ml.

Tablet cores containing chlorpromazine and filler are placed in a rotating 12 inch coating pan and are sugar coated and dried. While continuing to rotate the coating pantthetwater soluble shellac solution is thenaddeddirectly to the coated cores in the rotating pan and allowed to dry while rotating in the pan. The tablets are then removed from the coating pan and ink monogrammed. A polish coating of beeswax is then applied to the printed tablets.

What is claimed is:

1. In a method of preparing printed pharmaceutical forms comprising coating pharmaceutical forms rotating in a coating pan to give coated forms, drying said coated forms and ink printing said coated forms, the novel'step of covering said coated forms with a Water soluble shellac solution prior to said ink printing.

2; The method of claim 1 characterized in that all coating operations including the application ofthe water soluble shellac are continuous.

3. The method of claim 1 further characterized in tha the pharmaceutical forms are coated with a sugar coating.

References Cited in the file of this patent UNITED STATES PATENTS 3,015,609 Sanders l Jan. 2, 1962

Claims (1)

1. IN A METHOD OF PREPARING PRINTGED PHARMACEUTICAL FORMS COMPRISING COATING PHARMACEUTICAL FORMS ROTATING IN A COATING PAN TO GIVE COATED FORMS, DRYING SAID COATED FORMS AND INK PRINTING SAID COATED FORMS, THE NOVEL STEP OF COVERING SAID COATED FORMS WITH A WATER SOLUBLE SHELLAC SOLUTION PRIOR TO SAID INK PRINTING.