US3576665A - Method for applying high luster coating to tablets - Google Patents

Abstract

A METHOD OF IMPARTING A HIGH LUSTER COATING TO INGESTIBLE TABLETS IS CARRIED OUT BY COATING WITH A LIQUID COMPOSITION WHICH IS 30-40% POWDERED CARNAUBA WAX, 10-20% WAX WHITE AND 40-60% METHYLCHLOROFORM OR PETROLEUM BENZIN.

Description

Unitcd States Patent 3,576,665 METHOD FOR APPLYING HIGH LUSTER COATING TO TABLETS Allan H. Cheiken, Elkins Park, and Joseph F. Bavitz, Willow Grove, Pa., assignors to Merck & Co., Inc., Rahway, NJ. No Drawing. Filed July 1, 1968, Ser. No. 741,274 Int. Cl. B44d 1/02; A61]; 9/00 U.S. Cl. 117-100 1 Claim ABSTRACT OF THE DISCLOSURE A method of imparting a high luster coating to ingestible tablets is carried out by coating with a liquid composition which is 30-40% powdered carnauba wax, 10-20% wax white and 40-60% methylchloroform or petroleum benzin.

PRIOR .ART

Remingtons Practice of Pharmacy and Pharmaceutical Sciences 13th ed. pages 598-599 contains related prior art.

This invention relates to a liquid wax and the techniques used in applying this mixture to sugar and film coated tablets in order to induce a high luster onto the tablets thereby improving the elegance of this finished product.

It is a generally acknowledged fact that a shiny surface on a tablet makes it more acceptable to the consumer. A dull surface creates an unfavorable impression to the point that some consumer will unthinkingly conclude that the tablet and its contents are of a low quality. This is especially true of pharmaceutical tablets but it applies as well to tablets in general such as candy and chewing gum tablets. A high luster therefore induces the consumer to place a higher intrinsic 'value on the tablet.

In the past the luster of film coated tablets has been achieved by a so-called dry polishing operation in which the tablets, in a dry condition, are dusted with a dry, ground wax mixture and then continually rubbed against each other in a conventional tumbling barrel. This constant frictional contact serves to achieve a generalized polishing eifect but the resulting tablets failed to attain a high degree of luster.

Sugar coated tablets, on the other hand, require a very critical so-called set-up step during the process just prior to the application of the dry waxes in order to finally achieve a high luster. The use of the liquid wax mixture induces a high luster onto film coated tablets and eliminates the set-up in the sugar coating process.

The composition which is applied to the tablets has the following relative proportions on a weight basis:

TABLE Percent Carnauba wax powdered 30-40 Wax white USP 10-20 Solvent 40-60 "ice The solution is applied at room temperature to the tablets in a tumbling barrel by pouring it onto them. It is applied either continuously or discontinuously and at such a rate that one to two ml. per kg. of tablets is applied in 10 minutes.

The amount applied per tablet will average less than 1 mg. for a /8" diameter tablet and a smaller or larger tablet will require a corresponding amount based on its surface area. Usually, the total application time will be 35 to 45 minutes, at the rate stated above, and thereafter a final drying period may be expedited by a blast of warmed drying air as in conventional practice.

Representative examples are the following:

EXAMPLE 1 Ten kilos of pharmaceutical tablets having a conventional sugar coating and which were in diameter and thick were placed in a tumbling barrel and rotated at 25 r.p.m. 15 ml. of a previously prepared solution by weight of 35% powdered carnauba wax, 15% wax white USP and 50% methylchloroform was poured onto the sloping surface of the tablets. The tablets continued to tumble for 10 minutes at which time a second application of 15 ml. was applied. After 10 additional minutes of tumbling, 15 ml. of the solution was again applied and the tablets rolled for an additional 20 minutes. The tablets were removed and found to have a very high luster. Each tablet had an outer shiny coating.

EXAMPLE 2 Conventional sugar coated chewing gum tablets of the Chiclets type are put in the tumbling barrel and the process of Example 1 is carried out. The tablets will be found to be extremely shiny.

EXAMPLE 3 The process of Example 1 was carried out but petroleum benzin was substituted for the methylchloroform. The same high luster was produced.

EXAMPLE 4 The process of Example 1 is carried out using various compositions in the ranges of the above table and were found to have the same high luster.

EXAMPLE 5 The process of Example 1 is carried out several times, applying the solution at the rate of only 1 ml. in ten minutes and at 2 ml. in ten minutes. The application times were varied from 35 to 45 minutes and in all instances the same ultra shiny surface will appear.

EXAMPLE 6 The process of claim 1 is carried out using tablets which had been film coated with conventional synthetic resins and the same extremely high luster is imparted. These film coatings were the conventional ones such as are described in Pats. 3,383,236; 3,379,554; 3,112,220; 3,325,365 and 3,275,518, and the references cited in them disclosing synthetic film forming coatings.

EXAMPLE 7 The process of Example 1 is carried out as a supplement to ordinary coating without removal of the tablets from the coating pan. For instance, after a conventional sugar or synthetic coating has been applied to tablets in a conventional tablet tumbling pan the tablets are allowed to remain therein and vyith or wi thout 's topping' the pan rotation, the process of this invention is carried out.

What is claimed is:

1. The method of imparting a high luster t0 ingestible tablets 'which comprises applying to them a composition consisting essentially of by weight, 30-40% powdered earnauba Wax, 1020% Wax White and 4060% of a solvent selected from the group consisting of methylchloroform and petroleum benzin, at the rate of 1 to 2 ml. per kg. in 10 minutes over a 35 to 45 minute period, and drying said tablets.

References Cited UNITED STATES PATENTS 3 141,722. 174 264., with; i x

' 3,145,146 "8/1964'"iieliernian'ef'ali TIT- lOOX FOREIGN' PATENTS 256,128 4/1963 Australia 117100 683,244 3/1964 Canada 117100 OTHER REFE RENCES Hackhs Chemical Dictionary, 4th ed., p5 87. I Remingtons Practice of Pharmacy & Pharmaceutical Sciences, 13th ed., pp. 598-99. V

WILLIAM ID. MARTIN, Primary Examiner M. R. P. PERRONE, JR.', Assistant Examiner Us. 01. X.R.