GB2191117A - The production of coated intagliated articles - Google Patents

Abstract

The present invention provides a process for the preparation of a coloured article having at least one highlighted intagliation which comprises applying to a white intagliated article a film coating suspension comprising a colouring substance, at least one optically anisotropic substance and at least one film coating agent.

Description

SPECIFICATION The production of articles The present invention relates to the production of articles, such as tablets, boluses, sweets, and the like having intaligations which are highlighted.

Various methods are used for putting product names, company names, Trade Marks and other information on the surface of articles such astablets.

One common method involves printing the information on the surface of the article. This method is not always satisfactory if the article has a curved surface, e.g. a convex tablet as lettering towards the edges is either not clear or even missing.

Another method involves the use oftablets having intagliations, whereby the information is engraved or incised in the surface. The intagliations can be incorporated onto the articles easily during the preparation ofthe articles i.e. during stamping. Usually the intagliations are in the same colour as the remainder of the article and do not stand out very much.

EP 0060023 describes a method whereby the intagliations may be highlighted in a different colour from the remainder of the article. The method comprises applying to a coloured intagliated article a film coating suspension comprising at least one optically anisotropic substance having a minimum refractive index not greater than 2.00 and at least one film coating agent, which process is carried out in a conventional film coating apparatus such that a rubbing action takes place between the articles being coated.

We have now surprisingly found thatwhite (i.e.

non-coloured) intagliated articles may be treated in one step to highlightthe intagliations if the articles are coated with a coloured film coating suspension containing an optically anisotropic substance.

Accordingly the present invention provides a pro cessforthe preparation of a coloured article having at least one highlighted intagliation which comprises applying to a white intagliated article a film coating suspension comprising a colouring substance, at least one optically anisotropic substance and at least one film coating agent.

The intagliated article may be a medicinal tablet or bolus i.e. for veterinary use, or a piece of sugarconfectionery e.g. sweets or any other intagliated article where it is desirable to highlight the intagliations.

The colouring substance may be any which is approved for the purpose in question. For instance a pharmaceutically acceptable colouring substance would be used on medicinal tablets. The colouring substance may be a dye, a laked dye or a pigment.

Suitable substances include iron oxide (red, yellow or black), carmine, indigo carmine, ponceau watersoluble dye and aluminium lakes of water-soluble dyes.

The optically anisotropic substance preferably has a minimum refractive index the same as or very close to that ofthe film coating agent used. The greaterthe difference between the minimum and maximum refractive indices, the betterthe highlighting of the intagliations. Suitable substances include calcium carbonate, barium carbonate, magnesium carbonate, aluminium hydroxide, kaolin, talc, sucrose, lactose andtartaricacid. Of these magnesium carbonate has the largest difference in its refractive indices (1.51 and 1.70) and is preferred.

In addition we have found thatsmall particles of the anisotropic substance show better highlighting of the intagliations than do larger particles. We pre ferto use a particle size of below (500 ), and prefer ably below (20 > ).

The amount of optically anisotropic substance de pends not only on the difference in refractive indices and particle size, but also on the colouring substance used. Suitable amounts may vary between 0.1 and 10%, preferably between 1 % and 5% by weight of the intagliated article.

The film coatings agent may be anywhich are known in the art, for example a cellulose ether such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose or odium carboxymethyl cellulose, or cellulose acetate phthalate, hydroxypropyl methy Icellulose phthalate, polyvinyl acetate, polyvinyl acetate phthalate, cellulose acetate, shellac or an ac rylic resin, or a mixture of one or more ofthese.

The film coating suspension may also contain one or more adjuvants which are conventional in film coating, such as surface active agents e.g. polyoxyethylene sorbitan monooleate, waxes, e.g.

beeswax or carnuba wax and plasticisers, e.g. glycerol, propyleneglycol, polyethylene glycol, diethyl phthalate,glyceryl monostearateandcastoroil.

The resulting article with highlighted intagliations may optionally be further coated with a second coat similar to the first coat but without the optically anisotropic substance. The second coating may contain a different colour two that in the first coat thugs leading to articles in which the intagliations are highlighted in a differentcolourthanthe main bodyofthearticle.

The film coating process may be carried out in conventional apparatus such as a coating drum, e.g. a side-vented coating drum apparatus a coating pin, or afluidised bed apparatus, e.g.aWurstercolumn.

The invention is illustrated by the following Examples.

Example I A batch of 2,000 345 mg intagliated white placebo tablets and a batch of 36,700 105 mg intagliated white placebo tablets are heated to 600coin a side vented perforated coating drum 24 inch Accela-Cota machine. A solution of hydroxypropyl methylcellulose 1 20g and glycerol 24g dissolved in water, 2.4 litres, and containing magnesium carbonate 1209 and red iron oxide 3.29 suspended therein is applied continuously at 30 ml/min by means of a low pressure airsprayunit. The drum speed is kept at between 12 and 18 rpm and the temperature of the inlet drying air at 60"C. After addition of all of the coating suspension the drum is stopped and the tablets removed. There are thus obtained brown film coated placebo tablets with intagliations highlighted in white.

Example2 A batch of 2,000 345 mg intagliated white placebo tablets and a batch of 11,100310 mg non-intagliated white medicinal tables are heated to 60"C in a side vented perforated coating drum 24 inch Accela-Cota machine. A solution of hydroxypropyl methyicellulose 150g, glycerol 309 and Ponceau water-soluble dye 3.09, dissolved in water, 3 litres, and containing magnesium carbonate 150g, suspended therein, is applied continuously at30 ml/min by means of a low pressure air spray unit. The drum speed is kept at 12 rpm and the temperature of the inlet drying air at 60"C. After addition of all of the coating suspension the drum is stopped and the tablets removed.There are thus obtained red film coated medicinal tablets and red film coated placebo tablets with intagliations highlighted in white.

Example 3 A batch of 2,000 345 mg intagliated white placebo tablets and a batch of 36,700 105 mg intagliated white placebo tablets are heated to 60"C in a side vented perforated coating drum 24 inch Accela-Cota machine.Asolution of hydroxypropyl methylcellulose 1209 and glycerol 249 dissolved in water, 2.4 litres, and containing magnesium carbonate 1 20g and FD+C red No.3 aluminium lake 3.09, suspended therein is applied continuously at 30 ml/min by means of a low pressure air spray unit. The drum speed is keptat between 12 and 18 rpm andthetemperature of the inlet drying air at 60 C. After addition of all ofthe coating suspension the drum is stopped and the tablets removed.There are thus obtained pinkfilm coated placebo tablets with intagliations highlighted in white.

Example 4 A batch of 2,000 3459 intagliated white placebo tablets and a batch of 11,100 310 mg non-intagliated white medicinal tablets are heated to 60"C in a side vented perforated coating drum 24 inch Accela-Cota machine. A solution of hydroxypropyl methylcel lulose 1 50g, glycerol 30g and ponceau water soluble dye3.0g dissolved in water,3 litres, and containing calcium carbonate 300g suspended therein is app lied continuously at30 ml/min by means of a low pressure air spray unit. The drum speed is kept at 12 rpmandthetemperatureoftheinletdryingairat 60"C. After addition of all of the coating suspension the drum is stopped and the tablets removed.There are thus obtained red film coated medicinal tablets and red film coated placebo tablets with intagliations highlighted in white.

Example 5 A batch of 2,000 345 mg intagliated white placebo tablets and a batch of 11,100310 mg non-intagliated white medicinal tablets are heated to 60"C in a side vented performated coating drum 24 inch Accela Cota. A solution of hydroxypropyl methylcellulose 120g, poiyethylene glycol 400 249, indigo carmine watersoluble dye 50 mg and FD+C red No.3water soluble dye 5.0g dissolved in water, 2.4 litres, and containing magnesium carbonate 1209 suspended therein is applied continuouslyat30 ml/min by means of a low pressure air spray unit. The drum speed is kept at 12 rpm and the temperature of the inlet drying air at 60"C.After addition of all of the coating suspension the drum is stopped and the tablets removed. There arethus obtained mauvefllm coated placebo tablets with intagliations highlighted in white.

Example 6 The batch of 38,700 brown film coated placebo tablets with intagliations highlighted in white obtained from Example 1 and approximately 200 red film coated placebo tablets with intagliations highlighted in white obtained from Example 2 are heated to 60"C in a side vented perforated coating drum 24 inch Ac- cela-Cota machine. A solution of hydroxypropyl methylcellulose 30g, glycerol 39 and indigo carmine water soluble dye 250 mg dissolved in water, 1 litre, is applied continuously at 30 ml/min by means of a low pessure air spray unit. The drum speed is kept at between 12 and 18 rpm and the temperature ofthe inlet drying air at 600C. After addition of all of the coating solution, the drum is stopped and the tablets removed. There are thus obtained black film coated placebo tablets with intagliations highlighted in blue (obtained from the original brown intagliated tablets) and purple film coated placebo tablets in- tagliations highlighted in blue (obtained from the original red intagliated tablets).

Claims (14)

1. A process for the preparation of a coloured article having at least one highlighted intagliation which comprises applying to a white intagliated article a film coating suspension comprising a colouring substance, at least one optically anisotropic substance and at least one film coating agent.

2. A process as claimed in claim 1 in which the article is a medicinal tablet or bolus or a piece of sugar confectionery.

3. A process as claimed in claim 1 or 2 in which the colouring substance is a dye, a laked dye ora pigment.

4. A process as claimed in claim 3 in which the colouring substance is red, yellow or black iron oxide, carmine, indigo carmine, ponceau watersoluble dye oran aluminium lakeofa water soluble dye.

5. A process as claimed in any preceding claim in which the optically anisotropic substance has a minimum refractive index the same as or very close to that of the film coating agent.

6. A process as claimed in any preceding claim in which the optically anisotropic substance is calcium carbonate, barium carbonate, magnesium carbonate, aluminium hydroxide, kaolin, talc, sucrose, lactose ortartaric acid.

7. A process as claimed in any preceding claim in which the optically anisotropic substance has a particle size below (500 p).

8. A process as claimed in any preceding claim in which the amount of optically anisotropic substance is from 0.1 % to 10% by weight of the intagliated article.

9. A process as claimed in any preceding claim in which the film coating agent is a cellulose ether.

10. A process as claimed in any preceding claim in which the resulting'article with highlighted in- tagliations is coated with a second coat similar to the first coat but without the optically anisotropic substance.

11. Aprocess as claimed in claim lOin which the second coat comprises a different colour to that in the first coat.

12. A process as claimed in any preceding claim which is carried out in a coating drum, a coating pan or a fluidised bed apparatus.

13. A process as claimed in claim 1 substantially as hereinbefore described with reference to any one oftheforegoing Examples.

14. An article bearing at least one highlighted intagliation whenever prepared by a process as claimed in anyone of claims 1 to 13.