DE302334C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

CLASS 30 ^. GROUP

LEONHARD PINK in BERLIN.

It is known that preparations, such as pills and the like, can be used against the destructive effects of the atmosphere and to prevent the escape of volatile substances with protective layers made of wax, fats or cellulose derivatives . Mistake. In these procedures, wax and fats are used as such by adding them heated to melt and then the preparations to be protected into the melted

ίο crowds dives. With the pressed, hard ones Formaldehyde-containing tablets, above procedures are not applicable because they are thick overlying fat or wax coatings are very difficult to digest and the tablets give an irregular, unsightly appearance. Such coating by immersion in molten masses can at most in the pharmacy with a small number of Conveniently carried out by hand commercially, but not well in large-scale production.

It is also known from British patent 27775/09, alcoholic wax solutions to be used for the production of protective layers. However . you can only wax in dissolve boiling alcohol; such hot solution is not for coating tablets usable, even after the slow evaporation of the alcohol the wax remains on the Heat-altered tablets in greasy or easily crumbling crystalline form Shape back.

The present process is based on the fact that to obtain formaldehyde almost gas-tight, very thin coatings, which clearly show the embossing of the tablets. - Let it step forward, first by means of a cold solution of wax in a mixture of Petroleum ether and chloroform produces a thin wax coating and on this with a solution of acetyl cellulose or nitrocellulose in acetone brings a second.

Example:

1st solution: 100 g of crushed wax will be dissolved in 600 g of petroleum ether and 300 g of chloroform at ordinary temperature.

2nd solution: 10 g of nitrocellulose are in 990 g of acetone dissolved.

500 tablets are poured with solution 1 in a vessel at normal temperature and poured the whole contents into a large funnel; the excess solution expires and can be regained. The tablets are dry in a short time and are then treated with solution 2 in the same way.

Comparative tests were carried out to prove the superiority of the new double coating performed:

From a vessel with 5000 tablets ₇ the 500 tablets were used each time for a sample, namely:

No. o: Common, freshly made tablets containing formaldehyde.

- ι: The same tablets with melted

coated with zenem wax.

- ι a: the same with a thin wax

layer of a solution of wax in petroleum ether chloroform coated.

- 2: The same with a layer of

Nitrocellulose solution
overdrawn.

(1 percent)

No. 2a: The same with a thin layer

Wax from a solution of wax

in petroleum ether chloroform and then

with a layer of nitrocellulose (from ι percent solution)

■ moved.

No. 2 a corresponds to the present proceedings. ·.

JSIr tablets. 1 were made by dipping in wax melted at 100 °. If you kept the temperature of the Melt to about 75 ° and then dipped the tablets into the melted wax, so the whole mass solidified in a sticky pulp. But at higher temperatures the tablets melt and lose their shape easily. When making the pattern went consequently most of it is lost; even the best ones were not edible. Of the Attempt to give tablets a suitable coating with an alcoholic wax solution, failed completely. Most of it lost its shape in the hot solution, the rest of it wilted a greasy, crystal-riddled coating. As a result of slow evaporation such tablets lost within 3 days of alcohol Half of the formaldehyde. "

All samples were exposed to air under the same conditions in open dishes and each time 10 'tablets were used Related to analysis.

The following results were obtained:

Formaldehyde content of one tablet after various periods of time:

sample sample sample sample sample No. ο No. ι No. ι a No. 2 No. 2 a ι. Day: 0.0105 0.0102 0.0105 0.0090 0.0105, 3- - ■ 0.0051 0.0102 0.0084 0.0048 0.0096, 5 - 0.0028 0.0099 0.0078 0.0045 0.0096, 7 - 0.0026 0.0099 0.0069 p, OO26 0.0090, ο. - - .—. - 0.0078.

Melted wax can be used as a coating to prevent the release of formaldehyde, but the tablets produced in this way are inedible and indigestible. The tablets with wax from alcoholic solutions are unusable and lose the very quickly Formaldehyde. The tablets without a coating become ineffective, as is the coating from a cellulose derivative alone does not increase evaporation. The wax layer off the cold solution gives a comparatively favorable result. But only in. Connection with the cellulose layer, the exclusion of air is practically sufficient. Additional to that, that in the tropics and during the warm season, even when stored in a warm one Place the cellulose layer neutralizes the damaging influence of heat on the wax layer.

Claims (1)

Patent-An saying: Process for increasing the shelf life of tablets containing formaldehyde, characterized in that in order to achieve almost gas-tight for formaldehyde, very thin protective layers that still leave the embossing of the tablets Make it stand out sharply, initially by means of a cold solution of wax in one Mixture of petroleum ether and chloroform a thin wax coating and then a solution of acetyl cellulose or nitrocellulose in acetone a thin coating of a cellulose derivative on the Tablets produced.