MXPA01000257A - Dry-copying method for producing flat, individually dosed preparations of active agents - Google Patents

Abstract

The invention relates to a method for dosing active agents in powder form onto a given surface. The method is characterised in that the active agent is transferred onto a roller in the form of an electrically charged powder, said roller having an opposite electric charge, in that the active agent transferred to the roller is then transferred onto a flat substrate with the opposite electriccharge to the active agent and in that the active agent transferred onto the substrate is fixed by means of heat treatment.

Description

DRY COPY PROCESS FOR THE PREPARATION OF LAMINAR ACTIVE SUBSTANCE PREPARATIONS AND IN INDIVIDUAL DOSES DESCRIPTION OF THE INVENTION Preparations of active substance in individual doses are understood to be those preparations containing a predefined quantity of active substance in separate preparation units which can be handled one by one. For the purposes of the present invention, it can be understood by active substance, for example, a medicine, an insecticide, a pesticide, a reagent, etc. If active substance means, for example, a medicinal active substance, the drug forms in individual doses can be tablets, capsules, suppositories or transcutaneous therapeutic systems (STT). They would not be prepared in individual doses, for example, sprays, syrups, ointments and drops, in which the actual dosage is not prepared until a moment before use. In active compound preparations in individual doses, the active substance must be processed in a dosed amount together with the auxiliary substances that may be necessary for the application of preparations with that active substance. This technique can be considered successful in the manufacture of tablets and capsules. The presses of Ref: 126566 tablets and modern capsule filling machines guarantee a high production speed and a very accurate dosage in a range of 95 to 105% of the theoretical value. In contrast, transcutaneous therapeutic systems are still a relatively new pharmacological form, which is applied to the skin in the form of a patch and transfers the active substance to the body through the skin. For the production of these STT, special dosing techniques are used and it is still possible to incorporate other innovations related to new dosing techniques. In a variant of these STTs, the active substance is contained in the glue itself and during processing it is dosed in film form on a sheet together with the glue. Thus, STTs are the only preparations in which it occurs that a medicinal active substance is dosed in a predefined quantity on a preset surface. If non-medicinal active substances are considered, such as for example insecticides, pesticides or reagents, laminar preparations in the form of impregnated papers, sheets or cartons have been known for a long time. But these applications do not impose very demanding requirements on the accuracy of the dosage on the surface of the support.

The present invention proposes the task of providing a method for the dosing of powdered active substances on a pre-fixed surface. The task is solved by the use of the known technique of dry copying with a process that responds to the characteristics of the main claim 1. It has been shown that this technique is in a position to dose active substances in powder on a surface with an accuracy Enough also for medications. It is advisable to exercise prudence when using color copiers, in which each color is dosed separately and large inaccuracies would distort the colors. The process of dry copying or xerography works in the way explained below. A roller coated with a photoconductive material is provided with a positive electric charge and illuminated by a suitable lens with the pattern to be copied. This process causes the charge to be removed, at least in part, where the exposure increases the conductivity of the photoconductive material. In a next step, negatively charged ink particles (toner) are applied to the roller, which only adhere to the still charged surfaces of the roller in an amount that depends on the magnitude of the load and creates a visible image thereon. Next, the ink particles (toner) are transferred to a paper or sheet loaded with a positive sign, where they are fixed by a heat treatment. A modern variant of the procedure is applied in so-called laser printers. In them, the roller lights without pattern, with a direct laser beam, and the image is recorded directly on the roller with the help of a computer. For the rest, laser printers use the same technique as in dry copiers. The present invention is based on the use of these processes to transfer particles of active substance instead of ink pigments to paper or sheets.

In tests performed with a normal black and white copier, the quantities of toner that can be transferred to a sheet and the reproducibility of the process were calculated.

The sheets used were ordinary polyester sheets, of the usual size in commerce, in DIN A4 format.

The pattern used was an intense black sheet of paper and the strongest degree of blackening was selected for the copy. results are collected in the following table, Table 1 The results indicate that while a relatively small amount of toner was transferred, it was done with an accuracy that is appropriate even for medicinal applications. In a subsequent test it was ascertained whether the quantity can be increased by multiple dosing. The results are represented in FIG. 1 and show that the amount of toner transferred is proportional to the number of copying processes. This result shows that, although the amount transferred in a copying process is small, this drawback can be overcome if the copying is multiple, without adversely affecting the accuracy of the dosage. The amount of toner or active substance transferred depends on the state of charge of the copying roller and can be increased by a denser load, higher than usual in copying machines. When the active substance is dosed without a special sample, the exposure phase can be dispensed with. In this case, it is not necessary that the copy roller be made of a photoconductive material. If you want to perform the dosage in a sample, it is necessary to apply the exposure phase and use a copy roller coated with a photoconductive material, for example selenium. The exposure can be done on a pattern or also by a computer controlled laser. Naturally, the maximum variability is obtained with computer controlled exposure. It must be assumed that most of the active substances are colorless. In light of this evidence, it is prudent to add an indicator dye to the powdery mixture of active substance and auxiliary substance. This dye then allows, after the corresponding calibration, to measure by direct optical methods the quantity of active substance that is transferred and automatically counteract possible deviations from the theoretical value. The laminar substrate to whose surface the active substance is transferred can, in principle, consist of any material, provided that the substrate is flexible and suitable to support the fixing process. It is conceivable that the material is used in the form of sheets or comes from a roll. This material is then cut into smaller parts in the course of further processing and thus transferred to the preparation of active substance in individual doses. An alternative is that the material is perforated, and then the dosage is matched to the perforations.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (7)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. Procedure for the dosing of powder active substance on a predefined surface, characterized by

- Transfer the active substance in the form of an electrically charged powder onto a roller with charges of opposite sign, - Transfer the active substance transferred to the roller to a laminar substrate having an electrical charge opposite to that of the active substance, - Fix the active substance transferred to the substrate by a heat treatment. 2. Process according to claim 1, characterized in that other powdered auxiliary substances are metered in together with the active substance.

3. Method according to claim 2, characterized in that at least one auxiliary substance is used as a fixative.

4. Process according to claim 2, characterized in that an auxiliary substance is used that is used for the optical calculation of the quantity of active substance. Method according to claims 1 to 4, characterized in that the roller is coated with a photoconductive material.

ID

6. Process according to claim 1, characterized by influencing the exposure of the loaded roller in the charge of the roller and therefore in the amount and / or the pattern of transfer of active substance. Method according to claim 6, characterized in that the exposure of the roller is carried out by means of a laser with the aid of a computer or, in the traditional manner, by the optical reproduction of a pattern.