Coating processes – Medical or dental purpose product; parts; subcombinations;... – Particulate or unit-dosage-article base
Patent
1997-06-20
1999-04-27
Dudash, Diana
Coating processes
Medical or dental purpose product; parts; subcombinations;...
Particulate or unit-dosage-article base
427 221, 427358, 427365, 427366, B05D 312, A61J 306, A61J 307
Patent
active
058979107
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a process for the production of covered tablets by molding a melt which contains an active ingredient in a calender with counter-rotating molding rolls which have on their surface depressions for receiving and molding the tablet composition (melt calendering).
The production of tablets by calendering a melt containing an active ingredient is disclosed in DE-A 1 766 546 and U.S. Pat. No. 4,880,585. The basis of this process is the embedding of an active ingredient in a melt of a carrier, eg. fatty substances or water-soluble thermoplastic polymers. The melt is produced by melting the mixture of active ingredient, polymer and, where appropriate, other ancillary substances, for example in an extruder, and molding the melt in a downstream molding calender to give tablets, which harden on cooling. The molding calender comprises a pair of counter-rotating molding rolls which have on their surface engravings (depressions) which correspond to the shape of one half of the required tablet. The tablet molding takes place in the region of contact of the two rolls by combination of the tablet composition in one depression on one roll with that in the opposite depression on the other roll.
Most of the tablets on the market are produced as film-coated tablets, ie. a thin layer of water-soluble polymers is applied to the tablets in the last production step. This film-coating is often indispensable for various reasons, because, for example, substances used must be masked until the tablet reaches the stomach, etc.,
The protective layers (the coating) have to date been applied almost exclusively by spraying on solutions of water-soluble polymers (organic solvents and/or water) with simultaneous drying. Besides the film coating (layer thickness in the micrometer range) which is conventional nowadays, there is the sugar-coating process in which thick layers, which are sometimes in the millimeter range, of sugar-containing mixtures are applied. These widely used techniques are described in various textbooks (see H. Sucker, P. Fuchs, P. Speiser: Pharmazeutische Technologie; 2nd edition, G. Thieme Verlag Stuttgart (1991), pages 347-368).
If a coating was required over the tablets produced by melt calendering it was necessary to apply this coating in a separate step after the tablets had cooled. This took place in a conventional way, for example by spraying on in rotating drums, by the dip pipe process or in a fluidized bed etc.
The conventional processes for applying coating layers or for sugar coating all require comparatively very high energy input, because the solvents used in the spray solutions must be removed again rapidly after spraying onto the tablets. In addition, a coating process usually takes several hours because the spraying rate cannot be set as high as may be required.
The application of the coating in a separate step thus requires considerable expenditure of time, additional machinery and additional staff, which has marked effects on the production costs.
It is an object of the present invention to provide a process for the production of covered tablets by melt calendering in which covering of the tablets is possible in a simple and cost-saving manner.
We have found that this object is achieved by producing tablets by melt calendering with the melt containing active ingredient being introduced between two sheets of the covering material into the calender molding rolls.
The present invention therefore relates to a process for the production of covered tablets by molding a melt containing active ingredient in a calender with two counter-rotating molding rolls which have on their surface mutually opposite depressions for receiving and molding the tablet composition, wherein the melt containing active ingredient is introduced between two sheets of the covering material into the molding rolls.
The tablets are produced starting from a mixture which contains one or more pharmaceutical active ingredients and one or more conventional ancillary substances and which becomes a paste or visco
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Breitenbach Jorg
Grabowski Sven
Maier Werner
Rosenberg Joerg
BASF - Aktiengesellschaft
Dudash Diana
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