Plastic and nonmetallic article shaping or treating: processes – Forming articles by uniting randomly associated particles
Reexamination Certificate
2001-10-10
2004-09-07
Theisen, Mary Lynn (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Forming articles by uniting randomly associated particles
C264S123000, C425S344000, C425S345000, C425S352000, C425S353000, C425S469000
Reexamination Certificate
active
06787082
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a punch, which is used for the preparation of tablets containing an acidic substance, for example, an acidic pharmacologically active substance, an acidic excipient or the like, and which is excellent in corrosion resistance and in releasing property. In addition, the present invention relates to a punch, which is used in the preparation of tablets containing an adhesive substance, for example, an adhesive pharmacologically active substance, an adhesive excipient (for example, a sugar alcohol) or the like, and which has a favorable releasing property.
Moreover, the present invention relates to a tablet machine equipped with such a punch, a process for preparation of tablets using said tablet machine and tablets prepared by said process for preparation.
BACKGROUND ART
Common tablets are prepared by compressing powders to form tablets by the us e of punches and dies provided in a tablet machine. Briefly, the machine is constituted as follows: die bore is perforated in dies provided in a die table; height of lower punches provided at lower side in the die bore is adjusted so that respective spaces in the holes have a predetermined volume; powders for tablet including powdery pharmaceuticals or the like are filled in the die bore; the powders are compressed with upper punches to form tablets; and the tablets are pushed upward by the lower punches to eject the tablets from the die bore.
The above-described punches should not be deformed easily, and a high mechanical strength is required for punches. Therefore, they have been conventionally made of super steel alloy or alloy tool steel. In addition, punches having chrome plating layer or the like on the punch surface are also used as a measure against corrosion.
DISCLOSURE OF THE INVENTION
The conventional punches made of alloy tool steel or the like as described above have a problem that a metal material or basis metal of punches has a corrosion-susceptible nature in principle, and particularly when the powders for compressing to form tablets contain an acidic substance such as an acidic drug or the like, the above metal material is more easily corroded by compressing such powders and corrosion can commence even during the compressing of powders to form tablets.
When the corrosion occurs on the punches, the slippage between the tablets prepared and die bore is not smooth and releasing property for powders become inferior, so that pushing out of the prepared tablets from die bore becomes difficult and there is a possibility that foreign materials formed by the above-described corrosion are mixed in tablets.
In addition, when the releasing property between the powders and the punch surface is inferior, problems arise that the powders for compressing tablet adhere on the punch surface so that the compressed tablet surface becomes roughened, a clear carved mark or indication cannot be formed on the tablet surface and so on.
The invention has a technical object that the above problems are solved and, particularly, that a punch is provided which is suitable for a tablet machine for molding tablets of pharmaceuticals containing an acidic substance such as an acidic drug or the like, and has excellent corrosion resistance and releasing property.
In addition, in the conventional punches using an alloy tool steel described above, a metal material has in principle a property that the powders for compressing to form tablets adhere on its surface, and particularly when the powders for compression contain an adhesive substance, for example, an adhesive pharmacologically active substance or an adhesive excipient (such as sugar alcohols) or the like, the adherence to the above-described metal material is more liable to proceed upon compressing. When such an adhesion generates, the releasing property between the powders for compressing tablet and the punch surface becomes inferior and problems arise that the compressed tablet surface becomes roughened, a clear carved mark cannot be formed on the tablets surface and so on.
The invention has a technical object that the above problems are solved and, particularly, it is an object of the present invention to provide a punch for preparing tablets, which is suitable for a tablet machine for molding or preparing tablets with a pharmaceutical preparation containing an adhesive substance for example, an adhesive pharmacologically active substance, an adhesive excipient (such as sugar alcohols) or the like, and has an excellent releasing property.
As the result of intensive researches conducted in order to solve the above-described problems, the present inventors have obtained an unexpectedly found that a punch having a coating with Cr-Dopé-N on the surface of a basis metal (for example, an alloy tool steel) has excellent corrosion resistance and releasing property. The invention has been completed upon such and further researches.
Therefore, the invention provides:
[1] A punch for compressing powders to prepare tablets, which is characterized in that the surface of the punch is coated with Cr-Dopé-N.
[2] A punch for compressing powders to prepare tablets, which is characterized in that the surface of the punch is coated for corrosion resistance with Cr-Dopé-N.
[3] A punch for compressing powders to prepare tablets, which is characterized in that the surface of the punch is coated for release with Cr-Dopé-N.
[4] A punch for compressing powders to prepare tablets, which is characterized in that the surface of the punch is coated for anti-adhesion with Cr-Dopé-N coating on the surface.
[5] The punch according to above [1], wherein the punch is applied to a punch (4 or 6) for use in a tablet machine (
1
) for preparing tablets containing an acidic substance or an adhesive substance.
[6] The punch according to above [5], wherein the acidic substance is Pioglitazone hydrochloride.
[7] The punch according to above [5], wherein the adhesive substance is a sugar alcohol.
[8] The punch according to above [7], wherein the sugar alcohol is D-mannitol.
[9] A tablet machine having a punch of which surface is coated with Cr-Dopé-N.
[10] A process for preparation of tablets which comprises using a tablet machine according to above [9].
[11] The process according to above [10], wherein tablets contain an acidic substance or an adhesive substance.
[12] The process according to above [11], wherein the acidic substance is Pioglitazone hydrochloride.
[13] Tablets containing Pioglitazone hydrochloride prepared by the process according to above [12].
[14] The process according to above [11], wherein the adhesive substance is a sugar alcohol.
[15] The process according to above [14], wherein the sugar alcohol is D-mannitol.
[16] Tablets containing D-mannitol prepared by the process according to above [15].
The basis metal or basis material used as a material before coating of the punch for preparing tablets of the invention may be any one that can be used as the material for punches for preparing tablets in the conventional technique. Specifically, the basis material may be any one that is not easily deformed under frequently repeated compressing procedure and has a high mechanical strength, for example, super steel alloy, carburized steel alloy or cemented carbide; alloy tool steel; sintered alloy and the like. More specifically, the material includes SKS 2, SKD, NH alloy, SUS440C and soon. The SKS2is the most preferred.
More precisely, preferred are SKS 2 prepared from an alloy tool steel containing 95% of iron, 1% of chromium, 1.5% of wolfram, 1% of carbon, 0.35% of silicon, 0.8% of manganese, 0.03% of phosphorus and 0.03% of sulfur (all percentages are weight based, and the same shall apply hereinafter), a sintered alloy characterized in that 0.2 to 5% of at least one of tantalum and niobium is added, and optiona
Fukada Hiroshi
Fukuyama Hikaru
Kameoka Norio
Nakamura Etsuji
Shimizu Toshihiro
Takeda Chemical Industries Ltd.
Theisen Mary Lynn
Wenderoth , Lind & Ponack, L.L.P.
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