Maltese-cross Scored Tablet

Abstract

A tablet having a breaker-score assuring accurate and easy breakage into predetermined portions.

Parent Case Text

This application is a continuation of Ser. No. 777,091 filed Nov. 19, 1968, now abandoned.

Description

DETAILED DESCRIPTION

The invention concerns scored tablets which can be broken accurately and easily into predetermined portions.

Surface scoring of compressed masses, such as tablets, is a common technique for halving or quartering the compressed shapes.

The tablet is thereby provided with one or with two tapered scores, which in the case of tablets having a circular horizontal cross-section, are placed diametrically. Where tablets have a cross-section which is not circular, the scores are placed diametrically or parallel to the edges. At the same time they are placed so that the foot-points forming the base line of the scores, formed in each case by two faces lying at an acute angle, lie in a plane which is parallel to the horizontal cross-sectional plane (base plane). The scores thus penetrate, e.g., in the case of the biplanar circular tablets, into the tablet everywhere to the same depth -- except within any existing outer edge bevel: tablets having a breaker-score or cross score.

The sectioning of scored tablets is designed so that the active substance contained in each tablet (medicaments, active pharmacological agents) can be administered fully or to the extent of half or a quarter, depending on prescription or requirement.

Each amount of active substance separated in this manner from the tablet, then constitutes in itself a new separate dosage of a medicament and is thus governed by the same presecriptions regarding accuracy and permissible limits of dosage, as in the case of the undivided tablet.

Variations in weight and therefore in content of the active substances in the separated portions of conventionally scored tablets having a single score or cross-score, are in many cases considerably greater than in the case of undivided tablets. The mass and therefore the active substance content in separated portions of tablets, having a single or cross-score according to the invention, are, on the other hand, subject to considerably less scatter around the theoretically mean value, than the scatter resulting from tablets provided with a single or cross-score in the conventional manner. This is shown from measurements which have been statistically evaluated and which have shown significant differences in weight variations.

Table

Divisibility of biplanar tablets having cross-scores with significance test (F-Test) of the variances of the mean mass of quarters of tablets.

The two variances S.sub.1 .sup.2 (for normally scored tablets) and S.sub.2 .sup.2 (for tablets having a Maltese-cross score) vary significantly with respect to each other, when (S.sub.1 .sup.2 S.sub.2 .sup.2) > F.sub.sign, whereby S.sub.1 > S.sub.2,

for a significance-probability of P = 0.05

(according to Geigy documentation Scientific Tables, 6th Edition, p. 146 ff. and General Methods-theory of Statistics II by J. Pfanzagel, Berlin 1962, p. 187-190).

Type of Mean S.sub.rel of the Variance Extreme weight-variations of tablet-quarters in % of the theoretical mean value of the tablet-quarters score mean value of the weight of tablet- quarters (4 .times. 40 quarters) in % S.sub.1.sup.2 /S.sub.2.sup.2 Normal 10.1 S.sub.1 .sup.2 = 102.0 up to + 50% and - 57% score (NK) 2.8 Maltese- 6.0 S.sub.2 .sup.2 = 36.0 up to + 18% and - 14% cross score (MK) according to invention F.sub.sign : upper significance-limit of F-distribution = 1.69 for (n-l) = 39 S.sub.1 .sup.2 : variance of means weight of tablet-quarters of normally scored tablets S.sub.2 .sup.2 : variance of mean weight of tablet-quarters of Maltese-cross scored tablets S.sub.rel : relative standard variation of the mean value of the tablet-quarters P : significance probability n : number of tablet quarters Calculations of S.sub.rel are based on measurements on 4 .times. 10 tablets which were divided up by four people into 40 quarters in each case.

As can be seen from the table, the extreme mass variations given by the tablet quarters in the case of tablets having normal scores, are quite appreciably greater than with tablets having the Maltese-cross score according to the present invention. The variances S.sub.1 .sup.2 and S.sub.2 .sup.2 differ significantly from each other. The object of the invention is therefore to score the tablets in such a way that the mass or the content or dosage of active substance in the parts separated by breaking off along the scoring, is considerably nearer to the theoretical mean value, than in the case of tablets scored in the conventional manner. The tablet according to the invention, having a breaker-score, is characterized in that the depth of the acute-angled breaker-score increases towards the periphery of the tablet.

The invention will now be described more particularly in connection with the accompanying drawing, in which:

FIG. 1 is a top view of the tablet according to the present invention;

FIG. 2 is a right side view thereof;

FIG. 3 is a cross-sectional view taken on line 3--3 of FIG. 1;

FIG. 4 is a bottom view thereof; and

FIG. 5 is a top plan view of a modified embodiment of the tablet disclosed in FIG. 1.

The tablets produced according to the invention are provided either with a single score (FIG. 5) or with a cross-score (FIG. 1), which is so arranged that the foot-points forming the base line of the score, fall below the base plane of the score towards the periphery of the tablets, the base plane being taken as running through a point on the base of the score at the center of the tablet, or through the point of intersection of the crossed scores.

The dipping of the base of the score below the base plane can either proceed uniformly towards the outer edge of the tablet (straight line connecting the base points of the score) (FIG. 3), or it can proceed nonuniformly (curved line connecting the base points of the score).

In FIGS. 2 and 3, h = depth of score at point of intersection of the scores, or in the middle of the overall length of a single score, this height being the distance from the surface of the tablet to the base-plane.

The wedge-shaped part of the upper punch which projects out beyond the outer bevelled edge, is advantageously machined at the ends to be steeply inclined inwards from the outer edge of the bevel (from the edge of the press tool to about the middle of the bevel), in order to avoid any damage to the edge of the die by the upper punch.

Depending on the breaking properties of the tablet material and the breaking strength (hardness) of the tablets, the amount of dip of the bottom edge of the score below the base plane at a point on the outer edge of the tablet, where the line of slope of the score is extended to, is

a. in the case of biplanar tablets, as much as tablet material, tablet strength and pressing technique require or permit, preferably, however, it is 11/2 to 3 times the score depth h at the center point of the tablet,

b. in the case of tablets, the curved outer surfaces of which are scored, as much as tablet material, tablet strength and pressing technique for press tools require or allow, depending on radius of curvature, preferably it is 1 to 3 times the score depth h.

The score has an opening angle formed by the two faces of the score meeting at the base of the score, of preferably 50.degree. to 55.degree., and this is maintained constant independently of the score depth (FIG. 2).

Claims

I claim:

1. A tablet having opposite generally plane surfaces, and a peripheral edge surface extending between said opposite plane surfaces and generally perpendicular to said plane surfaces, one of said plane surfaces having at least two scores in the surface thereof from the center of the plane surface to a point adjacent the peripheral edge thereof, the bottom of each score diverging from a base plane through the bottom of the score at the center of the said one plane surface and toward the interior of the tablet as it extends toward the peripheral surface of said tablet and being spaced from said plane at said point adjacent said peripheral edge surface a distance of from one to three times the distance of said base plane below said one plane surface at the center of said tablet, said tablet having a predetermined dose of medicament dispersed substantially uniformly throughout.