GB2148235A

GB2148235A - Die pressure moulded capsules

Info

Publication number: GB2148235A
Application number: GB08426387A
Authority: GB
Inventors: Fritz Wittwer; Thomas Raible
Original assignee: Warner Lambert Co LLC
Current assignee: Warner Lambert Co LLC
Priority date: 1983-10-20
Filing date: 1984-10-18
Publication date: 1985-05-30
Also published as: JPS60222060A; FR2555972B1; IT1178161B; DE3438235C2; DE3438235A1; CH664938A5; FR2555972A1; GB2148235B; JPH0561942B2; IT8449041A1; IT8449041A0; GB8426387D0

Abstract

A die pressure moulded article is made from a hydrophilic polymer, a mixture of such polymers, a starch, a starch derivative, or mixtures thereof. The articles may be injection moulded capsules having a joinable cap part (1) and body part (2). The cap part (1) may be die-moulded as a stopper directly onto the open end of the body part (2) after the body has been filled so as to seal the contents (3). Alternatively, each of the cap part (1) and body part (2) may have, in the side wall area, adjacent to its open end, at least one locking means (4). <IMAGE>

Description

SPECIFICATION Die-pressure moulded articles The present invention relates to die pressure molded shaped articles formed by die pressure molding of starch, hydrophilic polymers like gelatin or starch derivatives, all with a low water content.

The present invention especially relates to certain structures and forms of such die-molded articles, especially injection molded articles and especially capsules as described hereinafter.

In highspeed die pressure molding such as injection molding it is important that the molding process is carried out at high speed, that the material to be molded shows the quality of a thermoplastic material during the molding process and that the material hardens quickly in the mold so that it can be ejected rapidly without changing its dimensions. The latter is an important factor as the accuracy of very many die pressure molded articles must be within very narrow limits.

It has now been found that these mentioned materials can be die-molded, especially injectionmolded, to special structures and forms of high accuracy and dimension stability.

The present invention concerns die pressure molded articles and especially injection molded capsules, said capsules having a body part and a cap part, each having a side wall, an open end and a closed end, the two parts being joinable, characterized in that this capsule is made.

(i) from a hydrophilic polymer or a mixture of such polymers having a water content of 5 - 25% by weight (calculated to the hyrophilic polymer composition) and if formed from gelatin said gelatin having a water content of 10 - 20% by weight (calculated to the gelatin composition) and/or (ii) from a starch or a starch composition having a water content of 5 - 25% by weight (calculated to the starch composition) (iii) by die pressure molding and (iv) that the cap part is die-molded as a stopper directly onto the open end of the body part after the body has been filled so as to seal the contents within the capsule, or (v) that each of said cap and body parts has in the side wall area, adjacent to its open end, at least one locking means, said locking means being arranged to face each other and to achieve, after joining of said parts, a separation-resistant connection, the cap and body parts being worked at a deviation of less than 1% and being stable in dimension.

A special feature (vi) of such articles according to (v) is that at least one part of the open end has the side wall portion recessed with an annular shoulder for receiving and for constituting a stop means in the joining area for the side wall portion at its open end of the other part, both side wall portions being shaped so that the outside surface is smooth in the joining area of said two parts.

A further feature (vii) of such articles according to (v) is that the inner surface of the cap, when said cap is mounted on the open end of said body is at practically the same level or below the level of a horizontal plane touching the open end of the cylindrical side wall of said body, whereby, after the filling of the contents and after the closing of said cap and body, practically no air is entrapped between said inner surfaces of said cap and the level of said contents.

Articles prepared by the present invention have the further advantage (viii) that they can be diemolded so as to be joined in a distinctive shape to provide a palpable identification of the capsule.

It is also possible (ix) to prepare articles according to the present invention where the cap and/or the body have embossed printing of letters thereon.

A further embodiment (x) of thins invention is the complete liquid proof sealing of the cap and body parts by wetting the joining surfaces with water.

The preferred articles are two-piece capsules which have hitherto been made from gelatin by a dip-molding process. Such capsules can, according to this invention, also be made from starch by the method of die-pressure molding. They can be useful for the exact dosage of solid, creamy and liquid substances, especially for pharmaceutical use, said capsule having two parts, a cap part and a body part which are joinable; each of said capsule parts having a side wall, an open end and a closed end.

Preferred articles respectively capsules, according to this invention, are made from starch and by injection molding.

The injection molding of hyrophilic materials such as gelatin containing water has been described in the European Patent Application Publication No.

92908.

Hydrophilic polymers are polymers with molecular masses from approximately 1 103 to 107 Dalton carrying molecular groups in their backbone and/or in their side chains and capable of forming and/or participating in hydrogen bridges. Such hydrophilic polymers exhibit in their water adsorption isotherm (in the temperature range between approximately 0 to 200"C) and inflection point close to the water activity point at 0.5. Hydrophilic polymers are distinguished from the group called hydrocolloids by their molecular dispersity.For the maintenance of the molecular dispersity of said hydrophilic polymers a fraction of water - according to the working range of the present invention - of 5 to 25% by weight of said hydrophilic polymers must be included provided that the temperature of said hydrophilic polymers is in the working range between 50"C and 1900C of the present invention.

Gelatin as a preferred hydrophilic polymer is made from various types of gelatin, including acid or alkaline processed ossein, acid processed pigskin, or alkaline processed cattle hide. Said types of gelatin have a molecular proferably in the mass range of 10.000 to 2 x 107 Dalton or a molecular mass range of 10.000to2x 106and10x 106to20x 106Dalton.

It has a water content of preferably 10 - 19% and especially 12 - 18% by weight calculated to the gelatin composition.

Whilst the die pressure molded articles according to this invention are preferably made from gelatin of various types, all the hydrophilic polymers, gelatin included, may also contain various additives such as plasticizers, lubricants, cross-linking and coloring agents as described in the European Patent Application Publication No. 92908 in concentrations indicated in this European Patent Application.The polymers may also contain extenders up to 95% and preferably not more than 30% by weight such as proteins like sunflower proteins, soybean proteins, cotton seed proteins, peanut proteins, rape seed proteins, lactose, gum arabic, acrylates and methac rylates, water soluble derivatives of cellulose like cellulose acetyl phthalate (CAP), hydroxypropyl cel lulose, hydroxypropyl methyl-cellulose, hyroxy propyl methylcellulosephthalate (HPMCP), hydroxy methylcellulose, polyvinylpyrrolidone, shellac, bentonite, polyvinyl-acetatephthalate, phthalated gelatin, succinated gelatin, polysaccharides like agaragar.

Some of these extenders as well as others are hydrophilic polymers themselves and can be used to produce articles according to this invention.

Such hydrophilic polymers are hydroxypropyl methylcellulosephthalate (HPMCP), polyvinylacetatephathalate (PVAP), celluloseacetylphthalate (CAP), acrylates and methacrylates (Eudragit), phthalated gelatin, succinated gelatin, crotonic acid, and shellac. These polymers are preferred when enteric properties are required. They contain preferably 5 - 25% of water, preferably 15 - 22% by weight, calculated to the waterfree polymer. Preferred is HPMCP, PVAP and CAP, and specially PVAP and CAP; most preferred is PVAP, all being worked by injection molding having a water content of 5% to 25%, preferably of 15% to 22% by weight, calculated to the composition.

Many of these polymers are non-thermoplastic and it is very surprising that they can be die-pressure molded according to this invention.

Molding temperatures range from 50 to 1900Cand pressures from 600 to 3.000 x 105 N/m2 known apparatus can be used.

Preferred is a moldable starch composition made from wheat, potatoes, rice, tapioca and the like.

The starch contains about 0 to 100% of amylose, and about 100 to 0% of amylo-pectin; preferably 0 to 70% of amylose, and about 100 to 30% of amylopectin and most preferably potato starch and maize starch.

When in the following description the term 'starch' is used, this also includes foams, modifications or derivatives of starch, and combinations thereof with hydrophilic polymer compositions whose properties are acceptable for the intended die-pressure molded products, especially capsule materials.

The starch has a water content of 5 - 25%, preferably of 15 - 22% and especially of 17 - 20% (calculated to the starch composition).

The starch may contain various additives such as plasticizers, lubricants, cross-linking and/or coloring agents, as well as extenders. All these are the same as mentioned above for the hydrophilic materials.

Molding temperatures for starch are 80 - 240 C and pressures ranging from 600 to 3.000x 105 N/m2.

The starch containing the water and optionally further additives is molten under these temperatures and pressures in a manner known per se and in molding apparatuses known per se.

The skilled in the art will be able to work with die pressure molding, i.e. profile extrusion, crompres sion molding, vacuum forming, thermal forming, extrusion molding, polymer casting in combination with vacuum forming. Preferred however is injection molding.

According to point (iv), the cap part is diemolded as a stopper directly onto the open end of the body.

This works unexpectedly well with the mentioned compositions and the high speed process, prefer ably injection molding and extrusion, to produce liquid proof capsules. The body may be produced by any known method from a material specified hereinabove.

Detailed description of embodiment (iv): Figure 1 is a longitudinal sectional view of an embodiment of the capsule of the present invention Figure 2 is a longitudinal sectional view of another embodiment; and Figure 3 is a longitudinal sectional view of a further embodiment.

In Figure 1 there is shown an embodiment of a capsule which might be filled with a pharmaceutical product to be swallowed by the patient. In this embodiment the cap-stopper 1 is formed by diemolding so as to provide a smooth outer surface when joined, i.e. it has the same outer diameter as the capsule body 2 which is filled with the contents 3.

Figure 2 shows another embodiment wherein a body 2 is provided with a groove 4 to assure additional tightness of the stopper 1 when joined over the contents 3.

In Figure 3 there is shown a further embodiment wherein a flat, circular plate or disc 4 was inserted into the body 2, so as to completely cover the filling material 3. In this embodiment the stopper 1 is formed by die-molding so as to provide a smooth outer surface when joined, i.e. it has the same outer diameter as the capsule body 2 which is filled with the material contents 3. The cover plate 4 will permit injection molding of the closing stopper at a very high speed.

The present invention provides also the possibility to mold high precision locking articles especially capsules which are liquid- and tamper-proof.

In this application a 'locking capsule' is defined to include a filled and joined capsule wherein the capsule parts are formed so as to impede separation and tampering with the filled contents.

Due to the limitations of manufacture of prior art capsules by the prior art dip-molding process, prior art capsules have a disadvantage that they do not have secure locking means to prevent separation after filling and joining. There is a problem if such a capsule, especially one containing food or drugs, can be opened or tampered with.

It is therefore an object of the present invention to provide a capsule which has a structural configuration so as to prevent tampering. The advantages of the present invention will become apparent to those skilled in the art from a consideration of the detailed description which follows with reference to the accompanying drawings.

Detailed description Figure 4 is a longitudinal section of a first embodiment.

Figures 6 to 14 are partial sections showing nine further embodiments of Figure 1.

Figure 15 is a longitudinal section of another embodiment.

Figures 16to 20 are partial sections showing five further embodiments of Figure 15.

Figure 22 is a partial sectional enlargement of Figure 21.

Figure 23 is a longitudinal section of another embodiment.

Figure 24 is a partial sectional enlargement of Figure 23.

Figure 25 is a longitudinal section of another embodiment.

Figure 26 is a longitudinal section of another embodiment.

Figure 27 is a longitudinal section of another embodiment.

Figures 28to 30 are longitudinal sections of another embodiment.

Figures 31 to 37 are longitudinal sections of further embodiments.

Figure 38 is a longitudinal section of another embodiment.

Figure 39 is a section along line 35 - 35 of Figure 38.

Figure 40 is a view of Figure 39 after one of its parts has been axially rotated with respect to its other capsule part.

Figure 41 is a side view of a further embodiment.

Figure 42 is a longitudinal section of another embodiment.

The capsule shown in Figure 4 of the drawings has a cap part 1 and a body part 2. The cap part 1 has an annular ridge 3 protruding from the inner surface of the side wall adjacent to the open end of the body part 2 which mates with a recessed annular groove 4 of the body part 2. The ridge 3 and the groove 4 are structurally and dimensionally adapted to each other so that the ridge 3 and the groove 4 are interlocked by snap-in action when the capsule parts are joined.

It is to be understood that: - the ridge 3 may be a continuous ring or be constituted by a number of segments or cams cooperating with a continuous or discontinuous groove; - the locking means may comprise one or more ridge and groove structures.

- the cross-sectional shape of the locking means may comprise not only semicircle forms but any other suitable form such as a triangle, a semi-oval or other fractions of circles or ovals.

Figures 6 to 14 are alternate embodiments of the capsule shown in Figure 4. In Figure 6 the cap part 1 has a right angle groove 5 which mates with a right angle ridge 6 of cap part 2.

Figure 7 shows another embodiment wherein the cap part 1 has an annular conical ridge 7 which mates and locks with an annular conical groove 8 on body part 1.

Figure 8 shows another embodiment wherein the cap part 1 has an annular triangular ridge 9 which mates and locks with a corresponding annular triangular groove 10 on body part 2. For better locking the short side of the triangular ridge 9 faces the short side of the triangular groove 10. It has been found that the optimum locking force occurs when the short side of the triangular ridge 9 faces the open end of the other part. The joining of the capsule parts if facilitated when the shortest side of the triangular ridge facing the open end of the other capsule part forms with the adjacent side wall an angle of about 90 to 134 degrees.

Figure 9 shows another cap part 1 having a triangular ridge 9 in mating and locking engagement with a triangular groove 10 on body part 2.

Figure 10 shows a cap part 1 having annular rectangular ring 11 in mating and locking engagement with a corresponding annular groove 12 on body part 2.

Figure 11 shows a cap part 1 having a annular ridge with a triangular cross section 13 wherein the shortest face of the triangle 15 mates and locks with the top surface of a rectangular groove 14 in body part 2.

Figure 12 shows another embodiment of a cap part 1 having a triangular ridge 9 in mating configuration with a triangular groove 10 on body part 2.

Figure 13 shows a cap part 1 having a ridge 15 with the cross sectional area of a bead mating and locking with a corresponding annular groove 16 having a corresponding cross sectional area of a circular segment 1 on body part 2.

Figure 14 is another embodiment showing a cap part 1 having an annular ridge 17 with a generally parallel-epipedonal cross sectional area which mates and locks with an annular groove 18 having a corresponding parallel-epipedonal cross sectional area on body part 2.

Figure 15 another embodiment of the invention showing a cap part 1 having one or more windows 19 arranged on its cylindrical side walls near the open end and on a circular path which is coaxial with the axis of the capsule. The body part 2 has a corresponding number of locking cams 20 which are protuberances on its cylindrical side walls near its open end. Said cams 20 mate with the windows 19 in locking engagement when the capsule parts are joined.

Figures 16 to 20 show alternate embodiments of the locking window 19 and cam 20 of Figure 15; in Figure 16, the cross sectional area is rectangular; in Figure 17, circular; in Figures 18 and 19, triangular; in Figure 20, oval.

Figure 21 shows an alternate embodiment of the present invention wherein the cap part 1 has a male thread 21 on the outside surface of its cylindrical side walls at its open end. The male thread 21 engages with a female thread 22 on the inside surface of the body part 2 at its open end. It is another feature of this embodiment that the body part 1 and the cap part 2 can be joined with an outside smooth surface, as at J, so as to make separation difficult, thereby enhancing the locking feature of the capsule.

Figure 22 is a partial enlargement of Figure 21 showing the mating engagement of the male thread 21 with the female thread 22, and with the smooth surface J at the joining area.

Figure 23 is an alternate embodiment of Figure 21 wherein the body part 2 has a male thread at the outside surface of its open end. The male thread 21 mates and engages with a female thread 22 on the inside surface at the open end of cap part 1.

Figure 24 is a partial enlargement of Figure 23 showing the smooth surface J at the joining area.

Figure 25 shows a further embodiment of the invention having a bayonet-tape locking arrangement wherein the cap part 1 has an annular rectangular groove 3 adjacent to the open end of the cap 1 in a direction generally parallels to the capsule axis.

The body part has a triangular ridge 4 on the inside surface at the open end of the body part 2. The triangular ridge 4 has a conical taper 6 at the leading edge in order that the open end of body part 2 can enter more easily within body part 1. In addition, cap part 1 has a window 7 for mating with a protruding cam 8 on cap part 1. The combination of the groove 3 engagement with ridge 4 plus the window 7 with the cam 8 gives a secure bayonet-tape lock engagement to enhance the locking aspect of this embodiment.

Figure 26 is an alternate embodiment ofthe invention wherein the cap part 1 has an annular dove-tail ring 9 on its cylindrical side wall at its open end for mating engagement with a dove-tailed groove 10 on the cylindrical side wall at the open end of the body part 2.

Figure 27 shows an alternate embodiment of the invention wherein the cap 1 is provided on its cylindrical sidewall at its open end with an annular slit 27 which is symmetrically arranged with respect to the main axis of the capsule. The slit 27 is defined by two annular wall parts 28,29 of different length.

The body part 2 has an upright side wall 31 of reduced thickness and tapering towards its open end. In the joined position shown in Figure 27, the side wall 31 of the body 2 is held by flexible pressure in the annular slit 27 which preferably has a tapered configuration.

According to Figures 28, 29 and 30, a capsule is shown having a cap 1 joined with a body 2. At the joining area a locking means, as at 17, is provided in accordance with the embodiments previously disclosed. It is a feature of the present invention that the ratio can be variable between the outside diameter of the cylindrical side walls (D) and the overall length of the joined capsule (L). Figure 28 shows the capsule embodiment wherein D is less than L. In Figure 29, the capsule embodiment has a ratio of D equal to L. According to Figure 30, the ratio of D is greater than L.The advantages of a variable D to L ratio are that: - The volumetric contents of the capsule can be changed to meet particular requirements, especially for pharmaceutical and food use; and - the configuration can be varied to enable easier swallowing of the capsule, especially for pharmaceutical and food use, with children, adults and geriatric patients who differ markedly in their ability to swallow capsule medicaments. So a tablet shaped form can be obtained.

Figures 31,32 and 33 show different embodiments of the invention having a cap part 1 and a body part 2 with a locking means, as at 17, in accordance with the embodiments previously disclosed. Figure 31 shows a feature of the present invention that the locking means 17 can be utilized with a capsule having a smooth outside surface at the joinder J.

Figure 32 shows a capsule having a body part 2 with a protruding edge at the joinder J.

Figure 33 shows a capsule having a cap part 1 with a protruding edge at J.

Figure 34 shows a further embodiment of the present invention. The cap part 1 and the body part 2 have a locking means, a at 17, as previously disclosed. In addition, the body 2 has on its side wall inner surface a number of reinforcing ribs 14, molded with protruding from the inner side wall surface. The ribs preferably extend over the whole length of the body part 2 and join each other in the center of the closed end of the body 2. In the construction of said ribs 14, which may be of triangular, rectangular or any other cross section, the bending strength or rigidity of the body 2 is increased to such an extent that the wall thickness D may be substantially reduced. In addition, the upper end faces E of the ribs 14 form a stop and support means for the cap 1.The body 2 may be manufactured by injection molding, and the ribs 14 constitute a flow path for the injected materials so that the quick and regular distribution of said material is facilitated within the injection mold.

Alternatively, the ribs in the above figure could be undercut into the side of one or both parts so as to improve the disintegration of the capsule in the gastro-intestinal tract of the patient. Also, the ribs 14 could be molded with and protruded from the side wall outer surface of the body part 2.

In the capsule embodiment of Figure 35, a cap 1 has on the inner surface of its cylindrical side wall an annular groove 22 receiving a conically shaped portion 23 of the cylindrical side wall of the body 2.

The open end of the cap 1 rests upon the annular surface 25 of a shoulder formed in the side wall of the body 2. Joining of the cap and body is facilitated by tapered closed end 23a of body part 2.

In Figure 36 the reference numerals of Figure 35 are used for all parts which have remained unchanged. The cap 1 is identical to that shown in Figure 35. However, the body part 2 is additionally provided with a slit 20 - (one or more circumferentially arranged slits may be provided) - which confers upon the open end of the body a greater flexibility thereby assisting and simplifying the joining of cap and body.

Figure 37 shows an alternate embodiment of the present invention wherein the cap parts 1 and 2 are provided with two or more locking means as at 17. In addition, the cap part is provided with a slit means 20 for greater flexibility which assists and simplifies the joining operation of cap 1 and body 2.

Figure 38 shows an alternative embodiment of the present invention wherein the cap part 1 and the body part 2 are each provided with one or more ratchet teeth 3 on their surfaces facing each other.

Figure 39 is a sectional view of Figure 38 showing the teeth 3 when in mating engagement with each other.

Figure 40 is a sectional view of Figure 38 showing the teeth when not in mating engagement with each other. The application of torque in coaxial rotations of one of the capsule parts around the other capsule part causes a frictional and locking engagement of the teeth of one capsule part upon the facing surface of the other capsule part.

Figure 41 is a side view of a further embodiment of the present invention wherein the body part 2 is provided with one or more protrusions 4 on the outside surface of its side wall adjacent the open end which snaps into locking engagement with a corresponding recess 3 in the side wall of the cap part 1.

Figure 42 is a still further embodiment of the present invention showing the cap part 1 and the body part 2 in a locking engagement 3; both the cap part 1 and the body part 2 have a recessed groove 4 in the joining area which is filled by a band 5 of sealing or bonding material.

In any of the above embodiments, the body may have a reduced diameter at the open end to facilitate entry during joining of the capsule parts.

Figure 4 to 31,34-42 also show the embodiment as defined above under (vi) where the outside surface of the molded article, especially of the injection molded capsule, is smooth in the joining area of the cap and the body.

The present invention also provides articles, especially capsules, where the open end is closed by a coaxial cap characterized in that the inner surface of the cap, when the cap is mounted on the open end of the filled body, is at practically the same level or below the level of the plane touching the open end of the cylindrical side wall of the body, thereby avoiding air entrapment within the contents of the capsule.

Due to the limitations of manufacture of prior art capsules by the prior art dip-molding process, prior art capsules have the following disadvantages: - the air entrapped in the spherical closed end of the cap part of the filled and closed capsule results in a moving bubble of air when the content is a liquid; - numerous capsule contents, especially those which are creamy or liquid, deteriorate after exposure to the oxygen in the entrapped air; - capsules are neither liquid- nor gas-tight; - the capsules are neither tamper-proof nor separation-resistant. There is a disadvantage if such a capsule, especially one containing food or drugs, can be opened or tampered with; and - when used for pharmaceutical purposes, the protruding edge located on the periphery of the open end of the capsule is relatively sharp.The removal of the protruding edge would make the capsule more attractive to be swallowed.

It is therefore an object of the present invention to provide a capsule which has a structural configuration so as to avoid the afore-mentioned disadvantages. The capsule of the present invention is separation-resistant. Furthermore, air entrapment during filling is avoided.

Figure 43, 43a and 43b show such an embodiment as a longitudinal view. Of course, locking devices as shown in the foregoing figures may as well be used.

The present invention also provides the possibility to prepare distinctive shapes by die-pressure molding of the above described materials.

Prior art pharmaceutical capsules have axially joinable cylindrical cap and body parts which require that the inner diameter of the cap side wall frictionally engage the outer diameter of the body side wall.

When the cap and the body are joined, the open end of the cap forms a relatively sharp protruding edge.

The prior art capsules have the following principal disadvantages: - due to the limitations of manufacture by the prior art dip-molding process, the prior art capsules cannot differ much in their shapes and are, therefore, not very adaptable with regard to their shapes; - identification of the capsule contents must be indicated by means of different colors and imprinting, i.e. only by visual means and not by visual means and of palpable characteristics; and - confusion of prior art capsules with different contents may occur because of the limited number of distinctive shapes available.

These principal disadvantages are becoming more serious because the number of oral medications is increasing and there are only a limited number of visual means for identification.

Also prior art capsules have the following limitations: - they cannot be provided with a smooth outer surface in order to achieve an additional easy-toswallow effect; and - they have a relatively large empty space which causes a waste of material and of package volume.

It is therefore an object of the present invention to provide a capsule which has an adapted shape so as to avoid the aforementioned disadvantages and limitations.

The advantages of the present invention will become apparent to those skilled in the art from a consideration of the detailed description which follows with reference to the accompanying drawings.

In the detailed description it is convenient to group the embodiments of the present invention into categories: 1. Capsules with a shape which is distinctive The distinctively shaped capsules of this group help to avoid confusion and to support a palpable identification of the capsule.

For convenience, all of the figures in this application use the same reference numerals.

Figure 44 is a side view of a distinctively shaped capsule of the present invention having a cap part 1 and a body part 2. Figure 45 is a top view of Figure 43 showing the novel oval-shaped capsule.

Figure 46 is a side view of an alternative embodiment. Figure 47 is a top plan view of Figure 46 showing the pyramidical end-shaped capsule.

Figure 48 is a side view of another embodiment showing a flat shaped capsule. Figure 49 is a top plan view of Figure 48 showing the elongated oval-shaped capsule. Figure 50 is a refinement of the embodiment of Figures 48 and 49 showing a modified oval-shaped capsule. Figure 51 is a sectional side view of Figure 50 showing the side walls of cap part 2 completely overlapping the side walls of body part 1 when joined. Also shown is the smooth outer surface of side walls at the joining area J. The use of completely overlapping side walls and a smooth outer surface at the joining make it difficult for potential tamperers to grip and separate the capsule parts. Figure 52 is a top plan view of another refinement of the embodiments of Figures 48,49,50 and 51 showing a rectangular oval-shaped capsule.

Figure 53 is a side view of the embodiment of Figure 52.

Figure 54 is a top plan view of a further embodiment showing a triangular-shaped capsule. Figure 55 is a side view of Figure 54.

Figure 56 is a top plan view of a still further embodiment showing a star-shaped capsule. Figure 57 is a side view of Figure 56.

2. Capsules with a shape which corresponds to a vendor's logogram.

The logogram-shaped capsules of this group help to identify the vendor. The logogram of imaginary companies have been given in Figures 58-61.

Figure 58 is a top plan view of an embodiment showing a parallelolipodonal-shaped capsule logogram. Figure 59 is a side view of Figure 58.

Figure 60 is a top plan view of another embodiment showing a C-shaped capsule logogram. With the use of the new die-molding processes to produce capsules, a great variety of shapes of capsules, including all the letters of the alphabet, is not obtainable, in marked contrast to the severe limitations of prior art hard shell capsule shapes made with the prior art dip-molding method.

Figure 61 is a side view of Figure 60.

3. Capsules with a shape which indicates its purpose.

The purpose-shaped capsules of this group help to indicate their field of application. As shown in Figures 62 and 63, the heart shape indicates the field of coronary applications.

4. Capsules with a shape for its dosage form The dosage-shaped capsules of this group indicate their use for other than oral medications. Figure 64 and 65 show a suppository-shaped capsule suitable for rectal medication. It will be understood by those skilled in the art that the embodiments above can enable the production of two-piece hard shell capsules with palpable shapes that can be recognized by visually impaired patients.

5. Capsules with a shape which provides a varying volume of contents.

The embodiments of this group provide varying volumes of contents for the same size of capsule.

Figure 67 shows a spherical shape providing the smallest possible package for the largest volume of contents, Figure 67 is a sectional view of Figure 66 along line 24-24, also showing separation-resistant locking means at the side walls of body part 1 and cap part 2 at the joining area J. Figure 68 is a top plan view showing a circular-shaped capsule having the same diameter as the spherical-shaped capsule of Figures 66 and 67. Figure 69 is a side view of Figure 68 showing the disc-shaped configuration which provides one of the largest possible packages for the smallest volume of contents. The great variety of capsule shapes by the new die-molding process provides a great flexibility in providing hard shell capsules with varying package to volume rations.

6. Capsules with a shape which enables a precise positioning on a joining machine.

There are various capsules which need an exact positioning of the two capsule parts before joining, e.g. a threaded or bayonette-type lock engagement.

This precise positioning can be achieved by means of a locator on the outer surface of the capsule.

Figure 70 is a side view of an embodiment of this group. Figure 61 is a top plan view of Figure 70 showing 4 locating positions possible with respect to the rotary angle around the capsule axis. This is a big advantage over a conventional dip-molded capsule which has a circular cross-section area. A capsule with four possible positions is shown having a bayonet-type lock engagement in Figure 70 consisting of e.g. four protruding cams 3 on one part which mates with four corresponding ridges 4 on the other part. A bayonettype closure system is shown in Figure 71 having an axial and a rotational movement of the body part, with the cap part 2. (Axial and rotational movement is shown by dotted lines).

It will be understood by those skilled in the art that there are capsule shapes of the present invention which meet the characteristics of more than one of the above mentioned groups.

In a further embodiment of the invention the die-pressure molded articles are manufactured so as to provide bossed imprinting of letters or designs thereon.

Prior art capsules are imprinted by means of an ink composition. This process is very complicated and, in addition, it requires a second step after the manufacturing of the capsules. Furthermore, it is difficult to imprint the closed ends of the capsule body and cap parts. With the bossed imprinting of the present invention it is possible to obtain an imprinted capsule without the use of chemical inks.

Thus, the imprinted capsule may be fully natural. It is therefore an imprinting of letters or designs so a to avoid the aforementioned disadvantages.

The present invention was achieved by means of die-molding, the capsule parts with a mold which is provided with the desired imprinting (debossed or embossed) of letters or designs thereon.

In the present invention, the capsule manufacturing and the imprinting consist of single and simple steps. Furthermore, during debossing by injection molding, the capsule material is not adversely affected as in the prior art when the imprinting is made by a hot stamp. When a hot stamp is used there is also the disadvantage that a second processing step is necessary. Also, with a hot stamp, an embossing is not possible.

Figure 72 is a side elevated view of an embodiment of the present invention showing a joined capsule with a body part 1 and a cap part 2.

Imprinted on the outside surface of the side wall of the cap is the embossing 3 of the letters in the name of the vendor CAPSUGEL. Such imprint was not possible with the prior art dip-molding process, but embossing can be achieved with the new diemolding process. Figure 73 is a sectional view of Figure 72 along line 2-2.

The present invention may also include sealing or bonding of the joined capsule parts provides an additional securing which further impedes separation and tampering. Such sealing or bonding also makes the capsule liquid, moisture vapor and gastight.

For sealing gelatin it is appropriate to wet the joining surfaces of the cap and body parts with water, either with water alone or a mixture of water with a water miscible organic solvent like an alcohol with 1-4 carbon atoms like ethanol. Optionally the capsule is heated to about 40 - 75 C. Due to the high precision and the special locking means achieved by this die-pressure molding, heating is not absolutely necessary through it improves coniderably the sealing quality. For starch and many of the starch derivatives it was surprisingly found that wetting the joining surfaces of the cap and the body part with water at room temperature without additional heating brings an excellent effect, the capsule being absolutely liquid and tamperproof.

It should be understood that this disclosure is for the purpose of illustration only and that the present invention includes all modifications and equivalents faliingwithin the scope of the appended claims.

Example 1 A capsule body was die-molded on an injection moiding machine. The material was bone gelatin, 150 Bloom, B grade, having a water content of 17% based on the weight of the composition. The material was plasticized at 130"C and injected into a die at 20"C. The capsule body was then removed from the mold, filled with lactose and inserted into a second mold. The second mold was mounted in the injection molding machine wherein the stopper was injection molded onto the open end of the filled capsule body. The material of the stopper was the same as forth body. During injection molding of the stopper, a seal was formed between the stopper and the body so that the capsule was liquid, moisture vapor and gas-tight as well as tamperproof.

Example 2 A capsule body was die-molded on an injection molding machine. The material was bone gelatin, 150 Bloom, B grade, having a water content of 10% and a content of organic plasticizers: sorbitol of 6% and glycerol of 3%, all based on the weight of the gelatin. The material was plasticized at 130"C and injected into a die at 19"C.

After removing the capsule body from the mold, it was filled with a creamy content, LabrafilR, trademark owned and material supplied by Gattefosse, 39 ave Ed. - Vaillant 92100 Boulogne/France, for C12 to C13 exthoxylated saturated glycerides. Then the procedure described in Example 1 above was followed.

Example 3 A wheat starch containing 20.6% of water was injection molded to a capsule body at 140"C and a pressure of 200 x 1 06N/cm2 as well as to a capsule at the same conditions. The cap and body having the form as disclosed in Figure 4. An excellent locking capsule was obtained with smooth outer surface.

Example 4 Example 3 was repeated using the form of Figure 8. The joining surfaces of the cap and body parts where wetted with water. Excellent sealing was the result.

Example 5 Example 3 was repeated using the form of Figure 43, having embossed the name CAPSUGEL on the cap, with very good result with respect to airentrapment and sealing quality. The depth of the embossed letters was 0.03mm which was sufficient for clean reading. The same result is obtained with debossing.

Claims

1. Die pressure molded articles and especially injection molded capsules, said capsules having a body part and a cap part, each having a side wall, an open end and a close end, the two parts being joinable, characterized in that these articles are made (i) from a hydrophilic polymer or a mixture of such polymers having a water content of 5 - 25% by weight (calculated to the hydrophilic polymer composition) and if formed from gelatin said gelatin having a water content of 10 - 20% by weight (calculated to the gelatin composition) and/or (ii) from a starch - or a starch composition having a water content of 5 - 25% by weight (calculated to the starch composition) (iii) by die pressure molding and -for capsules (iv) that the cap part is die-molded as a stopper directly onto the open end of the body part after the body has been filled so as to seal the contents within the capsule, or (v) that each of said cap and body part has in the side wall area, adjacent to its open end, at least one locking means, said locking means being arranged to face each other and to achieve, after joining of said parts, a separation-resistant connection, the cap and body parts being worked at a deviation of less than 1% and being stable in dimension.

2. Capsules according to claim 1 characterized in that they are made by injection molding of starch or a starch composition having a water content of 5 25% by weight preferably 17 - 20% by weight calculated to the starch composition.

3. Capsules according to any one of claims 1 - 2 characterized in that the starch is wheat, potatoe, rice or tapioka starch, or a mixture thereof.

4. Capsules according to claim 1 characterized in that they are made by injection molding of gelatin having a water content of 10 - 20% by weight calculated to the gelatin composition.

5. Capsules according to any one of claims 1 - 4 characterized in that the starch and/or the gelatin composition contains one or more plasticizers, extenders, lubricants and/or coloring agents.

6. Capsules according to any one of claims 1 - 5 characterized in that at least one part of the open end has the side wall portion recessed with an annular shoulder for receiving and for constituting a stop means in the joining area for the side wall portion at its open end of the other part, both side wall portions being shaped so that the outside surface is smooth in the joining area of said two parts.

7. Capsules according to any one of claims 1 - 6 characterized in that the inner surface of the cap, when said cap is mounted on the open end of said body is at practically the same level or below the level of a horizontal plane touching the open end of the cylindrical side wall of said body, whereby, after the filling of the contents and after the closing of said cap and body, practically no air is entrapped between said inner surfaces of said cap and the level of said contents.

8. Capsules according to claim 7 characterized in that said cap is a circular disc which is coaxially joined with the open end of said body by having the plane surface of the circular disc in circumferential engagement with the annular periphery of the open end of said body.

9. Capsule according to claim 7 characterized in that said cap has an annular recess located at its circumferential edge facing the open end of said body, the side wall portion of said body, mating with and protruding into said recess.

10. Capsules according to anyone of claims 1 - 5 characterized in that each of the cap and the body part is die-molded so as to be joined in a distinctive shape to provide a palpable identification of the capsule.

11. Capsules according to claim 10 characterized in that the capsule parts are molded so as to be formed in a shape adapted to the logogram of its vendor.

12. Capsules according to claim 10 having a shape adapted to its field of application.

13. Capsules according to anyone of claims 1 12, characterized in that at least one of the cap and the body part has embossed or debossed printing of letters andlor designs thereon.

14. Capsules according to anyone of claims 1 - 5 and 10 having a shape for its dosage forms.

15. Capsules according to anyone of claims 1-5 and 10 having a shape which provides varying volume of contents.

16. Capsules according to anyone of claims 1 - 5 having a shape which enables a precise positioning on a filling machine.

17. Capsules according to anyone of claims 1 - 5 having atabletform.

18. Capsules according to anyone of claims 1 - 17 wherein a liquid proof sealing ofthe cap and the body parts is achieved by wetting the joining surfaces with water or a mixture of water with a water miscible organic solvent.

19. A die pressure molded article substantially as hereinbefore described with reference to, and as illustrated in the accompanying drawings.