Multi-Component Bolus

Abstract

Disclosed is a bolus for oral administration to an animal, the bolus comprising at least one beneficial substance to be delivered to the animal, the bolus comprising two components which are adhered together by a water-soluble adhesive or sealant, such that the two components are separable in vivo, and wherein at least one of the aforesaid components is frangible in vivo, the frangible component being initially stabilised by the adherence thereto of the other of the aforesaid components, such that separation of the two components in vivo facilitates the breakage of the frangible component.

Claims

1. A bolus for oral administration to an animal, the bolus comprising at least one beneficial substance to be delivered to the animal, the bolus comprising two components which are adhered together by a water-soluble adhesive or sealant, such that the two components are separable in vivo, and wherein at least one of the aforesaid components is frangible in vivo, the frangible component being initially stabilised by the adherence thereto of the other of the aforesaid components, such that separation of the two components in vivo facilitates the breakage of the frangible component.

2. The bolus in accordance with claim 1, wherein the bolus comprises two or more frangible components.

3. The bolus in accordance with claim 1, wherein the frangible component comprises one or more frangible zones or regions.

4. The bolus in accordance with claim 3, wherein the frangible zone or region is structurally weaker than the bulk of the frangible component.

5. The bolus in accordance with claim 4, wherein the frangible zone or region is relatively thin.

6. The bolus in accordance with claim 3, wherein a frangible zone or region runs along substantially the entire length of the frangible component.

7. The bolus in accordance with claim 1, wherein one of the bolus components is wholly or partially inserted into the other bolus component.

8. The bolus in accordance with claim 7, wherein one of the bolus components is wholly or partially inserted into a longitudinal groove or recess formed in the frangible component.

9. The bolus in accordance with claim 1, wherein the bolus components comprise different respective beneficial substance or substances.

10. The bolus in accordance with claim 9, wherein one bolus component comprises a cobalt-containing compound and the other bolus component comprises a selenium-containing compound.

11. A method of making a bolus in accordance with claim 1, the method comprising the steps of: forming a first bolus component; forming a second bolus component; and adhering the first and second components together by means of a water-soluble adhesive; wherein at least one of said bolus components is frangible in vivo, and is stabilised by the adherence of the other component.

Description

[0030] The various features of the invention will now be further described by way of illustrative embodiment and with reference to the accompanying drawings, in which:

[0031] FIG. 1 shows a perspective view of one embodiment of a first component of a multi-component bolus in accordance with the invention;

[0032] FIG. 2 shows a sectional view of the component shown in FIG. 1;

[0033] FIG. 3 is a perspective view of an embodiment of a second component, which co-operates with the component illustrated in FIGS. 1 and 2, to form a multi-component bolus in accordance of the invention.

[0034] For the avoidance of doubt, it is hereby expressly stated that the features described herein as “preferred”, “preferable”, “convenient”, “advantageous” and the like may be present in embodiments of the invention in isolation, or in combination with any other features so described, unless the context dictates otherwise.

DETAILED DESCRIPTION OF AN EMBODIMENT

[0035] Referring to FIGS. 1 and 3, there is provided a two component solid bolus for delivering a beneficial substance to a farm animal such as a sheep or cow. The components 2 and 4 co-operate to form a substantially circular-section cylinder. Component 2 has a U section and may be referred to for present purposes as the “sheath component”. Component 4 is a blade-like wedge portion and may be referred to for present purposes as the “wedge component”.

[0036] Sheath component 2 is formed with a deep longitudinal recess or groove 6 running along the long axis of the component. The wedge component 4 is substantially entirely accommodated within the recess or groove 6, and is shaped and dimensioned accordingly. The two components 2, 4 are joined by a water-soluble adhesive or sealand, which is applied over all, most or part (as desired) of the co-operating surfaces of the two components. The outside of the bolus (once the two components are joined together) is coated with a thin layer of water-impermeable wax.

[0037] The sheath component 2 comprises sodium selenite, potassium iodide and calcium iodate homogeneously distributed within a rosin matrix/binder. The concentration of the beneficial substances in this embodiment are sufficient to provide 1 gram of selenium and 7.8 grams of iodine in bioavailable form.

[0038] The wedge component 4 comprises cobalt sulfate monohydrate, at a concentration sufficient to provide 1 gram of cobalt per bolus. In addition, each component of the bolus comprises a zinc and/or copper metal ballast agent, which serves to help keep the bolus components within the animal's digestive tract rather than being regurgitated. The total mass of the cobalt-containing bolus may typically be in the region of ˜40 gms.

[0039] As to the dimensions of the bolus, the sheath component 2 is 84 mm long, 24 mm high and, at its widest, 30-31 mm wide. The recess or groove 6 runs the entire length of the sheath component and is about 20 mm deep, such that it is almost as deep as the sheath component is high. The recess or groove 6 is about 10-11 mm wide.

[0040] As well as the recess or groove 6 on the interior of the component 2, the component has four parallel grooves on the exterior surface, three of which, 8, 10, 12 are visible in FIG. 1. The fourth groove 14, is visible in FIG. 2. The grooves in the exterior surface are longitudinal grooves, parallel to the long axis of the component, and parallel to the interior recess or groove 6.

[0041] With reference to FIG. 2 it can be seen that, in section, component 2 has the appearance of a U. The two pointing arms ‘A’ and ‘B’ are relatively thick and are joined by a relatively thin bridging portion, which constitutes a frangible region or zone 20. The frangible zone 20 runs along the length of the bolus component such that, in vivo, when the stabilising wedge component 4 falls out from the between the arms A and B, the frangible sheath component 2 tends to rupture along its length, releasing the two arms A and B.

[0042] The longitudinal grooves 8-14 in the exterior surface of the component are symmetrically positioned, such that when the component breaks along it length, each of the resulting pieces comprises two grooves (8 and 10 in arm B; and 12 and 14 in arm A). The grooves 10 and 12 have a section with a radius of curvature of 5.1 mm, whilst grooves 8 and 14 are a little wider having a section with a radius of curvature of 5.6 mm. The function of the exterior grooves 8-14 is to allow the wax-coating of different parts of the bolus to be eroded at different rates. Thus, the portions of the wax directly beneath the grooves 8-14 are protected to some extent from the abrasion which takes place in vivo, whilst the surrounding portions are relatively protruding and so will be eroded, and their incorporated beneficial substance released, more quickly. This feature is already described in our GB patent no. 2510826.

[0043] In the actual bolus, the wedge component 4 is inserted into, and substantially entirely accommodated within, the groove or recess 6 in the sheath component 2, such that the bolus as a whole has a reasonably smooth, flush surface at the junction of the two components. The two components are held together in the bolus, ex vivo, by a water soluble adhesive or sealant, such as rice paper, which may be applied to the abutting surface of one or other, or both, of the bolus components, and the bolus as a whole is coated with a thin water-impermeable coating, such as a wax, the function of which, at least in part, is to protect the water-soluble adhesive from exposure to moisture prior to administration to an animal.

[0044] Once in vivo, the water-impermeable coating is removed from the bolus by abrasion with the wall of the animal's digestive tract, exposing the water-soluble adhesive to the aqueous environment of the digestive tract.