NZ549365A - Palatability improvement method - Google Patents

Abstract

Disclosed is a dry granular poison bait composition including solid and granular porous substrates coated with a gel where in the gel includes: (a) at least one gum; (b) at least one oil; (c) at least one poison agent; and characterised in that the agent or agents are at least partially absorbed into the pores of the substrate. Also disclosed is a method for preparing the composition and a method of avoiding bait shyness by pest animals by use of the composition in pest control applications.

Description

10054155837* ;Intellectual Property Office of N.Z. ;2 2 AUG 2007 ;RECEIVED ;PATENTS FORM NO. 5 ;Fee No. 4: $250.00 ;James & Wells ref: 43978NZ/29 ;PATENTS ACT 1953 COMPLETE SPECIFICATION ;After Provisional ;Cognate of No: 549365, 549368, 549366, 549367 Dated: 22 August 2006 ;A COMPOSITION TO IMPROVE DELIVERY OF AN ACTIVE AGENT ;We, EnCoate Limited, a New Zealand company cl- AgResearch Limited, East Street, Ruakura Campus, Hamilton, New Zealand hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: ;A COMPOSITION TO IMPROVE DELIVERY OF AN ACTIVE AGENT STATEMENT OF CORRESPONDING APPLICATIONS ;This application is based on the Provisional specifications filed in relation to New 5 Zealand Patent Application Numbers: 549365, 549568, 549366, and 549367, the entire contents of which are incorporated herein by reference. ;TECHNICAL FIELD ;The invention relates to a composition to improve delivery of an active agent. More 10 specifically, the invention relates to a composition and method of producing and using the composition that masks palatability characteristics of an agent on oral administration to a human or animal and delays release of the agent or agents. ;BACKGROUND ART ;15 In the prior art many medicines that include beneficial agents have been found that offer positive health benefits but lack broad consumer appeal and sales on account of their poor palatability such as bad taste or unpleasant mouth feel on oral administration. ;Similar problems are seen in the administration of poisons to pest animals where the 20 animals for example reject the poisoned bait without digestion based on the unpleasant taste or poor mouth feel. In the case of pest baits the result of rejection by the pest is low mortality. ;A further problem is that the agent or agents may be released to quickly, for example ;2 ;in the mouth before the agent is swallowed. In this case, the agent which may have been intended for delivery to the gut is released too early and may loose potency. In another application, speed of release may be important in avoiding the need to reapply fertiliser or pesticides in agricultural applications. Release too quickly may also 5 result in leeching of the pesticide or fertiliser in waterways causing environmental damage. ;A yet further problem with the agents (beneficial or otherwise) is that they may have limited stability over time for example due to oxidation reactions or degradation due to heat. Addressing stability problems is important in the delivery and efficacy of such 10 agents. ;One method used to stabilise agents is to mix the agent or agents with a polysaccharide carrier such as a wax, starch or gum. Whilst this method may address the stability of the agent or agents, it does not address palatability issues. For example, the polysaccharide is usually aqueous soluble and on oral administration, 15 dissolves in the mouth releasing the agents into the mouth and causing an unpleasant palatability reaction. In most cases this means the agent is rejected by the animal or human if the palatability is unacceptable. At the very least, with the agent being released in the mouth, the efficacy may be reduced as release in the stomach and/or gut may be preferable. ;20 In another example, a method used to control pests such as rats, possums and other animals is poisoned baits, for example carrots laced with cyanide. The aim of the bait is to attract the pest animal into eating the bait and the poison then kills the pest. ;Given the desire to kill the animal humanely, an aim of this method is to not only kill the pest animal, but also to kill the animal quickly to reduce any potential for animal 25 suffering. A problem with this aim though is that the pest animals often die adjacent or close to the poisoned bait as the poison works sufficiently quickly that the pest animals do not have time or are physically unable to move away from the bait eaten. ;3 ;Remaining pest animals then develop an aversion to the bait where fellow pest animals have died and so consequently, the bait is only eaten once by a limited number of pest animals. ;Ideally it should be appreciated it would be an advantage to mask palatability 5 characteristics of the agent or agents where the agent(s) are orally administered and that, on administration to an aqueous environment, stops or reduces dispersion of the agent for a sufficient time to allow the agent to be released within the animal stomach and/or gut and not in the mouth. ;It is an object of the present invention to address the foregoing problems or at least to 10 provide the public with a useful choice. ;All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency 15 of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country. ;It is acknowledged that the term 'comprise' may, under varying jurisdictions, be 20 attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is 25 used in relation to one or more steps in a method or process. ;Further aspects and advantages of the present invention will become apparent from ;4 ;the ensuing description which is given by way of example only. ;DISCLOSURE OF THE INVENTION ;The inventors have found compositions and methods of forming and using the 5 compositions that have the effect of masking unfavourable palatability from active agents as well as being able to delay release of such agents. ;For the purposes of this specification, the term 'palatability' refers to properties relating to the mouth including but not limited to taste, bitterness, acidity, texture such as grittiness, olfactory sensations and the like. ;10 The term 'unfavourable' refers to the agent or agents having palatability characteristics that an animal (including humans) dislikes or would not choose to eat. ;The term 'agent' or 'agents' include chemical and biological substances with a desired activity. For example, agents may be those that are taken prophylactically to confer health giving benefits; those taken to alleviate or cure a condition; toxic agents 15 administered for pest control; and agents used in pasture control such as those used to prevent fungi attack of plants and seeds or fertilisers. ;The term 'delayed release' refers to the composition completely preventing release of the agent or agents from the substrate for a desired time period when kept absent of an aqueous environment and, also slows or partly delays release when the 20 composition is exposed to an aqueous environment. ;The term 'substrate' refers to a solid or semi-solid material on which other materials are coated. ;According to one aspect of the present invention there is provided a composition including; ;5 ;(a) a porous substrate; ;(b) at least one agent; ;(c) at least one gum; and characterised in that the agent or agents are at least partially absorbed into the pores 5 of the substrate. ;According to a further aspect of the present invention, there is provided a poison bait for pest animal control including: ;(a) a porous substrate; ;(b) at least agent poisonous to a target pest animal; ;10 (c) at least one gum; and characterised in that the poison agent or agents are at least partially absorbed into the pores of the substrate which masks the palatability of the agent or agents and delays release of the agent or agents on oral ingestion. ;According to a further aspect of the present invention there is provided a medicament 15 that masks the palatability of the beneficial agent or agents in the medicament including: ;(a) a porous substrate; ;(b) at least beneficial agent; ;(c) at least one gum; and ;20 characterised in that the beneficial agent or agents are at least partially absorbed into the pores of the substrate. ;According to a further aspect of the present invention there is provided a medicament targeted for delivery to the gastrointestinal tract of an animal including: ;(a) a porous substrate; ;(b) at least one agent which has activity in the gastrointestinal tract of the animal; ;5 (c) at least one gum; and characterised in that the beneficial agent or agents are at least partially absorbed into the pores of the substrate and release of the agent or agents is delayed on oral ingestion until the agent or agents reach the gastrointestinal tract of the animal. ;According to a further aspect of the present invention there is provided an agricultural 10 composition for use in pastoral management including: ;(a) a porous substrate; ;(b) at least one agent; ;(c) at least one gum; and characterised in that the agent or agents are at least partially absorbed into the pores 15 of the substrate and release of the agent or agents is delayed when the agricultural composition is broadcast into the environment. ;Preferably the compositions described above are stable in the absence of a solvent solution such as water and may be stored for prolonged periods of time (months) without degradation of the agent or agents. Storage temperatures may also be 20 maintained at normal ambient conditions (e.g. 4-30°C) and there is no requirement to chill or especially treat the compositions once prepared. ;Preferably, the porous substrate has a porosity of greater than 0.5 or 50% with tortuous paths rather than regular paths. The porosity is understood to be a key ;7 ;feature in order to absorb the agent from the exterior and into the substrate pores where it is more resistant to aqueous dispersion. ;As noted above, the agent or agents absorb into the substrate. This may be in isolation or in combination with the gum and other materials that may be used. 5 Absorption, is understood to occur by diffusion of the agent(s) into the pores of the substrate. ;Preferably, the agent or agents are fully or nearly fully absorbed into the pores of the substrate. For applications where the composition is taken orally, the inventors understand that fully or nearly fully absorbing the agent or agents is particularly 10 important as, with the agent fully absorbed, there is insufficient time for the agent to be desorbed when the composition is eaten. This delay in release avoids difficulties associated with poor mouth feel and taste. Absorption is also important in avoiding issues surrounding poor stability as, with the agent fully absorbed, it is harder for the agent to be released or deteriorated by external conditions such as moisture or 15 exposure to heat. ;Preferred porous substrates may be selected from natural materials including: peats, clays, aluminosilicate materials, zeolites, bentonites, diatomaceous earth, active carbons, and combinations thereof. Alternatively, the porous substrate may be synthetically produced materials selected from: cements, foams, ceramics, porous 20 glasses, charcoals, and combinations thereof. It should also be appreciated that combinations of both natural and synthetic porous materials may also be used without departing from the scope of the invention. ;In one preferred embodiment, the porous substrate is a solid granular material typically with a diameter of less than 1000 nm. In one embodiment, the porous 25 substance is crushed and broken into granules prior to use to a particle size distribution of between 245 and 450 jim. ;8 ;tn one particularly preferred embodiment, the porous substrate is zeolite. ;Preferably, the agent or agents used are soluble or are able to be wetted out with suspending and/or solvent solutions such as water. This should not be seen as limiting as other non-aqueous soluble agents may be used provided they are 5 formulated in a manner that alters their solubility such that mixing in an aqueous solution is possible. ;In one embodiment, the agent may be a medicament taken prophylactically to prevent or ameliorate a disease for example including: herbal extracts such as Echinacea, garlic extracts; omega 3 extracts; and combinations thereof. It should be appreciated 10 that as such medicaments may be extracted using solvents such as alcohol, the present invention may be advantageous in masking the bitter taste that residues from alcohol extraction may leave. ;In a further embodiment, the agent or agents may be prebiotics and/or probiotics. In this example, the delayed release effect of the composition may be beneficial in with-15 holding release of the agents until they reach the gastrointestinal tract (GIT). ;In another embodiment, the agent or agents may be medicaments taken to treat a condition. For example, the agent or agents may include one or more anthelmintic compounds used to treat a pest infestation. As may be appreciated, animals to whom the anthelmintic is administered may be resistant to taking normal medication but, by 20 masking the palatability via the present invention, animals may be more willing to take such medicaments. In another example, the agent or agents may include hormones taken by animals including humans to regulate hormone levels. In this example, the delayed release effects (as well as masking palatability) may be beneficial to ensure that the hormone(s) are released in a localised part of the body or after a certain time 25 period. ;In a further embodiment, the agent or agents are poisons used to treat pest animal ;9 ;infestations. For example, the poison agent or agents may be norbormide or cyanide used to control rodents. In this example, both the palatability masking effects and delayed release effects are an advantage. Firstly, as the pest animal does not taste the poison, they are inclined to eat the poison. Secondly, as release of the poison is 5 delayed, the animal has time to move away from the poison and later dies. This avoids the effect of bait shyness where other animals see dead animals and shy away from the area (and the poison). ;In a yet further embodiment, the agent or agents are one or more fungicides or bactericides or fertilisers which are broadcast to a pasture. In this embodiment the 10 delayed release characteristics of the composition are of value as this slows release of the fungicides/bactericides/fertilisers into the environment providing a longer duration of time before reapplication and may also help to prevent leeching of excess into the environment. ;Preferably, the gum is xanthan gum or a gum with equivalent chemical properties to 15 xanthan gum. Preferably, the gum has no strong taste and is food safe when used in oral administration applications. ;Preferably, as should be appreciated by those skilled in the art, a suspending and/or solvent agent is also used to assist with coating and gel formation. In one embodiment, the agent is water although non-aqueous solvents may also be used 20 such as alcohols. ;Preferably in use, the gum and agent or agents are pre-mixed for example with water as the solvent to form a gel which is then coated on the porous substrate. In one preferred embodiment, the viscosity of the gel once prepared is approximately 10 OOOcP with thixotropic properties. Formation of a gel is important to the success of 25 the composition. If the biopolymer viscosity is too low (liquid), the mixture will not uniformly mix through the substrate and will not form a stable layer on the substrate. ;10 ;By contrast, if the biopolymer is too viscous, limited or no coating and subsequent absorption into the substrate pores will occur. ;In preferred embodiments the composition also includes at least one oil. Preferably, the oil is a vegetable oil including but not limited to peanut oil. It should be 5 appreciated that other oils such as olive oil may be used with similar chemical and/or physical characteristics without departing from the scope of the invention. In one embodiment, the oil is the suspending and/or solvent agent. In other embodiments the oil is added in addition to other suspending and/or solvent agents. ;In further embodiments, other ingredients may be added to the composition selected 10 from: flavourings, colourings, further coating substances, and combinations thereof. ;Further, the composition may be dried and mixed with other materials such as dry carrier materials including tableting compounds and/or feed compounds. ;In a further embodiment, the composition may be coated or encased within animal bait materials, for example within a carrot. ;15 According to a further aspect of the invention there is provided a method of producing a composition with at least one agent absorbed into the pores of a porous substrate by the steps of: ;(a) adding the agent or agents to a suspending and/or solvent agent to form a solvent and agent composition; ;20 (b) mixing the solvent and agent composition from step (a) with at least one gum added in sufficient amounts to form a gel; ;(c) coating the gel of step (b) onto a porous substrate. ;Preferably, at least one oil substantially as described above is also mixed in at step (b). ;11 ;Preferably, the solid substrate is coated with the gel in step (c) by immersion and mixing of the substrate in the gel. ;Preferably, the mixture of step (b) is allowed to stand for 2-60 minutes before commencing step (c). ;5 Preferably, the coated substrate of step (c) is allowed to stand for 2-60 minutes before any further processing occurs. ;According to a further aspect of the present invention there is provided a method of improving the palatability of at least one agent by the method substantially as described above. ;10 According to a further aspect of the present invention there is provided a method of delaying the release of at least one agent by the method substantially as described above. ;According to a further aspect of the present invention, there is provided a method of avoiding bait shyness by pest animals by use of the composition substantially as 15 described above in pest control applications wherein the agent or agents are toxic to the pest animals. ;According to a further aspect of the present invention there is provided a method of manufacturing a pesticidal bait for use as a rodenticide by the method substantially as described above. ;20 According to a further aspect of the present invention there is provided a method of treating a gastrointestinal tract condition by oral administration of the composition substantially as described above. ;According to a further aspect of the present invention there is provided the use of an orally administered composition substantially as described above in the treatment of a ;12 ;gastrointestinal tract condition. ;According to a further aspect of the present invention there is provided a method of avoiding or ameliorating an animal condition by oral administration of the composition substantially as described above. ;5 According to a further aspect of the present invention there is provided the use of an orally administered composition substantially as described above to avoid or ameliorate an animal condition. ;According to a further aspect of the present invention there is provided a method of promoting gut health in an animal by oral administration of a composition containing 10 prebiotics and/or probiotics substantially as described above. ;According to a further aspect of the present invention there is provided the use of an orally administered composition containing prebiotics and/or probiotics substantially as described above in promotion of gut health in an animal. ;It should be appreciated from the above description that there is provided a 15 composition and method of producing the composition that masks the palatability of at least one agent included in the formulation. The composition and method have the advantage of removing both unpleasant taste characteristics as well as mouth feel issues such as grittiness. ;The composition and method also delays release of the agent or agents until the 20 substrate is exposed to an aqueous environment. Release is further delayed even after exposure to an aqueous environment. ;Further, the composition and method stabilises the agent or agents so that they may be stored at ambient temperatures without loss in activity. ;The method also prevents poison bait avoidance or bait shyness by pest animals due ;13 ;to dead animals being in close proximity to the bait source. Death of the pest animal occurs sufficiently long after ingestion that the pest animal has time to move away from the bait source. ;5 BRIEF DESCRIPTION OF DRAWINGS ;Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which: ;Figure 1 shows a diagram of a method of producing the composition of the 10 present invention. ;BEST MODES FOR CARRYING OUT THE INVENTION ;Examples are now provided showing the composition and uses of the composition as well as the method of manufacture. ;15 EXAMPLE 1 ;A generic process flow diagram used to manufacture the composition of the present invention is shown in Figure 1. The composition is produced by coating a porous substrate 2 with a gel containing at least one active agent 1 and at least one gum (not shown) and preferably also aqueous solution and oil (not shown). ;20 This gel may be termed a 'biopolymer' or 'biomatrix' for the purpose of subsequent Examples. ;The coated substrate 4 initially has a coating layer, which includes the agent 3. The agent 3 is then absorbed from the coating 5 and into the pores of the substrate 6. ;14 ;EXAMPLE 2 ;Experimental results are now provided showing usage of various carrier substrates with gel coatings to improve delivery of an agent (a rodenticide). ;Method ;Three carrier systems were used to form placebo and toxin containing baits being: ;1. Wheat grains ;2. Poppy seeds and ;3. Crushed zeolite granules. ;Wheat Grain ;Wheat formulations were produced as follows: ;Sample 1 Placebo: A 4% biopolymer matrix of xanthan gum and vegetable oil was prepared as follows: ;• 5 g of vegetable oil was added to 5 g of xanthan gum in a clean container and mixed thoroughly to form a crumble. ;• To this was added 115 ml of distilled water mixed with 2.5 ml of red food colour. ;• The mixture was left to polymerize for 10 minutes in a laminar flow cabinet before 100 g of the resulting gel was coated onto to 1 kg of wheat grain. ;• The coated grain was air dried in a laminar flow cabinet for 4 hours in a clean plastic tray to obtain a single grain flowable product. ;15 ;Sample 2 Placebo: A 4% biopolymer matrix of xanthan gum, vegetable oil and peanut butter was prepared by use of the process for Sample 1 but with the variation that the 115 ml of distilled water added to the crumble was homogenised with 12.5 g of peanut butter and 1 ml red food colour. ;5 Sample 3 Placebo: A 4% biopolymer matrix of xanthan gum, peanut oil and Paselli BC was prepared as follows: ;• 5 g of peanut oil was added to 2.5 g of xanthan gum in a clean container and mixed thoroughly to form a crumble. ;• To this was added 2.5 g of Paselli BC and 115 ml of distilled water ;10 homogenised with 12.5 g of peanut butter and 2.5 ml of red food colour. ;• The solution was mixed to prevent lumps and left to polymerize for 10 minutes in a laminar flow cabinet. ;• The resulting gel was homogenised before 100 g of the resulting gel was coated onto to 1 kg of wheat grain. ;15 • The coated grain was air dried in a laminar flow cabinet for 4 hours in a clean plastic tray to obtain a single grain flowable product. ;Sample 4 Active: An active containing 4% biopolymer matrix of xanthan gum, vegetable oil and norbormide (toxin) was prepared using the process of Sample 1 with the variation that the 115 ml of distilled water added to the crumble was polytroned 20 with 6.5 g of norbormide or cyanide (or both) and 2.5 ml of food colour. ;Sample 5 Active: An active containing 4% biopolymer matrix of xanthan gum, vegetable oil, norbormide (toxin) and peanut butter was prepared using the process of Sample 2 with the variation that the 127.5 ml distilled water added to the crumble was ;16 ;polytroned with 7.22 g of norbormide, along with the 12.5 g of peanut butter and 1 ml red food colour. ;Sample 6 Active: An active containing 4% biopolymer matrix of xanthan gum, vegetable oil, norbormide (toxin) and peanut butter was prepared using the process of 5 Sample 3 with the variation that the 127.5 ml of distilled water added to the crumble was polytroned with 7.22 g norbormide along with red food colour and peanut butter. ;The above biopolymer formulations were modified procedures used for seed coatings. Peanut butter and dyes were added to increase the bait appeal and allow visual coverage. ;10 Poppy Seeds ;Poppy seed formulations were produced as follows: ;Sample 7 Placebo: A poppy seed mixture was produced as follows: ;• Poppy seeds were mixed and sieved to a grain size of 500 pm. ;• Seeds (20 g) were then coated with 4 g of a biopolymer gel composed of 0.5 g 15 xanthan gum, 0.5 g vegetable oil and 15.5 ml of distilled water, and dried at ;80° C for 5 hours. ;• 10 g of coated poppy seed was then mixed with corn grits 15 g, white millet 3 g, red milo 3 g and oat groats 7.5 g which had been sieved to a grain size of £ 1 mm. ;1.5 g of icing sugar, 1 g peanut oil and 1 g of peanut butter was added to the dry seed mix. ;The ingredients were thoroughly mixed and added to 20 g of wax that had been heated to 100 0 C. ;20 ;17 ;• The wax mixture was added to an ice cube tray and cooled at 4° C. ;• The resulting wax blocks were removed from the tray by tapping it upside down on the bench. ;Sample 8 Active: A poppy seed mixture was produced as using the process of ;Sample 7 but with the following variations: ;• 2.606 g norbormide was polytroned into the distilled water used to make the poppy seed gel coating. ;• 2 g of the gel was coated onto 10 g poppy seed. ;• A secondary coat was applied to the dried seeds of Polyox N10 gel prepared as follows: 20 g Polyox N 10 was added to 50 ml of distilled water and stirred for 2 hours at low speed using a stirrer. ;Sample 9 Active: A poppy seed mixture was produced as using the process of ;Sample 7 but with the following variations: ;• 0.227 g of norbormide was added to the dry ingredients before the addition of peanut butter and oil. ;Zeolite Granules ;Zeolite formulations were produced as follows: ;Sample 10 Placebo: A zeolite based product was produced by the steps of: ;• 7.5 g of crushed and sieved zeolite granules, with diameters between 245 and 450 mid, were coated with 3 g of a biopolymer gel composed of 1 g xanthan gum, 1 g vegetable oil and 23 ml of distilled water. ;18 ;• A secondary coat of 1 g of 40 % Polyox N10 (prepared as in the process for Sample 8) was also applied, and the granules dried at 80°C for 30 min. ;• 22.3 g corn grits, 4.5 g white millet, 4.5 g red milo and 11.2 g oat groats were blended and sieved to a grain size of £ 1 mm. ;5 • These were added to the dried zeolite granules along with 2.2 g of icing sugar, 1.5 g peanut oil and 1.5 g of peanut butter. ;• Ingredients were thoroughly mixed and added to 44.8 g of wax that had been heated to 100 0 C. ;• The wax mixture was spread on an ice cube tray and cooled at 4 ° C. ;10 • The resulting wax blocks were removed from the tray by tapping it upside down on the bench. ;Sample 11 Active: A zeolite based product containing norbormide toxin was produce using the process of Sample 10 with the variation that 2.61 g norbormide was polytroned into the distilled water used to make the zeolite granule gel coating. ;15 Sample 12 Active: A lower dose sample was prepared using the process of Sample 11 with the variation that only 0.284 g of norbormide was mixed in with the dry ingredients before the addition of peanut butter and oil. ;EXAMPLE 4 ;20 Efficacy in terms of reducing palatability and delayed release were then tested by feeding the compositions of Example 2 to live rats and observing the results. ;19 ;For the wheat and poppy seed compositions, consumption was low indicating that the compositions were unable to mask toxin mouth feel and consequently rats remained alive throughout the study. These substrates have a low porosity. ;By contrast, the zeolite compositions were readily consumed by rats and caused high 5 levels of mortality. Zeolite has a high porosity and, as this bait was readily consumed, the rats obviously were unable to taste or otherwise identify the presence of poison. ;The above results showed that the zeolite acts to absorb the toxin into the granule and the gel coating clearly prevents the animal from tasting the toxin on eating. The toxin still retains its effectiveness once eaten as evidenced by the high mortality rate for the 10 zeolite formulated samples. ;The composition also appeared to delay release of the poison as rats that ate the bait were able to move away from the bait before toxic effects were observed. ;EXAMPLE 5 ;15 In this example the agents used in the composition include prebiotics and probiotic bacteria known to be beneficial for gut health. As may be appreciated, delivery of these agents to the gut is important for maximum efficacy. Also, as probiotic bacteria can be unstable when exposed to the environment, compositions containing such bacteria need to be chilled or used quickly. ;20 In this example the composition is produced in accordance with the method described in Example 1 and subsequently mixed into a food. No chilling is completed and the bacteria remain viable (no less than 2 log loss in viability) over a time period of 3 months. On administration, the composition does not leave any noticeable taste or other palate characteristics. The delayed release characteristics of the composition 25 assist in the agents being released in the gut. ;20 ;EXAMPLE 6 ;The method of forming the composition is completed as per Example 1 and the agent used is a herbal extract produced via an alcohol solvent extraction. As may be appreciated, alcohol is a powerful solvent in such applications but, even with thorough 5 subsequent processing, the alcohol may leave a sharp bitter taste in the extract which some patients find unpleasant. ;By processing the extract to form the composition of the present invention, the taste is masked and the patient is able to take the extract without experiencing the unpleasant bitter taste. ;10 EXAMPLE 7 ;In this example, the same method as Example 1 was undertaken and the agent is a known fertiliser for use in promoting grass growth on farms. The composition produced is broadcast onto a field and, due to the delayed release characteristics of the composition, the fertiliser is released over a pro-longed length of time therefore 15 reducing the need to re-apply new fertiliser (and potentially also reducing the risk of leeching of fertiliser into waterways). ;It should be appreciated from the above examples that there is provided a composition and method of producing the composition that masks palatability characteristics of agents within the compositions and also delays release of the agent or agents from 20 the composition. Products utilising the composition are wide ranging with immediate applications including poison delivery, medicament delivery and agricultural uses to deliver pesticides and fertilisers. ;Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without 25 departing from the scope thereof as defined in the appended claims. ;21 *

Claims (20)

WHAT WE CLAIM IS:

1. A dry granular poison bait composition including solid and granular porous substrates coated with a gel where in the gel includes: (a) at least one gum; 5 (b) at least one oil; (c) at least one poison agent; and characterised in that the agent or agents are at least partially absorbed into the pores of the substrate.

2. The poison bait composition as claimed in claim 1 wherein the poison agent or 10 agents are selected from; norbormide, cyanide, and combinations thereof.

3. The poison bait composition as claimed in claim 1 or claim 2 wherein the poison agent or agents are stable in the absence of aqueous solution and may be stored for greater than 3 months at ambient temperatures with minimal degradation of the poison agent or agents. 15

4. The poison bait composition as claimed in any one of the above claims wherein the porous substrate has a porosity of greater than 0.5 or 50%.

5. The poison bait composition as claimed in any one of the above claims wherein the poison agent or agents are fully absorbed into the pores of the substrate.

6. The poison bait composition as claimed in any one of the above claims wherein the 20 porous substrates are selected from; peats, clays, aluminosilicate materials, zeolites, bentonites, diatomaceous earth, active carbons, and combinations thereof.

7. The poison bait composition as claimed in any one of the above claims wherein the porous substrates are synthetically produced materials selected from: cements, foams, ceramics, porous glasses, charcoals, and combinations thereof.

8. The poison bait composition as claimed in any one of the above claims wherein the porous substrate has an approximate diameter of less than 1000 nm. 5

9. The poison bait composition as claimed in any one of the above claims wherein the porous substrate is zeolite.

10. The poison bait composition as claimed in any one of the above claims wherein the poison agent or agents used are soluble in aqueous solutions.

11. The poison bait composition as claimed in any one of the above claims wherein 10 the gum is xanthan gum.

12. The poison bait composition as claimed in any one of the above claims wherein the oil is a vegetable oil.

13. The poison bait composition as claimed in claim 12 wherein the oil is selected from peanut oil and olive oil. 15

14. The poison bait composition as claimed in any one of the above claims wherein the composition also includes additional substances selected from: flavourings, colourings, further coating substances, carrier materials, tableting compounds, feed compounds, animal baits, and combinations thereof.

15. A method of producing a dry granular poison bait composition with at least one 20 poison agent absorbed into the pores of a solid and granular porous substrate by the steps of: (a) adding the poison agent or agents to a suspending and/or solvent agent to form a solvent and poison agent mixture; 23 (b) adding the solvent and poison agent mixture from step (a) to at least one oil and at least one gum added in sufficient amounts to form a gel; (c) coating the gel of step (b) onto a porous substrate.

16. The method as claimed in claim 15 wherein the porous substrate is coated with 5 the gel in step (c) by immersion and mixing of the substrate in the gel.

17. The method as claimed in claim 15 or claim 16 wherein the mixture of step (b) is allowed to stand for 2-60 minutes before commencing step (c).

18. The method as claimed in claim 15 or claim 16 wherein the coated substrate of step (c) is allowed to stand for 2-60 minutes before any further processing occurs. 10

19. A method of avoiding bait shyness by pest animals by use of the composition as claimed in any one of claims 1 to 14 in pest control applications wherein the poison agent or agents used are toxic to the pest animals.

20. A method of manufacturing a pesticidal bait for use as a rodenticide by the method as claimed in any one of claims 15 to 18. 15 ENCOATE HOLDINGS LIMITED by their authorised agents 20 JAMES & WELLS per: 24