WO2025207585A1 - Environmentally safe moisture activated rodenticide composition and delivery system - Google Patents

Abstract

A regulatory compliant and environmentally safe rodenticide and method of manufacture are disclosed. The invention utilizes environmentally safe ingredients including calcium sulfate hemihydrate (plaster of Paris), sodium chloride, edible attractants, and dry lubricants. These are dry -compressed into a stable, moisture-activated tablet that remains inert under ambient conditions and becomes lethal upon ingestion by a rodent. Once consumed, moisture in the digestive tract triggers gastrointestinal obstruction and systemic dehydration, leading to rapid mortality without secondary poisoning risk. The dry compression manufacturing method enables scalable, shelf-stable production compatible with commercial pest control deployment. The bait may be produced in multiple secure-use formats — including washer-style tablets, briquette blocks, and scatter bait tablets — for safe and flexible application in tamper-resistant bait stations or direct placement.

Description

TITLE OF THE INVENTION

ENVIRONMENTALLY SAFE MOISTURE ACTIVATED RODENTICIDE COMPOSITION AND DELIVERY SYSTEM

CROSS REFERENCE TO RELATED APPLICATIONS

This is a PCT application, which claims priority from U.S. Provisional Application No. 63/569,618 filed on March 25, 2024, the disclosure of which is incorporated by reference in its entirety to provide continuity of disclosure.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

[0001] This invention relates to fields of pest control and rodenticides. Specifically, this invention comprises a rodenticide composition of non-toxic ingredients, which are dry compressed into a bait tablet for killing rodents. Said composition utilizes calcium sulfate (plaster of Paris) and other food-grade ingredients in a stable, solid form that remains inert until ingested by a rodent and is activated by moisture once in a rodent’s digestive tract. [0002] It is well known that rodent infestations pose serious public health and economic challenges. Such infestations are traditionally managed with chemical poisons (anticoagulants, neurotoxins, etc.) or mechanical traps. Conventional chemical rodenticides can be effective but suffer from several drawbacks: rodents can develop resistance, and the poisons pose risks of accidental poisoning to non-target animals and children (secondary poisoning and environmental contamination are well-known issues). As such there is a need for rodenticides that are safer for other animals and the environment while still effectively controlling rodents.

[0003] Non-toxic and mechanical -kill rodenticides have been explored as alternatives to traditional chemical poisons. Some existing products rely on dehydration as the primary mode of action, typically using food-grade ingredients designed to physiologically disrupt hydration pathways in rodents. In contrast, the present invention utilizes an entirely different composition and mechanism. The formulation features a dry-compressed tablet comprised of calcium sulfate hemihydrate (plaster of Paris) that remains inert until ingested. Upon exposure to moisture inside the digestive tract, the calcium sulfate reacts to form a solid mass, creating a gastrointestinal blockage. This physical obstruction mechanism can be complemented by the inclusion of sodium chloride (salt), a known desiccant, and additional drying agents such as silica and cellulose, which together promote systemic dehydration. The resulting dual mechanism — mechanical and physiological — is distinct from prior dehydration-based approaches that depend solely on internal thirst suppression.

[0004] Furthermore, this invention represents the only known regulatory-compliant rodenticide specifically designed for use in commercial pest control settings. The bait is manufactured in formats such as washer-style tablets and briquettes with central apertures, allowing secure deployment in standard bait stations. This compatibility, combined with shelfstable, tamper-resistant construction, makes it uniquely suited for professional use while maintaining regulatory compliance and environmental safety, thus eliminating secondary poisoning risk.

[0005] Conventional rodenticides such as anticoagulants, neurotoxins, and cholecalciferol -based baits are widely used in professional and residential pest control but present several limitations. These formulations typically take three to ten days to induce mortality and often require repeated ingestion. Many carry a risk of secondary poisoning to nontarget species, including pets, wildlife, and predators. In contrast, the present invention offers a regulatory-compliant, environmentally friendly formulation that induces mortality between three and five days post-ingestion, with no secondary poisoning risk. The bait’s dual mode of action — mechanical gastrointestinal obstruction combined with systemic dehydration — delivers lethal outcomes with fewer risks and without the use of synthetic toxins. This makes it a safer, faster, and more environmentally responsible alternative to traditional rodenticides and more palatable than current rodenticides on the market.

[0006] Prior art rodenticides generally fall into two categories: toxic chemical baits with significant safety and environmental risks, or non-toxic formulations that suffer from limitations in efficacy, stability, or field deployment. Traditional rodenticides, such as anticoagulants and neurotoxins, are effective but present hazards to non-target species and carry risks of secondary poisoning. Conversely, existing regulatory-compliant baits typically rely solely on food-based desiccants and require sustained ingestion over multiple days to achieve lethality, with limited mechanical action and vulnerability to moisture degradation.

[0007] These approaches often lack compatibility with commercial bait stations, suffer from palatability challenges. The present invention addresses these shortcomings by offering a shelf-stable, highly palatable dry-compressed bait with a unique dual mechanism of lethality — gastrointestinal obstruction and systemic dehydration — while maintaining full regulatory compliance. The present composition is specifically designed for safe deployment in commercial and residential settings as a scatter bait (small tablet form), washer-style, and/or briquette-style bait blocks for secure placement and tamper resistance in bait stations. This invention represents a scalable, safe, and field-ready alternative that bridges the gap between performance, safety, and professional usability.

BRIEF SUMMARY OF THE INVENTION

[0008] The present invention provides a dry-compressed rodenticide tablet that addresses the above problems by combining multiple safe ingredients in a stable, solid dosage form. The invention uses a novel tablet compression process to create hard bait tablets containing plaster of Paris, edible food-grade attractants, and other functional ingredients. This unique formulation and process ensures the final bait remains inert and structurally intact under normal storage and field conditions, activating lethally only when consumed by a rodent.

[0009] Key aspects and advantages of the embodiments of the invention include: (1) A delayed activation mechanism, wherein the composition’s primary lethal agent is calcium sulfate hemihydrate (plaster of Paris), which is kept dry and in an unreacted state until ingested by a rodent. A compressed tablet bait form of the composition resists moisture uptake from the environment, preventing premature activation. Only when a rodent consumes the bait and the composition comes into contact with significant moisture (e.g. in the animal’s stomach or if the rodent drinks water) does the plaster of Paris react and harden in situ, forming a solid mass that causes a fatal mechanical blockage of the rodent’s gastrointestinal tract. This moisture-triggered activation means the product remains safe and inert during handling and deployment, becoming lethal only once consumed by the target rodent.

[0010] Another key advantage of the embodiments of the invention includes: (2) An innovative ingredient composition, wherein the formulation preferably includes a blend of edible food-grade attractants, such as sugars in different particle sizes (e.g. powdered sugar and milled grains/legumes/nuts), to entice rodents to consume a sufficient dose. By using both powdered and milled grains/legume/nuts, the tablet achieves good compressibility during manufacture and palatability when encountered by the targeted rodent. Fine sugar particles fill in space during compression to create a solid matrix and provide immediate sweetness, while milled grains/legumes/nuts offers texture and sustained attraction. The bait may also include other foodbased attractants (e.g. ground grains, nuts, or chocolate powder) to maximize appeal, but sucrose-based ingredients are a novel focus of this formula. In another embodiment, sugar granules can be combined with the powdered sugar to create the solid composition matrix as well.

[0011] In yet another embodiment, the composition is comprised of a dehydrating salt active such as sodium chloride (salt). Common salt is a regulatory minimum-risk pesticide active substance that powerfully dehydrates a rodent. Sodium chloride creates an osmotic imbalance, causing the rodent’s body to draw water into the gut and bloodstream to excess, leading to systemic dehydration and organ failure. The combined action of sodium chloride (rapid systemic dehydration) and plaster of Paris (internal blockage and localized drying) yields a potent dual mechanism of lethality. Optionally, further desiccating agents like amorphous silica gel or cellulose can be included to further absorb fluids in the digestive tract to amplify the effect of the primary plaster of Paris ingredient.

[0012] Yet another key advantage of the embodiments of the invention include: (3) the use of dry lubricants and excipients for stability and processability. A critical innovation of this invention is the inclusion of pharmaceutical -grade dry lubricants and anti-caking agents (e.g. zinc stearate, lactose and colloidal silicon dioxide) in the composition. These ingredients serve dual purposes. Zinc stearate is a hydrophobic lubricant that coats the composition particles, preventing them from sticking to each other and prevents adhesion to a tablet press during manufacture. Furthermore, zinc stearate’s water-repellent qualities prevents ambient moisture from initiating the plaster of Paris reaction during product storage and deployment. Silicon dioxide (SiCh) acts as a glidant and moisture absorber, which improves powder flow and uniform blending during manufacture by reducing inter-particle friction, and absorbing trace moisture. Only a small percentage of silica (approximately 0.5-2% w/w) is needed to achieve these effects. In the present invention about 2% SiO2 w/w was found to optimize both manufacturing and shelf-life of the final composition tablets. The use of dry excipients allows tablet formation without any liquid binders or wet granulation, which preserves the plaster of Paris in a completely dry, inactive state prior to use. This approach is novel in the context of rodenticide baits.

[0013] Yet another key advantage of the embodiments of the invention include: (4) its method of scalability and mass-production. The rodenticide tablet is designed to be manufactured with tablet press machinery. All ingredients of the composition are dry blended and then compressed in a punch-and-die press to form hard tablets (pellets or pills) of a predetermined size and weight. By utilizing tablet compression, the invention achieves high- volume production with consistent dosage and quality. This is a significant improvement over handmade mixes or extrusion processes common in the rodenticide field. The tablet press method allows precise control over tablet hardness, disintegration properties, and weight variation. It also drastically reduces unit cost by producing thousands of tablets per hour on automated equipment. The result is a commercially viable rodent bait that can be produced at scale with uniform performance, which is not possible with the improvised manufacturing methods common in the industry.

[0014] Yet another key advantage of the embodiments of the invention include: (5) enhanced durability for bait stations and storage. The final compressed composition tablets are structurally robust and resistant to crumbling, making them well-suited for placement in bait stations (including outdoor stations) without disintegrating. The formulation is optimized to withstand long-term storage and field conditions - the combination of hydrophobic lubricants and desiccant excipients keeps the tablets stable in varying humidity and temperature conditions. Unlike grain-based loose baits that might mold or degrade, these tablets are largely inorganic (plaster and salt) and dry, which inhibits microbial growth and spoilage. In one embodiment, the tablet is shaped with a central hole or aperture (a “washer” form) to allow it to be securely mounted on rods in tamper-resistant bait stations. This feature prevents rodents from carrying the bait away (bait theft) and ensures the tablet stays in the station despite rodent gnawing or environmental disturbances. The aperture design also facilitates better air circulation around the tablet, aiding in keeping it dry, and is fully compatible with standard bait station hardware. Overall, the invention provides a bait that lasts in the field - it can remain palatable and potent over weeks of deployment, yet still delivers rapid lethality once consumed by a target rodent.

[0015] The dry-compressed rodenticide tablet of this invention represents a novel integration of elements into a unique pest control product. It combines the proven rodent-killing effect of calcium sulfate and sodium chloride) with innovations in formulation (sugar attractants, silica, lubricants) and manufacturing (tablet pressing) to solve long-standing issues of bait stability and efficacy. No prior rodenticide provides this particular combination of ingredients nor the delayed activation mechanism achieved by the present formulation. By differentiating from existing baits, which lack moisture control and scalability, and from dehydration products, which require large intakes and days to work, this invention offers a fast-acting, lethal bait that is safe, shelf-stable, and easy to produce and deploy. These features give it significant competitive advantage and patentable novelty in the field of rodent control.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is an overhead perspective view of a prior art rodent bait station with the cover removed to show a prior art bait configuration of a bait block with a central hole or aperture mounted on to a vertical rod of the bait station.

[0017] FIG. 2 is a perspective view of an embodiment of the invention comprising a pressed tablet.

[0018] FIG. 3 is a perspective view of an alternative embodiment of the invention comprising a pressed tablet with a central hole or aperture, which allows the tablet to be mounted onto a rod for deployment.

[0019] FIG. 4 is a perspective view of an alternative embodiment of the invention comprising pressed tablets with a central hole or aperture, which are mounted on vertical rods of a prior art rodent bait station.

[0020] FIG. 5 is a perspective view of a bait block embodiment of the invention; wherein said bait block can include a central hole for mounting on to a vertical rod for deployment in a prior art rodent bait station.

DETAILED DESCRIPTION OF THE INVENTION

[0021] The invention will now be described in detail by reference to the drawings, specific embodiments, and examples. These examples are intended to illustrate the invention and assist in its understanding, but they do not limit the scope of the invention as defined by the claims. [0022] Composition Overview. In its basic form, the described rodenticide composition is comprised of the following ingredients:

[0023] Essential Components.

1. Calcium Sulfate Hemihydrate (plaster of Paris): This is the principal inert ingredient, which effectuates rodent death upon activation. Preferably, plaster of Paris constitutes a significant portion of the composition (for example, approximately 20-60% w/w). In the preferred embodiment, plaster of Paris is present at approximately 45-60% w/w. This ensures that when the composition is consumed and exposed to moisture, enough plaster of Paris will react to create a solid cast or thick paste in the rodent’s gastrointestinal tract. Preferably, plaster of Paris utilized should be comprised of a fine powder grade to ensure even distribution and quick reaction. Plaster of Paris must be thoroughly dried and milled to avoid any premature hydration and reaction.

2. Edible Attractants/Food Base: One or more palatable, food-grade materials are included to encourage rodents to consume the final composition tablet in lethal quantities. The invention has a flexible system for attractants, comprised of a combination of powdered sugar (finely ground sucrose) and other food attractants such as cornmeal or lactose etc. Sugars appeal to many rodents (particularly mice) due to their sweetness, and they also help mask any bitter or unpalatable tastes from other ingredients. The powdered sugar (preferably -10-20% w/w) fills voids between particles and enhances the compressibility of the composition by providing a fine, pliable matrix. Using powdered sugar is an innovation in bait formulation that improves both manufacturing (a better particle size distribution for compression) and feeding appeal. In addition to sugar, other attractants can be used or added, such as ground grains (oat flour, cornmeal), seeds, or flavorings (like peanut meal or chocolate powder) - all within minimumrisk regulatory exempt substances. These can partly replace or complement the sugar base. Regardless of the exact edible base chosen, it can make up about 10-60% of the composition weight (to balance the higher proportion of inorganic actives).

[0024] Optional Components.

3. Dehydrating Agent (Active): In another particularly effective embodiment, the composition is further comprised of sodium chloride (common salt) as an active ingredient (approximately 04-15% w/w). Sodium chloride is recognized as a safe ingredient for minimumrisk rodenticides, and it serves to induce systemic dehydration in the rodent. Upon ingestion, a high salt content in the gut and bloodstream will cause the rodent’s cells to lose water (via osmotic pressure), leading to neurological dysfunction, organ failure, and death. Salt begins its lethal action even before the plaster of Paris fully reacts. Salt can drive a rodent to a state of severe thirst and shock. Moreover, the presence of salt may encourage the rodent to drink water (due to salt’s thirst-inducing effect), which hastens the plaster of Paris’s activation and hardening in the gastrointestinal tract. This synergy means rodents consuming the composition induces a lethal dual action: immediate dehydration stress from salt; and a physical blockage from hydrated plaster of Paris shortly thereafter. Importantly, sodium chloride is also a preservative and helps deter microbial growth in the composition, which contributes to composition stability and shelf life.

4. Dry Lubricant: A metallic stearate, such as zinc stearate (or alternatively magnesium stearate), is included at a low concentration (approximately 0.5-2% w/w, preferably 1-2% w/w). Zinc stearate is a water-insoluble waxy powder, which coats the other particles of the composition, providing lubricity and water repellency to the final composition. During tablet pressing, zinc stearate prevents the compressed tablet from sticking to the die and punches used in the manufacturing process and enables a clean release of a final pressed tablet. This is crucial for maintaining tablet integrity and achieving high production speeds. Additionally, by creating a hydrophobic barrier throughout the final composition matrix, zinc stearate protects the plaster of Paris and other ingredients from activating from ambient humidity. Furthermore, zinc stearate acts as a “dry binder,” which aids in holding a compressed composition tablet together without the use of any wet binders. Alternatively, Lactose can be utilized as a dry lubricant as well.

5. Glidant/ Anti-Caking Agent: Colloidal silicon dioxide (silica) is added at about 1-4% w/w (most preferably 2-4% w/w). This extremely fine amorphous silica has a high surface area and occupies the microscopic gaps between particles, which improves flow properties of the powder blend during manufacture. Proper powder flow is essential for uniform die filling in the tablet press during manufacture, which translates to consistent tablet weights and doses. Silica also provides anti -caking benefits, which prevents clumping of the powder during the mixing and storage phases of manufacture. Critically, silica also acts as a desiccant at the micro-scale to adsorb residual moisture from ingredients (such as any slight pre-hydration of plaster of Paris or moisture in sugars) and also absorbs moisture that may be introduced from environmental exposure. By doing so, silica prolongs the shelf-life of the final composition. Critically, silica protects the moisture-sensitive plaster of Paris from premature activation. The amount of silica is kept low (around 2% w/w) because only a small quantity is needed to be effective, and excessive silica could potentially reduce the palatability of the final composition or cause the final compressed tablet to be too friable. The chosen level has been found to markedly increase the shelf-life of the product by reducing moisture uptake.

6. Optional Binding Agent: While the core formula can be made from the above components alone, the final composition can optionally include additional fillers or binding aids to enhance tablet robustness. For example, microcrystalline cellulose (MCC), and Colloidal Silica be used (5-30% w/w) as a dry binder; it helps tablets hold together and also contributes to the desiccating action by absorbing water and swelling (which could further block the rodent’s gastrointestinal tract once activated). MCC and Colloidal Silica are also inert ingredients, which have been noted to synergize with the plaster of Paris’s obstruction effect by adding bulk fiber that the rodent’s system struggles to process. Other edible fillers like wheat millings or com cob flour could similarly be used. Any such filler should be dry and finely powdered. These ingredients are not essential but can be utilized to change tablet hardness, density, or cost (for example, using a cheap grain flour as filler if needed).

[0025] All ingredients used are chosen from food-grade or regulatory minimum risk exempt substances to ensure the final product is compliant with “non-toxic” pesticide regulations. There are no chemical preservatives or synthetic binders required - the formula is inherently shelf-stable due to its dryness and inorganic content.

[0026] Manufacturing Process (Dry Compression Technique).

A key aspect of this invention is the method of manufacture, which utilizes a direct dry compression process to form tablets without any addition of water or other solvents. The process is summarized as follows:

1. Dry Blending: The powdered ingredients (plaster of Paris, salt (if used), sugars, any other attractants or fillers, etc.) are measured and combined in a suitable mixer or blender and milled. Care is taken to achieve a homogeneous mixture. In one embodiment, a two-step mixing is preferred: first, the large and medium-size particles (e g. plaster of Paris, granulated sugar, salt) are tumble-mixed. Second, the fine powders (powdered sugar, microcrystalline cellulose, etc.) are added and mixed further until uniform. This staggered approach helps prevent segregation and ensures even coating of the attractants onto the plaster of Paris particles.

2. Addition of Lubricants and Glidants: The dry lubricant (zinc stearate) and glidant (silica) are added typically in the final phase of mixing. These are blended gently and briefly with the bulk powder — often for just a few minutes — to avoid over-milling. Overmixing with stearates can negatively affect tablet hardness by overly coating particles, so the process is controlled to achieve just enough distribution of lubricant. The resulting finished blend should have good flow (due to the silica) and should not clump or cake. At this stage, the powder is free-flowing and is an entirely dry blend - no liquids have been introduced at any point.

3. Dry Compression: The dry powder blend is fed into a tablet press. This can be a singlestation (eccentric) tablet press for small-scale production, or a rotary multi-station press for large-scale manufacturing. The tablet press is fitted with tooling of the desired tablet size and shape to dry compress the composition to form a final composition bait. In one preferred embodiment, the final composition bait is comprised of standard cylindrical tablets 200 as shown in FIG. 2 of about 2 cm diameter and 0.5-1 cm thickness are made, each weighing roughly 5-10 grams. This size is convenient for both rats and mice. In another embodiment aimed at bait station 100 use, the final composition bait is comprised of cylindrical tablets 300 with a central hole 301 as shown in FIG. 3, which are compressed using modified ring-shaped tooling - for example, a tablet 2.5 cm in diameter, 1 cm tall, with a 5 mm diameter hole 301 through the center. The compression force is adjusted to yield final composition bait tablets that are firm enough not to crumble during handling, yet not so hard as to deter rodents from gnawing and consuming them. Typically, a compression force in the range of 1-5 tons on a 1 cm² area is sufficient to bind the dry blend powder into a cohesive tablet. Because of the presence of lubricants, the tablets eject cleanly from the press without sticking. The manufactured tablets are collected and can be used immediately or packaged for storage.

[0027] This dry compression method of manufacture to form a final composition bait, ensures that the plaster of Paris remains dehydrated and inactive during storage. Unlike some pelletizing methods, there is no addition of water, oils, or adhesives which could either activate the plaster of Paris or create a semi-moist tablet prone to molding. The final composition bait tablets exit the press dry and ready-to-use. Each tablet is a concentrated dose containing a lethal amount of the composition ingredients for a rodent. The process is highly scalable; for instance, a rotary press with multiple punches can produce tens of thousands of identical tablets per hour, each with minimal variation in weight (ensuring consistent efficacy).

[0028] Tablet Properties and Storage.

The resulting final composition bait tablets are generally off-white to light tan in color, with a hard, smooth texture. The final composition bait tablets are shelf-stable for extended periods. All composition ingredients are either inorganic minerals or dry foods, which means there are no volatile actives to degrade over time. Preliminary accelerated aging tests indicate that the final composition tablets resist crumbling and remain stable even after exposure to high humidity. The inclusion of silica and hydrophobic lubricant maintains the tablet’s integrity. As such, the final composition bait tablets demonstrate high suitability for warehouse storage and field deployment in non-ideal conditions.

[0029] During extended field testing, final composition bait tablets were placed in tamper-resistant bait stations 100 from September through April. These deployments demonstrated both consistent rodent feeding activity and strong durability of the final composition tablets under environmental conditions. The tablets remained largely intact despite seasonal fluctuations, with visible signs of gnawing and progressive consumption over time. Early field use of cylindrical tablets 300 with a central hole 301 placed within bait stations 100 has shown promising results. Tablets 300 were mounted on to vertical rods 101 of commonly used bait stations 100. Rodents were observed feeding on the tablet 300 bait in place, rather than dislodging or removing the tablets 300. The cylindrical tablets 300 with a central hole 301 allowed the bait to remain secured on the station vertical rod 101 until nearly consumed, reducing the risk of bait being carried off to inaccessible locations.

[0030] The dry-compressed formulation demonstrated notable resilience against moderate environmental moisture, such as dew or nighttime humidity. Protective excipients in the composition — such as microcrystalline cellulose and colloidal silica — help prevent premature activation of the plaster of Paris. However, once ingested, the composition activates rapidly in the moist environment of the gastrointestinal tract, triggering the intended mechanical blockage and dehydration-based effects.

[0031] Mechanism of Action Upon Ingestion.

When a rodent (rat or mouse) is attracted to the final composition bait tablet, it will typically start gnawing on it. The sugar content immediately rewards the rodent with a sweet taste, encouraging continued feeding. As the rodent chews, it breaks the tablet into smaller fragments which it swallows. At this point, the water in the rodent’s saliva has minimal effect on the tablet fragments - the presence of zinc stearate and the compressed nature of the tablet limit how quickly saliva can penetrate and initiate the plaster of Paris reaction before swallowing.

Essentially, the formulation ensures that most of the plaster of Paris reaches the stomach still in a dry or only slightly activated state, which concentrates the composition’s action inside the rodent’ s gastrointestinal tract.

[0032] Once in the rodent’s stomach tablet fragments encounter body moisture (gastric fluids or any water the rodent drinks shortly after feeding). The plaster of Paris rapidly hydrates and expands, converting to gypsum. Because the tablet fragments are now dispersed in the stomach, the plaster of Paris can form a contoured cast that conforms to the interior stomach or intestinal wall. This results in a mechanical blockage of the pylorus of the stomach or the duodenum of the small intestine. The rodent typically experiences discomfort and a feeling of fullness, causing it to cease consumption of any further bait, which is advantageous to prevent excessive bait consumption.

[0033] If included in the final composition, sodium chloride dissolves readily in the stomach contents, being absorbed into the bloodstream and drawing water out of the rodent’s tissues (intensifying dehydration). The salt also makes the rodent extremely thirsty. If the rodent drinks water to quench their thirst, the increased water in the digestive tract in turn reacts with any remaining plaster of Paris, thus enhancing the mechanical blockage of the plaster of Paris. Meanwhile, silica particles and any cellulose in the final composition absorb fluids in the stomach and gut, further desiccating the environment inside the rodent. The combined effect of these processes is catastrophic for the rodent’s physiology: organs begin to dry out or fail (as observed in histopathology data, extreme hemoconcentration and kidney failure can occur), and the hardened mass in the stomach/intestine prevents any relief. Notably, rodents cannot vomit, so they are unable to expel the material. Death often follows relatively quickly - in some cases within just a few hours for mice, and within a day for larger rats, depending on the quantity consumed.

[0034] Another significant benefit of this mode of action is that it is humane and minimizes suffering time compared to sub-lethal poisoning. The rodent typically slips into a lethargic state due to dehydration and shock before expiring, and it is less likely to experience prolonged pain as can happen with anticoagulants (which can take days of internal bleeding). Another benefit is the lack of secondary toxicity: the expired carcass contains essentially just hardened gypsum and naturally occurring substances (salt, sugars). Predators or scavengers consuming the dead rodent will not be poisoned. In fact, as mentioned, the gypsum mass will not be digested by a predator; it remains like a stone or bone in the stomach, which can be regurgitated or passed without harm. This greatly reduces the ecological impact and disposal concerns of using the composition.

[0035] Formulation and Performance.

Example 1 : Formulation and Manufacturing of Dry-Compressed Bait Tablets. A preferred batch of rodenticide tablets was prepared with the following formulation (percentages by weight):

• 48.5 % Calcium Sulfate Hemihydrate (plaster of Paris, fine powder)

• 15% (edible attractant) Powdered Sugar/peanut butter powder (confectioner’s sugar- 1 Ox grind)

• 5% Sodium Chloride (fine granulated salt, dehydrating agent)

• 2% Zinc Stearate (dry lubricant)

• 4% Colloidal Silicon Dioxide (glidant)(fumed silica, -0.2-0.3 pm particle size)

• 25.5 % Microcrystalline Cellulose (binding agent) All ingredients above are food-grade or regulatory-exempt substances. The powdered sugar and peanut butter powder are optional in this example; they were included to demonstrate a potential variant with additional bulk and flavor. One familiar in the art would recognize that any enticing dry food-grade material could be substituted as an attractant. For example, granulated sugar could be utilized in conjunction with powdered sugar to provide added sweetness and enhance material matrix. Furthermore, one familiar in the art would recognize that the above percentages by weight could be altered while still maintaining the composition’s effectiveness.

[0036] Mixing.

The plaster of Paris, sodium chloride, edible attractants, and microcrystalline cellulose, colloidal silica were loaded into a disc mill or grinding mill and tumbled for 10 minutes to achieve a uniform powder wherein particles were 300 pm or less. Next, silicon dioxide and zinc stearate were added and the blender was run for an additional 3 minutes to distribute the fine excipients without over-coating. The resulting powder blend mixture showed excellent flowability through a funnel with no clumping. The resulting powder blend should pass through a 50-mesh sieve (less than 300 pm). Particles over 300 pm should be re-milled to achieve a homogenous powder blend.

[0037] Tablet 200 Formation.

The powder blend was fed into a laboratory rotary tablet press fitted with 1/2-inch (12.7 mm) flat-faced round punches. Tablets 200 weighing approximately 5.0 grams each were pressed. Compression force was adjusted to about 2 tons, yielding tablets 200 with a hardness of 30 N or above (as measured by a tablet hardness tester), which was found to be hard enough to resist breakage but be easily gnawed by rodents. The tablets had a smooth texture and did not cap or crack upon ejection. No sticking to tooling was observed, confirming adequate lubrication. Approximately 1000 tablets 200 were produced in this batch.

[0038] Results.

The tablets were stored in unsealed containers at ambient laboratory conditions (-50-60% relative humidity) for two weeks. They remained dry and intact, with no signs of surface hydration or softening. Meanwhile, tablets left on a shelf did not change over weeks, illustrating the stability in the absence of liquid water.

[0039] Palatability and Efficacy Test.

To evaluate the palatability and efficacy of the composition described herein, a controlled 5-day acute oral toxicity study was conducted in compliance with OPP 1.210 guidelines. Thirty male ICR (CD-I) mice, aged 6 weeks, were randomized into three groups (n=10 per group): Group I (Control), Group II (Positive Control - other rodenticide with corn gluten meal as primary ingredient), and Group III (Test Substance - final composition). During acclimation (Days -7 to -1), all animals received a standard diet. On Day 0, Group II and Group III mice had their food replaced with ad libitum access to the assigned test substance. Group III mice consumed an average of 9.4 tablets per animal between Days 0 and 3, demonstrating high voluntary intake and palatability compared to 2.3 tablets consumed by Group II.

[0040] Abnormal health signs in Group III began on Day 1, including white feces, followed by tremors, hunched posture, and activity reduction by Day 2. Mortality in Group III began on Day 3 (90% cumulative) and reached 100% by Day 5, confirming rapid and complete lethality. Notably, all 10 mice of Group III demonstrated white feces by Day 1 demonstrating plaster of Paris reactivity in the subjects’ digestive tracts. No mice in Groups I or II demonstrated white feces during the study. At necropsy, internal abnormalities consistent with ingestion of the test substance-final composition were observed, including white or gray paste in the digestive tract, red lungs, and mottled liver tissue. Statistical analysis showed significant reductions (p < 0.0001) in gastrointestinal tract, kidney, and spleen weights in treated mice compared to controls. Histopathological evaluation revealed no cellular or microscopic lesions contributive to death, indicating a non-toxic, mechanical or physiological mode of action, consistent with the physical effects of digestive obstruction and dehydration. These results establish the composition as a highly palatable and effective rodenticide, achieving 100% mortality with ingestion alone and supporting the claim of efficacy without secondary poisoning risk. [0041] Example 2: Alternate Embodiment - Pressed Tablet with Central Hole for use in Commercial Bait Stations.

In another embodiment, tablets were pressed in a larger 1-inch (25 mm) diameter with a 5 mm hole 301 in the center using custom tooling to yield the cylindrical tablets 300 with central hole 301 as previously described. The composition was similar to Example 1 with the powdered sugar and MCC, cornmeal, (demonstrating flexibility to use grain as attractant in lieu of some sugar/cellulose). These pressed cylindrical tablets 300 with central hole 301 baits can be mounted on vertical metal rods 101 inside outdoor commercial bait stations 100. We have tested versions of this in bait stations 100 in Montana through harsh winters over a period of 6 months with no degradation and evidence of rodent feeding. The hydrophobic ingredients of the final composition prevented moisture absorption, as no plaster of Paris activation was evident until after rodent consumption had occurred. Rodents (both mice and rats) consumed portions of the pressed tablets in the testing in bait stations 100. Therefore, the central hole 301 allowed it to remain secured on the vertical bait rods of the bait box even after being partially eaten and ensured that rodents could not carry full tablets to nesting areas (a common problem with loose baits). This example highlights how the invention can be adapted in shape and attractant content while maintaining its core functionality. This also allows us to be able to apply bait safely in the commercial pest control sector. This is how most bait is applied by the professional pest management industry.

[0042] Comparison with other rodenticides and advantages.

The described composition and method of manufacture provides a number of advantages over existing rodenticides and methods.

1. Moisture Stability. Unlike prior bait mixtures that had to “remain dry at all times” to avoid premature activation, the final composition tablets incorporate hydrophobic moisturebuffering excipients (silica, stearate) and use compression formation to significantly delay activation until the bait has been consumed by the rodent. This is a novel improvement over existing formulations, which makes the product viable for real-world use where perfect dryness cannot be guaranteed.

2. Feeding Efficacy. The combination of mechanical blockage (plaster of Paris) and fastacting dehydration (salt) means rodents typically need to consume less of the composition to receive a fatal dose. This contrasts with known products, which require rodents to feed multiple times over days or weeks to accumulate a lethal dose. Increased lethality improves efficacy but also reduces the window in which a rodent continues to cause damage and/or reproduce.

3. Safety and Non-Toxicity. The final composition achieves lethality without conventional poisons. All active effects are mechanical/physiological using inert ingredients and food-grade materials. Therefore, non-target animals (pets, wildlife) are at drastically lower risk of collateral harm. Furthermore, any predator that consumes a rodent killed by this composition will not be secondarily poisoned as they would in the case of an anti -coagulant-based product. As such, this composition is an eco-friendly rodent control solution, aligning with the growing regulatory and market trend towards environmentally safe pesticides.

4. Shelf-Life and Storage. The composition and method of manufacture yields a dry tablet, which can be packaged in bulk and stored for long periods without losing effectiveness. There are no special storage requirements beyond keeping tablet containers sealed and in a dry place. Traditional soft baits or liquids have much shorter shelf lives and can spoil; even wax blocks can go rancid or be affected by high heat. In contrast, these tablets are largely inert until consumed by the target rodent.

5. Manufacturing Efficiency. Due to the final composition’s method of manufacture, production of the final composition tablet can scale quickly with relatively low cost per unit. Equipment and process controls ensure high quality (each tablet contains the intended proportion of ingredients) and high output. One familiar in the art would recognize the described method of manufacture can easily be customized to create tablets of different sizes or shapes for different target rodents or scenarios by changing tooling and/or the shape of tablet presses. For example, this disclosure contemplates a final composition block 400 with a central hole 401 embodiment as shown in FIG. 5.

6. Commercial Field Deployment. Pest control professionals can deploy the final cylindrical tablets 300 with central hole 301 and/or block 400 with a central hole 401 baits in standard commercial bait stations 100 with confidence that the baits will remain effective over time. These embodiments integrate into existing bait station 100 systems, which often use vertical 101 or horizontal rods for securing bait blocks. Even without a hole, final composition tablets 200 can be placed in trays or compartments for deployment. The final composition tablet’s hardness ensures tablets will not be easily shredded or removed by the rodent in one piece. The design minimizes bait fragments being scattered (reducing risk to birds or pets that might find a stray piece on the ground, as could happen with grain baits).

[0043] In light of the above, this invention fills an unmet need in the rodent control field for a non-toxic, durable, and effective rodenticide. It is understood that the foregoing examples are merely illustrative of the present invention. Certain modifications of the composition and/or method may be made and still achieve the objectives of the invention. Such modifications are contemplated as within the scope of the claimed invention.

Claims

CLAIMS What is claimed is:

1. A rodenticide composition comprising: an amount by weight of calcium sulfate hemihydrate (plaster of Paris); and an amount by weight of edible attractant; wherein said composition is dry compressed to form a final composition bait.

2. The rodenticide composition of claim 1 wherein said composition further comprises an amount by weight of a dehydrating agent.

3. The rodenticide composition of claim 1 wherein said composition further comprises an amount by weight of a dry lubricant.

4. The rodenticide composition of claim 1 wherein said composition further comprises an amount by weight of a glidant.

5. The rodenticide composition of claim 1 wherein said composition further comprises an amount by weight of a binding agent.

6. The rodenticide composition of claim 2 wherein said dehydrating agent is comprised of sodium chloride.

7. The rodenticide composition of claim 3 wherein said dry lubricant is comprised of a metallic stearate wherein said metallic stearate is comprised of zinc stearate or magnesium stearate.

8. The rodenticide composition of claim 4 wherein said glidant is comprised of colloidal silicon dioxide.

9. The rodenticide composition of claim 5 wherein said binding agent is comprised of microcrystalline cellulose or colloidal silica.

10. The rodenticide composition of claim 1 wherein said edible attractant is comprised of a mixture selected from the group consisting of powdered sugar, granulated sugar or powdered peanut butter.

11. A rodenticide composition comprising: an amount by weight of calcium sulfate hemihydrate (plaster of Paris); an amount by weight of edible attractant; an amount by weight of a dehydrating agent; an amount by weight of a dry lubricant; an amount by weight of a glidant; and an amount by weight of a binding agent; wherein said composition is dry compressed to form a final composition bait.

12. The rodenticide composition of claim 11, wherein the amount by weight of said calcium sulfate hemihydrate (plaster of Paris) is approximately 48.5%; the amount by weight of said edible attractant is approximately 15%; the amount by weight of said dehydrating agent is approximately 5%; the amount by weight of said dry lubricant is approximately 2%; the amount by weight of said glidant is approximately 4%; and the amount by weight of said binding agent is approximately 25.5%.

13. The rodenticide composition of claim 12, wherein said edible attractant is comprised of a mixture selected from the group consisting of powdered sugar, granulated sugar or powdered peanut butter; said dehydrating agent is comprised of sodium chloride; said dry lubricant is comprised of a metallic stearate wherein said metallic stearate is comprised of zinc stearate or magnesium stearate; said glidant is comprised of colloidal silicon dioxide; and said binding agent is comprised of microcrystalline cellulose or colloidal silica.

14. A method of manufacturing a rodenticide composition comprising the steps of

A. milling an amount by weight of calcium sulfate hemihydrate (plaster of Paris) and an amount by weight of edible attractant to achieve a powder blend wherein particles of said powder blend measure 300 pm or less; and

B. dry compressing said powder blend to form a final composition bait.

15. The method of manufacturing a rodenticide composition of claim 14, wherein step A further comprises the step of milling an amount by weight of a dehydrating agent; an amount by weight of a dry lubricant; an amount by weight of a glidant; and an amount by weight of a binding agent to be added to said powder blend.

16. The method of manufacturing a rodenticide composition of claim 14, wherein said powder blend is dry compressed to a force in the range of 1-5 tons per cm².

17. The method of manufacturing a rodenticide composition of claim 14, wherein said final composition bait’s hardness measures greater than or equal to 30 N.

18. The method of manufacturing a rodenticide composition of claim 14, wherein said final composition bait is comprised of a tablet.

19. The method of manufacturing a rodenticide composition of claim 14, wherein said final composition bait is comprised of a tablet with a central hole.

20. The method of manufacturing a rodenticide composition of claim 14, wherein said final composition bait is comprised of a block with a central hole.