Astaxanthin directional controlled release chewable tablet for pets as well as preparation method and application of astaxanthin directional controlled release chewable tablet

Abstract

The invention discloses an astaxanthin directional controlled-release chewable tablet for pets as well as a preparation method and application thereof, and relates to the field of astaxanthin, the chewable tablet comprises a tablet core and a double-layer coating, the tablet core is prepared from the following components in parts by mass: 0.5 to 2 parts of microencapsulated astaxanthin oil; 30-40 parts of sweet potato starch; 20-25 parts of skimmed milk powder; 5-8 parts of a natural phagostimulant; the double-layer coating comprises a gastric-soluble layer and an enteric-soluble layer; the gastric-soluble layer is prepared from hydroxypropyl methylcellulose, and the enteric-soluble layer is prepared from shellac and pectin through compounding. Through interaction and function complementation of an enteric layer coating material and a gastric soluble layer coating material, a gastric soluble-enteric double-layer coating system is constructed outside the tablet core, so that rapid antioxidation of the stomach and efficient absorption of the intestinal tract are realized, segmented controlled release of astaxanthin is achieved, and the problems of gastric acid damage and insufficient targeted release are solved; therefore, loss of active ingredients is effectively reduced, and absorption efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of astaxanthin technology, and in particular to a controlled-release astaxanthin chewable tablet for pets, its preparation method, and its application. Background Technology

[0002] With the booming development of the pet economy, pet health issues are receiving increasing attention from pet owners. As important members of the family, the health of pets directly affects the quality of life and emotional support of their owners. Astaxanthin, a highly effective natural antioxidant, has been widely used in human health due to its excellent antioxidant properties. In recent years, scientific research has gradually revealed the enormous potential of astaxanthin in the field of pet health, such as enhancing pet immunity, improving skin and coat health, and delaying aging. These benefits have made astaxanthin a hot ingredient in the research and development of functional pet foods.

[0003] However, in practical applications, astaxanthin exhibits poor stability in the acidic environment of a pet's stomach (pH 1.5-3.5), with a loss rate exceeding 50%. Its chemical structure is easily destroyed by the acidic environment, leading to a significant reduction in antioxidant activity and hindering its full health benefits. Furthermore, most pet chewable tablets currently on the market have a single-layer structure. While this allows for sustained drug release, it lacks the ability to precisely control release across different segments of the digestive tract. Since the primary absorption site for astaxanthin is the small intestine, the single-layer structure cannot ensure targeted release within the small intestinal environment, resulting in premature degradation of a large amount of active ingredients in the stomach, significantly limiting bioavailability. In addition, the inherent fishy odor of astaxanthin is extremely unpalatable to pets with sensitive senses of smell. Traditional products rely on chemically synthesized palatability enhancers (such as artificial flavorings) to mask the odor, but long-term use may burden the pet's digestive system or cause allergic reactions, posing potential health risks.

[0004] At the technical implementation level, traditional enteric materials (such as...) Although widely used in human pharmaceuticals, the compatibility of astaxanthin in pet food has not been fully validated due to significant differences in the physiological and metabolic mechanisms of pets compared to humans. Meanwhile, the manufacturing process of double-coated tablets faces severe challenges. The pressure exerted by pets during chewing typically exceeds 200N, far exceeding the tolerance threshold of ordinary tablets. Conventional double-coating is prone to delamination or cracking under high pressure, leading to coating system failure. Once the coating structure is damaged, not only is the targeted release function lost, but the unprotected astaxanthin in the tablet core is also rapidly exposed to gastric acid, exacerbating the loss of active ingredients and potentially causing digestive discomfort in pets due to uncontrolled release. These issues collectively restrict the commercial application of astaxanthin in the field of functional pet foods, necessitating the development of innovative dosage forms that combine high-efficiency controlled release, chewability, and palatability. Summary of the Invention

[0005] This invention overcomes the shortcomings of the prior art and provides a controlled-release astaxanthin chewable tablet for pets and its preparation method. Through a gastric-enteric double-layer coating system combined with the application of natural palatability enhancers, it provides pets with a highly efficient, safe, and palatable controlled-release astaxanthin chewable tablet, which has significant practical application value and market prospects.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a pet astaxanthin controlled-release chewable tablet, comprising: a tablet core and a double-layer coating;

[0007] The chip core comprises the following components in parts by weight:

[0008]

[0009] The double-layer coating includes a gastric coating layer and an enteric coating layer; the gastric coating layer is composed of hydroxypropyl methylcellulose, and the enteric coating layer is composed of shellac and pectin.

[0010] In a preferred embodiment of the present invention, the natural palatability enhancer is selected from at least two of yeast extract, chicken liver powder, bonito powder, or taurine.

[0011] In a preferred embodiment of the present invention, the core has a hardness of 80-100N and a diameter of 8-10mm.

[0012] In a preferred embodiment of the present invention, the amount of hydroxypropyl methylcellulose added is 5-8% of the total mass of the tablet core.

[0013] In a preferred embodiment of the present invention, the amount of shellac added is 3-5% of the total mass of the core, and the amount of pectin added is 2-4% of the total mass of the core.

[0014] This invention provides a method for preparing astaxanthin-targeted controlled-release chewable tablets for pets, comprising the following steps:

[0015] S1. Microencapsulated astaxanthin oil, sweet potato starch, skim milk powder and natural palatability enhancer are mixed and then wet-granulated and compressed into tablets to obtain tablet cores.

[0016] S2. Dissolve shellac and pectin in an ethanol solution to prepare an 8-12 wt% shellac-pectin ethanol solution, place it in the storage tank of a fluidized bed coating machine, and coat the tablet cores with an enteric coating layer to obtain primary coated tablet cores.

[0017] S3. Prepare a 5-8 wt% hydroxypropyl methylcellulose solution and place it in the storage tank of a fluidized bed coating machine to perform gastric lysate coating on the primary coated tablet core to obtain astaxanthin-directed controlled-release chewable tablets.

[0018] In a preferred embodiment of the present invention, in step S1, the stirring speed is 100-200 rpm and the time is 10-15 min; the wet granulation uses an ethanol-water mixed wetting agent with a volume ratio of ethanol to water of 1-3:1; the tableting uses a rotary tablet press with a pressure parameter of 6-8 MPa.

[0019] In a preferred embodiment of the present invention, in step S2, the inlet air temperature of the fluidized bed coating machine is 40-50°C, the spray rate is 2-5 mL / min, and the weight gain of the enteric coating layer is 2-4%.

[0020] In a preferred embodiment of the present invention, in step S3, the inlet air temperature of the fluidized bed coating machine is 40-50°C, the spray rate is 2-5 mL / min, and the weight gain of the gastric lysate coating is 3-5%.

[0021] The present invention provides the application of the chewable tablet described in any one of the preceding statements in the preparation of antioxidant health food for pets, wherein the pet is a canine or a feline.

[0022] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0023] (1) This invention provides a pet astaxanthin targeted controlled-release chewable tablet, its preparation method and application. Through the interaction and functional complementarity between the enteric coating material and the gastric coating material, a gastric-enteric double-layer coating system is constructed on the outside of the tablet core to achieve rapid anti-oxidation in the stomach and efficient absorption in the intestine, thereby achieving the segmented controlled release of astaxanthin, solving the problems of gastric acid destruction and insufficient targeted release, thus effectively reducing the loss of active ingredients and improving absorption efficiency.

[0024] (2) In this invention, the multi-scale synergy from the tablet core to the coating structure ensures the structural stability of the tablet under extreme chewing pressure. The hydroxyl hydrogen bonds of sweet potato starch in the tablet core and the hydrophobic interaction of skim milk powder form a dense network of interpenetrating polymers. Combined with the polysaccharide wall material of microencapsulated astaxanthin and the electrostatic bonding of starch, a rigid skeleton is constructed to resist stress concentration. The enteric coating layer forms a dual energy dissipation mechanism through the hydrophobic stacking of shellac and the dynamic hydrogen bonds of pectin. The flexible molecular chains of HPMC in the gastric coating layer fill microscopic defects through hydrogen bonds and elastically deform to buffer pressure. Thus, under a chewing pressure of 200N, the tablet can achieve uniform stress distribution through the synergistic mechanism of energy absorption, stress dispersion and interface strengthening, avoid crack propagation, meet the pressure requirements of pets during chewing, and ensure the quality and stability of the product.

[0025] (3) In this invention, natural ingredients such as yeast extract and chicken liver powder are used as palatability enhancers. They are electrostatically adsorbed onto the surface of microcapsules, effectively masking the fishy smell of astaxanthin. At the same time, volatile flavor substances (such as nucleotide derivatives in chicken liver powder) are released and specifically bind to the olfactory receptors of pets, improving the palatability of the product, reducing the use of chemical palatability enhancers, thereby reducing the use of chemical palatability enhancers, reducing health risks, and improving the practicality of the product. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of a half-section of the astaxanthin-directed controlled-release chewable tablet according to a preferred embodiment of the present invention;

[0028] Figure 2 This is a flowchart of a preferred embodiment of the present invention for preparing a targeted controlled-release astaxanthin chewable tablet for pets;

[0029] In the diagram: 1. Tablet core; 2. Enteric coating layer; 3. Gastric coating layer. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0032] It should be noted that the raw materials, equipment and reagents used in this invention can all be purchased from the market or obtained through existing preparation methods.

[0033] like Figure 1 As shown, a controlled-release astaxanthin chewable tablet for pets includes: a tablet core 1 and a double-layer coating;

[0034] Core 1 comprises the following components in parts by weight:

[0035]

[0036] The double coating consists of a gastric coating 3 and an enteric coating 2; the gastric coating 3 is composed of hydroxypropyl methylcellulose, and the enteric coating 2 is composed of shellac and pectin.

[0037] In some specific embodiments, the natural palatability enhancer is selected from at least two of yeast extract, chicken liver powder, bonito powder, or taurine.

[0038] In some specific embodiments, the core 1 has a hardness of 80-100N and a diameter of 8-10mm.

[0039] In some specific embodiments, the amount of hydroxypropyl methylcellulose added is 5-8% of the total mass of the core 1.

[0040] In some specific embodiments, the amount of shellac added is 3-5% of the total mass of core 1, and the amount of pectin added is 2-4% of the total mass of core 1.

[0041] like Figure 2 As shown, this invention provides a method for preparing astaxanthin-targeted controlled-release chewable tablets for pets, comprising the following steps:

[0042] S1. Microencapsulated astaxanthin oil, sweet potato starch, skim milk powder and natural palatability enhancer are stirred and mixed, wet granulated and then compressed into tablets to obtain tablet core 1;

[0043] S2. Dissolve shellac and pectin in an ethanol solution to prepare an 8-12 wt% shellac-pectin ethanol solution, place it in the storage tank of a fluidized bed coating machine, and coat the tablet core 1 with an enteric coating layer 2 to obtain a primary coated tablet core.

[0044] S3. Prepare a 5-8 wt% hydroxypropyl methylcellulose (HPMC) solution and place it in the storage tank of a fluidized bed coating machine to perform gastric lysate coating on the primary coated tablet core to obtain astaxanthin-directed controlled-release chewable tablets.

[0045] In some specific embodiments, in step S1, the stirring speed is 100-200 rpm and the time is 10-15 min; wet granulation uses an ethanol-water mixed wetting agent with a volume ratio of ethanol to water of 1-3:1; tableting uses a rotary tablet press with a pressure parameter of 6-8 MPa.

[0046] In some specific embodiments, in step S2, the inlet air temperature of the fluidized bed coating machine is 40-50°C, the spray rate is 2-5 mL / min, and the weight gain of the enteric coating layer 2 is 2-4%.

[0047] In some specific implementations, in step S3, the inlet air temperature of the fluidized bed coating machine is 40-50°C, the spray rate is 2-5 mL / min, and the weight gain of the gastric lysate 3 coating is 3-5%.

[0048] This invention provides the application of any of the aforementioned chewable tablets in the preparation of antioxidant health food for pets, wherein the pet is a canine or feline.

[0049] To further simplify and make the objectives and effects of the present invention easier to understand, the present invention will be further described in conjunction with embodiments.

[0050] The raw materials and proportions of the tablet core 1 in the astaxanthin targeted controlled-release chewable tablets of Examples 1-2 are different, as shown in Table 1, with the raw materials measured in parts by mass.

[0051] Table 1: Raw materials and proportions for preparing tablet core 1 in the astaxanthin targeted controlled-release chewable tablets of Examples 1-2

[0052]

[0053]

[0054] Example 1

[0055] A method for preparing a canine pet astaxanthin controlled-release chewable tablet includes the following steps:

[0056] S1. Microencapsulated astaxanthin oil, sweet potato starch, skim milk powder, yeast extract, and chicken liver powder are mixed evenly at 160 rpm for 15 minutes. Wet granulation is performed using an ethanol-water mixture with a volume ratio of 2:1. The wetting agent is added slowly and evenly while stirring to form uniformly dispersed particles. The tablets are then compressed using a rotary tablet press at a pressure of 7 MPa to obtain tablet cores 1 with a hardness of 90 N and a diameter of 10 mm.

[0057] S2. Dissolve 4% shellac and 3% pectin of the total mass of core 1 in an ethanol solution to prepare a 10wt% shellac-pectin ethanol solution. Place the solution in the storage tank of the fluidized bed coating machine. Place the core 1 in the fluidized bed coating machine and spray it at an inlet air temperature of 45℃ and a spray rate of 4mL / min to uniformly coat the surface of the core 1 with the shellac-pectin ethanol solution. When the weight gain of the enteric layer 2 reaches 3%, the enteric layer 2 coating is completed, and the primary coated core is obtained.

[0058] S3. Prepare a 6wt% HPMC solution by adding 7% of the total mass of the tablet core 1 to the HPMC solution. Place the solution in the storage tank of the fluidized bed coating machine and spray it at an inlet air temperature of 45°C and a spray rate of 4mL / min to evenly cover the enteric layer 2 with the HPMC solution. When the weight gain of the enteric layer 3 reaches 4%, the coating of the enteric layer 3 is completed, and astaxanthin-directed controlled-release chewable tablets are obtained.

[0059] The preparation of microencapsulated astaxanthin oil includes the following steps:

[0060] S11. Mix astaxanthin oil, sodium alginate and whey protein in a mass ratio of 1:0.3:0.5, and then homogenize them in a high-shear homogenizer at 10,000 rpm for 5 minutes to form a colostrum.

[0061] S12. Colostrum is added dropwise at a rate of 15 drops per minute to a 2 wt% calcium chloride solution to form sodium alginate-whey protein microspheres.

[0062] S13. The sodium alginate-whey protein microspheres were spray-dried for 25 minutes at an inlet air temperature of 150°C and an outlet air temperature of 80°C to obtain powdered microencapsulated astaxanthin oil.

[0063] Performance testing: The astaxanthin targeted controlled-release chewable tablets obtained in Example 1 were subjected to performance tests in sequence, including chewing pressure resistance, gastric juice release rate, intestinal juice release rate, and palatability.

[0064] Chewing pressure test: A universal testing machine was used to apply vertical pressure to the chewable tablets at a loading rate of 10 N / s to simulate the chewing speed of a pet. The test was terminated when the chewable tablet broke or maintained at 200 N for 10 seconds. Ten tablets were tested. Of the ten astaxanthin-directed controlled-release chewable tablets in Example 1, only one tablet broke at 184 N, while the remaining nine tablets showed a thickness change rate of 3.2-4.8% under 200 N pressure.

[0065] Gastric juice release rate: A simulated gastric juice environment was prepared with a pH value between 1.5 and 3.5, simulating the gastric juice environment of canine pets. The astaxanthin-directed controlled-release chewable tablets from Example 1 were placed in the simulated gastric juice and stirred at 50-60 rpm / min under a constant temperature of 37°C. Samples were taken at 30 min, 1 h, and 2 h, and the released astaxanthin content was determined using high-performance liquid chromatography (HPLC). The gastric juice release rate was calculated. The results showed that the gastric juice release rate of the astaxanthin-directed controlled-release chewable tablets from Example 1 was 28.3% within 2 h.

[0066] Intestinal fluid release rate: The chewable tablets treated with gastric juice were transferred to a simulated canine intestinal fluid environment (pH≥6.5) and kept at a constant temperature of 37°C, with stirring at 50-60 rpm / min. Samples were taken at 1h, 2h, and 4h, and the astaxanthin content was detected by high-performance liquid chromatography (HPLC) to calculate the intestinal fluid release rate. The results showed that the astaxanthin-directed controlled-release chewable tablets of Example 1 had an intestinal fluid release rate of 71.5% within 4h.

[0067] Palatability Test: Fifty healthy dogs were selected for palatability testing. A two-bowl test was used, placing the astaxanthin controlled-release chewable tablets from Example 1 and commercially available fish oil tablets in two identical food bowls, respectively. Both bowls were placed in the dogs' activity area, and the dogs' choice of the two foods was observed and recorded. After three parallel tests, the selection rate of the astaxanthin controlled-release chewable tablets from Example 1 was 37% higher than that of the commercially available fish oil tablets, indicating a higher preference for the product of this invention in canine pets.

[0068] Example 2

[0069] A method for preparing a controlled-release astaxanthin chewable tablet for feline pets is described in this embodiment, which is basically the same as that in Example 1, except that the raw materials and their proportions are different, as shown in Table 1. The specific steps of S1 are as follows: microencapsulated astaxanthin oil, sweet potato starch, skim milk powder, bonito powder and taurine are mixed evenly at a speed of 160 rpm for 15 minutes. Wet granulation is performed using an ethanol-water mixture with a volume ratio of 2:1. The wetting agent is added slowly and evenly while stirring to form uniformly dispersed particles. The tablets are then compressed using a rotary tablet press at a pressure of 7 MPa to obtain a tablet core 1 with a hardness of 90 N and a diameter of 10 mm.

[0070] Performance testing: The astaxanthin targeted controlled-release chewable tablets obtained in Example 2 were subjected to performance tests in sequence, including chewing pressure resistance, gastric juice release rate, intestinal juice release rate, and palatability.

[0071] Chewing pressure test: A universal testing machine was used to apply vertical pressure to the chewable tablets at a loading rate of 10 N / s to simulate the chewing speed of a pet. The test was terminated when the chewable tablet broke or maintained at 200 N for 10 seconds. Ten tablets were tested. In Example 2, one of the ten astaxanthin-directed controlled-release chewable tablets broke at 188 N, one broke at 196 N, and the remaining eight tablets showed a thickness change rate of 2.9-4.2% under 200 N pressure.

[0072] Gastric juice release rate: Simulating the gastric juice environment of a feline pet, a simulated gastric juice with a pH of 1.5-3.5 was prepared. The astaxanthin-directed controlled-release chewable tablets from Example 2 were placed in the simulated gastric juice and stirred at 50-60 rpm / min under a constant temperature of 37°C. Samples were taken at 30 min, 1 h, and 2 h, and the released astaxanthin content was determined using high-performance liquid chromatography (HPLC) to calculate the gastric juice release rate. The results showed that the gastric juice release rate of the astaxanthin-directed controlled-release chewable tablets from Example 2 was 27.5% within 2 h.

[0073] Intestinal fluid release rate: The chewable tablets treated with gastric juice were transferred to a simulated feline intestinal fluid environment (pH≥6.5) and kept at a constant temperature of 37°C, with stirring at 50-60 rpm / min. Samples were taken at 1 h, 2 h, and 4 h, and the astaxanthin content was detected by high performance liquid chromatography (HPLC) to calculate the intestinal fluid release rate. The results showed that the astaxanthin-directed controlled-release chewable tablets of Example 2 had an intestinal fluid release rate of 71.8% within 4 h.

[0074] Palatability Test: Fifty healthy cats were selected for palatability testing. A two-bowl test was used, placing the astaxanthin-targeted controlled-release chewable tablets from Example 2 and a commercially available cat nutritional supplement in two identical food bowls, respectively. Both bowls were placed in the cats' activity area, and the cats' choice of the two foods was observed and recorded. After three parallel tests, the selection rate of the astaxanthin-targeted controlled-release chewable tablets from Example 2 was 36% higher than that of the commercially available nutritional supplement, indicating a higher preference for the product of this invention among felines.

[0075] The performance test results of the astaxanthin targeted controlled-release chewable tablets in Examples 1 and 2 above show that targeted release of astaxanthin in the pet's digestive tract was achieved, reducing the loss of astaxanthin in gastric acid and improving the absorption efficiency in the intestine.

[0076] Specifically, this invention forms an enteric coating 2 on the outside of the core 1. The hydrophobic chains of shellac terpene esters are physically adsorbed onto the hydroxyl groups of sweet potato starch in the core 1 through van der Waals forces. At the same time, the carboxylic acid groups of pectin and the lactose hydroxyl groups of skim milk powder are bonded by hydrogen bonds to jointly construct a dense network of enteric coating 2. During the fluidized bed coating process, the methoxy and hydroxypropoxy groups of HPMC in the gastric coating 3 are partially embedded in the gaps of the shellac-pectin network. Its linear cellulose ether chains unfold in the ethanol-water system and temporarily bind to the unprotonated carboxylic acid groups of pectin through hydrogen bonds. During drying and film formation, the helical conformation of its molecular chains forms a physical interlock with the microporous structure on the surface of the enteric coating 2. At the same time, the ether oxygen atoms of HPMC and the ester groups of shellac generate weak coordination, thereby constructing a continuous and flexible gastric coating 3 film on the outside of the enteric coating 2.

[0077] In summary, through the interaction and functional complementarity between the enteric coating layer 2 and the gastric coating layer 3, a gastric-enteric bilayer coating system is constructed on the outside of the tablet core 1. In the acidic environment of the stomach, the ether bonds of HPMC rapidly hydrate, the molecular chains unwind and dissolve. The short-chain cellulose residue remaining after the HPMC dissolution fills the surface defects of the enteric coating layer 2, thus enhancing the stability of the shellac-pectin network under acidic conditions and preventing the tablet core 1 from being exposed to gastric acid. Furthermore, in the alkaline environment of the intestine, the carboxylic acid groups of pectin deprotonate, forming negatively charged carboxylate ions. These ions, with their hydrophilic galacturonic acid chains absorbing water and swelling, lead to… The hydrophobic network of the insecticidal colloid swells and breaks down, and the pores left after the HPMC dissolves become channels for alkaline media to permeate, accelerating the disintegration of the enteric layer 2. The microcapsule wall material is gradually degraded under the action of intestinal enzymes. The amino groups of its chitosan molecules and the carboxylic acid groups of pectin form an ionic gel through electrostatic attraction, which delays the burst release of astaxanthin and creates a concentration gradient on the surface of the small intestinal villi epithelial cells, promoting passive diffusion across the membrane. This achieves rapid antioxidant activity in the stomach and efficient absorption in the intestine, enabling the segmented controlled release of astaxanthin. It solves the problems of gastric acid destruction and insufficient targeted release, effectively reducing the loss of active ingredients and improving absorption efficiency.

[0078] To further illustrate the present invention, the preferred embodiment 1 is used as the basis for comparison.

[0079] Comparative Example 1

[0080] This comparative example is basically the same as Example 1, except that: the enteric coating 3 was not performed, and step S3 was omitted. Step S2 is as follows: 4% shellac and 3% pectin of the total mass of tablet core 1 were dissolved in an ethanol solution to prepare a 10wt% shellac-pectin ethanol solution, which was placed in the storage tank of a fluidized bed coating machine. The tablet core 1 was placed in the fluidized bed coating machine, and the shellac-pectin ethanol solution was evenly coated on the surface of the tablet core 1 with an inlet air temperature of 45°C and a spray rate of 4mL / min. When the enteric coating 2 increased in weight by 3%, the coating of tablet core 1 was completed, and astaxanthin controlled-release chewable tablets were obtained.

[0081] Comparative Example 2

[0082] This comparative example is basically the same as Example 1, except that: the enteric coating 2 was not performed, and step S2 was omitted. Step S3 is as follows: 7% of the total mass of HPMC in the tablet core 1 is prepared into a 6wt% HPMC solution, which is placed in the storage tank of a fluidized bed coating machine. The HPMC solution is uniformly coated on the surface of the tablet core 1 at an inlet air temperature of 45°C and a spray rate of 4mL / min. When the weight gain of the enteric coating 3 reaches 4%, the coating of the tablet core 1 is completed, and astaxanthin controlled-release chewable tablets are obtained.

[0083] Comparative Example 3

[0084] This comparative example is basically the same as Example 1, except that the concentration of the shellac-pectin ethanol solution is different. The specific steps of S2 are as follows: 4% shellac and 3% pectin of the total mass of the core 1 are dissolved in an ethanol solution to prepare a 14wt% shellac-pectin ethanol solution, which is placed in the storage tank of the fluidized bed coating machine. The core 1 is placed in the fluidized bed coating machine, and the shellac-pectin ethanol solution is evenly coated on the surface of the core 1 with an inlet air temperature of 45°C and a spray rate of 4mL / min. When the weight gain of the enteric layer 2 reaches 3%, the enteric layer 2 coating is completed, and the primary coated core is obtained.

[0085] Comparative Example 4

[0086] This comparative example is basically the same as Example 1, except that the concentration of the shellac-pectin ethanol solution is different. The specific steps of S2 are as follows: 4% shellac and 3% pectin of the total mass of the core 1 are dissolved in an ethanol solution to prepare a 6wt% shellac-pectin ethanol solution, which is placed in the storage tank of the fluidized bed coating machine. The core 1 is placed in the fluidized bed coating machine, and the shellac-pectin ethanol solution is evenly coated on the surface of the core 1 with an inlet air temperature of 45°C and a spray rate of 4mL / min. When the weight gain of the enteric layer 2 reaches 3%, the enteric layer 2 coating is completed, and the primary coated core is obtained.

[0087] Comparative Example 5

[0088] This comparative example is basically the same as Example 1, except that the concentration of the HPMC solution is different. The specific steps of S3 are as follows: 7% of the total mass of HPMC in the tablet core 1 is prepared into a 10wt% HPMC solution, which is placed in the storage tank of the fluidized bed coating machine. The HPMC solution is uniformly covered on the enteric layer 2 with an air inlet temperature of 45°C and a spray rate of 4mL / min. When the weight gain of the enteric layer 3 reaches 4%, the coating of the enteric layer 3 is completed, and astaxanthin-directed controlled-release chewable tablets are obtained.

[0089] Comparative Example 6

[0090] This comparative example is basically the same as Example 1, except that the concentration of the HPMC solution is different. The specific steps of S3 are as follows: 7% of the total mass of HPMC in the tablet core 1 is prepared into a 4wt% HPMC solution, which is placed in the storage tank of a fluidized bed coating machine. The HPMC solution is uniformly covered on the enteric layer 2 with an air inlet temperature of 45°C and a spray rate of 4mL / min. When the weight gain of the enteric layer 3 reaches 4%, the coating of the enteric layer 3 is completed, and astaxanthin-directed controlled-release chewable tablets are obtained.

[0091] Comparative Example 7

[0092] This comparative example is basically the same as Example 1, except that the astaxanthin oil is not microencapsulated. The specific steps of S1 are as follows: the astaxanthin oil, sweet potato starch, skim milk powder, yeast extract and chicken liver powder are mixed evenly at 160 rpm for 15 minutes. The ethanol-water mixture with a volume ratio of 2:1 is used as a wetting agent for wet granulation. The wetting agent is added slowly and evenly while stirring to form uniformly dispersed particles. The tablets are compressed using a rotary tablet press at a pressure of 7 MPa to obtain tablet core 1 with a hardness of 90 N and a diameter of 10 mm.

[0093] Performance testing: The chewable tablets obtained in Comparative Examples 1-7 were tested for gastric juice release rate and intestinal juice release rate using the same performance testing method as in Example 1. The results are shown in Table 2.

[0094] Table 2: Performance test results of chewable tablets obtained from Comparative Examples 1-7

[0095] Performance testing Gastric juice release rate (%) within 2 hours Intestinal fluid release rate (%) within 4 hours Example 1 28.3 71.5 Comparative Example 1 62.7 18.4 Comparative Example 2 56.4 33.1 Comparative Example 3 45.2 50.4 Comparative Example 4 37.8 49.1 Comparative Example 5 31.2 65.3 Comparative Example 6 34.5 58.2 Comparative Example 7 44.7 50.9

[0096] As shown in Table 2:

[0097] A comparison between Example 1 and Comparative Example 1 reveals that the presence of HPMC gastric coating 3 allows the linear cellulose ether chains of HPMC to rapidly dissolve through ether bond hydration in an acidic environment, forming porous channels that release 20-30% astaxanthin. Simultaneously, the flexible conformation of its molecular chains can fill the micropores of enteric coating 2, enhancing interfacial bonding. In Comparative Example 1, only enteric coating 2 is retained, lacking HPMC gastric coating 3. The shellac-pectin network of enteric coating 2 is directly exposed to gastric acid. While the hydrophobic chains of shellac's terpene esters can temporarily maintain density in an acidic environment, the protonation and contraction of pectin carboxylic acid groups lead to a reduction in inter-chain hydrogen bonds and decreased interfacial stability. Gastric acid rapidly penetrates through cracks, disrupting the β-1,4 glycosidic bonds of the microcapsule wall material, resulting in premature astaxanthin release in gastric juice (62.7%). Enteric coating 2, due to premature damage, only releases 18.4%, ultimately leading to an imbalance in the segmented controlled release.

[0098] A comparison between Example 1 and Comparative Example 2 reveals that Comparative Example 2 only retained the gastric coating layer 3, lacking the shellac-pectin enteric coating layer 2. After HPMC dissolved in the stomach, the tablet core 1 was directly exposed to the alkaline intestinal environment. Due to the lack of enteric coating layer 2, the electrostatic attraction between the amino groups and pectin carboxylic acid groups of the microcapsule wall material could not form an ionic gel, leading to the burst release of astaxanthin in the intestine. Simultaneously, the tablet core 1 without enteric coating layer 2 released 56.4% astaxanthin in gastric juice due to the rapid dissolution of HPMC. This indicates that enteric coating layer 2 is a crucial barrier protecting astaxanthin from gastric acid degradation; its absence directly leads to the loss of active ingredients and the failure of targeted release.

[0099] A comparison of Example 1 and Comparative Examples 3-4 reveals the following: In Comparative Example 3, the high concentration resulted in excessively high solution viscosity, preventing uniform droplet dispersion during spray coating. Shellac molecules excessively aggregated, forming localized hydrophobic block structures, and the pectin carboxylic acid groups were encapsulated, hindering effective deprotonation in the alkaline intestinal environment, thus delaying the disintegration of the enteric layer 2. In Comparative Example 4, the low-concentration solution exhibited poor film-forming properties, a sparse shellac-pectin network, and insufficient intermolecular hydrogen bonds and hydrophobic interactions, making it easily permeable to gastric acid and increasing the gastric juice release rate. Simultaneously, the enteric layer 2, due to its fragile structure, only achieved a release rate of 49.1% after disintegration. The synergistic effect of shellac and pectin depends on the molecular ratio and cross-linking density; concentration deviations from the optimal range disrupt the hydrophobic-hydrophilic balance, affecting the segmented controlled-release effect.

[0100] A comparison of Example 1 and Comparative Examples 5-6 reveals the following: In Comparative Example 5, the HPMC solution concentration was too high. During the coating process, the HPMC molecular chains became entangled, forming a rigid film that limited its hydration and dissolution rate in gastric acid. Furthermore, residual HPMC fragments hindered the disintegration of the enteric layer 2, reducing the intestinal fluid release rate to 65.3%. In Comparative Example 6, the gastric layer 3 film formed by the low-concentration HPMC solution was too thin, preventing the HPMC molecular chains from fully filling the micropores of the enteric layer 2, resulting in weak interfacial bonding. In gastric acid, HPMC dissolved too quickly, causing the enteric layer 2 to be prematurely exposed to the acidic environment, increasing the gastric fluid release rate and decreasing the intestinal fluid release rate to 58.2%.

[0101] A comparison of Example 1 and Comparative Example 7 reveals that: Astaxanthin oil, without microencapsulation, was directly dispersed in liquid form on the substrate of tablet core 1. Although the enteric layer 2 and the gastric soluble layer 3 formed a double barrier, the unmicroencapsulated astaxanthin oil was distributed in a free state within tablet core 1. After the HPMC in the gastric soluble layer 3 dissolved in gastric acid, the free astaxanthin molecules gradually diffused into the gastric juice through the micropores of the enteric layer 2. While the shellac-pectin hydrophobic network could delay gastric acid penetration, it could not completely block the migration of small-molecule lipid-soluble components, leading to an increased gastric juice release rate.

[0102] The above description is based on the preferred embodiments of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0103] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A controlled-release astaxanthin chewable tablet for pets, characterized in that, include: Core and double coating; The chip core comprises the following components in parts by weight: The double-layer coating includes a gastric coating layer and an enteric coating layer; the gastric coating layer is composed of hydroxypropyl methylcellulose, and the enteric coating layer is composed of shellac and pectin.

2. The astaxanthin targeted-release chewable tablet for pets according to claim 1, characterized in that: The natural palatability enhancer is selected from at least two of yeast extract, chicken liver powder, bonito powder, or taurine.

3. The astaxanthin targeted-release chewable tablet for pets according to claim 1, characterized in that: The core has a hardness of 80-100N and a diameter of 8-10mm.

4. The astaxanthin targeted-release chewable tablet for pets according to claim 1, characterized in that: The amount of hydroxypropyl methylcellulose added is 5-8% of the total mass of the tablet core.

5. A controlled-release astaxanthin chewable tablet for pets according to claim 1, characterized in that: The amount of shellac added is 3-5% of the total mass of the core, and the amount of pectin added is 2-4% of the total mass of the core.

6. A method for preparing a pet astaxanthin targeted-release chewable tablet according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Microencapsulated astaxanthin oil, sweet potato starch, skim milk powder and natural palatability enhancer are mixed and then wet-granulated and compressed into tablets to obtain tablet cores. S2. Dissolve shellac and pectin in an ethanol solution to prepare an 8-12 wt% shellac-pectin ethanol solution, place it in the storage tank of a fluidized bed coating machine, and coat the tablet cores with an enteric coating layer to obtain primary coated tablet cores. S3. Prepare a 5-8 wt% hydroxypropyl methylcellulose solution and place it in the storage tank of a fluidized bed coating machine to perform gastric lysate coating on the primary coated tablet core to obtain astaxanthin-directed controlled-release chewable tablets.

7. The method for preparing a pet astaxanthin targeted controlled-release chewable tablet according to claim 6, characterized in that: In step S1, the stirring speed is 100-200 rpm and the time is 10-15 min; the wet granulation uses an ethanol-water mixed wetting agent with a volume ratio of ethanol to water of 1-3:1; the tableting uses a rotary tablet press with a pressure parameter of 6-8 MPa.

8. The method for preparing a pet astaxanthin targeted controlled-release chewable tablet according to claim 6, characterized in that: In step S2, the inlet air temperature of the fluidized bed coating machine is 40-50℃, the spray rate is 2-5 mL / min, and the weight gain of the enteric coating layer is 2-4%.

9. The method for preparing a pet astaxanthin targeted controlled-release chewable tablet according to claim 6, characterized in that: In step S3, the inlet air temperature of the fluidized bed coating machine is 40-50℃, the spray rate is 2-5 mL / min, and the weight gain of the gastric lysate coating is 3-5%.

10. The use of a chewable tablet according to any one of claims 1-5 in the preparation of an antioxidant health food for pets, wherein the pet is a canine or a feline.

Images