A cervus nippon and cervus canadensis off-season antler absorbable sustained-release control agent and a preparation method thereof

Abstract

This invention relates to an absorbable, slow-release regulator for off-season antler growth in sika deer and red deer, and its preparation method, belonging to the field of off-season antler growth regulators. The regulator comprises 330 mg–360 mg medroxyprogesterone acetate (MPA), 50 mg–55 mg dextran sulfate (DS), and 200 mg–220 mg sodium hyaluronate (HA), diluted with water for injection to a final volume of 1.0 mL. The molecular weight of medroxyprogesterone acetate (MPA) is 386.52 kDa; the molecular weight of dextran sulfate (DS) is 36–50 kDa; and the molecular weight of sodium hyaluronate (HA) is 20–400 kDa. This invention utilizes exogenous progesterone to induce off-season antler growth in male deer through hormonal regulation. The use of absorbable materials is environmentally friendly and harmless to the body, allowing for natural absorption and normal excretion through the body's metabolic processes. A single injection is sufficient to provide efficacy for over 35 days. Using progesterone to regulate off-season antler growth is low-cost and has a high success rate.

Description

Technical Field

[0001] This invention belongs to the field of off-season antler growth regulators, specifically relating to an absorbable slow-release regulator for off-season antler growth of sika deer and red deer and its preparation method. Background Technology

[0002] Deer antlers have significant economic and medicinal value. In the Northern Hemisphere, they typically grow during spring and autumn. Antlers begin to grow from the skull bone tissue of male deer (the antler base on the frontal bone), exhibiting extremely high regenerative and rapid growth capabilities. During this period, the antler is in a soft tissue state, rich in blood vessels and a nervous system, and covered with a layer of soft skin and a velvety structure called "velvet skin." After reaching its maximum size during its growth period, the antler enters the ossification stage, which usually occurs in late summer (approximately July to September). The cartilaginous tissue in the antler gradually mineralizes, transforming into a hard bony structure, becoming the "antler." Traditionally, antler harvesting usually occurs within the deer's normal growth cycle (March to August), mainly concentrated during the normal antler-growing season from June to August. However, due to seasonal fluctuations in market demand, off-season antler production has become an important research direction in the deer industry. The research on off-season (outside of March to August) antler growth regulation technology aims to artificially regulate the growth environment or physiological state of deer so that they can grow antlers normally during non-growing seasons (such as winter), thereby meeting market demand.

[0003] Studies have shown that antler growth in deer is closely related to photoperiod. Changes in light directly affect hormone levels in deer, especially the secretion of sex hormones. Photoperiod-regulated off-season technology simulates the light conditions of the normal antler-growing season (March to August) by artificially controlling the duration, intensity, and photoperiod of light in deer enclosures, inducing antler growth in deer during this non-normal growth period. However, the effect of light regulation is unstable and can be affected by environmental factors such as temperature and humidity. Photo-regulated antler growth technology still has certain shortcomings. First, the effect of light regulation varies greatly among different deer due to differences in age, health status, and sensitivity to photoperiod, leading to unstable regulation results. Second, the effects of photoperiod regulation on hormone secretion take a long time to manifest, making it difficult to meet the demand for rapidly improving antler growth quality in the short term. Third, this technology is highly dependent on the breeding environment, such as light intensity, wavelength, and site facilities, making precise implementation difficult in complex natural environments or when equipment is insufficient. Long-term use of artificial photoperiodism may disrupt the physiological rhythms of deer, affecting their health and reproduction. Furthermore, photoregulation has limited direct effects on key hormones such as growth hormone (GH), making it difficult to achieve comprehensive regulation of antler growth through a single method. Simultaneously, the equipment costs and energy consumption of this technology are high, potentially posing economic challenges for its widespread adoption in small and medium-sized farms. Existing photoperiod, hormone, and nutrient regulation methods show inconsistent results across different deer species and environments, failing to achieve the desired off-season antler growth. While off-season antler growth can be achieved by regulating photoperiod, it is time-consuming, costly, and technically unstable, limiting its widespread application in production.

[0004] Besides photoperiod and hormonal regulation, environmental factors such as temperature, humidity, and nutrition also significantly influence the growth cycle of deer and the growth of antlers, but primarily play a supporting role. For example, suitable temperature and humidity help improve the quality of antlers. In actual production, the widespread application of environmental control technologies faces challenges of high cost and complexity, and their adaptability varies considerably across different geographical environments.

[0005] The germination, growth, ossification, shedding, and regeneration of deer antlers are mainly driven by changes in hormone levels caused by photoperiod variations, achieved through the synergistic action of multiple hormones along the hypothalamic-pituitary-gonadal axis. Under normal circumstances, when the deer's testosterone levels drop to a certain level, the antler disc detaches, and antler growth begins. The technology of using exogenous progesterone to achieve off-season antler growth primarily promotes antler germination and growth by regulating hormone levels within the deer, especially during the non-growth period. Progesterone's role in regulating growth hormone and sex hormones helps achieve off-season antler growth. Currently, in the breeding of sika deer and red deer, anesthesia is required for all procedures except feeding and watering, which can cause damage to the deer and even pose a risk of death. However, administering medication through feeding or watering cannot achieve precise delivery. Therefore, this invention uses a single injection to deliver the medication in a long-acting, absorbable, sustained-release formulation. Our laboratory conducted a one-year hormone data tracking study on 150 sika deer to obtain the necessary baseline data. Summary of the Invention

[0006] The purpose of this invention is to utilize the principle that the growth cycle of deer antlers is affected by the synergistic effect of multiple hormones in the hypothalamus-pituitary-gonadal axis, and to use exogenous progesterone hormone to regulate the hypothalamus-pituitary-gonadal axis to achieve off-season antler production, meet the market demand for off-season fresh deer antler production, and increase the yield and efficiency of deer antlers. To this end, this invention provides a simple and safe absorbable slow-release regulator for off-season antler production of sika deer and red deer, and its preparation method.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] An absorbable, sustained-release regulator for off-season antler growth in sika deer and red deer, the regulator comprising 330 mg to 360 mg medroxyprogesterone acetate (MPA), 50 mg to 55 mg dextran sulfate (DS), and 200 mg to 220 mg sodium hyaluronate (HA), diluted with water for injection to a final volume of 1.0 mL.

[0009] Furthermore, the molecular weight of medroxyprogesterone acetate (MPA) is 386.52 Da; the molecular weight of dextran sulfate (DS) is 36~50 kDa; and the molecular weight of sodium hyaluronate (HA) is 20~400 kDa.

[0010] A method for preparing the above-mentioned absorbable sustained-release regulator of off-season antler growth from sika deer and red deer, wherein the method comprises:

[0011] Step 1: Preparation of sustained-release hydrogel: Mix dextran sulfate and sodium hyaluronate, dissolve in 0.3 mL to 0.5 mL of water for injection, and vortex for 5 to 8 minutes to ensure that the drug is fully mixed and dissolved to form a gel;

[0012] Step 2: Drug loading: After preheating the gel in a constant temperature water bath at 40~50℃, add medroxyprogesterone acetate powder, and dilute to 1mL with water for injection. Vortex for 5~8min and seal the drug dissolving container.

[0013] Step 3: Coating: Place the sealed dissolving container in a 40~50℃ electric thermostatic incubator and continue to dissolve in the sol state for 3~5 hours. Use a vortex shaker to shake for 5~8 minutes until the MPA is completely dissolved and coated.

[0014] Step 4: Dispensing: Dispense and seal each dose in 1.5mL~2mL portions under constant temperature conditions of 40~50℃;

[0015] Step 5: Storage: Store the dispensed sustained-release formulation in the refrigerator or freezer.

[0016] The advantages of this invention compared to existing technologies are as follows: This invention utilizes exogenous progesterone to induce off-season antler growth in male deer through hormonal regulation. It uses absorbable materials, making it environmentally friendly and harmless to the body, allowing for natural absorption and normal excretion through the body's metabolic processes. The medication requires only a single injection and its effects last for over 35 days. Using progesterone to regulate off-season antler growth is low-cost and has a high success rate. Attached Figure Description

[0017] Figure 1 A comparison of serum T levels after male sika deer were injected with a sustained-release agent;

[0018] Figure 2 A comparison of serum P levels after male sika deer were injected with a sustained-release agent;

[0019] Figure 3 A comparison of serum GnRH levels after male sika deer were injected with a sustained-release agent;

[0020] Figure 4 A comparison of serum LH levels after male sika deer were injected with a sustained-release agent;

[0021] Figure 5 A comparison of serum GH levels in male sika deer after injection of a sustained-release agent. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0023] Example 1:

[0024] 1. Formulation (taking 1.0mL absorbable sustained-release regulator as an example)

[0025] Medroxyprogesterone acetate (MPA) 330mg, molecular weight 386.52Da

[0026] 50mg of dextran sulfate (DS), low molecular weight 36~50kDa

[0027] Sodium hyaluronate (HA) 200mg, medium molecular weight 20~400kDa

[0028] Prepare an appropriate amount of water for injection (WFI) (dilute with water for injection and bring the volume to 1.0 mL).

[0029] 2. Production process

[0030] (1) Preparation of sustained-release hydrogel: Low molecular weight dextran sulfate (DS) and medium molecular weight sodium hyaluronate (HA) are mixed in a mass ratio of 1:4 and dissolved in 0.3 mL of water for injection. The mixture is shaken for 5 minutes using a vortex mixer to ensure that the drug is fully mixed and dissolved to form a gel.

[0031] (2) Drug loading: After preheating the gel in a constant temperature water bath at 40~50℃, add 330mg of medroxyprogesterone acetate (MPA) powder, dilute to 1mL with water for injection, shake with a vortex shaker for 5 minutes, and seal the drug dissolving container.

[0032] (3) Coating: Place the sealed drug dissolving container in a 40~50℃ electric thermostatic incubator and continue to dissolve in the sol state for 3 hours. Use a vortex shaker to shake for 5 minutes until the MPA is completely dissolved and coated.

[0033] (4) Dispensing: Dispense and seal each dose in 1.5 mL at a constant temperature of 40~50℃.

[0034] (5) Storage: The repackaged sustained-release formulation should be stored in the refrigerator or freezer.

[0035] Note: During solid-liquid mixing, be careful not to let the solid stick to the test tube wall, as the solution is viscous and sticking to the test tube wall will affect dissolution. Do not allow MPA to settle at the bottom of the test tube, otherwise it will be difficult to dissolve. After shaking, place the tube flat in a 40-50℃ incubator, and check its dissolution status several times, mixing appropriately to ensure complete dissolution.

[0036] 3. Application

[0037] (1) Application time

[0038] Red deer: Mid-to-late August to early September, or late December to early February of the following year.

[0039] Sika deer: Late August to early September, or early February of the following year.

[0040] Offspring of sika deer and red deer: same as red deer.

[0041] (2) Age requirement for the deer to be treated: It should be a healthy, mature male deer.

[0042] (3) Injection dosage: The injection dosage is determined by the weight of the male deer (sika deer, red deer and their hybrid offspring). When the weight is about 150kg, 1.5mL is injected intramuscularly, and MPA 495mg is injected.

[0043] This invention, based on the established normal antler-growing hormone levels, uses exogenous absorbable slow-release progesterone to regulate hormone levels in male deer, simulating the hormonal environment of the normal antler-growing season in spring and autumn, particularly affecting testosterone secretion. This induces deer to grow antlers during non-growth periods (such as winter), thus achieving off-season antler growth (outside of March to August). Off-season antler growth is achieved with only one injection, a simple and easy-to-implement technique, low cost, safety, and high success rate. It allows for 1-2 more antler harvests per year, increasing economic benefits per deer by over 80%.

[0044] Studies have shown that changes in serum hormone levels in male stags during antler growth and estrus cycles vary significantly between species and individuals, but the overall trend is consistent. However, data on hormones are limited. Therefore, this invention establishes hormone levels in normal male sika deer to assess the effects of drugs on hormones, screens for optimal drug dosages through controlled experiments, and evaluates economic benefits, as detailed below:

[0045] (1) Hormone levels in male sika deer after injection of sustained-release agent during non-antler-growing period

[0046] The experiment was divided into a control group (no drug injection group) and an experimental group (MPA dosages of 330mg, 495mg, and 660mg for groups 1-3, respectively). The injections were administered on January 30th and on May 2nd. The results are shown in Tables 1 to 5.

[0047] Table 1. Statistical results of testosterone (T) levels in male sika deer after injection of sustained-release agent.

[0048]

[0049] Note: When comparing data in the same row with group 0, data in the same row with the same letter or no letter in the superscript indicates no significant difference (P>0.05), while data with different letters indicates a significant difference (P<0.05), and the same applies below.

[0050] Depend on Figure 1As shown in Table 1, the serum testosterone concentration in the experimental groups (groups 1, 2, and 3) was significantly lower than that in the control group (group 0), indicating that progesterone injection significantly inhibited testosterone secretion and had a sustained effect in suppressing testosterone secretion. At 21 days, the concentrations in the experimental groups (groups 1, 2, and 3) were significantly lower than those in the control group (P < 0.05); at 64 days, the control group (group 0) was still significantly higher than that in the experimental groups (groups 1, 2, and 3) (P < 0.05), while the concentrations in groups 1, 2, and 3 were similar to those at 21 days, with no significant differences among the experimental groups; at 93 days, the control group (group 0) was significantly higher than that in the experimental groups (groups 1, 2, and 3) (P < 0.05), and the concentration in group 1 was slightly lower than that in groups 2 and 3. Testosterone plays a crucial role in the antler growth process of deer. Deer antlers are the tender antlers that grow on male deer at a specific time and contain abundant bioactive components. As deer antlers grow, testosterone levels first increase, then reach their maximum during the peak growth period, and finally decrease as the antlers mature and fall off.

[0051] Table 2. Statistical results of progesterone (P) levels in male sika deer after injection of sustained-release agent.

[0052]

[0053] Depend on Figure 2 As shown in Table 2, the serum progesterone concentration in the experimental groups (groups 1, 2, and 3) was higher than that in the control group (group 0), indicating that the detected progesterone concentration was the sum of the drug-released concentration and the endogenous progesterone concentration in the body. At day 21, groups 1, 2, and 3 were significantly higher than the control group (P < 0.05); at day 64, groups 1 and 2 were higher than the control group, but not significantly (P > 0.05), while group 3 was lower than the control group without significant difference; at day 93, groups 2 and 3 were significantly lower than the control group (P < 0.05), while group 1 had no significant difference from the control group. This indicates that by day 93, the drug in groups 2 and 3 had been completely released, while group 1 still had drug release in the body at day 64. This suggests that after progesterone injection, the progesterone level in the experimental groups significantly increased, but the drug effect weakened over time, and some experimental groups still showed an inhibitory effect.

[0054] Table 3. Statistical results of gonadotropin-releasing hormone (GnRH) levels in male sika deer after injection of sustained-release agent.

[0055]

[0056] High progesterone levels may have a negative feedback regulation of GnRH, thereby affecting other GnRH-related hormones. (See Table 3 and...) Figure 3As can be seen, at 21 days, Group 1 was lower than the control group, with a significant difference (P < 0.05), while Groups 2 and 3 were lower than the control group, but not significantly. At 64 days, Groups 1, 2, and 3 were all lower than the control group, with significant differences (P < 0.05). At 93 days, Groups 1 and 2 were lower than the control group, but not significantly; Group 3 was significantly higher than the control group, with a significant difference (P < 0.05). GnRH secretion has a certain periodicity, and the negative feedback effect of GnRH may weaken at 93 days.

[0057] Table 4. Statistical results of luteinizing hormone (LH) levels in male sika deer after injection of sustained-release agent.

[0058]

[0059] GnRH is a key hormone that stimulates the pituitary gland to secrete LH. Therefore, an increase in progesterone concentration leads to a decrease in GnRH secretion, which in turn affects LH levels. (See Table 4 and...) Figure 4 As can be seen, from day 21 to day 93, groups 1, 2, and 3 were all lower than the control group (group 0), and at day 21, groups 1, 2, and 3 were significantly lower than the control group (P < 0.05). At day 21, the LH concentration in the experimental groups was lower than that in the control group, and groups 1, 2, and 3 were significantly lower than the control group (P < 0.05). At day 64, the concentration in the experimental groups was lower than that in the control group, with group 1 being significantly lower (P < 0.05), while groups 2 and 3 were lower than the control group, but the difference was not significant. At day 93, the LH concentration in the experimental groups was lower than that in the control group, with groups 1 and 2 being significantly lower than the control group (P < 0.05). LH secretion depends on the pulsatile release of GnRH. During the periodic release of GnRH, the frequency and amplitude of GnRH directly affect LH secretion. Normally, when GnRH secretion increases, LH secretion increases; conversely, when GnRH secretion decreases, LH secretion decreases. Increased progesterone concentration in the negative feedback mechanism inhibits GnRH release, thereby reducing LH secretion.

[0060] Table 5. Statistical results of growth hormone (GH) levels in male sika deer after injection of sustained-release agent.

[0061]

[0062] Growth hormone secretion is regulated by testosterone, and the synergistic effect of the two can effectively promote the rapid growth of deer antlers. Figure 5As shown in Table 5, at 21 days, Group 1 was lower than the control group, but the difference was not significant; Groups 2 and 3 were higher than the control group, but the differences were not significant. At 64 days, Group 1 was higher than the control group, but the difference was not significant; Groups 2 and 3 were significantly higher than the control group (P < 0.05); at 94 days, Groups 1 and 3 were significantly higher than the control group (P < 0.05), while Group 2 was not significantly different from the control group. This indicates that the progesterone drug's regulatory effect on GH was initially apparent at 21 days, and the level was significantly higher than the control group at 64 days, showing that the progesterone drug had a significant promoting effect on GH secretion. At 93 days, the drug metabolism was completed, and significant differences appeared between the groups.

[0063] (2) Antler growth and antler yield of male sika deer after injection of sustained-release agent

[0064] After drug injection, the antler growth was observed and the actual yield was recorded. The actual control group did not grow antlers in the same year during the off-season. However, the experimental groups (groups 1, 2, and 3) grew antlers off-season in the same year, and the average weight of the antlers produced was 1.249 kg / head.

[0065] The above experimental results all demonstrate that the drug of this invention has a good antler-growth effect when applied to male deer during off-season antler growth, and can achieve multiple antler productions per year. A single intramuscular injection ensures that the dosage is the same for each deer, and only one anesthesia is required, eliminating the need for multiple anesthesias and reducing the risk of damage to the deer's body.

Claims

1. An absorbable, slow-release regulator for off-season antler growth of sika deer and red deer, characterized in that: The regulator comprises 330 mg to 360 mg medroxyprogesterone acetate (MPA), 50 mg to 55 mg dextran sulfate (DS), and 200 mg to 220 mg sodium hyaluronate (HA), diluted with water for injection to a final volume of 1.0 mL.

2. The absorbable, slow-release regulator for off-season antler growth of sika deer and red deer according to claim 1, characterized in that: The molecular weight of medroxyprogesterone acetate (MPA) is 386.52 Da; the molecular weight of dextran sulfate (DS) is 36~50 kDa; and the molecular weight of sodium hyaluronate (HA) is 20~400 kDa.

3. A method for preparing an absorbable, sustained-release regulator of off-season antler growth from sika deer or red deer as described in claim 1 or 2, characterized in that: The method is as follows: Step 1: Preparation of sustained-release hydrogel: Mix dextran sulfate and sodium hyaluronate, dissolve in 0.3 mL to 0.5 mL of water for injection, and vortex for 5 to 8 minutes to ensure that the drug is fully mixed and dissolved to form a gel; Step 2: Drug loading: After preheating the gel in a constant temperature water bath at 40~50℃, add medroxyprogesterone acetate powder, and dilute to 1mL with water for injection. Vortex for 5~8min and seal the drug dissolving container. Step 3: Coating: Place the sealed dissolving container in a 40~50℃ electric thermostatic incubator and continue to dissolve in the sol state for 3~5 hours. Use a vortex shaker to shake for 5~8 minutes until the MPA is completely dissolved and coated. Step 4: Dispensing: Dispense and seal each dose in 1.5mL~2mL portions under constant temperature conditions of 40~50℃; Step 5: Storage: Store the dispensed sustained-release formulation in the refrigerator or freezer.

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