A pharmaceutical of a rhizoma of curcuma zedoaria for treating diarrhea and a preparation method thereof

Abstract

The present application discloses a kind of for stopping shieliang Xianglian pellet and preparation method thereof.The pellet is successively from inside to outside drug-loading pellet core, microflora trigger degradation layer and pH-dependent enteric layer;Drug-loading pellet core includes Huanglian and mukhallat extract paste, β-cyclodextrin inclusion compound of safflower volatile oil and microcrystalline cellulose, lactose, mannitol, is prepared by extrusion spheronization method;Microflora trigger degradation layer includes konjac glucomannan and chitosan, and pH-dependent enteric layer includes Eudragit S100, and two layers are physical isolation independent layered structure.Preparation when using fluidized bed bottom spray method layered coating, and by online near infrared spectrum real-time monitoring outer coating film thickness to accurately control coating end point.The present application utilizes the sequence double insurance mechanism of pH trigger outer layer dissolution and microflora enzymatic inner layer, effectively solves the defect that single pH-dependent preparation is easily leaked in advance at pathological low pH, significantly improves colon target accuracy.

Description

Technical Field

[0001] This invention relates to the field of traditional Chinese medicine preparation technology, and in particular to a Xianglian preparation for stopping diarrhea and its preparation method. Background Technology

[0002] Xianglian Pills, composed of Aucklandia lappa and Coptis chinensis, are a classic formula for treating intestinal diseases such as diarrhea and dysentery. Developing Xianglian Pills into a colon-targeted preparation would allow for concentrated drug release at the lesion site, improving efficacy and reducing irritation to the stomach and small intestine.

[0003] Currently, pH-dependent colon-targeted delivery systems are the most widely used technology. This approach typically uses methacrylic acid copolymers such as Eudragit S100 as coating materials. While Eudragit S100 undergoes macroscopic disintegration and dissolution at pH levels above 7.0, it is well known to those skilled in the art that in environments close to its dissolution threshold (pH 6.5–6.8), the material experiences significant hydration and swelling, intensifying polymer chain movement and causing membrane permeability to increase exponentially with prolonged immersion time. For small-molecule water-soluble drugs such as berberine, even if the membrane remains macroscopically intact, the drug can still diffuse and permeate extensively through the swollen hydrogel layer within hours to 24 hours, leading to premature depletion of the drug before release at the colonic lesion. Therefore, relying solely on 'dissolution' as a criterion for colon-targeting ignores the long-term permeation risk within the critical pH range, which is another significant drawback of a single pH strategy. The pH of the human gastrointestinal tract exhibits significant individual variation and is influenced by various factors such as diet, disease state, and age. For example, the colonic pH of patients with ulcerative colitis may be below 6.8, while the pH of the terminal small intestine in some healthy individuals or patients with diarrhea may periodically rise above 7.4. This directly leads to pH-dependent agents potentially being released prematurely in the small intestine or failing to be fully released in the colon, severely impacting the reliability and reproducibility of drug efficacy. Therefore, relying solely on pH changes for triggering colonic targeting requires improvement in precision. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a method for preparing a Xianglian preparation for stopping diarrhea, comprising the following steps:

[0005] The volatile oil of Costus root was extracted and encapsulated with β-cyclodextrin to obtain the Costus root volatile oil β-cyclodextrin inclusion complex; Coptis chinensis and the Costus root residue after volatile oil extraction were extracted to obtain a clear extract; the clear extract, microcrystalline cellulose, lactose, mannitol and the Costus root volatile oil β-cyclodextrin inclusion complex were mixed and pellet cores were prepared by extrusion and spheronization.

[0006] A microbial degradation-triggered layer is coated around the drug-loaded pellet core;

[0007] A pH-dependent enteric layer is coated around the microbial community-triggered degradation layer;

[0008] The preparation of drug-loaded pellet cores.

[0009] Furthermore, the coating microbial community-triggered degradation layer is produced by bottom spraying in a fluidized bed. The coating solution contains konjac glucomannan, chitosan, triethyl citrate, and an acidic aqueous solution containing 1%–2% acetic acid.

[0010] Furthermore, the pH-dependent enteric coating was applied using a fluidized bed bottom spray method. The coating solution contained Eudragit S100, triethyl citrate, talc, and a 1:1 volume ratio of isopropanol to acetone. The coating endpoint was controlled by real-time monitoring of the film thickness using online near-infrared spectroscopy.

[0011] The present invention also proposes a xianglian preparation for antidiarrheal purposes prepared by the above preparation method, comprising a drug-loaded pellet core, a microbial-triggered degradation layer covering the outside of the drug-loaded pellet core, and a pH-dependent enteric coating layer covering the outside of the microbial-triggered degradation layer.

[0012] Furthermore, the drug-loaded pellet core contains a β-cyclodextrin inclusion complex of costus root volatile oil, an extract of Coptis chinensis and costus root residue, and microcrystalline cellulose, lactose, mannitol and β-cyclodextrin as excipients.

[0013] Furthermore, the microbial-triggered degradation layer comprises konjac glucomannan and chitosan.

[0014] Furthermore, the pH-dependent enteric layer contains Eudragit S100 as an enteric material.

[0015] Furthermore, the weight gain of the microbial community-triggered degradation layer relative to the drug-loaded pellet core is 5% to 8%.

[0016] Furthermore, the pH-dependent enteric coating layer accounts for 16% to 18% of the total weight of the pellet core and the microbial-triggered degradation layer.

[0017] Furthermore, the microbial community-triggered degradation layer and the pH-dependent enteric layer are physically isolated independent layered structures.

[0018] The present invention has the following beneficial technical effects:

[0019] 1. This invention designs the pH-dependent enteric coating layer and the microbial-triggered degradation layer as physically isolated independent layered structures, achieving a sequential response mechanism. In vitro release experiments show that in a simulated pathological low-pH environment without microbial flora, the comparative sample showed a cumulative release rate of up to 89.7% after 124 hours, indicating severe premature drug leakage; while the cumulative release rate of the microparticles of this invention was only 12.3% after 24 hours, demonstrating that even if the outer pH membrane fails at low pH, the intact and dense inner microbial-triggered degradation layer can still serve as a robust internal barrier, effectively preventing drug leakage and exhibiting excellent adaptability to pathological environments.

[0020] 2. In a pH 6.8 release medium containing colonic flora, the microspheres of this invention exhibit a time-delayed burst release characteristic, with a cumulative release rate rapidly reaching 95.3% within 4 hours. This process clearly demonstrates that the outer pH membrane first swells and removes the barrier, followed by colon-specific enzymes precisely enzymatically cleaving the inner konjac glucomannan and chitosan, triggering a sequential process in which the core drug is concentrated and released at the lesion site. In contrast, Comparative Example 1 showed no significant change in release behavior under the same bacterial conditions, lacking a specific response to the bacterial flora, proving that this invention achieves truly microbial-triggered, precisely targeted release.

[0021] 3. Regarding the method in Comparative Example 2 where the microbial triggering material and the enteric coating material are mixed and coated, this invention, through a layered isolation design, avoids the risk of process failure due to the precipitation of Eudragit S100 when the aqueous polysaccharide solution is mixed with the organic solvent system, thus preventing film formation. Simultaneously, it eliminates the problem of premature barrier damage caused by microcracks resulting from water absorption and swelling of the hydrophobic membrane when the hydrophilic polysaccharide is uniformly dispersed within it. This physical isolation structure ensures that each functional layer independently performs its respective function, forming the structural basis for achieving the dual release mechanism.

[0022] 4. Pharmacodynamic experiments in a mouse diarrhea model demonstrated that the high-dose group of the microcapsules of this invention significantly delayed the onset of diarrhea and reduced the frequency and severity of diarrhea. Its antidiarrheal effect was significantly superior to that of an equivalent dose of berberine hydrochloride raw material. This indicates that through colon-targeted delivery, the volatile oil of Aucklandia lappa and the alkaloids of Coptis chinensis achieve a synergistic effect at the colonic lesion site, endowing the product with excellent antidiarrheal therapeutic function. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the three-layer structure and dual-trigger release mechanism of the Xianglian micro-pellets of the present invention;

[0024] Figure 2 The process flow diagram for the preparation of Xianglian micro-pellets;

[0025] Figure 3 Here is a SEM image of the microparticles from Example 2;

[0026] Figure 4 A comparison chart of the cumulative release rates of various microparticles at different time points. Detailed Implementation

[0027] The following detailed embodiments illustrate a medicament for treating diarrhea using the herbal medicine Xianglian preparation and its preparation method. These embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0028] Example 1

[0029] The composition of the drug-loaded core of Xianglian micro-pills is as follows:

[0030] 300 grams of costus root;

[0031] 200 grams of Coptis chinensis (processed with Evodia rutaecarpa);

[0032] Microcrystalline cellulose, commercial model pH-101, 180g;

[0033] 100 grams of lactose;

[0034] 70 grams of mannitol;

[0035] 100 grams of β-cyclodextrin is used for the inclusion of volatile oils;

[0036] A suitable amount of 50% ethanol aqueous solution is used as a wetting adhesive.

[0037] The composition of the coating solution for the microbial community-triggered degradation layer is as follows:

[0038] 10-20 ml of glacial acetic acid (analytical grade) (to make the volume fraction of acetic acid in the solution 1%-2%).

[0039] 25 grams of konjac glucomannan;

[0040] 5 grams of chitosan;

[0041] 3 grams of triethyl citrate, used as a plasticizer;

[0042] Add purified water to a final volume of 1000 ml.

[0043] The specific specifications of the key auxiliary materials are as follows:

[0044] Konjac glucomannan: glucomannan content ≥90% (on a dry basis), weight average molecular weight (Mw) of 500,000 to 1,000,000 Daltons, dynamic viscosity of 1% aqueous solution at 25℃ of 5,000 to 10,000 mPa·s, moisture ≤10%, ash content ≤5%.

[0045] Chitosan: Deacetylation degree ≥90% (based on glucosamine), dynamic viscosity (1% chitosan dissolved in 1% acetic acid solution, 25℃) 50–200 mPa·s, weight-average molecular weight 100,000–300,000 Daltons, moisture ≤8%, ash content ≤1%. Chitosan requires weakly acidic conditions (such as 1%–2% acetic acid solution) to dissolve completely.

[0046] The pH-dependent enteric coating solution consists of Eudragit S100 powder with an intrinsic viscosity range of 50 to 200 mPa·s, 75 g.

[0047] 7.5 grams of triethyl citrate;

[0048] 37.5 grams of talcum powder;

[0049] A suitable amount of a 1:1 volume ratio of isopropanol and acetone is used for dissolution and dispersion. After preparation, the total solid content of the coating solution is precisely controlled at a mass fraction of 8.0% ± 0.2%.

[0050] like Figure 1 As shown, the microcapsules of this invention consist of three physically isolated, independent layered structures. After oral administration, as the microcapsules pass through the stomach and small intestine, the outermost pH-dependent enteric layer, Eudragit S100, undergoes high hydration and swelling in the physiological colonic environment of pH 6.8–7.0, with a swelling degree ≥15%, forming water-containing microporous channels that allow water-soluble macromolecules with a molecular weight below 100 kDa to permeate. However, in the stomach and upper small intestine (pH < 6.5), it maintains a glassy, ​​dense structure with no significant enzyme permeability. This swollen state is not structural disintegration, but rather a physical gate switch for enzyme permeability. Figure 1 Mid-section). When the microspheres reach the colon region, if the local pH reaches above 7.0, the outer layer dissolves first. Figure 1 (Lower left), at this time, the inner layer of bacteria triggers the degradation of konjac glucomannan and chitosan in the colonic flora, exposing them to specific enzymes produced by the colonic flora. Enzymatic hydrolysis causes the inner layer structure to disintegrate. Figure 1 (Lower middle section), ultimately the effective components of costus root and coptis root in the pill core are released in a concentrated burst at the lesion site. Figure 1 (Lower right side). The microcapsules in this embodiment consist of a three-layer structure: a drug-loaded core, a microbial degradation-triggered layer, and a pH-dependent enteric coating layer.

[0051] The invention is characterized by the spatiotemporal overlap and complementarity of the outer and inner layers: in the colonic region, the outer pH membrane does not need to be completely dissolved, but only needs to swell to a critical state to transmit enzyme signals; the inner microbial-triggered degradation layer acts as an enzyme response substrate, and once it senses trace amounts of enzyme molecules penetrating the outer layer, it initiates self-accelerated enzymatic digestion. The outer barrier function targets small drug molecules (preventing leakage) rather than large microbial enzyme molecules (allowing transduction), thereby achieving zero premature drug leakage, but with anomalous selective permeability for normal enzyme signal transmission.

[0052] Example 2

[0053] like Figure 2 As shown, this embodiment fully demonstrates the entire preparation process of the microparticles described in Example 1.

[0054] Step 1: Extraction and Nano-Encapsulation of Costus Root Volatile Oil

[0055] Take 300 grams of the prescribed amount of costus root, crush it and pass it through a 40-mesh sieve. Place it in a volatile oil extractor and extract it using steam distillation for 5 hours. Collect about 10 ml of volatile oil and store it separately. Collect about 500 ml of the resulting aromatic aqueous solution after distillation and keep it for later use.

[0056] Collected costus root volatile oil and 100g of β-cyclodextrin were incorporated using a saturated aqueous solution method. First, the β-cyclodextrin was dissolved in an appropriate amount of purified water by heating to prepare a saturated solution at 60℃. While continuously stirring, the volatile oil was dissolved in a small amount of anhydrous ethanol and slowly added dropwise to the saturated β-cyclodextrin solution. The mixture was stirred at a constant temperature of 60℃ for 2 hours to induce incorporation. The incorporation solution was then refrigerated at 4℃ for 24 hours to allow complete precipitation. The mixture was filtered, the filter cake was washed with a small amount of purified water, and then dried in a vacuum drying oven at 40℃. After drying, the mixture was pulverized and passed through an 80-mesh sieve to obtain approximately 105g of costus root volatile oil β-cyclodextrin incorporation powder for later use.

[0057] Step Two: Extraction and Concentration of Coptis chinensis and Aucklandia lappa Residue

[0058] Take 200 grams of Coptis chinensis (processed with Evodia rutaecarpa) and the residue of Aucklandia lappa after the volatile oil extraction in step one, combine them, and soak in 10 times the amount of water for 1 hour. Then decoct twice: first, add 10 times the amount of water and decoct for 2 hours; second, add 8 times the amount of water and decoct for 1 hour. Filter and combine the filtrates from the two decoctions.

[0059] Combine the aromatic aqueous solution of costus root distillation collected in step one with the above decoction and stir well. Concentrate under reduced pressure at 60°C. During concentration, monitor the moisture content using a rapid moisture analyzer or Karl Fischer method until the moisture content of the clarified extract drops to between 25% and 30%, i.e., the solid content is approximately 70% to 75%. At this point, the relative density of the clarified extract is approximately 1.25 to 1.30 when measured at 60°C, and the total weight is approximately 140 to 160 grams. Set aside for later use.

[0060] Step 3: Preparation of drug-loaded pellet cores

[0061] Weigh out the extract obtained in step two, 180 g of microcrystalline cellulose pH-101, 100 g of lactose, and 70 g of mannitol, and put them into a wet granulator or kneader for initial mixing. Add approximately 105 g of the costus root volatile oil β-cyclodextrin inclusion complex powder prepared in step one, and continue mixing until homogeneous. While stirring, slowly spray a 50% ethanol aqueous solution as a wetting and binding agent, and continuously observe the state of the soft material until it reaches the ideal state where it can be formed into a ball by hand and crumbles easily when lightly pressed.

[0062] The soft material is fed into the hopper of an extruder. The extrusion screen has a aperture of 0.9 mm. The extrusion speed is set to allow the material to be continuously and densely extruded in thin strips. The extruded material has a smooth surface and no obvious heat generation. The extruded strips are then transferred to a rounding machine. The rotation speed of the rounding disc is adjusted to achieve the optimal shear and rolling balance. The rounding time is about 5 minutes, which breaks the strips and fully rounds them into spherical particles.

[0063] The microcapsules were removed and dried in a 60℃ hot air circulating drying oven for 10 hours. After drying, they were sieved using 18-mesh and 24-mesh standard sieves. Microcapsules of intermediate particle size that could pass through the 18-mesh sieve but not the 24-mesh sieve were collected, yielding drug-loaded cores with smooth surfaces and good sphericity, with a yield of approximately 470 grams. Measurements showed that the angle of repose of these cores was less than 30 degrees, indicating good flowability.

[0064] Step 4: Microbial community-triggered degradation layer coating

[0065] All the drug-loaded pellets obtained in step three are fed into a fluidized bed coating machine and coated with a shell using a bottom spray method.

[0066] The preparation method for the bacterial community-triggered degradation layer coating solution is as follows: Measure approximately 1000 mL of purified water and add 10–20 mL of glacial acetic acid (analytical grade) (to make the acetic acid volume fraction in the solution 1%–2%), stir well to obtain an acidic solvent. Weigh 25 g of konjac glucomannan and 5 g of chitosan, and slowly add them to the above acidic solvent while continuously stirring. Continue stirring at room temperature for approximately 30–60 minutes until the chitosan is completely dissolved, forming a clear or slightly opalescent viscous solution, with no particulate insoluble matter visible to the naked eye. Then add 3 g of triethyl citrate as a plasticizer, and continue stirring until well mixed to obtain the coating solution.

[0067] Set the fluidized bed coating parameters as follows: set the inlet air temperature to 50 to 55 degrees Celsius, maintain the material temperature at 38 to 42 degrees Celsius, set the atomizing gas pressure to 0.15 MPa, and control the coating liquid flow rate at 1.5 to 2.0 ml per minute.

[0068] Under these parameters, the liquid was continuously sprayed until the shell weight gain reached 5% to 8% of the initial pellet weight. After coating, the pellets were fluidized and dried at 40 degrees Celsius or in an oven for 2 hours to obtain intermediate pellets with a microbial-triggered degradation layer.

[0069] Step 5: pH-dependent encapsulation of the enteric layer

[0070] The shelled pellets obtained in step four are then coated with an outer layer using a bottom-spray method in the same or another fluidized bed coating machine.

[0071] The preparation of the outer coating solution is a critical operation, and is detailed as follows: In a fume hood, 75 g of Eudragit S100 powder is slowly added to a sufficient amount of a 1:1 volume ratio of isopropanol to acetone mixture while continuously stirring. Stirring continues until the polymer is completely dissolved, forming a clear solution. Subsequently, 7.5 g of the plasticizer triethyl citrate and 37.5 g of the anti-sticking agent talc are added sequentially. This suspension is then subjected to high-speed shear homogenization for 10 minutes and passed through an 80-mesh sieve to remove any undispersed particles. Finally, the total solids content of the coating solution is precisely adjusted to 8.0% ± 0.2% using the aforementioned mixed solvent, while continuously and slowly stirring to maintain homogeneity until the coating process is complete.

[0072] Set the fluidized bed parameters for the outer coating: set the inlet air temperature to 30 to 35 degrees Celsius, maintain the material temperature between 28 and 32 degrees Celsius, set the atomizing gas pressure to 0.18 MPa, and optimize the coating liquid flow rate to 0.8 to 1.0 ml per minute to prevent microparticle adhesion and ensure film quality.

[0073] In this embodiment, an online near-infrared spectroscopy probe is used to monitor the coating thickness of the microcapsules in real time and non-destructively. A partial least squares model is established to obtain the average value and coefficient of variation of the coating thickness in real time. When the average coating thickness reaches the preset target value and the coefficient of variation of the coating thickness for this batch of microcapsules is less than 5%, the spraying process is automatically terminated, serving as the endpoint of the coating process. Using this method, the final weight gain of the outer coating is approximately 16% to 18% of the total weight of the core and shell. After the coating operation is completed, spraying is stopped, and the microcapsules are subjected to in-situ solidification treatment at 40 degrees Celsius in a fluidized state for 3 hours to allow the polymer coating particles to fully fuse and densify, ultimately obtaining the Xianglian microcapsules product.

[0074] To confirm the above disintegration mechanism, the inventors conducted a comparative experiment: the control membrane prepared solely with chitosan (without KGM) showed a release rate of less than 20% within 12 hours in the same bacterial medium at pH 6.8, confirming the slow degradation of pure chitosan. In contrast, the KGM-CS composite membrane (25:5) of this invention completely disintegrated and released the drug within 4 hours. This significant difference demonstrates that the disintegration of the composite layer of this invention does not depend on the enzymatic hydrolysis of chitosan, but rather on the skeletal collapse induced by the enzymatic hydrolysis of KGM. Chitosan here serves only as a structural modifier to adjust the hydrophilicity and mechanical strength of the membrane; its role in the composite membrane differs from its role as a single coating material in existing technologies.

[0075] Comparative Example 1

[0076] This comparative example prepares a microsphere that relies solely on a single pH mechanism for triggering degradation, i.e., it does not contain a microbial community-triggered degradation layer.

[0077] Preparation method:

[0078] Steps one and two, namely the extraction and inclusion of costus root volatile oil and the extraction and concentration of Coptis chinensis and costus root residue, are performed exactly the same as in Example 2.

[0079] Step 3, preparation of the drug-loaded pellet core. The formulation of this core, including the microcrystalline cellulose type, lactose, mannitol, ethanol concentration, and all other materials and process parameters, is exactly the same as Step 3 of Example 2.

[0080] Step four: This comparative example omits the microbial community-triggered degradation layer coating process in step four of Example 2, and directly uses the drug-loaded pellet core prepared in step three for the outer enteric coating.

[0081] Step five, pH-dependent enteric coating, uses Eudragit S100 with identical specifications, coating solution composition, solid content, fluidized bed operating parameters, and coating endpoint determination method based on online near-infrared spectroscopy, as well as is identical to step five in Example 2. The coating weight gain is also precisely controlled to 16% to 18% of the pellet core weight.

[0082] It should be noted that, in order to eliminate the influence of differences in the thickness of the outer coating film on the release behavior, the following equivalent design was performed between Comparative Example 1 and Example 2:

[0083] Based on 100g of drug-loaded pellet core, the weight gain of the outer coating in Comparative Example 1 was 16-18g (absolute dry film weight); the weight gain of the outer coating in Example 2 was 16%-18% of the weight of the intermediate micro-pellets (pill core and inner layer, weighing approximately 105-108g), which translates to an absolute dry film weight of approximately 16.8-19.4g. The absolute amount of Eudragit S100 used and the theoretical film thickness of both were essentially the same (deviation <2%), meeting the requirement of equal film thickness for release rate comparison.

[0084] Therefore, the huge difference in release behavior between the two under simulated pathological low pH (sterile pH 6.8) conditions (89.7% in Comparative Example 1 and 12.3% in Example 2) is entirely attributable to the structural difference in the presence or absence of a microbial-triggered degradation layer, rather than to the difference in outer membrane thickness.

[0085] Comparative Example 2

[0086] This comparative study prepared microspheres by mixing microbial degradation materials and pH-sensitive materials to form a single mixed coating layer. The intention of this design was to simplify the process, but no physically isolated independent functional layers were formed.

[0087] Preparation method:

[0088] Steps one and two, the extraction and concentration operations, are exactly the same as in Example 2.

[0089] Step 3, the preparation of the drug-loaded pellet core, is exactly the same as in Example 2.

[0090] Step four: This comparative example does not prepare a separate microbial community-triggered degradation layer. Instead, it attempts to formulate a mixed coating solution to combine the microbial community-triggered material and the pH-sensitive material in the same coating. The coating solution is prepared as follows: In a fume hood, 75 g of Eudragit S100 powder is dissolved in a 1:1 volume ratio of isopropanol to acetone, followed by the addition of 7.5 g of triethyl citrate and 37.5 g of talc. Separately, 25 g of konjac glucomannan and 5 g of chitosan are dissolved in 1000 mL of purified water under stirring. While stirring at high speed, the above aqueous polysaccharide solution is slowly added to the Eudragit S100 organic solvent system. However, since water is completely miscible with isopropanol and acetone, the mixing process did not form a water-in-oil emulsion suspension. Instead, because Eudragit S100 is insoluble in water, the organic solvent was diluted with the addition of the aqueous polysaccharide solution, causing Eudragit S100 to rapidly precipitate out of the mixing system in large quantities, forming white flocculent or granular precipitates, making it impossible to obtain a uniform and stable coated dispersion.

[0091] Step 5: The drug-loaded pellet core obtained in Step 3 is placed into a fluidized bed, and a single coating is performed using the same fluidized bed parameters as in Step 5 of Example 2. The coating endpoint is controlled by online near-infrared spectroscopy to ensure that the total weight gain of the coating layer reaches 21% to 25% of the pellet core weight, thus ensuring that its film thickness is substantially equivalent to the total thickness of the shell and film layers in Example 2. Subsequent curing treatment is the same as in Example 2.

[0092] Example 3

[0093] To demonstrate the advantages of Embodiment 2 of the present invention compared with the two comparative examples above, an in vitro release rate evaluation system capable of accurately simulating different pathological and physiological conditions in vivo was designed.

[0094] Experimental system construction:

[0095] Culture medium preparation: Prepare a standard pH 6.8 phosphate buffer solution. To simulate the colonic microbiota environment, fresh colonic contents from healthy rats were separately prepared into a 10% homogeneous suspension in an anaerobic chamber using deoxygenated pH 6.8 phosphate buffer solution, which served as the microbiota-triggered release medium.

[0096] Experimental groups: Equal amounts of the drug were taken from the microcapsules of Example 2, Comparative Example 1, and Comparative Example 2, and the following two experiments were conducted.

[0097] Experiment A: Simulating a pathological scenario where the pH-dependent mechanism partially or completely fails. The three groups of microcapsules were placed in a simple pH 6.8 phosphate buffer solution without any bacterial flora, and the drug release was monitored throughout the experiment at 37 degrees Celsius according to the pharmacopoeia release assay method.

[0098] Experiment B: Simulating a physiological scenario with normal colonic flora but potentially fluctuating pH. The three groups of microspheres were placed in a pH 6.8 phosphate buffer solution containing 10% rat colonic contents and the experiment was conducted under anaerobic conditions at 37 degrees Celsius, with drug release monitored throughout the process.

[0099] Experimental results:

[0100] In the simple pH 6.8 buffer system of Experiment A, the cumulative release rate after 24 hours is as follows:

[0101] Comparative Example 1 microparticles showed a cumulative release rate as high as 89.7%. This demonstrates that in a simulated pathological environment with low pH (pH 6.8) and no bacterial flora, Comparative Example 1 achieved a cumulative release rate of 89.7% over 24 hours. Notably, the coating membrane did not macroscopically dissolve or disintegrate (microscopic observation confirmed the membrane morphology was intact), but small drug molecules had already permeated and been released in large quantities through the diffusion channels of the swollen hydration layer.

[0102] After Experiment A, the microcapsules of Comparative Example 1 were removed and observed under an optical microscope. The outer Eudragit S100 coating membrane was found to be intact, without cracks or disintegration fragments. However, the core of the microcapsules was vacuolated, indicating a significant reduction in drug content. This phenomenon confirms that the 89.7% release over 24 hours was not due to physical membrane damage, but rather to molecular diffusion under long-term swelling conditions.

[0103] This result strongly demonstrates that even if Eudragit S100 does not reach its dissolution threshold, it cannot maintain effective barrier protection against small molecule drugs when exposed to a critical pH medium for extended periods (24 hours) as a single barrier. The term "single pH mechanism failure" used in this experiment refers to the failure of its barrier function, not the disintegration of the membrane structure, revealing a potential sub-dissolved permeation vulnerability overlooked by existing technologies.

[0104] In Comparative Example 2, the microcapsules were prepared because water, isopropanol, and acetone were completely miscible during the preparation of the coating solution. This caused a large amount of Eudragit S100 to precipitate out after the organic solvent was diluted, making it impossible to form a uniform and stable coating dispersion. Therefore, this comparative example could not actually produce a qualified microcapsule sample for testing, and its release rate data lacked experimental basis.

[0105] Theoretically, when this homogeneous mixed film-forming scheme comes into contact with an aqueous medium, the hydrophilic polysaccharide components, konjac glucomannan and chitosan, uniformly dispersed within the membrane, will rapidly absorb water and swell. Since the polysaccharide molecules are uniformly distributed at the molecular scale within a continuous hydrophobic polymer backbone, this swelling will generate anisotropic internal stresses within the membrane, leading to numerous microcracks and interconnected pores. This swelling-induced physical membrane disruption will severely damage the membrane's barrier function even before the pH reaches the dissolution threshold of 7.0, potentially resulting in significant premature drug leakage. Therefore, this mixed coating design cannot achieve reliable colon-targeted controlled release, either in practical processes or theoretically, highlighting the necessity and superiority of the layered structure design in this invention, which physically isolates the microbial trigger layer from the pH-dependent layer.

[0106] Given that the outer pH-dependent enteric coating layers of Comparative Example 1 and Example 2 have equivalent absolute membrane thicknesses (see the description of Comparative Example 1 for details), the significant difference in release rates (89.7% and 12.3%) in the sterile pH 6.8 environment can be rigorously attributed to the additional physical barrier effect provided by the inner microbial community-triggered degradation layer, rather than the difference in the amount of coating material used.

[0107] Example 2: The microcapsules showed a cumulative release rate of only 12.3%. This extremely low release demonstrates that the outer pH-dependent membrane effectively protects the interior in a pH 6.8 environment. Even with slight swelling of the outer membrane after prolonged immersion, the independent, intact, and dense microbial community-triggered degradation layer inside still acts as a robust internal barrier, preventing drug diffusion and demonstrating excellent adaptability to pathological low pH environments.

[0108] Although the sterile pH 6.8 medium in Experiment A had permeated into the inner layer and fully hydrated it, the 24-hour release rate of the microparticles in Example 2 was only 12.3%. This result strongly demonstrates that the hydrated konjac glucomannan-chitosan composite gel layer itself possesses excellent drug barrier properties. This is because the numerous hydrogen bond crosslinking points between the two polymer chains did not break after water absorption; instead, due to water molecule-mediated chain segment rearrangement, a denser transient network structure was formed, effectively binding free water and increasing the tortuosity of drug diffusion. Therefore, before enzymatic hydrolysis triggering, this layer does not rely on hydrophobicity as a barrier mechanism, but rather on physical sieving, which remains highly efficient even in a neutral hydration environment at pH 6.8.

[0109] In the pH 6.8 buffer system containing bacterial flora in Experiment B, the cumulative release rate after 4 hours is as follows:

[0110] Comparative Example 1 microparticle showed a release rate of 91.5% within 4 hours. Its release mechanism was solely dependent on pH. The membrane was already unstable at pH 6.8, and the presence of microorganisms did not significantly affect its release rate. The release behavior was similar to that of Experiment A, lacking a specific response to microorganisms.

[0111] The coating scheme for Comparative Example 2 microparticles failed to produce qualified microparticles due to polymer precipitation during coating solution preparation, preventing the formation of a continuous and dense coating membrane. Therefore, 4-hour release data are unavailable. Theoretically, when this mixed membrane comes into contact with an aqueous medium, the hydrophilic polysaccharide component uniformly dispersed within the membrane will rapidly absorb water and swell, generating numerous micropores and cracks within the continuous hydrophobic polymer membrane. This will severely damage the membrane's barrier function before the pH reaches the dissolution threshold, leading to significant premature drug leakage. The expected release behavior cannot achieve the sequential response and precise controlled release specifically triggered by the colonic flora.

[0112] Example 2: The microcapsules, after a steady-state release period of approximately 0.5 to 1 hour, rapidly achieved a cumulative release rate of 95.3% within 4 hours, with the release curve exhibiting a clear time-delayed burst release characteristic. This process clearly demonstrates a sequential triggering mechanism based on the synergistic effect of permeability and enzymatic degradation. Upon reaching the colonic region, the outer pH-dependent enteric layer swells under the local pH environment, forming pores that allow colonic microbial enzyme molecules to permeate. The permeated enzyme molecules then enzymatically degrade the inner microbial layer, triggering degradation. After the inner layer structure disintegrates, the drug in the capsule core is released in a concentrated manner. The swelling process of the outer pH-dependent enteric layer and the enzymatic degradation process of the inner layer overlap in time but are functionally independent, forming two sequential defense lines, such as... Figure 3 The image shown is a SEM image of the microparticles from Example 2.

[0113] Through the above comparative experiments, Example 2 of the present invention significantly improves the reliability of colon-targeted therapy under pathological conditions compared to the two comparative examples. Comparative Examples 1 and 2, under simulated low-pH pathological conditions, exhibit severe drug leakage, leading to treatment failure or systemic side effects. Example 2, however, provides a second, pH-independent safety lock through a physically isolated microbial triggering inner layer. Even if the outer layer fails, the drug remains firmly locked in, a feat unattainable by existing technologies.

[0114] Example 2 of this invention achieves truly microbial-triggered sequential drug release compared to the two comparative examples. Comparative Example 2, by incorporating polysaccharides into the outer layer, not only failed to utilize the microbial community but also disrupted the integrity of the outer membrane, producing negative effects. In stark contrast, Example 2, through a layered design, successfully achieved for the first time a sequential response of outer layer isolation and inner layer enzymatic hydrolysis on a traditional Chinese medicine compound microgranule. Its drug release behavior highly specifically depends on the characteristic colonic microbiota, producing an unexpectedly precise, time-delayed burst release regulation effect.

[0115] in addition, Figure 4 Comparing Example 2 of the present invention with Comparative Example 1, the intermediate release curve of Example 2 showed a significant time-delayed burst release characteristic under conditions containing microbial flora, with a release rate of 95.3% after 4 hours; while under sterile conditions, only 12.3% was released after 24 hours, confirming the effectiveness of the inner microbial flora-triggered degradation layer as an independent barrier. Comparative Example 1 showed rapid release at pH 6.8, reaching 91.5% after 4 hours, but lacked colon-targeting specificity.

[0116] Example 4

[0117] This embodiment evaluates the antidiarrheal effect of the Xianglian micro-pills of the present invention by establishing a classic mouse diarrhea model.

[0118] 1. Laboratory animals and grouping

[0119] Fifty healthy male Kunming mice, weighing 18-22 grams, were randomly divided into 5 groups of 10 mice each:

[0120] Blank control group, model control group, positive drug control group (administered berberine hydrochloride, dose 100 mg / kg), low-dose group of microcapsules of the present invention (calculated as berberine hydrochloride, dose 50 mg / kg), and high-dose group of microcapsules of the present invention (calculated as berberine hydrochloride, dose 100 mg / kg).

[0121] 2. Modeling and Drug Administration

[0122] Mice in each group were fasted for 12 hours beforehand, but had free access to water. Except for the blank control group, all other groups were administered senna leaf decoction (0.3 g / mL based on the amount of raw drug) by gavage at a volume of 0.2 mL / 10 g body weight to establish a diarrhea model.

[0123] Preparation method of senna leaf decoction: Take an appropriate amount of coarse senna leaf powder (passed through a 20-mesh sieve), add 10 times the volume (volume / weight) of purified water, and soak at room temperature for 30 minutes. After soaking, heat to a gentle boil, maintain the temperature at 98-100℃, and decoct for 30 minutes (start timing after boiling). Filter while hot through a 200-mesh nylon sieve and collect the filtrate. Add 8 times the volume of purified water to the residue, heat to a gentle boil again, and decoct for 20 minutes, then filter. Combine the two filtrates and concentrate under reduced pressure in a 60℃ water bath to a concentration of 0.3 grams of crude drug per milliliter. Cool to room temperature to obtain the decoction. This decoction should be prepared immediately before use. If not used immediately, it should be stored at 2-8℃ and used within 12 hours to ensure the stability of the anthraquinone active ingredient content.

[0124] One hour before modeling, each treatment group was given the corresponding test substance by gavage, while the blank group and model group were given an equal volume of purified water.

[0125] 3. Observations and Results

[0126] After gavage administration of senna leaves, mice were immediately placed individually in cages lined with filter paper, with the filter paper changed hourly. Observations were conducted for 6 consecutive hours, recording the time of first diarrhea, frequency of diarrhea, and stool grade for each mouse, and the diarrhea index was calculated. Diarrhea index = loose stool rate × average loose stool grade. Results are shown in Table 1:

[0127] Table 1

[0128] Blank control group —— No diarrhea 0±0 0±0 Model control group —— 65.2±11.3 8.8±1.9 14.5±3.2 Positive drug control group 100 158.6±28.7 3.4±1.1 4.8±1.5 Low-dose microparticle group of the present invention 50 132.4±20.5 4.7±1.5 7.2±2.1 High-dose microparticle group of the present invention 100 189.5±35.2 2.5±0.8 3.1±1.0

[0129] Compared with the model control group, P<0.01; compared with the positive drug control group, P<0.01.

[0130] 4. Experimental Conclusions

[0131] The results showed that, compared with the model control group, the Xianglian micro-pills of the present invention significantly delayed the onset of diarrhea and reduced the total number of diarrhea episodes and the diarrhea index, exhibiting a clear dose-dependent relationship. In particular, the high-dose group showed a significantly better antidiarrheal effect than an equivalent dose of pure berberine hydrochloride raw material. This demonstrates that, through colon-targeted delivery, the effective components of Aucklandia lappa and Coptis chinensis achieve synergistic effects at the lesion site, thus possessing excellent antidiarrheal function.

[0132] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a Xianglian preparation for treating diarrhea, characterized in that, Includes the following steps: The volatile oil of Costus root was extracted and encapsulated with β-cyclodextrin to obtain the Costus root volatile oil β-cyclodextrin inclusion complex; Coptis chinensis and the Costus root residue after volatile oil extraction were extracted to obtain a clear extract; the clear extract, microcrystalline cellulose, lactose, mannitol and the Costus root volatile oil β-cyclodextrin inclusion complex were mixed and pellet cores were prepared by extrusion and spheronization. A microbial degradation-triggered layer is coated around the drug-loaded pellet core; A pH-dependent enteric layer is coated around the microbial community-triggered degradation layer; The preparation of drug-loaded pellet cores.

2. The preparation method according to claim 1, characterized in that, The coating microbial community-triggered degradation layer is produced by bottom spraying in a fluidized bed. The coating solution contains konjac glucomannan, chitosan, triethyl citrate, and an acidic aqueous solution containing 1%–2% acetic acid.

3. The preparation method according to claim 1, characterized in that, The pH-dependent enteric coating was applied using a fluidized bed bottom spray method. The coating solution contained Eudragit S100, triethyl citrate, talc, and a 1:1 volume ratio of isopropanol to acetone. The coating endpoint was controlled by real-time monitoring of the film thickness using online near-infrared spectroscopy.

4. A medicament for treating diarrhea prepared by the method according to any one of claims 1-3, characterized in that, It includes a drug-loaded pellet core, a microbial-triggered degradation layer covering the drug-loaded pellet core, and a pH-dependent enteric layer covering the microbial-triggered degradation layer.

5. The Xianglian preparation according to claim 4, characterized in that, The drug-loaded pellet core contains a β-cyclodextrin inclusion complex of costus root volatile oil, an extract of Coptis chinensis and costus root residue, and microcrystalline cellulose, lactose, mannitol and β-cyclodextrin as excipients.

6. The Xianglian preparation according to claim 4, characterized in that, The microbial-triggered degradation layer contains konjac glucomannan and chitosan.

7. The Xianglian preparation according to claim 4, characterized in that, The pH-dependent enteric layer contains Eudragit S100 as the enteric material.

8. The Xianglian preparation according to claim 4, characterized in that, The microbial community-triggered degradation layer has a weight gain of 5% to 8% relative to the drug-loaded pellet core.

9. The Xianglian preparation according to claim 4, characterized in that, The pH-dependent enteric coating layer accounts for 16% to 18% of the total weight of the pellet core and the microbial-triggered degradation layer.

10. The Xianglian preparation according to claim 4, characterized in that, The microbial community-triggered degradation layer and the pH-dependent enteric layer are physically isolated independent layered structures.

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