Abstract:
Provided is a method for preparation of a sustained released pharmaceutical composition, wherein an active ingredient and a cellulose derivative dissolved in a lower alkyl alcohol solvent are processed with granulation such that the PEO does not need to be processed with granulation or sizing to achieve uniform drug distribution. Besides, the specific range of the viscosity of the cellulose derivate provides better uniformity to the sustained release pharmaceutical composition derived from the above preparation method.

Description:
CROSS REFERENCE 
       [0001]    This application claims priority to Taiwan Patent Application Serial No.104118277, filed on Jun. 5, 2015, the content of which is hereby incorporated by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
       [0002]    The present invention relates to a pharmaceutical composition, particularly to a sustained release pharmaceutical composition; the present invention also relates to a method for preparation of the above pharmaceutical composition, particular to a preparation method to obtain the sustained release pharmaceutical composition without granulating or sizing the polyalkylene oxide. 
       2. Description of the Prior Arts 
       [0003]    Drug release of sustained release oral dosage form is often affected by the food in the gastrointestinal tract, such that the dosage form is difficult to maintain and the release rate is unstable. The retention capacity of the dosage form in the gastrointestinal tract is poor, such that the drug is mostly released in the upper gastrointestinal tract, including the stomach and the small intestine, and shortening the drug absorption time. 
         [0004]    In view of this, Taiwan patent number 393320 discloses an oral hydrogel controlled release pharmaceutical tablet, wherein polyethylene oxide (PEO) is used as high molecular of hydrogel-forming base and then together with suitable hydrophilic base, such as polyethylene glycol (PEG). The tablet would completely gelatinize during its staying in the stomach and the small intestine of the upper gastrointestinal tract. The colloidal PEO has great plasticity after gelation, and the surface erosion rate of the dosage form is moderate and less susceptible to the impact of the food, thereby stably releasing the drug. When the dosage form is moved downward to the lower gastrointestinal tract, the active ingredient of the dosage form still can be released in the colon. However, in the preparation of the above mentioned patent, the active ingredient, the hydrophilic base and hydrogel-forming base are usually directly mixed and then proceed tableting (direct tableting), or the ingredients are directly mixed and then tableted after wet/dry granulation. In some embodiments, the active ingredient and portions of hydrophilic base and hydrogel-forming base are dissolved in alcohol solvent or its mixture with water, and the solution is sprayed and dried to obtain a spray-dried product. The spray-dried product is further mixed with the remaining hydrophilic base and hydrogel-forming base for tableting. The steps of direct tableting and wet/dry granulation described above is not suitable for tableting due to the poor fluidity of the powder after mixing and granulating, and the uniformity of drug content would be obviously diminished while preparing the pharmaceutical composition containing a low dose of active ingredient. Besides, the manufacture steps of producing the spray-dried product then mixing and tableting are too complicated and time consuming. 
         [0005]    Taiwan issued patent number I307632 further improves the oral hydrogel controlled release pharmaceutical tablet and the process thereof provided by Taiwan issued patent number 393320. The invention of patent I307632 also uses the PEO as hydrogel-forming base. In order to solve the problem of unequal distribution of particle sizes, non-uniformity of drug content and poor powder fluidity after mixing and granulation in the patent number 393320, the active ingredient and the hydrophilic base are dispersed and dissolved in the water to form a suspension, and then the PEO powder undergoes a sizing process by spraying the suspension on it. During the process of sizing, the hydrophilic base is used as sizing agent. Although the spraying and sizing process in the patent number 1307632 improves the disadvantages of non-uniformity of drug content and poor PEO powder fluidity after granulation, the condition of granulation and sizing are difficult to control due to the physicochemical properties of PEO. It requires tedious attempts to find the suitable condition of granulation and sizing. It also means that the granulation and sizing of PEO needs more sophisticated regulation during the stage of mass production. The disadvantages of Taiwan patent number 1307632 are that the spraying and sizing process needs to control many factors including the amount of the suspension containing the active ingredient, the spraying time and the spraying temperature, the drying time and the drying temperature, and the frequency of the vibration, etc. The manufacture is complicated and the equipment for spraying and sizing (such as fluidized bed granulator) is expensive and needs large space, the equipment is hard to clean after the process due to high viscosity of PEO, thereby being unfavorable for large scale preparation. 
         [0006]    European patent number EP 1205190 teaches that PEO as the component of the sustained release base drug would accelerate dissolution after exposure to light, leading to increased release rate of the active ingredient and changes of release profile. Furthermore, the side chain of the PEO contains a lot of ether bond such that PEO is easily degraded due to the oxygen attack, and heavy metal ions, oxidants and ultraviolet will accelerate the oxidative degradation process. As a result, the pharmaceutical composition using PEO as sustained release base can achieve sustained release effect, but PEO is expensive and the physicochemical properties of PEO is unstable and susceptible to oxidation, thereby increasing risk factors to the stability and storage of the drug. 
       SUMMARY OF THE INVENTION 
       [0007]    In view of the disadvantages of poor fluidity, unequal distribution of particle sizes, non-uniformity of drug content, complicated manufacture process, high time consumption, and cleaning difficulty of the equipment in the prior arts, the objective of the present invention is to provide a method for preparation of a sustained release pharmaceutical composition, comprising granulating the active ingredient and the cellulose derivative with a lower alkyl alcohol solvent, and then the PEO does not need to process granulation or sizing to achieve uniformity of drug content. 
         [0008]    To achieve the above purpose of the present invention, the objective of the invention is to provide a method for preparation of a sustained release pharmaceutical composition, comprising steps of: mixing and granulating an active ingredient, a lower alkyl alcohol solvent having a concentration not lower than 80% (w/v) and a cellulose derivate to obtain multiple granulated powders; drying the multiple granulated powders to remove the lower alkyl alcohol solvent; mixing the dried multiple granulated powders, polyalkylene oxide and a lubricant to form a mixture; compressing the mixture to obtain a sustained release pharmaceutical composition. 
         [0009]    Preferably, the active ingredient comprises an agent substance proposed to be formulated in a sustained release dosage form. 
         [0010]    Preferably, the active ingredient comprises an anti-benign prostatic hyperplasia (BPH) agent, an anti-urinary tract disease agent, an antihypertensive agent, an antipsychotic agent, an anti-inflammatory agent, an antipyretic agent, an analgesic agent, an anti-metabolic disorder agent, an anti-cardiovascular disease agent, an immunosuppressive agent, an anti-tumor agent, or any combination thereof 
         [0011]    Preferably, the active ingredient comprises tamsulosin, mirabegron, quetiapine, or a pharmaceutically acceptable salt thereof 
         [0012]    Preferably, in the step of mixing and granulating the active ingredient, the lower alkyl alcohol solvent having the concentration not lower than 80% (w/v) and the cellulose derivate, the active ingredient is dissolved in the lower alkyl alcohol solvent having the concentration not lower than 80% (w/v) followed by mixing and granulation with the cellulose derivate. 
         [0013]    Preferably, in the step of mixing and granulating the active ingredient, the lower alkyl alcohol solvent having the concentration not lower than 80% (w/v) and the cellulose derivate, the active ingredient is mixed with the cellulose derivate followed by granulating with the lower alkyl alcohol solvent having the concentration not lower than 80% (w/v). 
         [0014]    Preferably, the method after the step of compressing the mixture further includes film coating the compressed tablet. 
         [0015]    The “lower alkyl alcohol solvent having the concentration not lower than 80% (w/v)” refers to that the concentration of the lower alkyl alcohol solvent is from 80% (w/v) to 100% (w/v); preferably, the concentration of the lower alkyl alcohol solvent is from 90% (w/v) to 99.5% (w/v). 
         [0016]    Besides, the lower alkyl alcohol solvent includes, but is not limited to, methanol, ethanol, propanol, isopropanol, butanol, or any combination thereof. 
         [0017]    In the method for preparation of the present invention, the amount of the lower alkyl alcohol solvent is adjusted depending on the amount of powder for granulation during the step of mixing and granulating the active ingredient, the lower alkyl alcohol solvent having the concentration not lower than 80% (w/v) and the cellulose derivate; preferably, the weight ratio of the lower alkyl alcohol solvent and the powder for granulation is from 1:100 to 100:1. More preferably, the weight ratio of the lower alkyl alcohol solvent and the powder for granulation is from 1:10 to 10:1. Most preferably, the weight ratio of the lower alkyl alcohol solvent and the powder for granulation is from 1:5 to 5:1. 
         [0018]    Preferably, the cellulose derivate includes, but is not limited to, hydroxypropylcellulose (HPC), hypromellose (HPMC), methyl cellulose (MC), hydroxyethyl cellulose (HEC), ethyl cellulose (EC), or any combination thereof. 
         [0019]    Preferably, the cellulose derivate is hypromellose with a viscosity ranging from 50 millipascal seconds (mPa·s) to 100,000 mPa·s at 1% w/v, 20° C. 
         [0020]    Preferably, the polyalkylene oxide includes, but is not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), poly(propylene oxide-ethylene oxide), or any combination thereof. 
         [0021]    Preferably, the polyalkylene oxide is polyethylene oxide with a molecular weight ranging from 500,000dalton (Da) to 7,000,000 Da. 
         [0022]    Preferably, the method after the step of mixing and granulating the active ingredient, the lower alkyl alcohol solvent having the concentration not lower than 80% (w/v) and the cellulose derivate further comprises adding a solubilizer. 
         [0023]    More preferably, the solubilizer includes, but is not limited to, polyethylene glycol (PEG), docusate sodium, sodium lauryl sulfate, medium chain triglyceride, polyvinylpyrrolidone (PVP), xylitol, D-fructose, urea, acetylamine, polyoxyl 40 hydrogenated castor oil, polyoxyl 60 hydrogenated castor oil, poloxamer 407, benzoic acid, sodium benzoate, salicylic acid, sodium salicylate, or any combination thereof. 
         [0024]    In another aspect, the present invention relates to a sustained release pharmaceutical composition obtained from the above preparation method. 
         [0025]    In another aspect, the present invention relates to a sustained release pharmaceutical composition, which is made by uniformly mixing and tableting the ingredients consisting of an active ingredient; a cellulose derivate having viscosity from 50 mPa·s to 100,000 mPa·s and being hard to dissolve in a lower alkyl alcohol solvent having the concentration not lower than 80% (w/v); the lower alkyl alcohol solvent having the concentration not lower than 80% (w/v) in an amount of less than 5% in weight (wt %) based on the total weight of the sustained release pharmaceutical composition, wherein the lower alkyl alcohol solvent is used for mixing and granulating with the active ingredient and the cellulose derivate to obtain powder particles without agglomerating; a polyalkylene oxide having an average molecular weight above 500,000 Da; and a lubricant. 
         [0026]    Preferably, the polyalkylene oxide is un-granulated or un-sized. 
         [0027]    Preferably, the ratio of the cellulose derivate and the polyalkylene oxide of the sustained release pharmaceutical composition is from 1:100 to 100:1; more preferably, the ratio is from 1:10 to 10:1; most preferably, the ratio is from 1:5 to 5:1. 
         [0028]    Preferably, based on the total weight percent (wt %) of the sustained release pharmaceutical composition as mentioned above, the weight percent of the active ingredient is from 0.01 wt % to 25 wt %; the weight percent of the cellulose derivate having the viscosity from 50 mPa·s to 100,000 mPa·s is from 1 wt % to 50 wt %; the weight percent of the lower alkyl alcohol solvent having the concentration not lower than 80% (w/v) is from 0 wt % to 5 wt %; the weight percent of the polyalkylene oxide having an average molecular weight above 500,000 Da is from 30 wt % to 95 wt %; and the weight percent of the lubricant is from 0.1 wt % to 5 wt %; wherein the cellulose derivate is hard to dissolve in the lower alkyl alcohol solvent having the concentration not lower than 80% (w/v); wherein the lower alkyl alcohol solvent is used for mixing and granulating with the active ingredient and the cellulose derivate to obtain the powder particles without agglomerating. 
         [0029]    More preferably, the weight percent of the lower alkyl alcohol solvent having the concentration not lower than 80% (w/v) in the sustained release pharmaceutical composition is from 0 wt % to 2 wt %; most preferably, the weight percent is from 0 wt % to 1 wt %. 
         [0030]    More preferably, the sustained release pharmaceutical composition further comprises a solubilizer, which the weight percent is from 0 wt % to 10 wt %. 
         [0031]    As HPMC is hard to dissolve in the high concentration alcohol solvent, the method of spraying granulation will be chosen when having the active ingredient dissolved in the alcohol solvent followed by granulating with HPMC in the prior arts, rather than mixing and granulating the drug containing alcohol solvent and the HPMC powder directly as the present invention. The preparation method of the present invention can avoid time, space, and cost required for spraying granulation. Besides, the specific range of the viscosity of the cellulose derivate of the present invention provides better uniformity of the drug content to the sustained release pharmaceutical composition. 
         [0032]    Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]      FIG. 1  shows a line chart of dissolution rates of the tablets of the preparations A, B, E and F made by a preparation method of the present invention at 0 hour, 3 hours, 6 hours, 8 hours and 10 hours. 
           [0034]      FIG. 2  shows a line chart of dissolution rates of the tablets of the preparations C and D made by the preparation method of the present invention at 0 hour, 3 hours, 6 hours, 8 hours and 10 hours. 
           [0035]      FIG. 3  shows a line chart of dissolution rates of the tablets of the preparations A and C made by the preparation method of the present invention at 0 hour, 3 hours, 6 hours, 8 hours and 10 hours. 
           [0036]      FIG. 4  shows a line chart of dissolution rates of the tablet of the preparation A at 0 hour to 24 hours after storage for 0 month or 3 months. 
           [0037]      FIG. 5  shows a line chart of dissolution rates of the tablet of the preparation E at 0 hour to 24 hours after storage for 0 month or 3 months. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]    Preparation of 1,000 Units of Sustained Release Dosage Form 
         [0000]    
       
         
               
             
               
               
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Formulations [unit: gram (g)] 
               
             
          
           
               
                   
                 Hypromellose 
                 Hypromellose 
                 Hypromellose 
               
               
                   
                 50 
                 4000 
                 100000 
               
             
          
           
               
                 Preparation 
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
               
               
                   
               
             
          
           
               
                 Tamsulosin HCl 
                 0.4 
                 0.4 
                 0.4 
                 0.4 
                 0.4 
                 0.4 
               
               
                 PEG 6000 
                 4 
                 4 
                 4 
                 4 
                 4 
                 4 
               
               
                 Hypromellose 
                 45 
                 45 
                 140.5 
                 140.5 
                 45 
                 45 
               
               
                 POLYOX ™ 
                 191 
                 141 
                 95.5 
                 95.5 
                 191 
                 141 
               
               
                 WSR 303 
               
               
                 Magnesium 
                 4.6 
                 4.6 
                 4.6 
                 4.6 
                 4.6 
                 4.6 
               
               
                 stearate 
                   
               
               
                 Total weight 
                 245 
                 195 
                 245 
                 245 
                 245 
                 195 
               
               
                   
               
             
          
         
       
     
         [0039]    As shown in Table 1, tamsulosin hydrochloride (HCl) and PEG 6000 were dissolved in the proper amount of 95% ethanol to prepare an active ingredient-containing ethanol solution. The active ingredient-containing ethanol solution was mixed with HPMC with different viscosities, respectively Hypromellose 50 (manufacturer: Shin-Etsu Chemical Co., Ltd., category: Metolose® 60SH Grades 60SH-50) with the viscosity of 50 millipascal seconds (mPa·s), Hypromellose 4000 (manufacturer: The Dow Chemical Company, category: METHOCEL™ K4 m Premium Hydroxypropyl Methylcellulose ID34693) with the viscosity of 4,000 mPa·s and Hypromellose 100000 (manufacturer: Shin-Etsu Chemical Co., Ltd., category: Metolose® 90SH Grades 90SH-100000SR) with the viscosity of 100,000 mPa·s, and then was granulated by the granulator to obtain granular powder. The granular powder was dried by dryer at 65° C. to remove the ethanol, and then the dried granular powder was sieved through a proper sieve. Water-soluble polyethylene oxide (PEO) polymers such as POLYOX™ WSR 303(manufacturer: The Dow Chemical Company, category: POLYOX™ WSR 303-NF Grade), magnesium stearate and the dried granular powder after sieving were uniformly mixed to obtain a final mixture. The final mixture was compressed by tablet press into 195 milligrams (mg) or 245 mg of uncoated tablet (semi-finished). In the preferred embodiment, the uncoated tablet was further film coated. 
       EXAMPLE 1 
     Release Rate Test of the Sustained Release Dosage Form 
       [0040]    The tablets of preparations A, B, C, D, E and F were undergone a dissolution test in a dissolution apparatus [United States Pharmacopeia (USP) Apparatus II] at 100 rpm, using 500 milliliters (mL) of 0.1N hydrochloride. Each tablet was tested for the dissolution rates at 0 hour, 3 hours, 6 hours, 8 hours and 10 hours, and the test result was as shown in table 2,  FIG. 1 ,  FIG. 2  and  FIG. 3 . 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Release rate of sustained release dosage form 
               
             
          
           
               
                   
                 Prepa- 
                 Prepa- 
                 Prepa- 
                 Prepa- 
                 Prepa- 
                 Prepa- 
               
               
                 Time 
                 ration 
                 ration 
                 ration 
                 ration 
                 ration 
                 ration 
               
               
                 (hr) 
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
               
               
                   
               
             
          
           
               
                 0 
                 0.00% 
                 0.00% 
                 0.00% 
                 0.00% 
                 0.00% 
                 0.00% 
               
               
                 3 
                 30.97% 
                 39.27% 
                 36.70% 
                 27.86% 
                 26.13% 
                 35.44% 
               
               
                 6 
                 59.72% 
                 66.08% 
                 63.77% 
                 48.27% 
                 47.24% 
                 58.27% 
               
               
                 8 
                 75.35% 
                 79.53% 
                 78.68% 
                 58.27% 
                 60.81% 
                 70.93% 
               
               
                 10 
                 88.58% 
                 90.51% 
                 88.54% 
                 67.83% 
                 71.42% 
                 81.26% 
               
               
                   
               
             
          
         
       
     
         [0041]    As shown in  FIG. 1 , the ratio of each ingredient of the preparations A and E of the present invention was the same, but the viscosity of preparation A using Hypromellose 50 was lower than the viscosity of preparation E using Hypromellose 100000 such that the release rate of preparation A was faster than preparation E at the same time point. Similarly, the comparison of the release rate between the preparations B and F, preparations C and D (as shown in  FIG. 2 ) also had the same result. As above mentioned, the release rate was slower while the viscosity of the cellulose derivation used was higher. Therefore, the release rate can be controlled by selecting a high or low viscosity of the cellulose derivation. 
         [0042]    Furthermore, as shown in  FIG. 1 , the release rate of the preparation A of the present invention was lower than the preparation B because the content of POLYOX™ WSR 303 of the preparation A was higher than the preparation B. It also means that under the same ingredients of each preparation, the content of the polyalkylene oxide was higher, and the release rate was slower. However, upon further observation of the preparation C in  FIG. 3 , if the total weight of the tablet was 245 mg, same as preparation A, with different ratios of the cellulose derivation and polyalkylene oxide (such as increasing the content of Hypromellose 50 and lowering the content of POLYOX™ WSR 303), the release rate of preparation C can be nearly the same as preparation A. As a result, the composition of the present invention can increase the ratio of the cellulose derivation for decreasing the use of the polyalkylene oxide, thereby decreasing the uncertain factors and the preparation method inconvenience derived from the polyalkylene oxide. 
       EXAMPLE 2 
     Powder Particle Size Distribution and Fluidity Analysis 
       [0043]    1. Particle size distribution: the final mixtures of preparations A and E obtained from the preparation method were respectively and randomly sampled and quantitated, and the final mixtures were placed into a digital sieve shaker (manufacturer: Endecotts LTD., category: Octagon Digital) and shaken for 20 minutes with a frequency of 3600 vibrations per minute and the amplitude of mode 5. The preparations A and E were observed for retention status in various sieve meshes with different pore size. 
         [0044]    2. Angle of repose: the final mixtures of preparations A and E after quantitation were respectively and naturally fallen on the measurement platform by continuous vibration through a powder characteristics tester (manufacturer: Tsutsui Scientific, category: ABD-100), and the biggest angle was measured between the horizontal surface and the free surface of the powder on the platform forming a cone-shaped pile under static balance. The preferred angle of repose was below 40°, the smaller the angle of repose, the smaller the friction and the better the fluidity. 
         [0045]    3. Bulk density: the final mixtures of preparations A and E after quantitation were respectively and left naturally falling into a container with an internal volume of 100 mL by continuous vibration through a powder characteristics tester, and the density was measured after the powder naturally filled the container. 
         [0046]    4. Tap density: the final mixtures of preparations A and E after quantitation were respectively placed into a container with an internal volume of 100 mL and the powder-loaded container was continuously vibrated through a powder characteristics tester to condense the powder, and the density was measured under the compact powder. 
         [0047]    5. Compressibility: based on the above bulk density and tap density, the compressibility was calculated by the following formula (I). The preferred compressibility was equal to or smaller than 20%, the smaller the compressibility, the better the powder fluidity. 
         [0000]      Compressibility (%)=(Tap density−Bulk density)/Tap density×100   Formula (I)
 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
               
             
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 The fluidity test result 
               
               
                 The fluidity test of the final mixtures 
               
             
          
           
               
                   
                 Preparation A 
                 Preparation E 
               
               
                   
                   
               
             
          
           
               
                 Particle size 
                 75 μm to 425 μm 
                   79% 
                 80.3% 
               
               
                 distribution (%) 
                 &lt;75 μm 
                 20.4% 
                   19% 
               
             
          
           
               
                 Angle of repose (°) 
                 37.0 
                 36.2 
               
               
                 Bulk density (mL/g) 
                 0.356 
                 0.356 
               
               
                 Tap density (mL/g) 
                 0.444 
                 0.434 
               
               
                 Compressibility (%) 
                 19.81 
                 17.19 
               
               
                   
               
             
          
         
       
     
         [0048]    As shown in table 3, 80% of the particle size of the final mixtures of the preparations A and E of the present invention distributed in the range from 75 micrometers (μm) to 425 μm and the particle size smaller than 75 μm was less than 20%. Therefore, the preparations A and E had little adhesion and scattering during the tableting process. 
         [0049]    Besides, as shown in table 3, the angles of repose of the final mixtures of preparations A and E of the present invention were equal to or less than 37° and the compressibility was smaller than 20% such that the final mixtures of preparations A and E of the present invention have great powder fluidity. Furthermore, also as shown in table 3, although the viscosities of the cellulose derivatives used by the preparations A and E were different, the powder fluidities of the final mixtures do not decrease. The reason was that the preparation method of the present invention uses high concentration of alcohol solvent and cellulose derivate to granulation, and the granulation process does not produce the same sticky particle agglomerates as granulated by water but form fluffy powder because the cellulose derivate was hard to dissolve in the high concentration alcohol. Even high viscosity of cellulose derivate is used, the powder still can maintain great fluidity. 
       EXAMPLE 3 
     Uniformity Test of Drug Content 
       [0050]    The final mixtures of preparations A and E obtained from the preparation method were respectively and randomly sampled for 245 mg to process the active ingredient content analysis to determine the uniformity of the active ingredient content between intermediate (the final mixtures) and semi-finished product (uncoated tablets) during preparation. The sample analysis result as shown in table 4 was based on the active ingredient content of a single unit of a tablet. 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 Uniformity result of each sample and its uncoated tablet 
               
               
                 Content of active ingredient (unit: %) 
               
             
          
           
               
                   
                 Preparation A 
                 Preparation E 
               
               
                   
                   
               
             
          
           
               
                   
                 Final mixture 
                 101.72% 
                 102.12% 
               
               
                   
                   
                 RSD: 0.61% 
                 RSD: 0.86% 
               
               
                   
                 Uncoated tablet 
                 101.20% 
                 103.23% 
               
               
                   
                   
                 RSD: 0.77% 
                 RSD: 0.80% 
               
               
                   
                   
               
             
          
         
       
     
         [0051]    As shown in table 4, the drug contents of the final mixtures (intermediate) and uncoated tablets (semi-finished product) of preparations A and E obtained from the preparation method fell within the narrow range of 90% to 110% and had the relative standard deviation (RSD) less than 3%, meaning that the content uniformity of each preparation of the present invention was significantly better than the USP criteria, having the limits of 85% to 115% and the RSD less than 6%. Based on the above data, we can infer that in the preparation method of the present invention, even the polyalkylene oxide with high viscosity and poor fluidity does not be processed with sizing or granulating, the drug can also be uniformly distributed, thereby solving the disadvantages of poor powder fluidity, being inappropriate for tableting, or poor uniform distribution of drug in the prior arts. 
       EXAMPLE 4 
     Stability Test 
       [0052]    1. Stability Test of the Active Ingredient 
         [0053]    The tablets obtained from the preparations A and E were placed in a chamber with constant temperature of 40±2° C. and humidity of 75±5% for 0, 1, 2 and 3 months, and the active ingredient content in the tablet was measured to determine the degradation thereof in the dosage form of the present invention under the above condition, and the result was as shown in table 5. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 Stability test result 
               
               
                 Content of active ingredient (unit: %) 
               
             
          
           
               
                 Time 
                   
                   
               
               
                 (month) 
                 Preparation A 
                 Preparation E 
               
               
                   
               
               
                 0 
                 101.20% 
                 103.23% 
               
               
                   
                 RSD: 0.77% 
                 RSD: 0.80%% 
               
               
                 1 
                 102.36% 
                 103.87% 
               
               
                   
                 RSD: 0.60% 
                 RSD: 1.01% 
               
               
                 2 
                 101.36% 
                 102.40% 
               
               
                   
                 RSD: 0.38% 
                 RSD: 0.86% 
               
               
                 3 
                 102.05% 
                 102.40% 
               
               
                   
                 RSD: 0.43% 
                 RSD: 0.91% 
               
               
                   
               
             
          
         
       
     
         [0054]    As shown in table 5, after being stored under high temperature and high humidity condition for 1 month to 3 months, the active ingredient in the tablets obtained the preparations A and E did not significantly degrade and the active ingredient content was still inside the standard range of 95% to 105%, demonstrating that the dosage form of the present invention has high stability. 
         [0055]    2. Dissolution Stability Test 
         [0056]    The tablets obtained from the preparations A and E were placed in a chamber with constant temperature of 40±2° C. and humidity of 75±5% for 0 or 3 months, and then were undergone a dissolution test in a dissolution apparatus [United States Pharmacopeia (USP) Apparatus II] at 100 rpm, using 500 mL of 0.1N HCl. Each tablet was tested for the dissolution rates at 0, 1, 2, 3, 6, 8, 10, 16, 20 and 24 hours, and the results were as shown in table 6,  FIG. 4  and  FIG. 5 . 
         [0000]    
       
         
               
             
               
               
               
               
               
             
               
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 6 
               
             
             
               
                   
               
               
                 Dissolution test result 
               
               
                 Dissolution rate of the active ingredient (unit: %) 
               
             
          
           
               
                   
                 Preparation A 
                   
                 Preparation E 
                   
               
             
          
           
               
                 Time 
                 Month(s) 
                   
               
             
          
           
               
                 Hour(s) 
                 0 
                 3 
                 0 
                 3 
               
               
                   
               
             
          
           
               
                 0 
                 0.00% 
                 0.00% 
                 0.00% 
                 0.00% 
               
               
                 1 
                 12.03% 
                 12.02% 
                 10.70% 
                 9.43% 
               
               
                 2 
                 21.54% 
                 21.17% 
                 18.56% 
                 16.83% 
               
               
                 3 
                 30.97% 
                 29.77% 
                 26.13% 
                 24.46% 
               
               
                 6 
                 59.72% 
                 59.76% 
                 47.24% 
                 46.24% 
               
               
                 8 
                 75.35% 
                 75.51% 
                 60.81% 
                 58.54% 
               
               
                 10 
                 88.58% 
                 87.06% 
                 71.42% 
                 68.80% 
               
               
                 16 
                 101.72% 
                 98.79% 
                 94.61% 
                 90.80% 
               
               
                 20 
                 102.64% 
                 99.19% 
                 98.69% 
                 97.52% 
               
               
                 24 
                 103.48% 
                 99.93% 
                 102.24% 
                 99.16% 
               
               
                   
               
             
          
         
       
     
         [0057]    According to the dissolution rate of each time point shown in table 6, we can know that the tablet of preparations A and E of the present invention can continuously release the drug contents for 16 hours to 24 hours. As shown in  FIG. 4  and  FIG. 5 , even the tablets of preparations A and E were treated with high temperature and high humidity for 3 months, the dissolution rates thereof were found no significant difference with the untreated group (0 hour). The treated tablets still can exhibit the desired release profile. Therefore, the dosage form of the present invention has high stability. 
         [0058]    Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.