Abstract:
The present invention relates to pharmaceutical compositions of 5-HT 1  agonist. More particularly, the present invention relates to uncoated tablets of sumatriptan succinate. The present invention also relates to a process for the preparation of uncoated tablets of sumatriptan succinate.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to pharmaceutical compositions of 5-HT 1  agonist. More particularly, the present invention relates to uncoated tablets of sumatriptan succinate.  
         [0002]     The present invention also relates to a process for the preparation of uncoated tablets of sumatriptan succinate.  
       BACKGROUND OF THE INVENTION  
       [0003]     Sumatriptan and its acid salts, particularly the succinate salt, are selective 5-hydroxytryptamine-1 agonists. It is indicated for the acute treatment of migraine attacks with or without aura in adults. Chemically, Sumatriptan is 3-[2-(dimethylamino)ethyl]-N-methyl-indole-5-methanesulfonamide and is marketed as its succinate salt under the trade name IMITREX® in US and IMIGRAN® IN Europe. Sumatriptan and its succinate salt is disclosed specifically in U.S. Pat. No. 5,037,845.  
         [0004]     Sumatriptan and its pharmaceutically acceptable salts have an unpleasant taste profile and, when administered orally, may intensify the nausea and vomiting associated with migraines. This limits the use of sumatriptan orally, which is considered to be the most widely accepted and convenient route of administration.  
         [0005]     U.S. Pat. No. 5,863,559 discloses film-coated tablets of sumatriptan. The core is substantially covered with a coating that includes film-forming polymers, such as hydroxypropylmethylcellulose, hydroxypropylcellulose or methylcellulose, and copolymers of methacrylic acid and methyl methacrylate polymers.  
         [0006]     WO 01/37816 discloses a process for the coating of sumatriptan tablet cores and tablets to provide taste masking of the sumatriptan. The process includes spraying a coating solution or suspension of a sugar, a starch, or a mixture of a sugar and a starch, onto tablet cores to obtain coated tablets. There is the proviso that film-forming agents in the suspension or solution are excluded.  
         [0007]     WO 2004/009085 discloses uncoated, taste-masked sumatriptan tablet comprising: an intragranular portion comprising granules of sumatriptan or a pharmaceutically acceptable salt and one or more diluents and/or binders present in a sufficient amount to cause taste-masking of the sumatriptan or pharmaceutically acceptable salt; and an extragranular portion comprising one or more pharmaceutically acceptable excipients around the intragranular granules. This publication further discloses wax polishing of sumatriptan tablet. The wax polishing includes spraying a solution or suspension of wax material onto the tablet and/or sprinkling a powder grade wax onto the tablet.  
         [0008]     The wax coating is primarily a hydrophobic layer, which can inhibit the penetration of the fluids into the tablet cores and release the content in to the medium for absorption. Further, it is a tedious process to control the amount of solution or suspension of sprayed onto the tablets, which may result in non-uniform release of the drug. Non-uniform release of the active ingredient may create bioavailability related problems. Hence, there exists a need to develop uncoated tablets, which have better advantages over the coated tablets.  
         [0009]     WO 2005/70417 discloses a taste masking pharmaceutical composition for oral administration, comprising a core of active ingredient and one or more outer non-active taste masking layers formed on the core by application of pressure.  
         [0010]     Film-forming agents are usually polymers, which form a continuous, elastic and uniform covering around the tablet core, which is at least partially detachable as a continuous layer. Such a film in a film-coated tablet, however, may provide a considerable barrier to the penetration of aqueous fluids into the tablet cores, which is a pre-requisite for disintegration of the tablet core and release of the pharmaceutically active compound. Insufficient release of the pharmaceutically active compound may create bioavailability problems. Examination and control of such thin layers is difficult affording special and complex, but non-specific, testing methods. Varying film thickness in different film-coated tablets within the same batch may not be excluded.  
         [0011]     In the prior art, a coating over the core tablet has been used to mask the bitter taste of sumatriptan. Though the coating may mask the unpleasant taste, if the thickness and composition of the coating is not properly controlled it may affect the disintegration and dissolution characteristics of the tablet. Further, the coating operation is a highly controlled and costly process. Hence, there exists need to develop uncoated tablets, which have better advantages over the coated tablets.  
       OBJECTIVE OF THE INVENTION  
       [0012]     Accordingly, the main objective of present invention is to provide uncoated tablet of sumatriptan in such a way that it will comply with the reference product in terms of in vivo parameters like bioequivalence and in vitro parameters like dissolution, disintegration and etc.  
         [0013]     Yet another objective of the present invention is to provide taste masked uncoated tablets of sumatriptan, thereby avoiding the costly coating process.  
         [0014]     Yet another objective of the present invention is to provide a process to prepare uncoated tablets of sumatriptan on a commercial scale with adequate hardness and good reproducibility.  
       SUMMARY OF THE INVENTION  
       [0015]     According to the main embodiment of the present invention, there is provided uncoated tablets of sumatriptan or its pharmaceutically acceptable salts, comprising intragranular portion containing sumatriptan and its pharmaceutically acceptable salts and optionally disintegrant and/or surfactant and an extragranular portion comprising diluent, an alkaline agent, disintegrant and lubricant.  
         [0016]     In yet another embodiment of the present invention, there is provided a process for the preparation of uncoated tablets of sumatriptan comprising the steps of granulating sumatriptan or a pharmaceutically acceptable salt with or without disintegrant and surfactant; mixing the granules with diluent, an alkaline agent, disintegrant, lubricant and finally compressing the mixed blend into a tablet.  
         [0017]     In yet another embodiment of the present invention, there is provided uncoated tablets of sumatriptan or its pharmaceutically acceptable salt free of binder and/or diluents in the intragranular portion. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]     The term pharmaceutically acceptable salts as used herein includes inorganic or organic acids such as hydrochloride, hydrobromide, sulphate, nitrate, phosphate, formate, mesylate, citrate, benzoate, fumarate, maleate, tartrate and succinate.  
         [0019]     In yet another embodiment, the uncoated tablets of sumatriptan further comprise one or more sweetening agents or colorants.  
         [0020]     The diluents used according to the present invention are selected from calcium phosphate-dibasic, calcium carbonate, cellulose-microcrystalline, cellulose powdered, calcium silicate, kaolin, starch, lactose, sucrose, starch pregelatinized, polyols such as mannitol, sorbitol, lactitol, xylitol, maltitol, sucrose and combinations thereof.  
         [0021]     Suitable disintegrants used in accordance with the present invention are selected from croscarmellose sodium, crospovidone, sodium starch glycolate, sodium carboxymethylcellulose, calcium carboxymethylcellulose, hydroxypropylcellulose, xanthan gum, alginic acid, alginates, carbopols and the like or combination thereof, preferably croscarmellose sodium, crospovidone, sodium starch glycolate.  
         [0022]     Suitable surfactants used in accordance with the present invention are selected from polyoxyethylene sorbitan fatty acid esters (polysorbates), sodium lauryl sulfate, docusate sodium and the like or combination thereof.  
         [0023]     Suitable lubricants according to the present invention are selected from talc, magnesium stearate, stearic acid, sodium stearyl fumarate, hydrogenated vegetable oil or glyceryl behenate, and suitable glidants include colloidal silicon dioxide or talc, preferably colloidal silicon dioxide.  
         [0024]     The alkaline agent used in the present invention is selected from carbonate or bicarbonates of potassium, sodium or calcium.  
         [0025]     Suitable sweeteners used are selected from glucose, glycerol, fructose, sucrose, lactose, maltose, sorbitol, xylitol, maltitol, erythritol, aspartame, prosweet and the like.  
         [0026]     In yet another embodiment of the present invention, there is provided a process for the preparation of uncoated tablets of sumatriptan or its pharmaceutically acceptable salts, comprising intragranular portion containing sumatriptan and its pharmaceutically acceptable salts and optionally disintegrant and/or surfactant and an extragranular portion comprising diluent, an alkaline agent, disintegrant and lubricant, comprising the steps of:  
         [0000]     i) dry blending sumatriptan with or without disintegrants and/or surfactant,  
         [0000]     ii) granulating the blend obtained in step (i) with a solvent,  
         [0000]     iii) mixing the granules of step (ii) with diluent, an alkaline agent, disintegrant, lubricant and  
         [0000]     iv) compressing the mixed blend into tablet.  
         [0027]     The solvents used for preparing granules can be an aqueous and/or non-aqueous solvent. The non-aqueous solvent selected from alcohol or isopropyl alcohol.  
         [0028]     The process described herein avoids coating step and thereby reduce the processing time and costs associated with coating. Moreover, absence of any coating over the tablets helps to achieve the desired disintegration and dissolution characteristics without failure.  
         [0029]     In yet another embodiment, there is provided a method of treating a human suffering from a migraine condition. The method includes orally administering an uncoated, tablet of sumatriptan that includes an intragranular portion and an extragranular portion. The intragranular portion includes granules of sumatriptan or a pharmaceutically acceptable salt and optionally disintegrant and surfactant. The extragranular portion includes diluent, an alkaline agent, disintegrant, lubricant around the intragranular granules.  
         [0030]     In yet another embodiment, the tablet contains about 10 mg to 200 mg of sumatriptan.  
         [0031]     The following examples further exemplify the inventions and are not intended to limit the scope of the inventions. It is obvious to those skilled in the art to find out the composition for other dosage forms and substitute the equivalent excipients as described in this specification or with the one known to the industry.  
       EXAMPLE 1 
       [0032]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                   
               
               
                   
               
               
                 Formulation of uncoated tablets of sumatriptan without using 
               
               
                 disintegrant or surfactant 
               
             
          
           
               
                   
                 Ingredients 
                 Quantity mg/tablet 
               
               
                   
                   
               
             
          
           
               
                   
                 Intra granular 
                   
               
               
                   
                 Sumatriptan succinate eq. to 
                 140.00 
               
               
                   
                 Sumatriptan 100 mg 
               
               
                   
                 Purified water 
                 Qs 
               
               
                   
                 Extra granular 
               
               
                   
                 Dicalcium phosphate 
                 117.00 
               
               
                   
                 Microcrystalline cellulose 
                 59.00 
               
               
                   
                 Sodium bicarbonate 
                 15.00 
               
               
                   
                 Croscarmellose sodium 
                 4.50 
               
               
                   
                 Magnesium stearate 
                 4.50 
               
               
                   
                 Average weight 
                 340.00 
               
               
                   
                   
               
             
          
         
       
     
         [0033]     The processing steps that are involved in making uncoated tablets of sumatriptan disclosed above are given below:— 
         [0000]     i) sumatriptan succinate was granulated using purified water to get a cohesive mass of desired consistency,  
         [0000]     ii) dried and sieved to obtain uniform particle size through a suitable mesh,  
         [0000]     iii) dried and sieved granules of step (ii) were mixed with extra granular dicalcium phosphate, microcrystalline cellulose, croscarmellose sodium, sodium bicarbonate and magnesium stearate through a suitable mesh and  
         [0000]     iv) compressed the blend of step (iii) into tablets.  
         [0034]     The processing steps that are involved in making uncoated tablets of sumatriptan disclosed in examples 2-7 are as given below:— 
         [0000]     i) sumatriptan succinate and full or part of disintegrant and/or surfactant were sifted and mixed.  
         [0000]     ii) the blend from step 1 was granulated using purified water and dried the granules,  
         [0000]     iii) dried granules of step (ii) were sieved through a suitable mesh to get uniform granules,  
         [0000]     iv) granules of step (iii) were mixed with extragranular ingredients and  
         [0000]     v) compressed the blend from step (iv) into tablets.  
       EXAMPLE 2 
       [0035]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                   
               
               
                   
               
               
                 Formulation of uncoated tablets of sumatriptan with disintegrant 
               
             
          
           
               
                   
                 Ingredients 
                 Quantity mg/tablet 
               
               
                   
                   
               
             
          
           
               
                   
                 Intra granular 
                   
               
               
                   
                 Sumatriptan succinate eq. to 
                 140.0 
               
               
                   
                 Sumatriptan 100 mg 
               
               
                   
                 Croscarmellose sodium 
                 20.00 
               
               
                   
                 Purified water 
                 Qs 
               
               
                   
                 Extra granular 
               
               
                   
                 Dicalcium phosphate 
                 112.00 
               
               
                   
                 Microcrystalline cellulose 
                 46.50 
               
               
                   
                 Sodium bicarbonate 
                 15.00 
               
               
                   
                 Croscarmellose sodium 
                 2.00 
               
               
                   
                 Magnesium stearate 
                 4.50 
               
               
                   
                 Average weight 
                 340.0 
               
               
                   
                   
               
             
          
         
       
     
       EXAMPLE 3 
       [0036]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                   
               
               
                   
                 Ingredients 
                 Quantity mg/tablet 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Intra granular 
                   
               
               
                   
                 Sumatriptan Succinate eq. to 
                 140.0 
               
               
                   
                 Sumatriptan 100 mg 
               
               
                   
                 Sodium starch Glycolate 
                 20.00 
               
               
                   
                 Purified water 
                 Qs 
               
               
                   
                 Extra granular 
               
               
                   
                 Dicalcium phosphate 
                 112.00 
               
               
                   
                 Microcrystalline cellulose 
                 46.50 
               
               
                   
                 Sodium bicarbonate 
                 15.00 
               
               
                   
                 Croscarmellose sodium 
                 2.00 
               
               
                   
                 Magnesium stearate 
                 4.50 
               
               
                   
                 Average weight 
                 340.0 
               
               
                   
                   
               
             
          
         
       
     
       EXAMPLE 4 
       [0037]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                   
               
               
                   
               
               
                 Formulation of uncoated tablets of Sumatriptan with disintegrating agent 
               
               
                 and surfactant 
               
             
          
           
               
                   
                 Ingredients 
                 Quantity mg/tablet 
               
               
                   
                   
               
             
          
           
               
                   
                 Intra granular 
                   
               
               
                   
                 Sumatriptan succinate eq. to 
                 140.00 
               
               
                   
                 Sumatriptan 100 mg 
               
               
                   
                 Croscarmellose sodium 
                 20.00 
               
               
                   
                 Polysorbate 80 
                 1.40 
               
               
                   
                 Purified water 
                 Qs 
               
               
                   
                 Extra granular 
               
               
                   
                 Dicalcium phosphate 
                 107.10 
               
               
                   
                 Microcrystalline cellulose 
                 45.00 
               
               
                   
                 Sodium bicarbonate 
                 20.00 
               
               
                   
                 Croscarmellose sodium 
                 2.00 
               
               
                   
                 Magnesium stearate 
                 4.50 
               
               
                   
                 Average weight 
                 340.00 
               
               
                   
                   
               
             
          
         
       
     
       EXAMPLE 5 
       [0038]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                   
               
               
                   
                 Ingredients 
                 Quantity mg/tablet 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Intra granular 
                   
               
               
                   
                 Sumatriptan Succinate eq. to 
                 140.00 
               
               
                   
                 Sumatriptan 100 mg 
               
               
                   
                 Croscarmellose sodium 
                 20.00 
               
               
                   
                 Sodium lauryl Sulphate 
                 1.40 
               
               
                   
                 Purified water 
                 Qs 
               
               
                   
                 Extra granular 
               
               
                   
                 Dicalcium phosphate 
                 107.10 
               
               
                   
                 Microcrystalline cellulose 
                 45.00 
               
               
                   
                 Sodium bicarbonate 
                 20.00 
               
               
                   
                 Croscarmellose sodium 
                 2.00 
               
               
                   
                 Magnesium stearate 
                 4.50 
               
               
                   
                 Average weight 
                 340.00 
               
               
                   
                   
               
             
          
         
       
     
       EXAMPLE 6 
       [0039]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                   
               
               
                   
               
               
                 Formulation of uncoated tablets of sumatriptan with surfactant 
               
             
          
           
               
                   
                 Ingredients 
                 Quantity mg/tablet 
               
               
                   
                   
               
             
          
           
               
                   
                 Intra granular 
                   
               
               
                   
                 Sumatriptan succinate eq. to 
                 140.00 
               
               
                   
                 Sumatriptan 100 mg 
               
               
                   
                 Polysorbate 80 
                 4.20 
               
               
                   
                 Purified water 
                 Qs 
               
               
                   
                 Extra granular 
               
               
                   
                 Dicalcium phosphate 
                 124.30 
               
               
                   
                 Microcrystalline cellulose 
                 45.00 
               
               
                   
                 Sodium bicarbonate 
                 20.00 
               
               
                   
                 Croscarmellose sodium 
                 2.00 
               
               
                   
                 Magnesium stearate 
                 4.50 
               
               
                   
                 Average weight 
                 340.00 
               
               
                   
                   
               
             
          
         
       
     
       EXAMPLE 7 
       [0040]                                                                      Ingredients   Quantity mg/tablet                                        Intra granular               Sumatriptan Succinate eq. to   140.00           Sumatriptan 100 mg           Docusate Sodium   4.20           Purified water   Qs           Extra granular           Dicalcium phosphate   124.30           Microcrystalline cellulose   45.00           Sodium bicarbonate   20.00           Croscarmellose sodium   2.00           Magnesium stearate   4.50           Average weight   340.00                        
 Dissolution Profile: 
 
         [0041]     The dissolution studies were performed in 900 ml of 0.01 M Hydrochloric acid, at 30 RPM by USP II method. The release profile (% of drug released in minutes) is given in table 1.  
                                                                                                       TABLE I                                       Time   % Drug release            S. No.   in min.   Ex 1   Ex 2   Ex 3   Ex 4   Ex 5   Ex 6   Ex 7                    1   5   87   93   89   90   85   82   88       2   10   90   94   92   99   90   88   90       3   15   93   94   94   99   92   90   91       4   30   94   94   94   99   93   91   91       5   45   95   95   95   99   96   93   94                  
 
         [0042]     The stability study of Sumatriptan Succinate tablets at accelerated stability condition 40° C./75% RH was studied for a period of three months with the formulation and the data shows that the tablets are stable and there is no sign of degradation.