Abstract:
The invention relates to a high dose oral formulation of bisphosphonates and to a process for the preparation of such formulations.

Description:
FIELD OF THE INVENTION 
     The invention relates to a pharmaceutical composition for oral application consisting of a high dose of bisphosphonates or pharmaceutically acceptable salts thereof as active substance and to a process for the preparation of such compositions. 
     BACKGROUND OF THE INVENTION 
     Aminoalkyl-1,1-diphosphonic acid derivatives (hereinafter called by the general term bisphosphonates) are important pharmaceutical agents in the treatment of bone diseases and some disturbances of calcium metabolism such as hyper-calcaemia, osteoporosis, tumor osteolysis, Paget&#39;s disease, etc. 
     Bisphosphonates as pharmaceutical agents are described, for example, in EP-A-170,228; EP-A-197,478; EP-A-22,751; EP-A-252,504; EP-A-252,505; EP-A-258,618; EP-A-350,002; EP-A-273,190; and WO-A-90/00798, each of which are incorporated herein by reference. 
     Pharmaceutical forms of currently marketed bisphosphonates are oral formulations (tablets or capsules) or solutions for intravenous injection or infusion. They are systemically well-tolerated when administered at therapeutic doses. However, bisphosphonates as a class are irritant to skin and mucous membranes, and when given orally on a continuous basis, may result in digestive tract side effects, e.g., esophageal adverse events or gastrointestinal disturbances. As a consequence, and due to their low oral bioavailability, the oral route of administration has, to date, to follow inconvenient recommendations of use for the patient. 
     As described, bisphosphonates are accepted as providing strong efficacy in the management of osteoporosis. However, given the administration restrictions related to low oral bioavailability and potential for gastrointestinal side effects, there is a clear opportunity for regimens which offer improved convenience and flexibility, leading to a higher level of compliance and superior patient management/satisfaction. 
     Furthermore, it has been found in the ibandronate clinical development program, that ibandronate showed fracture reduction efficacy with a drug-free interval beyond daily administration. It was quite unexpected that fracture reduction benefit could be derived from a weekly or monthly administration of an oral bisphosphonate with a single or multiple tablet administration scheme. 
     SUMMARY OF THE INVENTION 
     Accordingly, a new composition comprising a high dose, namely up to 250 mg, preferably comprising 150 mg or 100 mg of a bisphosphonate derivative, especially of ibandronate or pharmaceutically acceptable salts thereof was prepared, which on the one hand has an increased ratio of active substances versus excipients, and on the other hand fulfills the requirements of stability. 
     It has been found that the stability of such high dose formulations is substantially increased by adding the disintegrant already in the granulation step together with the active substance and with a part of the filler material. Such compositions are easily dissolvable and have an increased stability on storage both with regard to temperature and humidity. 
     The pharmaceutical composition according to the invention comprises up to 250 mg, preferably up to 200 mg, more preferably up to 150 mg, and most preferably up to 100 mg of a bisphosphonate, especially of ibandronate or a pharmaceutically acceptable salt thereof as an active substance. The following bisphosphonates are active substances which can be used in the pharmaceutical compositions according to the invention in the form of free acids or pharmaceutically acceptable salts or hydrates, particularly sodium salts:
     (4-amino-1-hydroxybutylidene)bis-phosphonate (alendronate),   (dichloromethylene)bis-phosphonate (clodronate),   [1-hydroxy-3-(1-pyrrolidinyl)-propylidene]bis-phosphonate (EB-1053),   (1-hydroxyethylidene)bis-phosphonate (etidronate),   [1-hydroxy-3-(methyl pentyl amino)propylidene]bis-phosphonate (ibandronate),   [Cycloheptylamino)-methylene]bis-phosphonate (incadronate),   (6-amino-1-hydroxyhexylidene)bis-phosphonate (neridronate),   [3-(dimethylamino)-1-hydroxypropylidene]bis-phosphonate (olpadronate),   (3-amino-1-hydroxypropylidene)bis-phosphonate (pamidronate),   [1-hydroxy-2-(3-pyridinyl)ethylene]bis-phosphonate (risedronate),   [[(4-chlorophenyl)thiol]-methylene]bis-phosphonate (tiludronate),   [1-hydroxy-2-imidazo-(1,2-a)pyridin-3-yl ethylidene]bis-phosphonate (YH 529),   [1-hydroxy-2-(1H-imidazol-1-yl)ethylidene]bis-phosphonate (zoledronate); and   especially [1-hydroxy-3-(methyl pentyl amino)propylidene]bis-phosphonate (ibandronate).   

     These substances and their preparation are known and described, for example, in the following references:
     U.S. Pat. No. 4,705,651 (alendronate); U.S. Pat. No. 4,927,814 (ibandronate); U.S. Pat. Nos. 3,468,935; 3,400,147; and 3,475,486 (etidronate); O. T. Quimby et al, J. Org. Chem. 32, 4111 (1967) (clodronate); U.S. Pat. No. 4,505,321 (risedronate); U.S. Pat. Nos. 4,134,969 and 3,962,432 (pamidronate); U.S. Pat. No. 5,130,304 (EB-1053); U.S. Pat. No. 4,970,335 (incadronate); Belgian Patent No. 885139 (neridronate); U.S. Pat. No. 4,054,598 (olpadronate); U.S. Pat. Nos. 4,746,654; 4,876,248 and 4,980,171 (tiludronate); U.S. Pat. No. 4,990,503 (YH 529) and U.S. Pat. No. 4,939,130 (zoledronate).   

     Preferred are compositions comprising the equivalent of 150 mg bisphosphonates or pharmaceutically acceptable salts thereof and compositions comprising the equivalent of 100 mg bisphosphonates or pharmaceutical acceptable salts as active substances, respectively. Ibandronate or a pharmaceutically acceptable salt thereof is a particularly preferred active substance, particularly in the form of sodium-ibandronate monohydrate. 
     The composition further comprises adjuvants such as binders, for example, polyvinylpyrrolidone (e.g., Povidone®) or hydroxypropylmethyl cellulose (e.g., Pharmacoat®), fillers, for example, lactose in hydrate or anhydrate form, cellulose in microcrystalline or fibrous form (e.g. Avicel®), or starch, disintegrants, for example, cross-linked polyvinyl pyrrolidone (e.g. Crospovidone® USPNF) or cross carmelose, lubricants, for example, stearic acid or magnesium stearate, and flow-regulators for example colloidal silicon dioxide. 
     The preferred form of the composition are tablets, preferably coated by a film coating mixture and a plastiziser. Such film coating mixtures and plasticizers are known to the person skilled in the art. 
     According to this invention, the tablet kernel consists of from about 30.0 to about 36.0 5, preferably of about 33.3.% of active substance;
     of from about 4.0 to about 6.0%, preferably of from about 4.8 to about 5.2% by weight of binder;   of from about 39.6 to about 59.4%, preferably of from about 47.0 to about 52.0% by weight of filler;   of from about 4.5 to about 5.5%, preferably of from about 4.8 to about 5.2% by weight of disintegrant;   of from about 1.8 to about 2.2%, preferably of from about 1.9 to about 2.1% by weight of lubricant; and   of from about 0.9 to about 1.1%, preferably of from about 0.95 to about 1.05% by weight of flow regulator.   

     Preferably the active substance is ibandronate or a pharmaceutically acceptable salt thereof; preferably, the binder is polyvinylpyrrolidone; preferred fillers are lactose in hydrate or anhydrate form, or cellulose in microcrystalline or fibrous form; and a preferred disintegrant is cross-linked polyvinyl pyrrolidone. Preferred are compositions wherein the disintegrant is added already in the granulate together with the active substance and with a part of the filler material. 
     Furthermore, the invention relates to a process for the preparation of pharmaceutical compositions for the oral application comprising a high dose of bisphosphonates, especially of ibandronate or a pharmaceutically acceptable salt thereof. According to the invention, the pharmaceutical composition is prepared by the following process:
         wet granulating the bisphosphonate or pharmaceutically acceptable salt thereof in the presence of adjuvants such as the binder, and a part of fillers mentioned above, characterized in that the disintergrant is added into the granulation mixture;   fluidizing the granulation mixture in a manner known in the art;   subsequently drying the wet granulate and screening the dried granulate through a screen having a suitable mesh width;   adding the remaining adjuvants such as the fillers, lubricant and flow regulators mentioned above and blending the mixture before processing it by techniques known in the art to form pharmaceutical compositions.       

     In a preferred form of the invention, the active substance, a part of the filler, and the disintegrant in dry powder form are granulated by spraying an aqueous binder solution into the powder mixture. The process is preferably carried out at a temperature of 60 to 80° C., preferably at about 70° C. 
     The spray granulated material is then dried preferably at a temperature of 60 to 80° C., preferably at about 70° C. and subsequently screened through a fine sieve; the dried granulate is mixed with the remaining amount of the filler, the lubricant, and the flow regulator which were previously passed through a fine sieve. The final blend is then pressed into tablet kernels which are coated with a coating suspension using purified water and a film-coating mixture. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The process according to the invention is carried out as follows:
     a) dissolving the binder, preferably Povidone K25® in purified water;   b) charging a drier, preferably a fluid-bed drier with the bisphosphonate, preferably with the mono-sodium salt (1H 2 O) of ibandronic acid, a part of the filler, preferably with lactose monohydrate and up to 60% by weight of the total amount of microcrystalline cellulose, and the disintegrant;   c) spray-granulating the raw materials of step b) at a temperature of from about 60 to about 80° C., preferably at about 70° C. with the granulation fluid of step a),   d) drying the spray granulated material of step c) at a temperature of 60 to 80° C., preferably at about 70° C. (setpoint of inlet-air temperature) and subsequently screening the dried intermediate through a fine sieve;   e) mixing the granulate of step e) with the remaining amount of the filler, e.g., microcrystalline cellulose, the lubricant, preferably stearic acid and the flow regulator, for example, anhydrous colloidal silica which were previously passed through a fine sieve (e.g., 1 mm);   f) compressing the final blend of f) into tablet kernels; and coating the tablet with a coating suspension using purified water and a film-coating mixture comprising for example hypromellose, titanium dioxide and talc (the mixture being commercially available, e.g. Opadry® 00A28646) and Macrogol 6000®.   

     The adjuvants are known in the art and are commercially available. 
     The invention will now be explained in further detail with reference to examples, without being limited thereto. 
     EXAMPLE 1 
     The preparation of a film coated tablet containing 150 mg active substance is carried out as follows:
     1. Dissolve Povidone K25® in purified water.   2. Charge a fluid-bed drier with mono-sodium salt (1H 2 O) of ibandronic acid, lactose monohydrate, crospovidone and microcrystalline cellulose. Crospovidone and the microcrystalline cellulose were passed through a fine sieve (e.g., 1 mm) before mixing.   3. Spray-granulate the raw materials of step 2 at 70° C. (set point of inlet-air temperature) with the granulation fluid of step 1.   4. Perform a final drying of the spray granulated material of step 3 at 70° C. (setpoint of inlet-air temperature).   5. Screen the dried intermediate granulate through a fine sieve (e.g., 2 mm perforations) and   6. If required, repeat steps 1-5 to obtain the required final batch size.   7. Mix the granulate of step 6 in a container mixer with microcrystalline cellulose, stearic acid and anhydrous colloidal silica. The microcrystalline cellulose, the stearic acid and the anhydrous colloidal silica were passed through a fine sieve (e.g., 1 mm) before mixing.   8. Compress the final blend from step 7 into tablet kernels using a rotary tablet press.   9. Prepare the coating suspension using purified water, film-coating mixture comprising hypromellose (60.5%), titanium dioxide (29%) and talc (10.5%); the mixture is purchased from the market (e.g. Opadry® 00A28646) and Macrogol 6000®.   10. Spray the coating suspension of step 9 onto the tablet kernels using a coating unit.   

     The tablet composition is as follows: 
     
       
         
               
               
               
             
           
               
                   
               
             
             
               
                 Tablet kernel 
                   
                   
               
               
                 Ibandronic acid 
                 150.0 
                 mg 
               
               
                 as mono-sodium salt (1H 2 O) of Ibandronic acid 
                 168.75 
                 mg 
               
               
                 Povidone K25 ® 
                 22.5 
                 mg 
               
               
                 Lactose, monohydrate 
                 62.75 
                 mg 
               
               
                 Cellulose, microcrystalline 
                 60.0 
                 mg 
               
               
                 Crospovidone ® 
                 22.5 
                 mg 
               
               
                 Stearic acid 
                 9.0 
                 mg 
               
               
                 Silica, anhydrous colloidal 
                 4.5 
                 mg 
               
               
                 Film-coat 
                   
                   
               
               
                 Film-coating mixture* 
                 12.75 
                 mg 
               
               
                 Macrogol 6000 ® 
                 2.25 
                 mg 
               
               
                   
               
               
                 *this film-coating mixture contains: hypromellose (60.5%), titanium dioxide (29%) and talc (10.5%); the mixture is commercially available (e.g., Opadry ® 00A28646) 
               
             
          
         
       
     
     The kernel weight is 450 mg and the total tablet weight is 465 mg, the amount of active substance per tablet is equivalent to 150 mg of free ibandronic acid. 
     Example 1a 
     For a Batch of 110,000 Tablets 
     
         
         1. A suitable vessel was charged with 14.850 kg demineralized water and 2.475 kg of Povidone K25® was added under constant stirring. The time of addition was about 15 minutes. 
         2. A fluid-bed dryer was charged with 18.563 kg ibandronic acid mono sodium salt, 17.903 kg of lactose monohydrate 100, 4.125 kg Avicel PH-102® and 2.475 kg Crospovidone CL®. 
         3. The components were mixed and spray granulated at a temperature of 70° C. with the aqueous solution of Povidone K25® prepared above which was added at 300 g/min with a pressure of 2.5 bar. 
         4. The granulate was then dried in a fluid-bed dryer at 70° C. 
         5. Subsequently screened (2.0 mm meshes) to yield 44.540 kg of dried granulated material. 
         6. 2.426 kg AVICEL PH-102®, 0.970 kg stearic acid and 0.4850 kg silicic acid AEROSIL 200% were screened and added to the dried granulated material (44.650 kg), and the components were mixed. 
         7. The final blend was compressed into tablets kernels, yield 103,244 kernels. 
         8. A coating suspension was prepared by dissolving 0.290 kg PEG 6000® (MACROGOL 6000) in 7.743 kg demineralized water and subsequently disperging 1.645 kg OPADRY 00A28646® into this solution. 
         9. The kernels were coated with the coating suspension under standard conditions. 
       
    
     The tablets have the composition and the weight given in example 1. 
     EXAMPLE 2 
     The preparation of a film coated tablet containing 100 mg active substance was carried out as described in example 1: 
     
       
         
               
               
               
             
           
               
                   
               
             
             
               
                 Tablet kernel 
                   
                   
               
               
                 Ibandronic acid 
                 100.0 
                 mg 
               
               
                 as mono-sodium salt (1H 2 O) of Ibandronic acid 
                 112.50 
                 mg 
               
               
                 Povidone K25 ® 
                 15.0 
                 mg 
               
               
                 Lactose, monohydrate 
                 108.50 
                 mg 
               
               
                 Cellulose, microcrystalline 
                 40.0 
                 mg 
               
               
                 Crospovidone ® 
                 15.0 
                 mg 
               
               
                 Stearic acid 
                 6.0 
                 mg 
               
               
                 Silica, anhydrous colloidal 
                 3.0 
                 mg 
               
               
                 Film-coat 
                   
                   
               
               
                 Film-coating mixture* 
                 10.20 
                 mg 
               
               
                 Macrogol 6000 ® 
                 1.80 
                 mg 
               
               
                   
               
               
                 *composition as mentioned example 1 
               
             
          
         
       
     
     The kernel weight is 300 mg and the total tablet weight is 312 mg, the amount of active substance per tablet is equivalent to 100 mg of free ibandronic acid.