Patent Publication Number: US-2018028451-A1

Title: Immeadiate release oral tablet

Description:
The present invention relates to a process for the preparation of a tablet comprising the antihypertensive telmisartan and an immediate release oral tablet produced by the method. 
     BACKGROUND OF THE INVENTION 
     Telmisartan is an angiotensin II receptor antagonist developed for the treatment of hypertension and other medical indications as disclosed in EP-A-502314. Its chemical name is 4′-[2-n-propyl-4-methyl-6-(1-methylbenzimidazol-2-yl)-benzimidazol-1-ylmethyl]-biphenyl-2-carboxylic acid having the following structure: 
     
       
         
         
             
             
         
       
     
     Telmisartan is manufactured and supplied in the free acid form. It is characterized by its very poor solubility in aqueous systems at the physiological pH range of the gastro-intestinal tract between pH 1 to 7. As disclosed in WO 00/43370, crystalline telmisartan exists in two polymorphic forms having different melting points. Under the influence of heat and humidity, the lower melting polymorph B transforms irreversibly into the higher melting polymorph A. 
     An immediate release (IR) oral tablet is a solid pharmaceutical dosage form, from which the pharmaceutically active agent is rapidly released (in vitro criteria: 75% dissolved within 45 min according to the European Pharmacopoeia or 85% within 60 min according to the FDA Guidance for Industry on Dissolution Testing of Immediate Release Solid Oral Dosage Forms). 
     OBJECT OF THE INVENTION 
     By providing a process based on hot-melt extrusion technology for the preparation of telmisartan tablets with properties of immediate release the present invention facilitates the manufacturing of a pharmaceutical preparation with improved release characteristics of the poorly soluble drug telmisartan compared to current commercial preparations. 
     SUMMARY OF THE INVENTION 
     The present invention discloses a hot melt extrusion (HME) process for the preparation of a telmisartan tablet and an immediate release HME tablet obtained by such a process. 
    
    
     DESCRIPTION OF THE INVENTION 
     The present invention refers to a process for the preparation of telmisartan tablets comprising 
     (a) processing telmisartan, a basic agent and optionally a polymeric matrix excipient by hot melt extrusion to obtain an extrudate of telmisartan; 
     (b) comminuting the extrudate by milling to obtain a granulate and, optionally, split the granules into different particle size fractions by sieving; 
     (c) blending the granulate with a filler, a disintegrant; lubricant and glidant; and 
     (d) compressing the blend to obtain an immediate release tablet. 
     Optionally, the tablet obtained after process step (d) can be coated on the surface. 
     Unexpectedly, the present invention is able to improve the in-vitro dissolution performance of telmisartan compared to both, the crystalline drug and current commercial Micardis® formulations in dissolution media covering the complete physiologically relevant pH range from strongly acidic gastric conditions (pH 1.2) up to neutral intestinal conditions (pH 6.8). 
     The active ingredient telmisartan is generally supplied in its free acid form, although pharmaceutically acceptable salts such as the sodium salt may also be used. 
     Specific examples of suitable basic agents are alkali metal hydroxides such as NaOH and KOH; basic amino acids such as arginine and lysine; and meglumine (N-methyl-D-glucamine), meglumine being preferred. 
     The polymeric matrix excipient is chosen to form an amorphous solid dispersion with the active agent telmisartan, i.e. telmisartan is embedded into the polymer matrix. Specific examples are polyvinylpyrrolidone, vinylpyrrolidone-vinyl acetate copolymers, polyacrylates, polymethacrylates and cellulose derivatives. 
     Hot-melt extrusion means processing a powdered premix of an active agent such as telmisartan and functional excipients (e.g. polymers and/or pH modifiers) in an extruder at elevated temperature and mechanical stress to give a pharmaceutical intermediate characterized by a predominantly amorphous, ideally one-phasic structure of the mixture of active agent and excipients. Hot-melt extrusion is preferably performed in heatable twin-screw extruders. 
     Milling is performed by a cutting mill, hammer mill, ball mill or comparable equipment suitable for comminuting the extruded intermediate of active agent mixed with excipients. 
     A filler is selected from one or more agents selected from the group consisting of cellulose, lactose, dibasic calcium phosphate anhydrous, erythritol, mannitol, isomalt, pregelatinized starch, microcrystalline cellulose, hydroxypropyl cellulose and other cellulose derivatives. A preferred filler is microcrystalline cellulose or mannitol. 
     The disintegrant is selected from the group consisting of sodium starch glycolate, crospovidone (cross-linked polyvinylpyrrolidone), corn starch and pregelatinized starch. A preferred disintegrant is crospovidone 
     Suitable lubricants are sodium stearyl fumarate and magnesium stearate, the latter being preferred. 
     In process step (a) preferably, 20-70 wt-% of the active agent telmisartan is blended with 10-50 wt-% of a basifier and, optionally 0-60 wt-% of a matrix polymer. This premix is processed by a twin-screw extruder at barrel temperatures of preferably 120-180° C. to obtain extrusion strands of predominantly amorphous structure. In these, the active agent telmisartan is embedded homogeneously in the excipients, preferably as bi-phasic solid dispersion or, even more preferred, one-phasic solid solution. 
     Compression of tablets in step (d) is performed with a choice of non-functional tableting excipients, such that fast disintegrating tablets are obtained and the in-vitro dissolution performance of the telmisartan extrudate from process step (a) and the resulting tablets are preferably identical. The fraction of the telmisartan extrudate in the tablet is preferably in a range of 20-80 wt. %, even more preferred 40-60 wt-%. 
     A further embodiment of the present invention is an immediate release oral tablet comprising: 
     3 to 50 wt. %, preferably 5 to 30 wt. % of telmisartan; 
     3 to 30 wt. %, preferably 5 to 15 wt. % of basic agent; 
     0 to 50 wt. % preferably 0 to 30 wt. % of polymer; and 
     20 to 92 wt. %, preferably 10 to 80 wt. % of filler 
     1 to 20 wt %, preferably 1 to 10 wt. %disintegrant 
     0.5 to 5 wt % preferably 0.5 to 2 wt. % of lubricant and 
     0.5 to 5 wt %, preferably 0.5 to 2 wt. % of glidant 
     In particular the inventive immediate release oral tablet comprises 
     20-80 mg of the angiotensin II receptor antagonist telmisartan 
     20-80 mg of a basic excipient 
     20-350 mg filler selected from the group consisting of cellulose, dibasic calcium phosphate anhydrous, erythritol, mannitol, microcrystalline 
     5-50 mg disintegrant selected from the group consisting of sodium starch glycolate, crospovidone, corn starch and pregelatinized starch and 
     0.01-1.0 mg lubricant such as magnesium stearate. 
     The tablet contains 10-160 mg amorphous telmisartan, preferably 20-80 mg or 40-80 mg. 
     A preferred basic excipient is meglumine; 
     Preferred fillers are mannitol, lactose, starch and microcrystalline cellulose; 
     Preferred disintegrants are crospovidone (cross-linked polyvinylpyrrolidone), corn starch and pregelatinized starch; 
     Preferred lubricant is magnesium stearate; 
     Additionally, the tablet can comprise corn starch or pregelatinized starch as a coating agent. 
     The tablets obtained according to the invention release telmisartan rapidly (e.g. within 30-60 minutes). 
     To minimize hygroscopicity of the tablets of the present invention they can be packaged using a moisture-proof packaging material such as PVC/PVDC blister in aluminium pouch, aluminium sachet or glass bottles, polypropylene tubes and HDPE bottles which preferably contain a desiccant. 
     A method described above can be used for the manufacture of an immediate release oral tablet according to the present invention to treat hypertension either alone or in combination with the treatment or prevention of a condition selected from the group consisting of chronic stable angina, vasospastic angina, stroke, myocardial infarction, transient ischemic attack, congestive heart failure, cardiovascular disease, diabetes, insulin resistance, impaired glucose tolerance, pre-diabetes, type 2 diabetes mellitus, diabetic nephropathy, metabolic syndrome (syndrome X), obesity, dyslipidemia, hypertriglyceridemia, elevated serum concentrations of C-reactive protein, elevated serum concentrations of lipoprotein(a), elevated serum concentration of homocysteine, elevated serum concentration of low-density lipoprotein (LDL)-cholesterol, elevated serum concentration of lipoprotein-associated phospholipase (A2), reduced serum concentration of high density lipoprotein (HDL)-cholesterol, reduced serum concentration of HDL(2b)-cholesterol, reduced serum concentration of adiponectin, cognitive decline and dementia. 
     Particularly preferred is the additional treatment or prevention of chronic stable angina, vasospastic angina, stroke, myocardial infarction, congestive heart failure, diabetes, dyslipidemia or dementia. 
     In addition to lowering elevated blood pressure (hypertension) the tablet can be used in a method to treat or prevent chronic stable angina, vasospastic angina, stroke, myocardial infarction, congestive heart failure, diabetes, dyslipidemia or dementia. 
     In order to further illustrate the present invention two telmisartan HME extrudates (see examples 1 and 2) were formulated as 40 mg immediate release HME tablets (see examples 7 and 8). The in-vitro dissolution performance of both HME tablets was tested in comparison to a commercial telmisartan tablet (see examples 12 to 14) in different dissolution media covering in-vivo relevant pH ranges (0.1 M HCl having pH 1.2; Mcllvaine Buffer having pH 4.0; and Mcllvaine buffer having pH 6.8). The HME tablets were superior to the commercial tablet under all conditions investigated. Though final drug concentrations in solution are similar, the HME tablets show a faster initial release of telmisartan within the first 30 to 60 minutes of the dissolution experiment at all pH levels tested. 
     EXAMPLES 
     Example 1 
     Hot Melt Extrusion of Telmisartan 
     A powder blend containing the following constituents is prepared: 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
               
                   
                 Constituents 
                 function 
                 wt % 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Telmisartan 
                 active agent 
                 20.0 
               
               
                   
                 Meglumin 
                 basifier 
                 20.0 
               
               
                   
                 Polyvidon VA 64 
                 matrix polymer 
                 60.0 
               
               
                   
                 Total 
                   
                 100.0 
               
               
                   
                   
               
            
           
         
       
     
     The blend is subsequently processed in a heatable twin-screw extruder. Extrusion is performed at a maximum barrel temperature of 151° C. Extrusion strands obtained as intermediate product in this process are characterized by a predominantly amorphous structure according to analysis by X-ray powder diffraction and/or differential calorimetry. 
     Example 2 
     Hot Melt Extrusion of Telmisartan 
     A powder blend containing the following constituents is prepared: 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
               
                   
                 Constituents 
                 function 
                 wt % 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Telmisartan 
                 active agent 
                 50.0 
               
               
                   
                 Meglumin 
                 basifier 
                 50.0 
               
               
                   
                 Total 
                   
                 100.0 
               
               
                   
                   
               
            
           
         
       
     
     The blend is subsequently processed in a heatable twin-screw extruder. Extrusion is performed at a maximum barrel temperature of 142° C. Extrusion strands obtained as intermediate product in this process are characterized by a predominantly amorphous structure according to analysis by X-ray powder diffraction and/or differential calorimetry. 
     Example 3 
     Hot Melt Extrusion of Telmisartan 
     A powder blend containing the following constituents is prepared: 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
               
                   
                 Constituents 
                 function 
                 wt % 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Telmisartan 
                 active agent 
                 60.0 
               
               
                   
                 Meglumin 
                 basifier 
                 20.0 
               
               
                   
                 Eudragit E PO 
                 matrix polymer 
                 20.0 
               
               
                   
                 Total 
                   
                 100.0 
               
               
                   
                   
               
            
           
         
       
     
     The blend is subsequently processed in a heatable twin-screw extruder. Extrusion is performed at a maximum barrel temperature of 168° C. Extrusion strands obtained as intermediate product in this process are characterized by a predominantly amorphous structure according to analysis by X-ray powder diffraction and/or differential calorimetry. 
     Example 4 
     Hot Melt Extrusion of Telmisartan 
     A powder blend containing the following constituents is prepared: 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
               
                   
                 Constituents 
                 function 
                 wt % 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Telmisartan 
                 active agent 
                 60.0 
               
               
                   
                 Meglumin 
                 basifier 
                 20.0 
               
               
                   
                 Poloxamer 188 
                 matrix polymer 
                 20.0 
               
               
                   
                 Total 
                   
                 100.0 
               
               
                   
                   
               
            
           
         
       
     
     The blend is subsequently processed in a heatable twin-screw extruder. Extrusion is performed at a maximum barrel temperature of 149° C. Extrusion strands obtained as intermediate product in this process are characterized by a predominantly amorphous structure according to analysis by X-ray powder diffraction and/or differential calorimetry. 
     Example 5 
     Milling of the Telmisartan Extrudate 
     The extrusion strands obtained in the hot-melt extrusion (HME) process exhibit a typical diameter of 0.5-2 mm and length of 10-50 mm. To allow manufacturing of tablets with the required content uniformity, this intermediate product is comminuted by means of a cutting mill. Granule size of the comminuted extrudate is less than 630 μm with a calculated d50-value of 200-400 μm according to sieve analysis. 
     Example 6 
     Tableting 
     Intermediate granules are mixed with different excipients according to the following table and the blend is subsequently compressed to tablets by means of a single punch or rotary tablet press. 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
               
                   
                 Constituents 
                 function 
                 wt % 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 HME granules 
                 active agent 
                 40.0 
               
               
                   
                 MCC grade 101 
                 binder 
                 28.0 
               
               
                   
                 MCC grade 200 
                 binder 
                 28.0 
               
               
                   
                 crospovidone 
                 disintegrant 
                 3.0 
               
               
                   
                 silicon dioxide 
                 glidant 
                 0.5 
               
               
                   
                 magnesium stearate 
                 lubricant 
                 0.5 
               
               
                   
                 Total 
                   
                 100.0 
               
               
                   
                   
               
            
           
         
       
     
     Example 7 
     40 mg Telmisartan Immediate Release Tablet 
     The tablet is described by the following composition: 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
               
                   
                   
                 mg 
                 wt % 
               
               
                   
                 Constituents 
                 per tablet 
                 per tablet 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Telmisartan 
                 40.0 
                 8.0 
               
               
                   
                 Meglumin 
                 40.0 
                 8.0 
               
               
                   
                 Polyvidon VA 64 
                 120.0 
                 24.0 
               
               
                   
                 Microcrystalline Cellulose, 
                 140.0 
                 28.0 
               
               
                   
                 grade 101 
               
               
                   
                 Microcrystalline Cellulose, 
                 140.0 
                 28.0 
               
               
                   
                 grade 200 
               
               
                   
                 crospovidone 
                 15.0 
                 3.0 
               
               
                   
                 silicon dioxide 
                 2.5 
                 0.5 
               
               
                   
                 magnesium stearate 
                 2.5 
                 0.5 
               
               
                   
                 Total 
                 500.0 
                 100.0 
               
               
                   
                   
               
            
           
         
       
     
     Example 8 
     40 mg Telmisartan Immediate Release Tablet 
     The tablet is described by the following composition: 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
               
                   
                   
                 mg 
                 wt % 
               
               
                   
                 Constituents 
                 per tablet 
                 per tablet 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Telmisartan 
                 40.0 
                 20.0 
               
               
                   
                 Meglumin 
                 40.0 
                 20.0 
               
               
                   
                 Microcrystalline Cellulose, 
                 56.0 
                 28.0 
               
               
                   
                 grade 101 
               
               
                   
                 Microcrystalline Cellulose, 
                 56.0 
                 28.0 
               
               
                   
                 grade 200 
               
               
                   
                 crospovidone 
                 6.0 
                 3.0 
               
               
                   
                 silicon dioxide 
                 1.0 
                 0.5 
               
               
                   
                 magnesium stearate 
                 1.0 
                 0.5 
               
               
                   
                 Total 
                 200.0 
                 100.0 
               
               
                   
                   
               
            
           
         
       
     
     Example 9 
     20 mg Telmisartan Immediate Release Tablet 
     The tablet is described by the following composition: 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
               
                   
                   
                 mg 
                 wt % 
               
               
                   
                 Constituents 
                 per tablet 
                 per tablet 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Telmisartan 
                 20.00 
                 8.0 
               
               
                   
                 Meglumin 
                 20.00 
                 8.0 
               
               
                   
                 Polyvidon VA 64 
                 60.00 
                 24.0 
               
               
                   
                 Microcrystalline Cellulose, 
                 70.00 
                 28.0 
               
               
                   
                 grade 101 
               
               
                   
                 Microcrystalline Cellulose, 
                 70.00 
                 28.0 
               
               
                   
                 grade 200 
               
               
                   
                 crospovidone 
                 7.50 
                 3.0 
               
               
                   
                 silicon dioxide 
                 1.25 
                 0.5 
               
               
                   
                 magnesium stearate 
                 1.25 
                 0.5 
               
               
                   
                 Total 
                 250.0 
                 100.0 
               
               
                   
                   
               
            
           
         
       
     
     Example 10 
     80 mg Telmisartan Immediate Release Tablet 
     The tablet is described by the following composition: 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
               
                   
                   
                 mg 
                 wt % 
               
               
                   
                 Constituents 
                 per tablet 
                 per tablet 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Telmisartan 
                 80.0 
                 8.0 
               
               
                   
                 Meglumin 
                 80.0 
                 8.0 
               
               
                   
                 Polyvidon VA 64 
                 240.0 
                 24.0 
               
               
                   
                 Microcrystalline Cellulose, 
                 280.0 
                 28.0 
               
               
                   
                 grade 101 
               
               
                   
                 Microcrystalline Cellulose, 
                 280.0 
                 28.0 
               
               
                   
                 grade 200 
               
               
                   
                 crospovidone 
                 30.0 
                 3.0 
               
               
                   
                 silicon dioxide 
                 5.0 
                 0.5 
               
               
                   
                 magnesium stearate 
                 5.0 
                 0.5 
               
               
                   
                 Total 
                 1000.0 
                 100.0 
               
               
                   
                   
               
            
           
         
       
     
     Example 11 
     80 mg Telmisartan Immediate Release Tablet 
     The tablet is described by the following composition: 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
               
                   
                   
                 mg 
                 wt % 
               
               
                   
                 Constituents 
                 per tablet 
                 per tablet 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Telmisartan 
                 80.0 
                 20.0 
               
               
                   
                 Meglumin 
                 80.0 
                 20.0 
               
               
                   
                 Microcrystalline Cellulose, 
                 112.0 
                 28.0 
               
               
                   
                 grade 101 
               
               
                   
                 Microcrystalline Cellulose, 
                 112.0 
                 28.0 
               
               
                   
                 grade 200 
               
               
                   
                 crospovidone 
                 12.0 
                 3.0 
               
               
                   
                 silicon dioxide 
                 2.0 
                 0.5 
               
               
                   
                 magnesium stearate 
                 2.0 
                 0.5 
               
               
                   
                 Total 
                 400.0 
                 100.0 
               
               
                   
                   
               
            
           
         
       
     
     Example 12 
     In-Vitro Dissolution Performance at pH 1.2 
       
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                   
               
               
                 time 
                 [min] 
                 10 
                 15 
                 30 
                 45 
                 60 
                 90 
                 120 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 commercial 40 mg 
                 [%  
                 20.45 
                 28.50 
                 47.34 
                 63.32 
                 71.60 
                 79.55 
                 83.28 
               
               
                 Micardis ® tablet 
                 dissolved] 
                   
                   
                   
                   
                   
                   
                   
               
               
                 40 mg tablet 
                   
                 45.40 
                 48.35 
                 53.55 
                 58.05 
                 63.16 
                 71.46 
                 75.69 
               
               
                 according to 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 example 8 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 40 mg tablet 
                   
                 47.43 
                 55.69 
                 66.63 
                 70.33 
                 72.57 
                 75.17 
                 76.90 
               
               
                 according to 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 example 7 
               
               
                   
               
            
           
         
       
     
     Dissolution testing was performed applying a device similar to USP apparatus 2, at a paddle speed of 50 rpm, using 200 mL of 0.1 M HCl at 37° C. 
     Example 13 
     In-Vitro Dissolution Performance at pH 4.0 
       
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                   
               
               
                 time 
                 [min] 
                 10 
                 15 
                 30 
                 45 
                 60 
                 90 
                 120 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 commercial 40 mg 
                 [%  
                 0.15 
                 0.27 
                 0.65 
                 1.14 
                 1.61 
                 3.50 
                 6.80 
               
               
                 Micardis ® tablet 
                 dissolved] 
                   
                   
                   
                   
                   
                   
                   
               
               
                 40 mg tablet 
                   
                 8.13 
                 8.38 
                 9.95 
                 10.77 
                 11.45 
                 12.32 
                 12.75 
               
               
                 according to 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 example 8 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 40 mg tablet 
                   
                 9.04 
                 13.54 
                 17.66 
                 18.54 
                 19.00 
                 19.30 
                 19.32 
               
               
                 according to 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 example 7 
               
               
                   
               
            
           
         
       
     
     Dissolution testing was performed applying a device similar to USP apparatus 2, at a paddle speed of 50 rpm, using 200 mL of Mcllvaine buffer pH 4.0 at 37° C. 
     Example 14 
     In-Vitro Dissolution Performance at pH 6.8 
       
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                   
               
               
                 time 
                 [min] 
                 10 
                 15 
                 30 
                 45 
                 60 
                 90 
                 120 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 commercial 40 mg 
                 [%  
                 41.49 
                 54.99 
                 62.06 
                 53.82 
                 39.77 
                 16.40 
                 11.63 
               
               
                 Micardis ® tablet 
                 dissolved] 
                   
                   
                   
                   
                   
                   
                   
               
               
                 40 mg tablet 
                   
                 59.86 
                 62.59 
                 63.88 
                 46.55 
                 31.51 
                 15.42 
                 9.93 
               
               
                 according to 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 example 8 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 40 mg tablet 
                   
                 21.39 
                 24.97 
                 30.52 
                 33.14 
                 34.74 
                 36.40 
                 36.79 
               
               
                 according to 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 example 7 
               
               
                   
               
            
           
         
       
     
     Dissolution testing was performed applying a device similar to USP apparatus 2, at a paddle speed of 50 rpm, using 200 mL of Mcllvaine buffer pH 6.8 at 37° C.