Oral mopidamol preparation
This application is divisional of co-pending U.S. patent application Ser. No. 539,998, filed Oct. 7, 1983 now U.S. Pat. No. 4,596,705. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to vehicles for the administration of mopidamol. More specifically, this invention relates to a mopidamol-containing pharmaceutical form with improved bioavailability and to the use of said pharmaceutical form in treating cardiovascular disorders, malignancy, and thrombosis. 
     BACKGROUND OF THE INVENTION 
     The compound 2,6-bis-(diethanolamino)-4-piperidinopyrimido[5,4-d]pyrimidine, known as mopidamol, is disclosed in U.S. Pat. No. 3,031,450, incorporated herein by reference. This compound has been successfully used as an active substance, such as an antimetastic agent, for many years. The pharmaceutical preparations previously known which contain this active substance have a number of disadvantages for certain applications due to the special physical properties of mopidamol. 
     Mopidamol is readily water-soluble only in an acidic medium, and therefore it can only go into solution from solid pharmaceutical forms and then be absorbed if the pharmaceutical preparations remain in the acidic range for a sufficiently long period. Thus, the solubility and hence also the absorption greatly depend upon the retention time and the pH in the stomach and upper intestinal tract. This results in sharp inter-individual and intra-individual fluctuations in the blood levels since the motility of a patient, the pH of the patient&#39;s stomach and intestines, and the patient&#39;s food intake have a considerably influence on absorption. In some patients the blood levels may even be so low that they practically amount to an absence of absorption. 
     The problems concerning administration of mopidamol are similar to those of a related compound, dipyridamole. Improved delivery pharmaceutical forms for dipyridamole are described in co-pending, U.S. patent application Ser. No. 389,282, filed June 17, 1982, now U.S. Pat. No. 4,427,638, incorporated herein by reference. 
     OBJECTS OF THE INVENTION 
     It is an object of the invention to provide vehicles for administering mopidamol. 
     It is also an object of the invention to provide mopidamol-containing pharmaceutical forms with improved bioavailability and a method for their use. 
     It is a further object of the invention to provide a method of treating cardiovascular disorders, malignancy, or thrombosis in a host in need of such treatment which comprises administering to said host an effective amount of a composition comprised of (i) mopidamol or an acid addition salt thereof and (ii) at least one pharmacologically acceptable acid or acid substance, the total amount of acid from acid addition salt present and acid or acid substance being in a ratio of at least about 1 acid equivalent to 1 mol of mopidamol. 
     These and other objects of the invention will become more apparent in the discussion below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 represents the release characteristics at a pH of 6 of several different embodiments of the invention. 
     FIG. 2 represents a comparison of the release characteristics of two conventional mopidamol-containing pharmaceutical forms and of an embodiment of the invention. The release characteristics are shown by blood level curves. 
     FIG. 3 represents the release characteristics at a pH of 4 of several different embodiments of the invention. 
    
    
     BRIEF DESCRIPTION OF THE INVENTION 
     Applicants have developed a novel mopidamol-containing pharmaceutical form which is characterized by exhibiting an improved bioavailability and substantially lower inter-individual and intra-individual fluctuations in blood level. These novel pharmaceutical preparations represent particular pharmokinetic advantages over previously known pharmaceutical forms. 
     More specifically, the pharmaceutical form of this invention is comprised of (i) mopidamol or an acid addition salt thereof and (ii) at least one pharmacologically acceptable acid or acid substance, the total amount of acid from acid addition salt present and acid or acid substance being in a ratio of at least about 1 acid equivalent to 1 mol of mopidamol. Other, conventional additives may optionally be present. This mopidamol preparation is characterized in that, irrespective of the physiological conditions in the gastrointestinal tract--for example, irrespective of the pH, the buffering effect, and the motility of this tract--it results in a high reproducible bioavailability of the mopidamole. 
     The pharmaceutical forms according to the invention are distinguished in that they contain an intimate mixture of mopidamol or an acid addition salt thereof in the ratio of 1 mol of mopidamol or its acid addition salt to a total of at least about 1 acid equivalent of acid from acid addition salt present and from a pharmacologically acceptable acid or an acidly reacting substance (referred to collectively hereinafter as &#34;acid present&#34;). It was not to be expected that an excess of acid would suddenly lead to a significant increase in the bioavailability of the mopidamol. This increase is shown in FIG. 2, which sets forth blood-level values for a standard oral preparation, a film-coated tablet without any added acid, and a tablet containing 250 mg of added fumaric acid, according to the invention. There is a substantial increase in the speed of resorption and in the quantity of active substance resorbed. 
     The dependency of the solubility or speed of dissolution of the mopidamol upon the quantity of acid added thereto has been investigated for different dosages. The two tables below and FIG. 1 show this dependence as it relates to mopidamol-containing film-coated tablets also containing differing amounts of primary sodium citrate or fumaric acid per tablet. The tablets were tested in vitro using the USP XX paddle method at 100 rpm in 500 ml of dilute McIlvain buffer with a pH of 6. 
     
                       TABLE 1                                                     
______________________________________                                    
Percentage release in vitro from film-coated tablets                      
containing 250 mg of mopidamol each and varying                           
amounts of fumaric acid in dilute buffer solution (pH 6)                  
Amount of Fumaric                                                         
              Percent of Mopidamol Released                               
Acid (mg/tablet)                                                          
              After 5 minutes                                             
                          After 20 minutes                                
______________________________________                                    
0*            25          40                                              
50**          43          77                                              
125***        40          100                                             
______________________________________                                    
 *See Example 1                                                           
 **See Example 6                                                          
 ***See Example 7                                                         
 
    
     
                       TABLE 2                                                     
______________________________________                                    
Percentage release in vitro from film-coated tablets                      
containing 250 mg of mopidamol each and varying amounts                   
of primary sodium citrate in dilute buffer solution (pH 6)                
Amount of Primary                                                         
                Percent of Mopidamol Released                             
Sodium Citrate (mg/tablet)                                                
                After 5 minutes                                           
                            After 40 minutes                              
______________________________________                                    
0*              25          40                                            
25**            30          58                                            
 50***          35          66                                            
 100****        48          84                                            
______________________________________                                    
 *See Example 1                                                           
 **See Example 2                                                          
 ***See Example 3                                                         
 ****See Example 4                                                        
 
    
     It was not foreseeable that mopidamol which was present in only relatively small absolute quantities and was totally dissolved would form strongly supersaturated solutions and that this phenomenon would occur particularly if there is at least about 1 acid equivalent of acid present per mol of mopidamol. Another advantage of these preparations is that, due to the pH-independent solubility, the release profile and hence also the blood levels can be controlled without any loss in bioavailability. 
     The extremely surprising increase in relative bioavailability as compared with the standard oral preparation (mixture of mopidamol with fillers such as starch and lubricants such as magnesium stearate) may possibly arise from the fact that supersaturated and more highly concentrated solutions of active substance are formed. 
     Since mopidamol is a substance with a systemic activity, i.e., its therapeutic effect lasts only as long as maximum possible resorption is maintained, use of the mopidamol-containing pharmaceutical forms according to the invention results in a further improvement in the therapeutic activity. Thus, as a whole, use of the pharmaceutical forms according to the invention has the following advantages over use of conventional preparations: 
     1. Higher bioavailability. 
     2. Higher therapeutic reliability, which is achieved by the fact that, on the one hand, the inter-individual and intra-individual fluctuations which are typical of known forms are reduced and, on the other hand, totally inadequate blood level values are avoided. 
     3. By control of the release, it is possible to improve the therapeutic activity and to avoid side-effects at higher dosages. 
     4. In some cases the higher bioavailability makes it possible to reduce the dosage. 
     It has been found that the remarkable increase in the relative bioavailability of mopidamol can be achieved with a variety of pharmaceutical forms for oral administration. The essential prerequisite for the high blood levels is the determination of the correct ratio of acid present to mopidamol. 
     Extensive tests have shown that at least about 1 acid equivalent of acid present to 1 mol of mopidamol is required to obtain a significant improvement in the bioavailability of mopidamol. The quantity of acid present in relation to the mopidamol has no upper limit per se; it is limited only by the fact that if the quantity of acid present is too great, it is not possible to produce an oral form of mopidamol which can be easily swallowed. A ratio of from about 1 to 8 acid equivalents of acid present to 1 mol of mopidamol is preferred. 
     The acid addition salts of mopidamol comprise pharmacologically acceptable reaction products of mopidamol and inorganic or organic acids. Suitable such acids, which are well known to those skilled in the art, include hydrochloric acid, tartaric acid, and citric acid. 
     Useful acids or acid substances, that is, acidic excipients, comprise a plurality of toxicologically harmless, that is, pharmacologically acceptable, acids or acid substances. Suitable acids include, for example, fumaric acid, malic acid, tartaric acid, citric acid, succinic acid, ascorbic acid, adipic acid, and the like, and mixtures of any two or more of these acids. Suitable acid substances include monopotassium or monosodium salts of the aforementioned acids, such as, for example, monopotassium citrate or monopotassium tartarate, and acid salts selected from the group consisting of, for example, sodium or potassium bisulfate, betaine hydrochloride, and the like. Occasionally, anhydrides such as succinic anhydride, glutaric anhydride, or D-glucuronic acid-γ-lactone, which hydrolyze in the presence of water to form acids, may be used to increase the solubility of the mopidamol. Preparations containing fumaric acid, which are distinguished by their long shelf life, are preferred. 
     The ease with which optimum solid mopidamol preparations for oral administration can be produced was not foreseeable and was a complete surprise to anyone skilled in the art. According to the invention, preferred forms of mopidamol are produced, for example, by simply mixing mopidamol and fumaric acid together, with or without binders, and then compressing the mixture by means of tablet presses or roller compactors. The compressed masses are then broken up again by use of dry granulation equipment, and the resulting granules are transferred into hard gelatine capsules. The quantity of acidic excipients, the nature of these excipients, and the spectrum of particle sizes of the dry granulate are critical in achieving the optimum blood levels. In addition, mopidamol may be pelleted together with acidic excipients, and the pellets are sorted out and transferred into hard gelatine capsules. 
     The particle sizes of mopidamol-containing particles according to the invention are from about 0.1 to 2.0 mm, preferably from about 0.5 to 1.0 mm. This includes, for example, granules having particle sizes of from about 0.1 to 2.0 mm, preferably from about 0.25 to 1.25 mm, as well as pellets having particle sizes, that is, diameters, of from about 0.1 to 2.0 mm, preferably from about 0.5 to 1.5 mm. 
     Prior to insertion into hard gelatin capsules, mopidamol-containing granules or pellets can be coated with a lacquer coating which releases at least 90% of the active substance over a period of two hours in the gastrointestinal tract. 
     The active substance may also be combined with the acidic excipient and other additives which can be used directly in tablets and with the lubricant to form a mixture which can be made directly into tablets. This mixture is then compressed to form tablet cores which are subsequently covered with a coating to mask the flavor or a lacquer coating. If the lubricant is omitted and a film coating which delays release is used, the release of active substance can be spread over a longer period (cf. Example 15). 
     The active substance may also first be granulated with one or more acidic excipients, in a moist or dry state, and after the addition of further excipients, the granules are compressed to form tablet cores. However, it is also possible to first convert the active substance into a granulate with conventional excipients by wet or dry granulation and to subsequently add the acid excipients and a lubricant. Only then is the mass compressed to form tablet cores. 
     With respect to coatings, a flavor-masking coating may comprise any of the known pharmaceutically acceptable coatings such as, for example, hydroxypropyl methylcellulose. Suitable lacquer coatings include hydroxypropyl methylcellulose phthalate, copolymers of methacrylic acid and methacrylic acid ester, and mixtures thereof. The coatings may be present in amounts of from about 1 to 30% by weight, preferably from about 2 to 20% by weight, based upon the total weight of the coated granulate, pellets, or tablets. 
     Fumaric acid has proven to be a particularly suitable acid. It is physiologically non-toxic and easy to compress, and when combined with mopidamol, it does not produce a hydroscopic mixture. Its low solubility is essential to the invention; this ensures that, in the gastrointestinal tract, the mopidamol-containing particle is always surrounded by a sufficiently acidic microsphere in which the mopidamol, which does not dissolve readily, will dissolve safely and completely. 
     If, for medical reasons, it is desirable to have a maximum blood level which is less in intensity but at the same time longer in duration, there are a number of pharmaceutical possibilities. An increase in the amount of acid added leads to acceleration in the release of mopidamol, whereas a reduction slows down the release of active substance (cf. FIG. 1). 
     Other possible forms of mopidamol granulates differ in that, in addition to readily water-soluble binders such as polyvinylpyrrolidinone, excipients which form a mucilage in the presence of water, or even water-repellent excipients, may be added to the mopidamol and the acidic excipient. The solubility of the active substance and the stability of solutions thereof may be further improved by the addition of dissolution aids, such as fatty acid glycerol polyglycol esters (cf. Example 14). 
     If, on the other hand, a very rapidly rising blood level is required for the mopidamol, it is particularly advantageous to change the type of acid used, as well as to increase the quantity of acid added or to reduce the particle size of the granulate, thus enlarging the surface area. Due to the high solubility of each of tartaric acid, citric acid, malic acid, and ascorbic acid, in particular, the mopidamol dissolves completely in vitro in a short time, irrespective of the pH of the medium of release. 
     Formulations of mopidamol and acid may also be produced in tablet form surprisingly easily. It has been found that, even in the presence of conventional tablet-making excipients, the compressing operation during tablet making is sufficient to achieve a sufficiently intimate mechanical combination of active substance and added acid. The examples relating to tablets containing 25, 50, or 100 mg of primary sodium citrate to 250 mg of mopidamol and to tablets containing 50 or 125 mg of fumaric acid to 250 mg of mopidamol, illustrate this. For flavoring purposes, the tablets were all covered with a thin coating of hydroxypropyl methylcellulose. It should be readily apparent to anyone skilled in the art that due to the nature and quantity of excipients added, the nature and quantity of acidic excipient, and the method of preparation (particle size of granulate), the release of the mopidamol active substance can be controlled within wide limits to suit the medical requirements. 
     In addition to the conventional excipients used, namely, polyvinylpyrrolidone, hydrogenated castor oil, and polyacrylic acid, it is also possible to use excipients such as methylcellulose, ethylcellulose, hydroxyethylcellulose, or hydroxypropyl methylcellulose. Furthermore, to achieve the desired release, mixtures consisting of mopidamol and acidic substances may be granulated with fats dissolved in organic solvents or with lacquers resistant to gastric juices such as cellulose acetate phthalate, shellac, and hydroxypropyl methylcellulose phthalate, and then compressed and broken up again into granules. 
     If, for therapeutic reasons, higher dosages of mopidamol are required and high blood level peaks should be avoided because of possible side effects, these requirements are met, according to the invention, by the formulations described in Example 15. Since these formulations release the active substance in controlled manner, for example, over a period of from about 1 to 2 hours, the small particles are already located to a great extent in the duodenum, that is, in a pH range of above pH 4.0 (cf. also FIG. 3, which shows the rate of dissolution at a pH of 4). 
     Therefore, these forms must release the active substance in a pH medium in which the active substance is virtually no longer soluble, in the biological sense. If the release of mopidamol is delayed any longer, that is, if the small units of mopidamol pass into lower sections of the intestines, there is no longer any guarantee of total dissolution and absorption. The optimum absorption of mopidamol is achieved, according to the invention, by accurately adapting the correlations between the nature and quantity of acidic excipient, the nature of the additives, and the method of processing to the rate of release of active substance required. 
     IN VIVO TESTING IN MAN OF THE FORMS ACCORDING TO THE INVENTION 
     All the tests were made on healthy volunteers, mostly in the form of cross-over tests. Since mopidamol is only excreted in the urine to a very small extent, the only biological parameter used was the blood level, which was determined by fluorescence measurement. 
     Various pharmaceutical forms were tested on humans. However, since the oral pharmaceutical forms according to the invention without delayed release do not differ significantly from one another in vivo, FIG. 2 and Tables 3 and 4 only show the results pertaining to the formulation of Example 11. 
     FIG. 2 shows the average mopidamol blood levels of six test subjects after administration of a preparation according to the invention and two conventional preparations, respectively. It can be seen that substantially higher blood level values were obtained with the acid-containing pharmaceutical formulation according to the invention than with the conventional formulations. 
     A comparison of the values of the area under the blood level curve (AUC) of conventional tablets or capusles with the formulation according to the invention and the relative bioavailabilities, are shown in the following table: 
     
                       TABLE 3                                                     
______________________________________                                    
COMPARISON OF AUC VALUES AND                                              
RELATIVE BIOAVAILABILITY                                                  
Test                                                                      
Subject                                                                   
      AUC                Rel. Bioavail. (%)                               
No.   Tablet  Capsule  New Form                                           
                               Tab./new                                   
                                       Caps./new                          
______________________________________                                    
1     0.027   0.073    0.675   2500    924                                
2     2.173   1.754    1.89     87     108                                
3     1.742   2.002    1.431    82      71                                
4     0.232   0.177    1.631   703     921                                
5     2.496   1.656    3.768   151     228                                
6     0.690   1.881    1.465   212      78                                
______________________________________                                    
 
    
     The blood levels of the individual test subjects and Table 3 show that there is a very sharp increase in the blood level, particularly at low values of the standard commercial preparations, that is, of the conventional tablets or capsules and in the &#34;non-absorbers&#34; (who occur from time to time), whereas in test subjects who show good blood levels even with the standard commercial preparations there is only a relatively slight change. This significantly reduces the fluctuations in blood levels which are otherwise normally found and which make therapy more difficult. 
     The reduction in blood level fluctuation is also demonstrated by a comparison of the coefficients of variation of standard commercial forms and the formulation according to the invention (new form) set forth in the table below. The coefficients of variation of the new form have significantly lower values. 
     
                       TABLE 4                                                     
______________________________________                                    
Comparison of the variation coefficients of standard                      
commercial forms and a pharmaceutical form according to                   
the invention                                                             
Test                                                                      
Subject   Time    Variation coefficient                                   
No.       (hrs.)  Tablet    Capsule                                       
                                   New Form                               
______________________________________                                    
1         0.25    244.7     69.7   75.8                                   
2         0.50    155.7     111.9  47.2                                   
3         0.75    130.8     97.1   63.0                                   
4         1.00    96.1      89.0   55.1                                   
5         1.50    90.3      96.5   43.4                                   
6         2.00    97.4      92.9   44.0                                   
7         3.00    95.6      84.5   52.0                                   
8         4.00    83.9      75.7   60.0                                   
9         5.50    110.8     67.5   66.5                                   
Area      --      85.4      70.4   57.5                                   
(mcg ×                                                              
Time/ml)                                                                  
______________________________________                                    
 
    
     The following examples are intended to illustrate the invention and should not be construed as limiting the invention thereto. 
     EXAMPLES 
     Example 1 
     Each tablet had the following composition: 
     
         ______________________________________                                    
Component             Weight (mg)                                         
______________________________________                                    
(1) Mopidamol         250.0                                               
(2) Powdered lactose  91.0                                                
(3) Corn starch       37.0                                                
(4) Cross-linked polyvinylpyrrolidone                                     
                      10.0                                                
(5) AEROSIL ®     3.0                                                 
(6) Powdered triglyceride                                                 
                      6.0                                                 
(7) Magnesium stearate                                                    
                      3.0                                                 
Total:                400.0                                               
______________________________________                                    
 
    
     Preparation of 1000 tablets 
     Components (1) to (5) were admixed, the mixture was moistened with 125 mg of demineralized water, and the moistened misture was passed through a screen with a mesh size of 1.6 mm. The granulate was dried in a circulating air dryer at a temperature of 45° C., and then it was passed through the same screen again. Next, components (6) and (7), which had been finely screened, were added and mixed in, and the mixture was compressed. 
     Diameter of punch: 11 mm 
     Radius of curvature: 11 mm 
     The tablets were provided with a flavor-masking coating of hydroxypropyl methylcellulose. The finished film-coated tablets each weighed about 4 mg more than the uncoated tablets. 
     Example 2 
     Each tablet had the following composition: 
     
         ______________________________________                                    
Component             Weight (mg)                                         
______________________________________                                    
(1) Mopidamol         250.0                                               
(2) Lactose           91.0                                                
(3) Corn starch       37.0                                                
(4) Cross-linked polyvinylpyrrolidone                                     
                      10.0                                                
(5) AEROSIL           3.0                                                 
(6) Sodium dihydrogen citrate                                             
                      25.0                                                
(7) Powdered triglyceride                                                 
                      6.0                                                 
(8) Magnesium stearate                                                    
                      3.0                                                 
Total:                425.0                                               
______________________________________                                    
 
    
     Preparation 
     Components (1) to (5) were mixed as in Example 1. The mixture was moistened, dried, and screened, and Components (6) to (8), finely screened, were added. The mixture was compressed. 
     Diameter of punch: 11 mm 
     Radius of curvature: 11 mm 
     The tablets were provided with a flavor-masking coating of hydroxypropyl methylcellulose. The finished film-coated tablets each weighed about 4.25 mg more than the uncoated tablets. 
     Example 3 
     Each tablet had the following composition: 
     
         ______________________________________                                    
Component             Weight (mg)                                         
______________________________________                                    
(1) Mopidamol         250.0                                               
(2) Lactose           91.0                                                
(3) Corn starch       37.0                                                
(4) Cross-linked polyvinylpyrrolidone                                     
                      10.0                                                
(5) AEROSIL           3.0                                                 
(6) Sodium dihydrogen citrate                                             
                      50.0                                                
(7) Powdered triglyceride                                                 
                      6.0                                                 
(8) Magnesium stearate                                                    
                      3.0                                                 
Total:                450.0                                               
______________________________________                                    
 
    
     Preparation 
     Components (1) to (5) were mixed together as described in Example 1. The mixture was moistened, dried, and screened, and components (6) to (8) were finely screened and added. The mixture was compressed. 
     Diameter of punch: 11 mm 
     Radius of curvature: 11 mm 
     The tablets were provided with a flavor-masking coating of hydroxypropyl methylcellulose. The finished film-coated tablets each weighed about 4.5 mg more than the uncoated tablets. 
     Example 4 
     Each tablet had the following composition: 
     
         ______________________________________                                    
Component             Weight (mg)                                         
______________________________________                                    
(1) Mopidamol         250.0                                               
(2) Lactose           91.0                                                
(3) Corn starch       37.0                                                
(4) Cross-linked polyvinylpyrrolidone                                     
                      10.0                                                
(5) AEROSIL           3.0                                                 
(6) Sodium dihydrogen citrate                                             
                      100.0                                               
(7) Powdered triglyceride                                                 
                      6.0                                                 
(8) Magnesium stearate                                                    
                      3.0                                                 
Total:                500.0                                               
______________________________________                                    
 
    
     Preparation 
     Components (1) to (5) were mixed together as described in Example 1. The mixture was moistened, dried, and screened, and components (6) to (8) were finely screened and added. The mixture was compressed. 
     Diameter of punch: 11 mm 
     Radius of curvature: 11 mm 
     The tablets were provided with a flavor-masking coating of hydroxypropyl methylcellulose. The finished film-coated tablets each weighed about 5.0 mg more than the uncoated tablets. 
     Example 5 
     Each capsule had the following contents: 
     
         ______________________________________                                    
Component             Weight (mg)                                         
______________________________________                                    
(1) Mopidamol         250.0                                               
(2) Fumaric acid      250.0                                               
(3) Corn starch       37.0                                                
(4) Cross-linked polyvinylpyrrolidone                                     
                      10.0                                                
(5) Lactose           91.0                                                
(6) AEROSIL           3.0                                                 
(7) Powdered triglyceride                                                 
                      6.0                                                 
(8) Magnesium stearate                                                    
                      3.0                                                 
Total:                650.0                                               
______________________________________                                    
 
    
     Preparation of 1000 capsules 
     Components (1) and (2) were mixed together and moistened with 50 gm of ethanol, and the moistened mixture was passed through a screen with a mesh size of 1.6 mm and dried. After drying, this material was passed again through the same screen, and components (3) to (8) were finely screened and added thereto. The resulting mixture was packed into size 000 gelatine capsules. 
     Example 6 
     Each tablet had the following composition: 
     
         ______________________________________                                    
Component             Weight (mg)                                         
______________________________________                                    
(1) Mopidamol         250.0                                               
(2) Lactose           91.0                                                
(3) Corn starch       37.0                                                
(4) Cross-linked polyvinylpyrrolidone                                     
                      10.0                                                
(5) AEROSIL           3.0                                                 
(6) Fumaric acid      50.0                                                
(7) Powdered triglyceride                                                 
                      6.0                                                 
(8) Magnesium stearate                                                    
                      3.0                                                 
Total:                450.0                                               
______________________________________                                    
 
    
     Preparation 
     Components (1) to (5) were mixed together as described in Example 1. The mixture was moistened, dried, and screened, and components (6) to (8) were finely screened and added. The mixture was compressed. 
     Diameter of punch: 11 mm 
     Radius of curvature: 11 mm 
     The tablets were provided with a flavor-masking coating of hydroxypropyl methylcellulose. The finished film-coated tablets each weighed about 4.5 mg more than the uncoated tablets. 
     Example 7 
     Each tablet had the following composition: 
     
         ______________________________________                                    
Component             Weight (mg)                                         
______________________________________                                    
(1) Mopidamol         250.0                                               
(2) Lactose           91.0                                                
(3) Corn starch       37.0                                                
(4) Cross-linked polyvinylpyrrolidone                                     
                      10.0                                                
(5) AEROSIL           3.0                                                 
(6) Fumaric Acid      125.0                                               
(7) Powdered triglyceride                                                 
                      6.0                                                 
(8) Magnesium stearate                                                    
                      3.0                                                 
Total:                525.0                                               
______________________________________                                    
 
    
     Preparation 
     Components (1) to (5) were mixed together as described in Example 1. The mixture was moistened, dried, and screened, and components (6) to (8) were finely screened and added. The mixture was compressed. 
     Diameter of punch: 11 mm 
     Radius of curvature: 11 mm 
     The tablets were provided with a flavor-masking coating of hydroxypropyl methylcellulose. The finished film-coated tablets each weighed about 5.25 mg more than the uncoated tablets. 
     Example 8 
     Each tablet had the following composition: 
     
         ______________________________________                                    
Component             Weight (mg)                                         
______________________________________                                    
(1) Mopidamol         250.0                                               
(2) Lactose           91.0                                                
(3) Corn starch       37.0                                                
(4) Cross-linked polyvinylpyrrolidone                                     
                      10.0                                                
(5) AEROSIL           3.0                                                 
(6) Tartaric acid     20.0                                                
(7) Powdered triglyceride                                                 
                      6.0                                                 
(8) Magnesium stearate                                                    
                      3.0                                                 
Total:                420.0                                               
______________________________________                                    
 
    
     Preparation 
     Components (1) to (5) were mixed together as described in Example 1. The mixture was moistened, dried, and screened, and components (6) to (8) were finely screened and added. The mixture was compressed. 
     Diameter of punch: 11 mm 
     Radius of curvature: 11 mm 
     The tablets were provided with a flavor-masking coating of hydroxypropyl methylcellulose. The finished film-coated tablets each weighed about 4.2 mg more than the uncoated tablets. 
     Example 9 
     Each tablet had the following composition: 
     
         ______________________________________                                    
Component             Weight (mg)                                         
______________________________________                                    
(1) Mopidamol         250.0                                               
(2) Lactose           91.0                                                
(3) Corn starch       37.0                                                
(4) Cross-linked polyvinylpyrrolidone                                     
                      10.0                                                
(5) AEROSIL           3.0                                                 
(6) Tartaric acid     45.0                                                
(7) Powdered triglyceride                                                 
                      6.0                                                 
(8) Magnesium stearate                                                    
                      3.0                                                 
Total:                445.0                                               
______________________________________                                    
 
    
     Preparation 
     Components (1) to (5) were mixed together as described in Example 1. The mixture was moistened, dried, and screened, and components (6) to (8) were finely screened and added. The mixture was compressed. 
     Diameter of punch: 11 mm 
     Radius of curvature: 11 mm 
     The tablets were provided with a flavor-masking coating of hydroxypropyl methylcellulose. The finished film-coated tablets each weighed about 4.5 mg more than the uncoated tablets. 
     Example 10 
     Each tablet had the following composition: 
     
         ______________________________________                                    
Component             Weight (mg)                                         
______________________________________                                    
(1) Mopidamol         250.0                                               
(2) Lactose           91.0                                                
(3) Corn starch       37.0                                                
(4) Cross-linked polyvinylpyrrolidone                                     
                      10.0                                                
(5) AEROSIL           3.0                                                 
(6) Tartaric acid     90.0                                                
(7) Powdered triglyceride                                                 
                      6.0                                                 
(8) Magnesium stearate                                                    
                      3.0                                                 
Total:                490.0                                               
______________________________________                                    
 
    
     Preparation 
     Components (1) to (5) were mixed together as described in Example 1. The mixture was moistened, dried, and screened, and components (6) to (8) were finely screened and added. The mixture was compressed. 
     Diameter of punch: 11 mm 
     Radius of curvature: 11 mm 
     The tablets were provided with a flavor-masking coating of hydroxypropyl methylcellulose. The finished film-coated tablets each weighed about 4.9 mg more than the uncoated tablets. 
     Example 11 
     Each tablet had the following composition: 
     
         ______________________________________                                    
Component             Weight (mg)                                         
______________________________________                                    
(1) Mopidamol         250.0                                               
(2) Lactose           91.0                                                
(3) Corn starch       37.0                                                
(4) Cross-linked polyvinylpyrrolidone                                     
                      10.0                                                
(5) AEROSIL           3.0                                                 
(6) Fumaric acid      250.0                                               
(7) Powdered triglyceride                                                 
                      6.0                                                 
(8) Magnesium stearate                                                    
                      3.0                                                 
Total:                650.0                                               
______________________________________                                    
 
    
     Preparation 
     Components (1) to (5) were mixed together as described in Example 1. The mixture was moistened, dried, and screened, and components (6) to (8) were finely screened and added. The mixture was compressed. 
     Diameter of punch: 11 mm 
     Radius of curvature: 11 mm 
     The tablets were provided with a flavor-masking coating of hydroxypropyl methylcellulose. The finished film-coated tablets each weighed about 6.5 mg more than the uncoated tablets. 
     Example 12 
     Each tablet had the following composition: 
     
         ______________________________________                                    
Component          Weight (mg)                                            
______________________________________                                    
(1) Mopidamol      250.0                                                  
(2) Fumaric acid   250.0                                                  
(3) Carboxymethylcellulose                                                
                   97.0                                                   
(4) Polyvinyl acetate                                                     
                   20.0                                                   
(5) Magnesium stearate                                                    
                   3.0                                                    
Total:             620.0                                                  
______________________________________                                    
 
    
     Preparation of 1000 film-coated tablets 
     Components (1) to (3) were mixed together and moistened with a solution of component (4) in 100 ml of acetone. The damp mixture was passed through a screen with a mesh size of 1.6 mm, dried, and passed through the same screen again. Then, component (5) was added. The finished granulate was compressed to form tablets. 
     Punch: 12 mm 
     Radius of curvature: 10 mm 
     The tablets were provided with a flavor-masking coating of hydroxypropyl methylcellulose. This increased the weight of the film-coated tablets by about 6.2 mg apiece. 
     Example 13 
     Each tablet had the following composition: 
     
         ______________________________________                                    
Component             Weight (mg)                                         
______________________________________                                    
(1) Mopidamol         250.0                                               
(2) Tartaric acid     45.0                                                
(3) Lactose           91.0                                                
(4) Corn starch       37.0                                                
(5) Cross-linked polyvinylpyrrolidone                                     
                      10.0                                                
(6) AEROSIL           3.0                                                 
(7) Powdered triglyceride                                                 
                      6.0                                                 
(8) Magnesium stearate                                                    
                      3.0                                                 
Total:                445.0                                               
______________________________________                                    
 
    
     Preparation of 1000 film-coated tablets 
     Components (1) and (2) were triturated and moistened with 50 ml of acetone and then further processed as described in Example 1. Ingredients (3) to (8) were finely screened and added thereto. The mixture was compressed. 
     Diameter of punch: 11 mm 
     Radius of curvature: 11 mm 
     The tablets were provided with a flavor-masking coating of hydroxypropyl methylcellulose. The finished film-coated tablets each weighed about 4.5 mg more than the uncoated tablets. 
     Example 14 
     Each capsule contained the following: 
     
         ______________________________________                                    
Component           Weight (mg)                                           
______________________________________                                    
(1) Mopidamol       250.0                                                 
(2) Fumaric acid    250.0                                                 
(3) CREMOPHOR RH 40 ®                                                 
                    200.0                                                 
(4) Microcrystalline cellulose                                            
                    150.0                                                 
(5) Pyrogenic silicic acid                                                
                     50.0                                                 
Total:              900.0                                                 
______________________________________                                    
 
    
     Preparation of 1000 capsules 
     Components (1) and (2) were thoroughly triturated in component (3), and then component (4) and finally component (5) were added. The finished trituration was packed into size 000 capsules. 
     Example 15 
     Oblong tablets with delayed release of the active substance were prepared. The tablets had the following composition: 
     
         ______________________________________                                    
Component         Weight (kg)                                             
______________________________________                                    
(1) Mopidamol     3.00                                                    
(2) Fumaric acid  2.50                                                    
(3) Pyrogenic silicic acid                                                
                  0.20                                                    
Total:            5.70                                                    
______________________________________                                    
 
    
     The above ingredients were mixed together, compressed in a roller compactor, and granulated. After 0.06 kg of magnesium stearate had been added, the mixture was compressed into oblong tablets. These were sprayed with a solution of methacrylic acid/methacrylic acid ester copolymer and hydroxypropylmethyl cellulose phthalate in a ratio of 2:8 (acetone/iospropanol 1:1) until an intact diffusion membrane formed. 
     Example 16 
     The granulate prepared according to Example 15, by use of a roller compactor and subsequent dry granulation, was mixed with 0.5% magnesium stearate and packed into hard gelatine capsules. 
     Example 17 
     Hard gelatine capsules were filled with pellets having the following composition: 
     
         ______________________________________                                    
Component            Weight (mg)                                          
______________________________________                                    
(1) Tartaric acid    165.0                                                
(2) Mopidamol        200.0                                                
(3) Fumaric acid     105.0                                                
(4) Polyvinyl pyrrolidone                                                 
                     44.0                                                 
(5) Talc             16.0                                                 
(6) Hydroxypropyl methyl-cellulose                                        
                     7.0                                                  
Total:               537.0                                                
______________________________________                                    
 
    
     Preparation 
     Spherical tartaric acid crystals (1) were coated with component (6). After being moistened with component (4), dissolved in isopropanol, the crystals were coated in small batches with a powdered mixture of components (2), (3), and (5) in a suitable coating vessel. After all the powder mixture had been applied, the resulting pellets are screened, dried, and packed into hard gelatine capsules. 
     Example 18 
     Hard gelatine capsules were filled with pellets having the following composition: 
     
         ______________________________________                                    
Component              Weight (mg)                                        
______________________________________                                    
(1) Citric acid        150.0                                              
(2) Mopidamol          200.0                                              
(3) Fumaric acid       105.0                                              
(4) Polyvinylpyrrolidone                                                  
                       30.0                                               
(5) Talc               16.0                                               
(6) Polyoxyethylene-hydrogenated castor oil                               
                       29.0                                               
(7) Hydroxypropyl methyl-cellulose                                        
                       7.0                                                
Total:                 537.0                                              
______________________________________                                    
 
    
     In accordance with the procedure described in Example 17, the isolated citric acid crystals were coated with a mixture of components (2), (3), (5) and (6) using dissolved component (4). The screened pellets were packed into hard gelatine capsules. 
     Example 19 
     Pellets prepared according to Example 18 were sprayed with a solution of hydroxypropyl methyl-cellulose phthalate (acetone/isopropanol (3:7)), dried, and then packed into hard gelatine capsules. 
     The preceding specific embodiments are illustrative of the practice of the invention. It is to be understood, however, that other expedients known to those skilled in the art or disclosed herein, may be employed without departing from the spirit of the invention or the scope of the appended claims.