Abstract:
The invention relates to the novel compound mometasone furoate monohydrate, process for its preparation and pharmaceutical compositions containing said compound.

Description:
This application is a 371 of PCT/US91/06249 filed Sep. 6, 1991. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a novel composition of matter, 9α, 21-dichloro-16α-methyl-1,4-pregnadiene-11β,17α-diol-3,20-dione-17-(2&#39;-furoate) monohydrate, also designated mometasone furoate monohydrate, process for its preparation, and pharmaceutical preparation thereof. 
     Mometasone furoate is known to be useful in the treatment of inflammatory conditions. The compound is prepared by procedures disclosed in U.S. Pat. No. 4,472,393, which patent is hereby incorporated by reference. 
     When aqueous pharmaceutical compositions, e.g. suspensions, containing anhydrous mometasone furoate were subjected to stability testing by rotating for four weeks at room temperature and 35° C., formation of a crystalline material which is different from the anhydrous mometasone furoate crystal was observed in suspension. Experiments were designed to determine the nature of the crystalline material. It was postulated that formulation of mometasone furoate compositions with the stable crystalline form would reduce the probability of crystal growth during long term storage of the suspension leading to a more stable product. 
     SUMMARY OF THE INVENTION 
     The present invention provides mometasone furoate monohydrate of formula I ##STR1## a process for preparing said compound by crystallization from a saturated aqueous water miscible organic solution. The present invention also provides aqueous stable pharmaceutical compositions of mometasone furoate monohydrate. 
    
    
     DESCRIPTION OF THE FIGURES 
     FIG. 1: Infrared spectrum of crystalline mometasone furoate monohydrate 
     FIG. 2: X-ray diffraction pattern of crystalline mometasone furoate monohydrate 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The composition of matter of the present invention, mometasone furoate monohydrate has the following characteristics. 
     Molecular formula C 27  H 30  Cl 2  O 6  H 2  O 
     Formula weight 539.46 
     Elemental Analysis (theory) C=60.11%, H=5.98%; Cl=13.16% (found) C=59.99%; H=5.56%; Cl=13.17% 
     Water Analysis (% H 2  O) (theory) 3.34% (found) 3.31, 3.47 
     The crystalline mometasone furoate monohydrate exhibits an x-ray crystallographic powder diffraction pattern having essentially the values as shown in Table I. 
     
                       TABLE 1______________________________________Angle of      Spacing2θ      d        Relative Intensity(degrees)     (Å)  |/|______________________________________ 7.795        11.3324  10011.595        7.6256   612.035        7.3478   312.925        6.8437   1114.070        6.2893   2214.580        6.0704   514.985        5.9072   1215.225        5.8146   3315.635        5.6631   9616.710        5.3011   1517.515        5.0592   1418.735        4.7324   1220.175        4.3978   1320.355        4.3593   620.520        4.3246   421.600        4.1108   521.985        4.0396   2222.420        3.9622   822.895        3.8811   722.245        3.8234   1423.550        3.7746   1324.245        3.6680   424.795        3.5878   1124.900        3.5729   524.800        3.4503   525.985        3.4262   326.775        3.3268   8427.170        3.2794   1027.305        3.2635   927.710        3.2167   528.385        3.1417   729.165        3.0594   129.425        3.0330   229.725        3.0030   230.095        2.9670   730.255        2.1516   330.490        2.9294   1030.725        2.9075   631.115        2.8720   331.595        2.8294   4732.135        2.7831   632.985        2.7133   733.400        2.6805   233.820        2.6482   234.060        2.6301   834.625        2.5885   434.795        2.5762   235.315        2.5394   136.780        2.4416   2137.295        2.4090   2______________________________________ 
    
     Single crystal data of mometasone furoate monohydrate exhibits the following values as shown in Table II. 
     
                       TABLE II______________________________________Crystallographic Data.sup.aCrystal system triclinicSpace group    P1(C.sup.1.sub.1)-No. 1______________________________________a (Å)      8.481 (1)b (Å)      11.816 (2)c(Å)       7.323 (1)α(°)          95.00 (1)β(°)          110.66 (1)γ(°)          73.27 (1)V (Å.sup.3)          657.5 (3)D.sub.calcd. (g cm.sup.-3)          1.362.sup.______________________________________ 
    
     a An Enraf-Nonius CAD-4 diffractometer (Cu-Kα radiation, incident-beam graphite monochromator) was used for all measurements, Intensity data were corrected for the usual Lorentz and polarization effects; an empirical absorption correction was also applied. 
     The crystal structure was solved by direct methods (RANTAN). Approximate non-hydrogen atom positions were derived from an E-map. Hydrogen atoms were located in a series of difference Fourier syntheses evaluated following several rounds of full-matrix least-squares adjustment of non-hydrogen atom positional and anisotropic temperature factor parameters. Hydrogen atom positional and isotropic thermal parameters were included as variables in the later least-squares iterations which also involved refinement of an extinction correction. Crystallographic calculations were performed on PDP11/44 and MicroVAX computers by use of the Enfra-Nonius Structure Determination Package (SDP). For all structure-factor calculations, neutral atom scattering factors and their anomalous dispersion corrections were taken from International Tables for X-Ray Crystallography, vol. IV, The Knynock Press, Birmingham, England, 1974. 
     Mometasone furoate monohydrate can be prepared by forming a saturated homogeneous solution of anhydrous mometasone furoate in a mixture of water and a water miscible organic solvent. The saturated solution is prepared by dissolving the mometasone furoate in a water miscible organic solvent at the temperature of about 85° C. Hot water, about 85° C., is added dropwise with agitation. After removing the solution from the steam bath, the reaction is stirred for about one hour and then allowed to stand undisturbed overnight while cooling to room temperature. The solution is stirred while adding additional water at room temperature and the solution becomes cloudy and a white precipitate forms. The reaction is allowed to stir for a time, the preciptitate collected by filtration and the product dried to constant weight. 
     Organic solvents that can be employed in the process of this invention must be miscible with water and one in which mometasone furoate is soluble. Examples of water miscible organic solvents include alcohols, such as, ethanol, isopropanol, and the like; ketones, such as acetone, and the like; ethers, such as dioxane, and the like; esters such as ethyl acetate, and the like. The preferred solvents are acetone and isopropanol. 
     In another aspect, the present invention provides pharmaceutical compositions comprising mometasone furoate monohydrate of formula I in an inert pharmaceutically acceptable carrier or diluent. 
     The pharmaceutical compositions according to the invention can be prepared by combining mometasone furoate monohydrate with any suitable inert pharmaceutical carrier or diluent and administered orally, parentally or topically in a variety of formulations. 
     Of particular interest are aqueous suspension compositions of mometasone furoate monohydrate, e.g. for nasal administration. The aqueous suspensions of the invention may contain from 0.1 to 10.0 mg of mometasone furoate monohydrate per gram of suspension. 
     The aqueous suspension compositions according to the present invention may contain, inter alia, auxiliaries and/or more of the excipients, such as: suspending agents, e.g. microcrystalline cellulose, sodium carboxymethylcellulose, hydroxypropyl-methyl cellulose; humectants, e.g. glycerin and propylene glycol; acids, bases or buffer substances for adjusting the pH, e.g. citric acid, sodium citrate, phosphoric acid, sodium phosphate e.g. citrate and phosphate buffers; surfactants, e.g. Polysorbate 80; and antimicrobial preservatives, e.g. benzalkonium chloride, phenylethyl alcohol and potassium sorbate. 
     The following examples illustrate the present invention and the best made of practicing the process of the invention. It will be apparent to those skilled in the art that modifications thereof may be practical without departing from the purpose and intent of this disclosure. 
     General Experimental 
     Infrared absorption spectra were taken as Nujol Mull on a Nicolet FT-infrared spectrometer Model No. 5DXB. X-ray crystallograph powder diffraction patterns were taken on a Philips X-ray diffractometer Model APD-3720 equipped with a radiation source: copper Kα. Decomposition temperatures were measured on a Dupont differential scanning calorimeter, Model No. 990. 
     Moisture content of the crystalline mometasone furoate monohydrate was determined by titration with Karl Fisher reagent. 
     EXAMPLE 1 
     Place 4.5 liters of ethyl alcohol into a suitable vessel equipped with an appropriate agitator and closure. Dissolve 27 g of mometasone furoate anhydrous powder into the ethanol with stirring. Filter the saturated solution and slowly add purified water about 1.5 liters, at a flow rate of approximately 50 ml/minute while stirring at moderate speed. When the solvent mixture reaches a ratio of 1:3 (water:ethanol), the addition of water is stopped and stirring of the reaction mixture is continued for approximately 2 hours to facilitate seeding. Resume addition of water, about 7.5 liters at a rate of approximately 50 ml/minute, until a ratio of 2:1 (water:ethanol) is achieved. Continue stirring to complete crystallization. The crystals are collected by filtration and dried in a vacuum desiccator at room temperature to afford 24.83 g of mometasone furoate monohydrate having an infrared spectrum and X-ray diffraction graph substantially the same as that in FIGS. 1 and 2. 
     EXAMPLE 2 
     Place 24.3 liters of 2-propanol into a suitable container. Dissolve 340 grams of anhydrous mometasone furoate in the 2-propanol by heating the mixture (steam bath) to 85° C. with stirring. After the furoate has dissolved, add dropwise with stirring over 15 minutes 1950 ml of hot (85° C.) water. The hot solution is removed from the steam bath and the solution is stirred for 1 hour. The solution is allowed to cool to room temperature overnight without stirring. The remainder of water, about 24 liters is added with stirring; the solution becomes cloudy and a white precipitate begins to form. The reaction is stirred for one hour, following addition of the water. The white precipitate is collected by filtration, washed with 2 liters of water and air dried overnight. The solid is dried in a draft oven at 50° C. to constant weight. Mometasone furoate monohydrate, 316.5 g, weight yield 90%, is obtained having an infrared spectrum and X-ray diffraction graph substantially the same as that in FIGS. 1 and 2. 
     EXAMPLE 3 
     An aqueous nasal suspension of mometasone furoate monohydrate is prepared from the following: 
     
         ______________________________________         Concentration                    Representative BatchIngredients   mg/g       g/12 kg______________________________________Mometasone furoate         0.5        6.0monohydrateAvicel RC 591*         20.0       240.0Glycerin      21.0       252.0Citric Acid   2.0        24.0Sodium citrate         2.8        33.6Polysorbate 80**         0.1        1.2Benzalkonium chloride         0.2        2.4Phenylethyl alcohol         2.5        30.0Purified water q.s. ad            1.0 g     12.0 kg______________________________________ *Avicel RC591-is a trademark of FMC for a mixture of microcrystalline cellulose and sodium carboxymethyl cellulose. **Polysorbate 80 is a tradename for a mixture of an oleate ester of sorbitol and its anhydride copolymerized with approximately 20 moles of ethylene oxide for each mole of sorbitol and sorbitol anhydride. 
    
     After dispersing the Avicel RC 591 in 6 kg of purified water, the glycerin is added thereto. The citric acid and sodium citrate is dissolved in 240 ml of water, said solution is added to the Avicel-glycerin dispersion with mixing. In a separate vessel, Polysorbate 80 is dissolved in approximately 400 ml of purified water with stirring. The mometasone furoate monohydrate is dispersed in the aqueous Polysorbate 80 solution and; said slurry is then added with stirring to the Avicel-glycerin citric acid mixture. After dissolving benzalkonuim chloride and phenylethyl alcohol in purified water, said solution is added to the suspension mixture with stirring. The suspension is brought to 12 kg with purified water with mixing. The final pH of the suspension is 4.5±0.5. 
     EXAMPLE 4 
     The following compositions were prepared without the suspending agent, Avicel RC-591 to prevent interference in X-ray diffraction studies: 
     
         ______________________________________           Concentration           mg/gIngredients     4A        4B      4C______________________________________Mometasone Furoate           0.5       0.5     0.5Monohydrate MicronizedCitric Acid Monohydrate           2.0       2.0     2.0Sodium Citrate Dihydrate           2.8       --      2.8Sodium Phosphate Dibasic           --        4.0     --Polysorbate 80  0.1       0.1     0.1Benzalkonium Chloride           0.2       0.2     0.2Phenylethyl Alcohol           2.5       --      --Potassium Sorbate           --        3.4     --Propylene Glycol           --        --      100.0Glycerin        21.0      21.0    21.0Water Purified USP q.s. ad              1.0 g     1.0 g                                1.0 g______________________________________ 
    
     These compositions were prepared according to the procedure described in Example 3. 
     The three compositions 4A, 4B and 4C were rotated for five (5) days at 35° C. and a additional four (4) weeks at room temperature to assess crystal form stability. The crystals were isolated from the suspension and X-ray diffraction patterns determined. The results indicated that the crystals collected from each of the three compositions are in the form of mometasone furoate monohydrate. 
     EXAMPLE 5 
     The following compositions were prepared and tested to determine thermal stability of said compositions. 
     
         ______________________________________           Concentration           mg/gIngredients     4A        4B      4C______________________________________Mometasone Furoate           0.5       0.5     0.5Monohydrate MicronizedCitric Acid Monohydrate           2.0       2.0     2.0Sodium Citrate Dihydrate           2.8       --      2.8Sodium Phosphate Dibasic           --        4.0     --Polysorbate 80  0.1       0.1     0.1Benzalkonium Chloride           0.2       0.2     0.2Phenylethyl Alcohol           --        2.5     --Potassium Sorbate           --        --      3.4Propylene Glycol           100.0     --      --Glycerin        21.0      21.0    21.0Avicel RC-591   20.0      20.0    20.0Water Purified USP q.s. ad              1.0 g     1.0 g                                1.0 g______________________________________ 
    
     The compositions were prepared according to the procedure described in Example 3. 
     The compositions were thermally cycled between 4° C. (24 hours) and 30° C. (24 hours) for a period of one month. Microscopic analyses revealed no detectable mometasone furoate monohydrate crystal growth under these conditions.