ZA200506943B - Process for preparing cryalline ciclesonide with defined particle size - Google Patents

Description

Process for preparing crystalline ciclesonide with defined particle size

Field of the invention

The invention relates 10 a novel process for preparing crystalline ciclesonide with an advantageous particle size and particle size distribution and to the use for producing phasmaceutical preparations, in particular for topical use. The crystalline ciclesonide obtained by the novel process has advantageous properties, in particular for further processing to inhalable or nasally administered pharmaceutical preparations. :

Known technical backaround

US 4605517 is related to a method of preparing steroid compounds of controlled particle size comprising dissolving the staroid in an omanic solvent, precipitating the steroid by mixing a non-solvent for tha steroid with the resulting solution, and controlling the time of mixing and the degree of agitation during mixing.

Sjoestroem et al. [{. Pham. Sci (1993), 82(6), 584-9) describe a process for preparing small particles of sparingly water-soluble active compounds by precipitation in oil-in-water emulsions. For this purpose, the steroids cholesteryl acetate and B-sitosterol were dissolved in an organic solvent, and an emulsion was prepared with water in the presence of a surfactant. Evaporation of the organic solvent results in a precipitate of the steroid with particle sizes down to 25 nm.

Hem et al. [J. Pharm. Sci (1967), 56(2), 229-233] describe the mechanism of crystallization of hydrocortisone on exposure to ultrasound.

EP 142309 A2 describes the preparation of active compounds by dissolving in an organic solvent and mixing with a non-solvent for the active compound. Epostana was for this purpose dissolved in dimethyl formamide (DMF), and water was added. The precipitate obtained in this way has particle sizes which are within a narrow size range. * Ruch et al. {Joumal of Colloid and Interface Sclence (2000), 229(1), 207-211] describe the preparation of budesonide particles in the micrometer size range by precipitation in an ultrasonic bath. For this pur- pose, water is added to budesonide solutions exposed to ultrasound until a precipitate is obtained or, in : the case whare budesonide Is dissolved in solvent mixtures, the more volatile solvent Is evaporated at rgom temperature.

carrier solvent in order to form an injection solution, and adding the injection solution to an antisolvent which is a supercritical fluid, a compressed, liquefied gas or a dense vapour.

WO 92/08730 describes a process for crystallizing organic substances, especially steroids. For this purpose, the steroid is dissolved in a temary mixture of pophilic solvent, hydrophilic solvent and a surface-active substance, and crystallized. This is said to result in predeterminable and homogeneous particle sizes by non-mechanical means.

WO 00/38811 describes an apparatus for preparing crystalline particles with defined size distribution, in particular particles with a size suitable for inhalation. ] Ciclesonide is the INN (Intemational Norproprietary Name) for a compound with the chemical name . : 16,1 7-(cyclohexyimathylenajbis(oxy)] -11-hydroxy-21-(2-mathyl-1-oxcpropoxy)pregna-1,4-diene-3,20- dionz [11bata, 16aipha (R)]. The preparation of cickasonide and other epimeric preana-1,4-dizne-3,20- dione 16,17-acetal 21-esters with anti-inflammatory effect having a butyl, isopropyl, sec-butyl, cyciohex- yt or phenyl radical on the cyclic acetal ring, and whose C-21 hydroxyl group is acylated by an acetyl or isobutyryl radical, are disclosed in DE-A 41 29 535. Isolation of the respective R epimer starting from an

R/S mixture by preparative high-preszure liquid chrumatearaphy (HPLC) is desciibzd. The international patent application WO 28/08282 41 describes a process for epimer enrichment of the R epimer of ciclesonide by fractional crystallization. For this purpose, ciclesonide in the form of an R/S mixture is dissolved in a suitable water-miscible organic solvent at the boiling point, water is added, and the mixture is cooled to room temperature. The R epimer-enriched ciclesonide obtained in this way must, however, then be subjected to a mechanical micronization in order to obtain the particle sizes and distributions necessary for inhalable pharmaceutical preparations. It would be desirable during the chemical synthesis of ciclesonide to obtain the active compound as product of the process already in form having particle sizes and distribution suitable immediately for further processing to inhalable preparations. This would make it possible to dispense with the additional mechanical micronization and thus possible disadvantages of a mechanical micronization [e.g. risk of contamination, formation of particles which are too small, increased uptake of water owing to the amorphous structures of the micronized product compared with crystalline structures) could be avoided.

Description of the invention . It has now been found, surprisingly, that dissolution of ciclesonide in a water-miscible solvent and sub- sequent addition of this ciclesonide solution to water results in crystalline ciclesonide which - in contrast to the ciclesonide obtained by the process described in WO 98/09982 A1 - has particle sizes which are suitable for inhalation. It is therefore possible in the further processing to inhalable pharmaceutical preparations to dispense with mechanical micronization.

The invention therefore relates to a process for preparing a compound of the formula (0)

Oo, 2 fo)

HO, ET ATA

Formula 1 CH 1©' 0 eu 0" T6 a . in crystalling form, with defined partickz size, comprising the stsps of a) preparation of a solution of the compound of the formula | in a suitable water-miscible organic solvent; b) adding the solution obtained as in a) to water and n) icolating the precipitata of the compound of the formula | which is form.:d.

The compound of tha formula | is a compound with tha chemical name 16,174{({cyclohexyimethyl- ene)bis(oxy)]-11-hydroxy-21-(2-methy-1-oxopropoxy)pregna-1,4-diene-3,20-dione [11beta, 16alpha (R.S)]. The R epimer (based on the absolute configuration at C-22) of this compound has the INN (Internationa! Nonproprietary Name) ciclesonide. The term compound of the formula | encompasses according to the invention the pure R epimer, the pure S epimer, and R/S epimer mixtures in any mixing ratio and also pharmaceutically acceptable solvates of the compound of the formula I.

The procedure for the process of the invention advantageously starts from a compound of the formula which is mainty in the form of the R epimer (based on the absolute configuration at C-22). Mainly in : epimerically pure form means in this connection according to the invention that at least 90%, preferably at least 95%, in particular at least 97%, particularly preferably at least 99%, of the R epimer is present.

Such compounds of the formula t which are mainly in the form of the R epimer can be obtained for example in analogy to the synthesis process described in WO 02/38584 and subsequent acylation or by preparative HPLC or fractional crystallization of R/S epimer mixtures of the compound of the formula | as ) described in the International patent application WO 98/09982.

To carry out the process of the invention, the compound of the formula | is dissolved in a suitable water-

miscible organic solvent. Suitable water-miscible organic solvents which may be mentioned according to the invention are alcohols such as, for example, methanol, ethanol, N-propano! and isopropanol, acetone, tetrahydrofuran (THF) or dimethyiformamide (DMF) and mixtures thereof in any mixing ratio. it is expedient for the solvent to have a temperature during this of from 10°C to the boiling point of the solvent, preferably a temperature of from 15°C to a temperature which is 10°C below the boiling point of the solvent, in particular from 15°C to 35°C, particularly preferably from 20°C to 25°C, and the solvent is vary particularly preferably at room temperature (i.e. temperature of the solvent comesponds to the temperature of the room where the process is camied out). The subsequent addition of this solution to water expediently takes place with stirring and while maintaining the temperature of the solvent. The addition particularly preferably takes place by dropwise addition. The temperature of the water is according to the invention preferably from 10°C to 50°C, preferably 15°C to 40°C, very particularly preferably 20°C to 30°C. In a preferred embodiment, the water is at room temperature (i.e. temperature of the water corresponds to the temperature of the room where the process is carried out). The amount of . the sotvent used to dissolve the compound of the formula | depends on the nature of the solvent and the temparature. i is expedient to use at feast sufficient solvent for the compound of the formula 1 10 be : complately dissolved, preferably someivhat more. The amount of viater employed in the procass of tha invention is expediently to be chosen so that the dissolved compound of the formula | is precipitated in quantitative form after addition to the water.

The precipitate which is formed is isolated according to the invention preferably by removira the pre- cipitats from the solution, in particular by fittaring off the precipitate, vrashing the precipitate with water and subsequently drying.

The process of the invention results in the compound of the formula | with a defined particle size. The defined particle size is according to the invention a particle size and particle distribution suitable for in- halation. A form suitable for inhalation means particle sizes having an aerodynamic diameter between 1 and 10 um, preferably in the range from 1 to 5 um, particularly preferably 1 to 3 ym. Preparations which are preferred in this connection are those for which the particle size determination shows an X%g (unit: pm] of less than or equal to 10, preferably 7.5, very preferably 3, particularly preferably 2. An Xe in the range from 1.8 to 2.0 Is to be particularly emphasized according to the invention. The Xin the particle size determination means that the particle diameter for 50% of the total volume of all the par- ticles is less than the stated value. Determination of the particle size distribution is possible, for ex- . ample, by laser diffraction on the solid substance by known methods. It Is preferred according to the invention for the particle size distribution to be determined according to by the dry measurement method like that used for example in the Sympatec HELOS-LASER difractor or an equivalent instrument {the

R instrument parameters on the Sympatec HELOS-LASER diffractor can be set as follows, for example: measurement time (5 s), time base (1 000 ms), reference measurement duration (5 s), measurement rangefiens (R2 0.25/0.45 ..87.5 um), starting condition (0.000 s after starting button), dispersing module

(RHODOS + VIBRI), evaluation mode (HRLD), bed height (2 mm), output (50%), dispersing pressure (3.50 bar, permitted variation in the actually measured pressure is 3.30 bar to 3.70 bar and evaluation of the Fraunhofer diffraction diagram).

Preference is given according to the invention to a crystalline inhalable form of the compound of the formula | having a maximum proportion of particles with the particle size in the range from 1.5 pum to 7.5 pm, preferably 1.75 pm to 6.5 pm, particularly preferably 1.85 um to 5.5 um, in particular 2 pm to pm. (This range represents the inhalable fraction which, because of its size, is not deposited directly in the mouth or throat on inhalation or is exhaled again because of its fineness). An exemplary embodi- ment of the invention is a crystalline inhalable form of the compound of the formuia | in which a maximum of 55% [vol.] of the particles are smaller than or equal to 1.85 um, and at least 75% [vol.] are smaller than or equal to 4.5 ym. The compound preferably is not in micronised form. Micronised form : according to the invention means that the compound has bean subject to a mechanical micronizatior: : step (8.9. mechanical milling). [.

Th2 compourd of the formula | can be prepared in a manner inovn per se, for axampls as described in

DE -A 41 29 535. Altematively, the compounds of the formula | can also be prepared starting from the corresponding 21-hydroxy compounds of the formula 1)

NAOH

HO Jt CH, Mo ~22 t CH 16' O Formula ll

SUL

0"

H by acylation with a suitable acylating agent. Such 21-hydroxy compounds are described for example in

WO 95/24416 and WO 02/38584. The acylation can in this case take place in a manner known to the skilled person, e.g. as described in WO 98/09982.

The invention therefore further also relates to a process for preparing a compound of the formula

0, 0 2 bent

HO, Hy .o ) 1 CH gn" ! “SNL Formula

SUL oo x

H in crystalline form with defined particle size, comprising the steps of

Co a) preparing a compound of the formula | by acylation of a compound of the formula Il with a suitable acylating agent; b) crystallizing the compound of the formula | obtained in a) by adding water to solution of ths compourd in a suitable water-miccible organic solvent or heating a suspancion of tha compound of the formula | in a mixture of a suitable water-miscible organic solvent and water, c) removing the resulting R epimer-enriched precipitate of the compound of the formula § from the water/solvent mixture; d) it devired repeating step b); €} preparing a solution of the compound obtained in c) in a suitable watar-mizcible organic solvent; f) adding the solution obtained as in e) to water and g) isolating the precipitate which has been formed of the compound of the formula I.

To carry out steps a), b) and ¢) of the process of the invention, the R/S epimer mixture of the formula | is dissolved in a suitable water-miscible organic solvent, expediently at elevated temperature, in particular at the boiling point of the solvent used. The subsequent addition of water 10 this solution expediently takes place with stirring and while maintaining the elevated temperature, in particular the boiling point, with a cooling, preferably to room temperature, taking place with stirring after the addition of water is complete. Altematively, the R/S epimer mixture of the formula | can be suspended in a mixture of water and a suitable water-miscble organic solvent and be dissolved by heating, in particular to the boiling . point of the solvent mixture. The solution is subsequently cooled while stirring, preferably to room temperature. The cooling advantageously takes place slowly, preferably over a period of from 2 to 10 hours. The subsequent fractional crystallization can advantageously be influenced by adding crystal- . lization nuclei (e.g. seed crystals), preferably using seed crystals of the pure R epimer of the formula | in each case. Examples of suitable water-miscible organic solvents which may be mentioned for step b) of the process of the invention are acetone or, in particular, alcohols such as isopropanol, npropanol,

methanol and, preferably, ethanol, and mixtures thereof in any mixing ratio. it is expedient to use for dissolving 0.18 mol of R/S epimer mixture of the formula | 190-700 ml of the suitable water-miscible organic solvent, preferably 300-400 mi. The ratio of the water to the water-miscible organic solvent by volume is preferably in the range between 0.1-1 [v/v], in particular between 0.25-0.75 [viv].

The subsequent removal [step c)] of the R epimer-enriched R/S epimer mixture of the formula | from the solution takes place in a manner known to the skilled person, in particular by filtration.

The procedure for the process of the invention advantageously starts from compounds of the formula | in which the R epimer is already enviched, for example the R epimer content is > 75%, in particular > 85%.

The acylation in step a) moreover takes place in a manner known to the skilled person, e.g. as described in the examples by acytation with suitable acylating agents such as isobutyric anhydride.

The crystalline compound of the formula | with defined particle size obtained by the process of the ’ invention can then ba furthsr processed to pharmacautical praparations (preferably without further micronization stp), where appropyiate in combination with furthar pharmaczutical active compounds.

The compound of the formula | are employed in the pharmaceutical preparations either as such or, preferably, in combination with suitable pharmaceutical excipients, e.g. in the form of tablets, coated tablets, capsules, suppositories, plasters, emulsions, suspensions, gels or solutions, with the active compound conient ack-antagzously being between 0.1 and 5%. Pharmacautical preparations which are preferably mentioned are those for topical administration through the lungs and throuah mucous membranes, especially the nasal mucosa.

The excipients suitable for the desired pharmaceutical preparation are familiar to the skilled person on the basis of his expert knowledge. Besides solvents, gel formers, ointment bases and other active com- pound carriers, it is possible to use for example antioxidants, disparsants, emulsifiers, preservatives, solubilizers or permeation promoters.

The compound of the formula | obtained by the process of the invention is administered for the treatment of disorders of the respiratory tract preferably in inhaled form. For this purpose, the compound of the formula | is administered either directly as powder or atomization of solutions or suspensions containing it. The substances are for this purpose preferably administered by inhalation in the form of aerosols, with , the aerosol particles of solid, iquid or mixed composition having a diameter of from 0.5 to 10 pm, advantageously from 2 to 6 pm. . The aerosol can be generated for example by pressure-operated nozzle nebulizers or ultrasonic nebu- lizers, but advantageously by propellant gas -operated metered aerosols or propellant gas-free use of micronized active compounds from inhalation capsules.

Depending on the inhaler system used, the pharmaceutical preparations comprise besides the active compounds also the necessary excipients such as, for example, propellant gases (e.g. HFA 134a or 227), solvents (e.g. ethanol), surface-active substances, emulsifiers, stabilizers, preservatives, aro- matizing agents, fillers (e.g. lactose for powder inhalers) or, where appropriate, further active com- pounds.

Pharmaceutical preparations of ciclesonide suitable for inhalation or for administration to nasal mucosa, and the production, are described for example in US 6120752, US 6264923, W001/028562,

WO01/028563 or DE 19541689. The pharmaceutical preparations can be produced by processes known to the skilled person. Normally, the active compounds (i.e. the compound of the formula |, if desired combined with further active compounds) are mixed with a carrier, which consists of one or more excipients. In this cass, the active compounds are generally finaly divided in sofid and/or liquid carriers : and then further processed to the desired pharmaceutical preparation.

For inhalation purpo: 2 there are available a large numbar of appliances with which asiosoi: of optimal particle size can be generated and administered using an inhalation technique which is as appropriate as possible for the patient. Besides the use of attachments (spacers, expanders) and pear-shaped containers (e.g. Nebulator®, Volumatic®) and automatic delivery actuations (Autchater®) for metered aerosols, a ses of technical colutions are available in particular for poveder inhalers (e.g. Diskhalerd,

Rotadisk®, Turbohalent or the technologies dascribed in EP 0 505 321, EF 407028, EP 650-410, EP 691865, EP 725725, WO 99/21601, US 6120752 or US 6264923), with which optimal administration of active compound can be achieved.

Concerning the composition and production of pharmaceutical preparations for nasal administration, reference is made for example to WO 01/28562 and WO 01/28563.

The following examples illustrate the invention further without restricting it. RT stands for room temperature, min tor minute(s), h for hour(s), m.p. for melting point and abs. for absolute.

Examples 1 size 16,17{(Cyclohexylmethylene)bis(oxy)}-11-hydroxy-21-(2-methyl-1-oxopropoxy)pregna-1 4-diene-3,20- dione {11beta, 16atpha (R,S)] is dissolved at the temperature indicated in the table in the appropriate amount of ethanol. The solution is added dropwise, while maintaining the temperature and with vigorous stirring, to the stated amount of water at the stated temperature of the water. The precipitate is fittered off with suction, washed with water and dried.

The J In the table ks determined by laser diffraction by the dry measurement method in a Sympatec : HELOS-LASER diffractor or an equivalent instrument [paramaters: measuresnont time (5 s), time base : (1 000 ms), reference measurement duratian (5 s), measurement rangefiens (R2 0.25/0.45 ..87.5 pm), cot starting condition (0.000 ¢ after starting button), dispersing module (RHOD:OS + VIBRI), evaluation mode ! BE {HRLD), bad height (2 mm), output (503%), dispersing pressure (3.50 bar, pzrmitted variation of the actually measured pressure is 3.30 bar to 3.70 bar and evaluation of the Fraunhofer diffraction diagram].

In contrast to the crystakization process described in WO 98/09982, no epimer enrichment is observed.

Example Ethane Voter Water tons. | Vield eh

I al ey ve rl

EE CN CN NN CLAN CC CO

EN ECON CA CN CN CR

EN LCR CN SC A CE

EE CN LA LET LL CR CC

EH CEC CN I EC LO

I CCR LN CEI CN CC

EA CA CLA ICR LA CA

EN CA LAN EI CN CA ER

EHR COU AN ECO CO CA

RCH CONN A CORN CN CAN CO

SER CR CCR CN CON CN

EH CC CN ECON CON CN CO

EH CO COR CAN CN CO

SAREE CN CNN CHM (HN CN

EC CN CR CC CA

ECHR CN CCR ECR CON CA

2

WO 98/09982 2.1 316 g (584 mmol) of 16,17-[(cyclohexylmethylene)bis(oxy)] -11-hydroxy-21-(2-methyl-1-oxopro- poxy)pregna-1,4-diene-3,20-dione [11beta, 16alpha (R,S)), referred to as A hereinafter, (crude product, oil, R/S epimer ratio about 90/10) ase dissolved in 1.1 | of abs. ethanol and, while boiling, 700 ml of water are added. The mixture is allowed to reach RT while stirring vigorously, and the precipitate is fitered off with suction, washed with 500 mi of abs. ethanol/water: 2/1 and dried in a vacuum oven at 50°C for 5 h.

Yield: 237 g (438 mmol, 75%) of A, R/S epimer ratio about 95/5. mp.: 199-201<C

The product is dissolved in 900 ml of abs. ethanol and, while boiling, 650 mi of water are added, and the . : ! product is isolated as stated above. Lo :

Yield: 209 g (386.5 mmol, 88%) of A, R/S epimer ratio about 97/3. m.p.: 201-203°C

The product iz discolved in 800 mi of abs. ethanol and, while boiling, 459 ml of water are added, and the product is isolated as slated above.

Yield: 178 g (329 mmol, 85%) of A, R/S epimer ratio about 98.5/1.5. mp.: 205-206°C

The product is dissolved in 600 mi of abs. ethanol and, while boiling, 350 m! of water are added, and the product is isolated as stated above.

Yield: 161 g (298 mmol, 90.5%) of A, R/S epimer ratio > 99.5/0.5. m.p.: 206.5-207°C 22 15g (2.77 mmol) of A (R/S epimer ratio about 89/11) are dissolved in 3 ml of abs. methanol and, . while botling, 1 ml of water is added. The mixture is allowed fo reach RT while stirring, and the precipitate is filtered off with suction, washed with a little methanolwater = 3/1 and dried as above. . Yiald: 1.21 g (80.6%) of A, R/S epimer ratio about 93:7. 23 59 (9-25 mmol) of A (R/S epimer ratio about 91.5/8.5) are dissolved in 15 ml of boifing i WO 2004/085460 PCT/EP2004/050373 isopropanol, and 10 ml of water are added. The mixture is allowed to reach RT while stirring, and the precipitate is filtered off with suction, washed with a little isopropanol/water = 2/1 and dried as above.

Yield: 4g (80%) of A, R/S epimer ratio about 94/6. 2.4 1.59 (2.77 mmol) of A (R/S epimer ratio about 89/11) are dissolved in 4 ml of boiling acetone, and 1 mi of water is added. The mixture is allowed to reach RT while stirring, and the precipitate is filtered off with suction, washed with a little acetone/water = 2/1 and dried as above.

Yield: 1.12 g (75%) of A, R/S epimer ratio about 95/5. 2 Lwvalies for 1817 (evclnhie:nkantiriene)vic(nxil-11-hrdrons21-(2-metiyl- : Co co crystallization hy the wanes daceribhd in) WO QYNEIR2

The following table contains Xe, values for 16,17-[(cyclohexylmethylene)bis(oxy)}-11-hydroxy-21-(2- methyl-1-oxopropoxy)pregna-1,4-diene-3,20-dione [11beta, 16alpha (R,S)] obtained by the process described in WO 98/09982 (see Exampis 2). The Xx is determined by a suitable process. The ethanol/water column relates 10 the ratio of ethanol to vaater by volume used for the crystallization.

Example Ethanoliwater Ro (am)

I CN LS

Result: the 16,17-((cyclohexylmethylene)bis(oxy)}-11-hydroxy-21-{2-methyl-1-oxopropoxy)pregna-1,4- diene-3,20-dione [11beta, 16alpha (R,S)] obtained by the process described in WO 98/09382 has : distinctly higher Xe values. These are not in the range of X%,, values of particle sizes suitable for inhalation.

A: 3.20-dione [11beta, 16alpha (R.S)} g of 16,17-[(cyclohexylmethylene)bis(oxy)]-11,21-dihydroxypregna-1,4-diene3,20-dione [11bsta, 16aipha (R.S)] and 6 g of potassium carbonate are suspended in 50 mi of acetone and, while stirring, 4.4 ml of isobutyric anhydride are added, and the mixture is heated under reflux for 2.5 h. After cooling to RT, 100 ml of water are slowly added to the suspension. The product is filtered off with suction, washed with water and dried. The enrichment of the R epimer takes place as described above.

Yield of crude product: 11.4 g (99.3% of theory) of 16,17-{(cyclohexytmethylene)bis(oxy)]-11-hydroxy-21- (2-methyl-1-oxopropoxy)pregna-1,4-diene-3,20-dione [11beta, 16alpha (R,S))

Determination of the epimer ratios for coinpeunds of the formula | :

The epimer ratios are determined by HPLC.

HPLC conditions:

Column mate rial: Hypersil C18, 5 pm, 125%4.6 mm

Detector vavelength: 242 nin

Sample concentration: 0.51.5 mg/ml

Volume loaded: 20

Flow rate: 1 ml/min

Oven temperature 20°C

Compound A: eluent water (459)/ethanol (55%)

Claims (1)

1. Claims

   1. Process for preparing a compound of the formula 0] (0) 21 oO . HO, {Hs UT) Formula 1 CH} 6 O SUL 0” x EN in crystalline form, with dafinad particle size, comprising the steps of a) preparation of a solution of the compound of the formula | in a suitable water-miscible organic solvent; b) adding the solution obtained as in a) to water and c) isolating thz precipitate of the compound of the formula | which is formed.

   z. Process according to Claim 1, characterized in that the suitable water-miscible organic solvent ic an alcohol. 3 Process according to Claim 2, characterized in that the alcohol is selected from the group of methanol, ethanol, N-propano! and isopropanol or mixtures in any mixing ratio thereof.

   4. Process according to Claim 3, characterized in that ethanol is involved.

   5. Process according to Claim 1, characterized in that acetons, tetrahydrofuran or dimethytformamide is involved.

   6. Process according to Claim 1, characterized in that the temperature of the suitable water-miscible organic solvent is in the range from 15°C to 10°C below the boiling point of the solvent.

   7. Process according to Claim 6, characterized in that the temperature of the suitable water-miscible organic solvent corresponds to the room temperature at which the process is carried out.

   8. Process according to Claim 1, characterized in that the temperature of the water is from 10 to 50<C.

   9. Process according to Claim 7, characterized In that the temperature of the water corresponds to the room temperature at which the process is camied out.

   10. Process according to Claim 1, characterized in that the compound of the formula | has the chemical name 16,17-f(cyclohexylmethylene)bis(oxy)}-11-hydroxy-212-methyi-1-oxapro- poxy)pregna-1,4-diene-3,20-dione [1 1beta, 16alpha (R,S)].

   11. Process according to Claim 1, characterized in that the compound of the formula 1 is substantially in the form of the R epimer. 12 Process according to Claim 11, characterized in that the proportion of R epimer in the compound : : . of the formula | is more than 25%.

   13. Process according to Claim 11, characterized in that ciclesonide is involved.

   14. Process according to Claim 1, characterized in that the precipitate obtained after step c) is subsequently dried.

   13. Process for preparing a compound of the formula | according to Claim 1 in crystalline form with defined particle size, comprising the steps of a) preparing a compound of the formula | by acylation of a compound of the formula II Oo A-0H HO hs QT 1 CH i ‘0 Formula SUL o 4 6 H with a suitable acylating agent; : b) crystallizing the compound of the formula | obtained in a) by adding water 10 a solution of the compound in a suitable water-miscible organic solvent or heating a suspension of the compound of the formula | in a mixture of a suitable water-miscible organic solvent and water, c) removing the resulting R epimer-enriched precipitate of the compound of the formula | from the water/solvent mixture; d) if desired repeating step b); e) preparing a solution of the compound obtained in ¢) in a suitable water-miscible organic solvent; fi adding the solution obtained as in e) to water and g) isolating the precipitate which has been formed of the compound of the formula I.

   16. Process according to Claim 1, where the particle size is characterized by an X% of less than or equal to 10.

   17. Process according to Claim 16, where the particle size is characterized by an Xs of in the range ’ from 1.8 to 2.0. n 17, Progece according to Claim 15, where the organic solvents used in steps b) and +s) are tha same solvents.

   18. Compound of the formula | obtainable according to Claim 1 without further micronization step, vrherg the compound is in inhalable form.

   20. Compound according to Claim 19, where the particle size of the compound of the formula | has an Xu in the range from 1.8 to 2.0.

   21. Compound according to Claims 19 or 20, which compound is not in micronized form.

   22. Crystalline ciclesonide with a particle size characterized by an X of less than or equal to 10.

   23. Crysialline ciclesonide with a particle size characterized by an X, of in the range from 1.8 to 2.0.

   24. Crystalline ciclesonide according to Claims 22 or 23, which ciclesonide is not in micronized form. } 25. Phamaceutical composition comprising a compound according to Claims 19 to 24, which compound is present as solid particles together with pharmaceutically acceptable excipients. . 26. Pharmaceutical composition according to claim 25, which Is an aqueous suspension of the compound.