by way of illustration only , examples of the process conditions used to prepare a stable hydrate mix of dsff will now be described . all examples were run in a virtis pilot drier having an eight square foot shelf area and a condenser temperature of − 56 ° c . 7 . 5 mtorr is equivalent to 1 pa . vials ( 1320 ) having an internal diameter of 21 . 35 mm and a neck diameter of 20 mm were filled with 1 . 6 ml of a solution comprising 100 . 88 mg / ml fosfluconazole in naoh / citric acid , adjusted to ph 9 . 05 , thereby providing 179 . 8 mg of dsff . the vials were placed in the drier and frozen at a shelf temperature of − 30 ° c . for 3 hours . the shelf temperature was then increased to − 15 ° c . and the pressure reduced to 8 pa to facilitate sublimation . the prt was passed at approximately 26 h after the start of ice sublimation and the samples dried for a further 12 hours before terminating the cycle by stoppering at 5 ° c . and 89 . 2 kpa pressure . the product was a stable hydrate mix with a mean water content of 11 . 7 % w / w . temperature /° c . pressure / mtorr time / hrs loading 5 freezing 5 0 . 50 − 30 1 . 47 − 30 4 . 47 evacuation − 30 60 4 . 97 primary drying − 30 60 5 . 13 − 15 60 5 . 55 − 15 60 7 . 55 − 15 60 17 . 55 − 15 60 22 . 55 − 15 60 25 . 55 − 15 60 26 . 55 − 15 60 27 . 55 − 15 60 28 . 55 − 15 60 29 . 55 − 15 60 30 . 55 dehydration phase − 15 60 42 . 55 vials ( 1173 ) having an internal diameter of 22 . 6 mm and a neck diameter of 20 mm were filled with 2 . 8 ml of a solution comprising 100 . 88 mg / ml fosfluconazole in naoh / citric acid , adjusted to ph 9 . 05 , thereby providing 314 . 6 mg of dsff . the vials were placed in the drier and frozen at a shelf temperature of − 30 ° c . for 3 hours . the shelf temperature was then increased to − 15 ° c . and the pressure reduced to 8 pa to facilitate sublimation . the prt was passed at approximately 47 hours after the start of ice sublimation and the samples dried for a further 12 hours before terminating the cycle by stoppering at 5 ° c . and 89 . 2 kpa pressure . the product was a stable hydrate mix with a mean water content of 14 . 6 % w / w . temperature /° c . pressure / mtorr time / hrs loading 5 freezing 5 0 . 50 − 30 1 . 47 − 30 4 . 47 evacuation − 30 60 4 . 97 primary drying − 30 60 5 . 13 − 15 60 5 . 55 − 15 60 7 . 55 prt intervals − 15 60 17 . 55 − 15 60 27 . 55 − 15 60 37 . 55 − 15 60 47 . 55 − 15 60 49 . 55 − 15 60 50 . 55 − 15 60 51 . 55 dehydration phase − 15 60 63 . 55 vials ( 1173 ) having an internal diameter of 22 . 6 mm and a neck diameter of 20 mm were filled with 5 . 4 ml of a solution comprising 100 . 88 mg / ml fosfluconazole in naoh / citric acid , adjusted to ph 9 . 05 , thereby providing 606 . 8 mg of dsff . the shelf temperature was then increased to − 15 ° c . and the pressure reduced to 8 pa to facilitate sublimation . the prt was passed at approximately 96 h after the start of ice sublimation and the samples dried for a further 12 hours before terminating the cycle by stoppering at 5 ° c . and 89 . 2 kpa pressure . the product was a stable hydrate mix with a mean water content of 16 . 9 % w / w . temperature /° c . pressure / mtorr time / hrs loading 5 freezing 5 0 . 5 − 30 1 . 47 − 30 4 . 47 evacuation − 30 60 4 . 97 primary drying − 30 60 5 . 13 − 15 60 5 . 55 − 15 60 7 . 55 − 15 60 17 . 55 − 15 60 27 . 55 − 15 60 37 . 55 − 15 60 47 . 55 − 15 60 57 . 55 − 15 60 67 . 55 − 15 60 77 . 55 − 15 60 87 . 55 − 15 60 88 . 55 − 15 60 89 . 55 − 15 60 90 . 55 − 15 60 91 . 55 − 15 60 92 . 55 − 15 60 93 . 55 − 15 60 94 . 55 − 15 60 95 . 55 − 15 60 96 . 55 − 15 60 97 . 55 − 15 60 98 . 55 − 15 60 99 . 55 − 15 60 100 . 55 dehydration phase − 15 60 112 . 55 in the examples that follow , powder x - ray diffraction patterns were determined using a bruker - axs ltd d8 advance powder x - ray diffractometer fitted with a theta - theta goniometer , gobel mirror and a position - sensitive detector . the samples were prepared for analysis by placing the powder on to silicon wafer specimen mounts . each specimen was irradiated with copper k - alpha 1 x - rays ( wavelength = 1 . 5406 å ) with the x - ray tube operated at 40 kv / 40 ma . the analyses were performed with the goniometer running in continuous mode set for a 0 . 3 second count per 0 . 0140 step over a two theta range of 4 ° to 35 ° 2 . vials ( 582 ), 10 ml type 1 clear glass with a 20 mm neck diameter were filled with 2 . 9 ml of a solution comprising 100 . 88 mg / ml fosfluconazole in naoh / citric acid adjusted to ph 9 . 0 , thereby providing 325 . 8 mg of dsff . the vials were placed in the drier and frozen at a shelf temperature of − 30 ° c . for 3 . 5 hours . the shelf temperature was then increase to − 15 ° c . and the pressure reduced to 6 pa to facilitate sublimation . after 58 . 3 hours of sublimation the cycle was terminated by stoppering at 5 ° c . and 96 kpa pressure . temperature /° c . pressure / mtorr time / hrs loading 5 freezing − 30 3 . 00 − 30 3 . 50 evacuation − 30 45 4 . 25 primary − 30 45 4 . 50 drying / dehydration − 30 45 5 . 00 − 15 45 50 . 00 − 15 45 63 . 30 the product from the above process is found to have a water content consistent with a stoichiometry between the hexa - and trihydrate forms . powder x - ray diffraction ( pxrd ) analysis of the product suggests that immediately after processing it has little long - range order , but that it does , however , have a high degree of crystallinity , see fig1 . the crystallinity of the sample is seen to increase after a storage period of several weeks . the pxrd pattern of the sample can be interpreted as a mixture of tri - and hexahydrate forms of dsff . this mixture is both chemically and thermally stable . the pxrd data corresponding to fig1 follow : pxrd “ initial ” intensity intensity 2 - theta ° % 2 - theta ° % 2 - theta ° intensity % 5 . 011 64 . 3 15 . 826 32 26 . 768 29 . 1 5 . 412 100 17 . 336 45 . 8 29 . 115 24 . 1 5 . 7 75 . 3 21 . 63 41 . 5 30 . 194 24 . 1 9 . 959 25 . 7 22 . 456 64 . 1 31 . 874 24 . 1 11 . 005 32 23 . 089 50 . 2 33 . 175 24 . 1 11 . 545 42 . 3 24 . 802 37 . 4 34 . 824 24 . 9 12 . 33 75 . 2 [ 0038 ] pxrd “ 3 weeks ” intensity intensity 2 - theta ° % 2 - theta ° % 2 - theta ° intensity % 5 . 062 47 . 9 17 . 186 77 . 5 26 . 737 25 . 1 5 . 631 91 . 8 18 . 776 11 . 3 27 . 91 13 . 9 6 . 026 17 . 3 19 . 664 16 . 5 28 . 988 18 . 6 10 . 91 13 . 4 20 . 235 14 . 7 29 . 305 20 . 3 11 . 449 25 . 5 21 . 545 38 . 5 30 . 733 10 . 8 12 . 164 100 22 . 317 59 . 3 31 . 811 15 . 2 13 . 162 24 . 2 23 66 32 . 604 15 . 2 15 . 711 29 24 . 56 32 . 8 34 . 792 19 . 5 16 . 27 25 . 5 25 . 415 28 . 5 not wishing to be bound by any particular theory , it is thought that a significant change in structure , as might on first inspection be implied by the pxrd analysis , does not actually occur ; the molecules within the sample are thought to be in a crystalline array . rather , removal of water molecules during the drying process results in disordered distribution of those water molecules remaining in the sample and , it is believed , it is this disordered distribution of water molecules which disrupts the repetitive long range repeating order ( fig1 — initial ). over time the system equilibrates such that the water molecules redistribute and their resulting distribution no longer disrupts the repetitive long range repeating order ( fig1 - 3 weeks ). fosfluconazole ( 40 g ) was slurried in water ( 120 ml ) and sodium hydroxide ( 7 - 8 ml of a 47 % solution , circa 4 . 9 - 5 . 6 g naoh ) added stepwise , under nitrogen until a solution formed . the temperature was maintained between ambient and 30 ° c . the solution was filtered . sodium hydroxide ( 42 ml of a 47 % solution , circa 29 . 6 g naoh ) was added to the filtrate until precipitation occurred . the mixture was granulated for 4 hours , filtered under vacuum and dried in vacuo at 50 ° c . to afford the title compound ( 23 . 79 g ). pxrd : intensity intensity 2 - theta ° % 2 - theta ° % 2 - theta ° intensity % 4 . 938 8 . 3 19 . 756 5 . 4 28 . 6 17 . 6 9 . 969 7 20 . 14 30 . 8 28 . 722 19 . 8 11 . 038 10 . 1 20 . 709 11 . 6 29 . 092 29 . 5 12 . 114 12 . 9 21 . 625 44 . 4 29 . 986 35 . 7 12 . 383 9 21 . 924 30 . 9 30 . 45 15 . 7 13 . 0 7 . 2 22 . 269 84 . 6 30 . 636 18 . 3 13 . 226 17 . 1 22 . 465 100 31 . 503 29 . 5 14 . 608 3 . 6 23 . 113 20 . 6 31 . 91 32 . 7 15 . 035 23 23 . 604 48 . 4 31 . 997 30 15 . 579 28 . 3 24 . 536 25 . 3 32 . 27 32 . 2 16 . 582 13 . 4 24 . 777 33 . 8 33 . 127 58 . 1 16 . 978 27 . 4 25 . 011 35 . 2 33 . 678 13 17 . 163 9 . 4 25 . 263 67 34 . 302 25 . 9 17 . 477 22 . 7 26 . 549 20 . 2 34 . 693 27 . 8 18 . 307 13 . 6 27 . 19 24 . 5 34 . 976 30 . 3 19 . 232 23 . 6 28 . 416 22 . 3 the title compound was prepared in situ , from circa 5 mg of the dsff hexahydrate of example 5 ( a ), by heating at 60 ° c . on the pxrd stage . pxrd : intensity intensity 2 - theta ° % 2 - theta ° % 2 - theta ° intensity % 5 . 668 49 . 6 17 . 226 93 . 8 26 . 742 31 . 4 11 . 505 23 19 . 563 14 . 9 27 . 815 9 . 8 12 . 183 100 20 . 298 11 . 4 28 . 988 23 . 9 12 . 654 38 . 4 20 . 806 11 . 1 29 . 21 26 13 . 181 21 . 4 21 . 561 41 . 4 30 . 194 15 . 6 13 . 717 15 . 4 22 . 328 70 . 8 30 . 701 11 . 7 14 . 499 9 . 5 22 . 986 69 . 5 31 . 771 23 . 8 15 . 255 7 . 4 24 . 518 41 . 9 32 . 636 21 . 2 15 . 74 32 . 5 25 . 443 34 . 2 34 . 887 28 . 1 16 . 27 21 . 8 fosfluconazole ( 26 mmols , 10 g ) was dissolved in a solution of sodium hydroxide ( 54 mmols , 2 . 179 final volume circa 20 ml ) and heated to 70 ° c . isopropyl alcohol ( 108 ml ), was added , in the temperature range 60 - 72 ° c ., and the cloudy solution left to cool to provide the title compound as a slurry of crystals . a single crystal of dsff hexahydrate was removed therefrom and mounted on a bruker diffractometer . the pxrd of example 6 was consistent with that for example 5 ( a ).