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Synthesis and characterization of sulfathiazole-pyridine solvate polymorphs
ARTICLE IN PRESS
Journal of Crystal Growth 274 (2005) 569–572 www.elsevier.com/locate/jcrysgro
Synthesis and characterization of sulfathiazole-pyridine solvate polymorphs M.A. Mikhailenkoa, T.N. Drebushchaka,b, V.A. Drebushchaka,c,, E.V. Boldyrevaa,b, V.V. Boldyreva,b a
Research and Education Center ‘Molecular Design and Ecologically Safe Technologies’, REC-008, Novosibirsk State University, ul. Pirogova, 2, Novosibirsk, 630090, Russia b Institute of Solid State Chemistry, Siberian Branch of the Russian Academy of Sciences, ul. Kutateladze, 18, Novosibirsk, 630128, Russia c Institute of Mineralogy and Petrography, Siberian Branch of the Russian Academy of Sciences, pr. Koptyuga, 3, Novosibirsk, 630090, Russia Received 28 September 2004; accepted 23 October 2004 Communicated by R. Kern Available online 8 December 2004
Abstract Tetragonal and monoclinic polymorphs of sulfathiazole-pyridine solvate (C9H9N3O2S2dC5H5N) were crystallized from propanol–pyridine solutions. The two polymorphs are unstable under ambient conditions but can be stored for a long time under pyridine vapor. TG and DSC of freshly prepared samples prove the decomposition of the solvates with pyridine vapor and sulfathiazole I as products. Thermodynamic estimate shows that the decomposition can be considered just a sum of two processes: (1) high-energy sublimation of pyridine and (2) low-energy structural transformation of the remaining sulfathiazole. r 2004 Elsevier B.V. All rights reserved. PACS: 61.10.Nz; 64.60.My; 81.70.Pg; 82.30.Lp; 82.60.Fa Keywords: A1. Recrystallization; A2. Growth from solutions; B1. Organic compounds; B2. Drugs
One of the most important problems in the investigation of crystalline pharmaceutical solids, Corresponding author. Institute of Mineralogy and Petrography, Siberian Branch of the Russian Academy of Sciences, pr. Koptyuga, 3, Novosibirsk, 630090, Russia. Tel.: +7 3832 332112; fax: +7 3832 332792. E-mail addresses: [email protected], [email protected] (V.A. Drebushchak).
molecular crystals, is the reproducible preparation of a particular polymorph [1]. Varying crystallization conditions (solvent, temperature, time, external fields, etc.), one can receive different polymorphs. In following this way, we faced a new problem of the polymorphism among solvates formed by the ‘‘highly polymorphic’’ drug compounds. Pure sulfathiazole forms five crystalline
0022-0248/$ - see front matter r 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jcrysgro.2004.10.067
ARTICLE IN PRESS 570
M.A. Mikhailenko et al. / Journal of Crystal Growth 274 (2005) 569–572
polymorphs [2], and, furthermore, over 100 solvates of sulfathiazole were described [3]. In the present communication we report on the crystallization of two polymorphs, tetragonal and monoclinic, of a new 1:1 sulfathiazole:pyridine solvate (C9H9N3O2S2dC5H5N). Sulfathiazole (Merk, ‘‘for synthesis’’, 498% purity) was purified by recrystallization in water with transparent crystals of sulfathiazole III [4] as a product. Then the crystals were dissolved in a mixture of pyridine and propanol. Pyridine was distilled twice, and propanol-1 (Merk) was used ‘‘as received’’. C9H9N3O2S2dC5H5N polymorphs were crystallized from the propanol–pyridine solution (60 mL) of sulfathiazole (1.5 g) at ambient temperature under its slow evaporation. The solution was filtered (blue band), but not boiled. The first crystals appeared after about a half of the solution has evaporated. For a successful crystallization of the polymorphs, it was very important not to be in a hurry. The solution prepared must be stored for weeks to guarantee the proper crystallization. Previously, when crystallizing unstable b-glycine, we found that seemingly the same procedure could yield either g- or b-polymorphs [5]. The reason was in the time of the preliminary storage of the solution: freshly prepared solution produced gglycine, whereas that stored for a month yielded bglycine. Dipyramidal crystals up to 5 mm large (later shown by single-crystal X-ray analysis to have a tetragonal structure) grew from the 2:1 (40 mL propanol+20 mL pyridine) solution. Prismatic crystals (3 mm long, 0.5 mm across) grew from the propanol–pyridine solution of 1:2 (20 mL propanol+40 mL pyridine). Single-crystal X-ray analysis has shown them to have a monoclinic structure. Crystals of both polymorphs of C9H9N3O2S2 C5H5N were well-shaped and transparent. X-ray powder diffraction patterns of the crystallized samples were measured using D8 GADDS (Bruker). The measurements were carried out over the range of 2Y angles from 51 to 361, CuKa radiation. Diffraction patterns for both polymorphs are listed in Table 1. Structure of the polymorphs was solved using single-crystal X-ray
Table 1 X-ray diffraction patterns for tetragonal and monoclinic polymorphs of C9H9N3O2S2dC5H5N Tetragonal
Monoclinic
d (A˚)
Int (%)
h
k
l
d (A˚)
Int (%)
h
k
l
8.636 8.017 6.694 5.891 5.442 5.246 4.603 4.496 4.340 4.245 3.986 3.881 3.814 3.686 3.641 3.456 3.395 3.344 3.240 3.116 3.024 2.945 2.848 2.786 2.742 2.715 2.680 2.651 2.595 2.553
27 19 25 20 14 13 47 46 35 15 50 14 76 19 10 22 81 6 6 18 7 4 100 40 24 34 23 14 4 12
1 1 1 1 1 0 1 1 2 2 1 2 2 2 2 1 2 2 1 2 1 2 2 3 3 3 1 1 2 3
0 0 0 1 0 0 1 0 0 0 1 1 1 0 1 1 1 0 0 1 1 2 1 0 1 1 1 3 1 1
0 1 2 1 3 4 3 4 0 1 4 0 1 3 2 5 3 4 6 4 6 2 5 2 0 1 7 2 6 3
10.114 8.212 7.030 6.844 6.132 5.918 5.679 5.468 4.980 4.710 4.621 4.451 4.132 4.026 3.821 3.726 3.684 3.602 3.538 3.355 3.289 3.187 3.150 3.055 3.014 2.955 2.885 2.803 2.776 2.735 2.601
20 21 21 28 82 8 8 21 88 19 100 91 40 9 52 85 31 28 46 10 38 6 7 56 18 14 10 7 16 14 15
0 1 1 0 1 1 1 0 1 1 0 0 2 1 0 2 1 2 2 2 2 0 1 0 2 1 1 2 3 0 1
0 0 0 1 1 0 1 1 1 0 2 1 0 2 2 1 1 0 1 1 1 1 1 2 1 0 3 2 0 2 3
2 0 2 2 1 2 1 3 2 4 0 4 0 1 3 2 4 2 3 2 4 6 6 5 5 6 1 4 2 6 3
diffraction technique (STADI-4 four-circle diffractometer Stoe, Darmstadt). Atomic coordinates and data collection parameters are to be published. Tetragonal polymorph has the space group P41, unit cell parameters are a ¼ 8:681ð3Þ; c ¼ ( Monoclinic polymorph has the space 20:934ð13Þ A: group P21/c with unit cell parameters a ¼ 8:374ð4Þ; ( b ¼ 100:18ð3Þ1: The b ¼ 9:265ð3Þ; c ¼ 20:682ð9Þ A; powder diffraction patterns calculated on the basis of single-crystal structure solution were in good agreement with the experimentally measured spectra. The single-crystal diffraction data were used for indexing the reflections listed in Table 1.
ARTICLE IN PRESS M.A. Mikhailenko et al. / Journal of Crystal Growth 274 (2005) 569–572
Both tetragonal and monoclinic polymorphs turned out to be unstable and could not be stored under ambient conditions for a long time. They decomposed readily to give pyridine (evaporates) and sulfathiazole (polymorph I [4]). The decomposition started giving small white spots at the faces and edges of the crystals, probably at the crystal defects. The spots did not increase in number but grew in size. The spots gradually expanded, merged, and formed a white ‘‘skin’’ covering the surface of the starting crystal. When exposed to air, it took about one day to transform a transparent single crystal into a white pseudomorph. In a closed bottle under pyridine vapor, the crystals could be stored for a long time without traces of the decomposition. Such a stock was completely depleted in experiments for several weeks, special experiments on the duration of the storage were not carried out. The decomposition of the polymorphs on heating was investigated using TG-209 and DSC204 (Netzsch). Within the limits of experimental error, the mass loss agrees well with the theoretical value of 23.66% for the reaction C9 H9 N3 O2 S2 dC5 H5 N ! C9 H9 N3 O2 S2 þ C5 H5 N " :
Fig. 1 shows the results of DSC measurements of a freshly prepared single crystal of tetragonal polymorph (5.53 mg) at a heating rate of 6 1C min1. The decomposition started near 80 1C. At the
Fig. 1. DSC results of tetragonal polymorph of sulfathiazolepyridine solvate with the decomposition (100–140 1C) and melting of pure sulfathiazole (201.8 1C).
571
beginning, the shape of the peak was typical of a thermally activated reaction. When the decomposition reached a high rate, a smooth line of heat flow broke indicating the instability in the reaction. The decomposition finished just above 140 1C. Enthalpy of the decomposition was 155 J g1. Sulfathiazole I (melting at 201.8 1C, enthalpy of the melting 79 J g1) was formed as the solid product of the decomposition. Decomposition of 1 mole of the solvate is accompanied by the release of 1 mole of gaseous pyridine. Recalculated to the mass of pure pyridine, the enthalpy of the decomposition is Ddec H ¼ 51:8 kJ mol1 : On the other hand, pure crystalline pyridine melts at 42 1C (Dfus H ¼ 8:3 kJ mol1 ) [6] and then boils at 115 1C (Dvap H ¼ 40:2 kJ mol1 ) [7]. These three transformations take place at three different temperatures. To compare the changes of thermodynamic function at the transformations, one should use entropy instead of enthalpy: Ddec S ¼ 132 J mol1 K1 ; Dfus S ¼ 36 J mol1 K 1 and 1 1 Dvap S ¼ 90 J mol K : Entropy of decomposition of the solvate is close to the sum of fusion and evaporation of pure pyridine. The difference Ddec S Dfus S Dvap S ¼ 6 J mol1 K1 is equivalent to the changes in the enthalpy of the solvent decomposition of about 7 J g1. It can be attributed to the changes in energy of crystalline structures at the decomposition of the solvate, for it is close to the measured enthalpies by the order of magnitude. For example, the enthalpy of orthorhombic-monoclinic transformation in paracetamol is 2–3 J g1 [8,9], about 3 J g1 for b– a transformation in glycine [5] and about 20 J g1 for g– a in glycine [10]. For pure sulfathiazole, the enthalpy of transformation is about 30 J g1 for III–I [11] and about 25 J g1 for II–I (our unpublished data). The transformations with small enthalpies (orthorhombic-monoclinic in paracetamol and b– a in glycine) take place under ambient conditions spontaneously, like the decomposition of the sulfathiazole solvates, but the rest (g– a in glycine, III–I and II–I in sulfathiazole) only at heating. That rough thermodynamic estimate shows that thermal decomposition of the solvate is equivalent to the ‘‘sublimation’’ of pyridine out of solid state
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with structure transformation of the remaining solid sulfathiazole. Such a consideration agrees with the instability of the solvates under ambient conditions. This work was supported by the BRHEProgram (Grant NO-008-XI), Russian Ministry of Education (Grant Ch-0069 of the ‘‘Integration’’-Program; ZN-67-01; and yp.05.01.021 of the Program ‘‘Universities of Russia’’), Program of the Russian Academy of Sciences ‘‘Fundamental studies in medicine’’ (Grant 11.2), and the National Science Support Foundation for EVB (Program ‘‘Young Professors’’). References [1] S.L. Morissette, O¨. Almarsson, M.L. Peterson, J.F. Remenar, M.J. Read, A.V. Lemmo, S. Ellis, M.J. Cima, C.R. Gardner, Adv. Drug Delivery Rev. 56 (2004) 275–300.
[2] D.C. Apperley, R.A. Fletton, R.K. Harris, R.W. Lancaster, S. Tavener, T.L. Threlfall, J. Pharm. Sci. 88 (1999) 1275. [3] A.L. Bingham, D.S. Hughes, M.B. Hursthouse, R.W. Lancaster, S. Tavener, T.L. Threlfall, Chem. Commun. (2001) 603. [4] G.J. Kruger, G. Gafner, Acta Crystallogr. B28 (1972) 272. [5] V.A. Drebushchak, E.V. Boldyreva, T.N. Drebushchak, E.S. Shutova, J. Crystal Growth 241 (2002) 266. [6] E.S. Domalski, E.D. Hearing, J. Phys. Chem. Ref. Data 25 (1996) 1. [7] V. Majer, V. Svoboda, M. Lencka, J. Chem. Thermodyn. 16 (1984) 1019–1024. [8] M.A. Mikhailenko, J. Crystal Growth 265 (2004) 616. [9] E.V. Boldyreva, V.A. Drebushchak, I.E. Paukov, Y.A. Kovalevskaya, T.N. Drebushchak, J. Therm. Anal. Calorim. 77 (2004) 607. [10] E.V. Boldyreva, V.A. Drebushchak, T.N. Drebushchak, I.E. Paukov, Y.A. Kovalevskaya, E.S. Shutova, J. Therm. Anal. Calorim. 73 (2003) 419. [11] E. Marti, E. Kaisersberger, G. Kaiser, W.Y. Ma, Thermoanalytical characterization of pharmaceuticals, NETZSCH Annual Report 2000, NETZSCH, Selb, 2000, p. 38–40.
Journal of Crystal Growth 274 (2005) 569–572 www.elsevier.com/locate/jcrysgro
Synthesis and characterization of sulfathiazole-pyridine solvate polymorphs M.A. Mikhailenkoa, T.N. Drebushchaka,b, V.A. Drebushchaka,c,, E.V. Boldyrevaa,b, V.V. Boldyreva,b a
Research and Education Center ‘Molecular Design and Ecologically Safe Technologies’, REC-008, Novosibirsk State University, ul. Pirogova, 2, Novosibirsk, 630090, Russia b Institute of Solid State Chemistry, Siberian Branch of the Russian Academy of Sciences, ul. Kutateladze, 18, Novosibirsk, 630128, Russia c Institute of Mineralogy and Petrography, Siberian Branch of the Russian Academy of Sciences, pr. Koptyuga, 3, Novosibirsk, 630090, Russia Received 28 September 2004; accepted 23 October 2004 Communicated by R. Kern Available online 8 December 2004
Abstract Tetragonal and monoclinic polymorphs of sulfathiazole-pyridine solvate (C9H9N3O2S2dC5H5N) were crystallized from propanol–pyridine solutions. The two polymorphs are unstable under ambient conditions but can be stored for a long time under pyridine vapor. TG and DSC of freshly prepared samples prove the decomposition of the solvates with pyridine vapor and sulfathiazole I as products. Thermodynamic estimate shows that the decomposition can be considered just a sum of two processes: (1) high-energy sublimation of pyridine and (2) low-energy structural transformation of the remaining sulfathiazole. r 2004 Elsevier B.V. All rights reserved. PACS: 61.10.Nz; 64.60.My; 81.70.Pg; 82.30.Lp; 82.60.Fa Keywords: A1. Recrystallization; A2. Growth from solutions; B1. Organic compounds; B2. Drugs
One of the most important problems in the investigation of crystalline pharmaceutical solids, Corresponding author. Institute of Mineralogy and Petrography, Siberian Branch of the Russian Academy of Sciences, pr. Koptyuga, 3, Novosibirsk, 630090, Russia. Tel.: +7 3832 332112; fax: +7 3832 332792. E-mail addresses: [email protected], [email protected] (V.A. Drebushchak).
molecular crystals, is the reproducible preparation of a particular polymorph [1]. Varying crystallization conditions (solvent, temperature, time, external fields, etc.), one can receive different polymorphs. In following this way, we faced a new problem of the polymorphism among solvates formed by the ‘‘highly polymorphic’’ drug compounds. Pure sulfathiazole forms five crystalline
0022-0248/$ - see front matter r 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jcrysgro.2004.10.067
ARTICLE IN PRESS 570
M.A. Mikhailenko et al. / Journal of Crystal Growth 274 (2005) 569–572
polymorphs [2], and, furthermore, over 100 solvates of sulfathiazole were described [3]. In the present communication we report on the crystallization of two polymorphs, tetragonal and monoclinic, of a new 1:1 sulfathiazole:pyridine solvate (C9H9N3O2S2dC5H5N). Sulfathiazole (Merk, ‘‘for synthesis’’, 498% purity) was purified by recrystallization in water with transparent crystals of sulfathiazole III [4] as a product. Then the crystals were dissolved in a mixture of pyridine and propanol. Pyridine was distilled twice, and propanol-1 (Merk) was used ‘‘as received’’. C9H9N3O2S2dC5H5N polymorphs were crystallized from the propanol–pyridine solution (60 mL) of sulfathiazole (1.5 g) at ambient temperature under its slow evaporation. The solution was filtered (blue band), but not boiled. The first crystals appeared after about a half of the solution has evaporated. For a successful crystallization of the polymorphs, it was very important not to be in a hurry. The solution prepared must be stored for weeks to guarantee the proper crystallization. Previously, when crystallizing unstable b-glycine, we found that seemingly the same procedure could yield either g- or b-polymorphs [5]. The reason was in the time of the preliminary storage of the solution: freshly prepared solution produced gglycine, whereas that stored for a month yielded bglycine. Dipyramidal crystals up to 5 mm large (later shown by single-crystal X-ray analysis to have a tetragonal structure) grew from the 2:1 (40 mL propanol+20 mL pyridine) solution. Prismatic crystals (3 mm long, 0.5 mm across) grew from the propanol–pyridine solution of 1:2 (20 mL propanol+40 mL pyridine). Single-crystal X-ray analysis has shown them to have a monoclinic structure. Crystals of both polymorphs of C9H9N3O2S2 C5H5N were well-shaped and transparent. X-ray powder diffraction patterns of the crystallized samples were measured using D8 GADDS (Bruker). The measurements were carried out over the range of 2Y angles from 51 to 361, CuKa radiation. Diffraction patterns for both polymorphs are listed in Table 1. Structure of the polymorphs was solved using single-crystal X-ray
Table 1 X-ray diffraction patterns for tetragonal and monoclinic polymorphs of C9H9N3O2S2dC5H5N Tetragonal
Monoclinic
d (A˚)
Int (%)
h
k
l
d (A˚)
Int (%)
h
k
l
8.636 8.017 6.694 5.891 5.442 5.246 4.603 4.496 4.340 4.245 3.986 3.881 3.814 3.686 3.641 3.456 3.395 3.344 3.240 3.116 3.024 2.945 2.848 2.786 2.742 2.715 2.680 2.651 2.595 2.553
27 19 25 20 14 13 47 46 35 15 50 14 76 19 10 22 81 6 6 18 7 4 100 40 24 34 23 14 4 12
1 1 1 1 1 0 1 1 2 2 1 2 2 2 2 1 2 2 1 2 1 2 2 3 3 3 1 1 2 3
0 0 0 1 0 0 1 0 0 0 1 1 1 0 1 1 1 0 0 1 1 2 1 0 1 1 1 3 1 1
0 1 2 1 3 4 3 4 0 1 4 0 1 3 2 5 3 4 6 4 6 2 5 2 0 1 7 2 6 3
10.114 8.212 7.030 6.844 6.132 5.918 5.679 5.468 4.980 4.710 4.621 4.451 4.132 4.026 3.821 3.726 3.684 3.602 3.538 3.355 3.289 3.187 3.150 3.055 3.014 2.955 2.885 2.803 2.776 2.735 2.601
20 21 21 28 82 8 8 21 88 19 100 91 40 9 52 85 31 28 46 10 38 6 7 56 18 14 10 7 16 14 15
0 1 1 0 1 1 1 0 1 1 0 0 2 1 0 2 1 2 2 2 2 0 1 0 2 1 1 2 3 0 1
0 0 0 1 1 0 1 1 1 0 2 1 0 2 2 1 1 0 1 1 1 1 1 2 1 0 3 2 0 2 3
2 0 2 2 1 2 1 3 2 4 0 4 0 1 3 2 4 2 3 2 4 6 6 5 5 6 1 4 2 6 3
diffraction technique (STADI-4 four-circle diffractometer Stoe, Darmstadt). Atomic coordinates and data collection parameters are to be published. Tetragonal polymorph has the space group P41, unit cell parameters are a ¼ 8:681ð3Þ; c ¼ ( Monoclinic polymorph has the space 20:934ð13Þ A: group P21/c with unit cell parameters a ¼ 8:374ð4Þ; ( b ¼ 100:18ð3Þ1: The b ¼ 9:265ð3Þ; c ¼ 20:682ð9Þ A; powder diffraction patterns calculated on the basis of single-crystal structure solution were in good agreement with the experimentally measured spectra. The single-crystal diffraction data were used for indexing the reflections listed in Table 1.
ARTICLE IN PRESS M.A. Mikhailenko et al. / Journal of Crystal Growth 274 (2005) 569–572
Both tetragonal and monoclinic polymorphs turned out to be unstable and could not be stored under ambient conditions for a long time. They decomposed readily to give pyridine (evaporates) and sulfathiazole (polymorph I [4]). The decomposition started giving small white spots at the faces and edges of the crystals, probably at the crystal defects. The spots did not increase in number but grew in size. The spots gradually expanded, merged, and formed a white ‘‘skin’’ covering the surface of the starting crystal. When exposed to air, it took about one day to transform a transparent single crystal into a white pseudomorph. In a closed bottle under pyridine vapor, the crystals could be stored for a long time without traces of the decomposition. Such a stock was completely depleted in experiments for several weeks, special experiments on the duration of the storage were not carried out. The decomposition of the polymorphs on heating was investigated using TG-209 and DSC204 (Netzsch). Within the limits of experimental error, the mass loss agrees well with the theoretical value of 23.66% for the reaction C9 H9 N3 O2 S2 dC5 H5 N ! C9 H9 N3 O2 S2 þ C5 H5 N " :
Fig. 1 shows the results of DSC measurements of a freshly prepared single crystal of tetragonal polymorph (5.53 mg) at a heating rate of 6 1C min1. The decomposition started near 80 1C. At the
Fig. 1. DSC results of tetragonal polymorph of sulfathiazolepyridine solvate with the decomposition (100–140 1C) and melting of pure sulfathiazole (201.8 1C).
571
beginning, the shape of the peak was typical of a thermally activated reaction. When the decomposition reached a high rate, a smooth line of heat flow broke indicating the instability in the reaction. The decomposition finished just above 140 1C. Enthalpy of the decomposition was 155 J g1. Sulfathiazole I (melting at 201.8 1C, enthalpy of the melting 79 J g1) was formed as the solid product of the decomposition. Decomposition of 1 mole of the solvate is accompanied by the release of 1 mole of gaseous pyridine. Recalculated to the mass of pure pyridine, the enthalpy of the decomposition is Ddec H ¼ 51:8 kJ mol1 : On the other hand, pure crystalline pyridine melts at 42 1C (Dfus H ¼ 8:3 kJ mol1 ) [6] and then boils at 115 1C (Dvap H ¼ 40:2 kJ mol1 ) [7]. These three transformations take place at three different temperatures. To compare the changes of thermodynamic function at the transformations, one should use entropy instead of enthalpy: Ddec S ¼ 132 J mol1 K1 ; Dfus S ¼ 36 J mol1 K 1 and 1 1 Dvap S ¼ 90 J mol K : Entropy of decomposition of the solvate is close to the sum of fusion and evaporation of pure pyridine. The difference Ddec S Dfus S Dvap S ¼ 6 J mol1 K1 is equivalent to the changes in the enthalpy of the solvent decomposition of about 7 J g1. It can be attributed to the changes in energy of crystalline structures at the decomposition of the solvate, for it is close to the measured enthalpies by the order of magnitude. For example, the enthalpy of orthorhombic-monoclinic transformation in paracetamol is 2–3 J g1 [8,9], about 3 J g1 for b– a transformation in glycine [5] and about 20 J g1 for g– a in glycine [10]. For pure sulfathiazole, the enthalpy of transformation is about 30 J g1 for III–I [11] and about 25 J g1 for II–I (our unpublished data). The transformations with small enthalpies (orthorhombic-monoclinic in paracetamol and b– a in glycine) take place under ambient conditions spontaneously, like the decomposition of the sulfathiazole solvates, but the rest (g– a in glycine, III–I and II–I in sulfathiazole) only at heating. That rough thermodynamic estimate shows that thermal decomposition of the solvate is equivalent to the ‘‘sublimation’’ of pyridine out of solid state
ARTICLE IN PRESS 572
M.A. Mikhailenko et al. / Journal of Crystal Growth 274 (2005) 569–572
with structure transformation of the remaining solid sulfathiazole. Such a consideration agrees with the instability of the solvates under ambient conditions. This work was supported by the BRHEProgram (Grant NO-008-XI), Russian Ministry of Education (Grant Ch-0069 of the ‘‘Integration’’-Program; ZN-67-01; and yp.05.01.021 of the Program ‘‘Universities of Russia’’), Program of the Russian Academy of Sciences ‘‘Fundamental studies in medicine’’ (Grant 11.2), and the National Science Support Foundation for EVB (Program ‘‘Young Professors’’). References [1] S.L. Morissette, O¨. Almarsson, M.L. Peterson, J.F. Remenar, M.J. Read, A.V. Lemmo, S. Ellis, M.J. Cima, C.R. Gardner, Adv. Drug Delivery Rev. 56 (2004) 275–300.
[2] D.C. Apperley, R.A. Fletton, R.K. Harris, R.W. Lancaster, S. Tavener, T.L. Threlfall, J. Pharm. Sci. 88 (1999) 1275. [3] A.L. Bingham, D.S. Hughes, M.B. Hursthouse, R.W. Lancaster, S. Tavener, T.L. Threlfall, Chem. Commun. (2001) 603. [4] G.J. Kruger, G. Gafner, Acta Crystallogr. B28 (1972) 272. [5] V.A. Drebushchak, E.V. Boldyreva, T.N. Drebushchak, E.S. Shutova, J. Crystal Growth 241 (2002) 266. [6] E.S. Domalski, E.D. Hearing, J. Phys. Chem. Ref. Data 25 (1996) 1. [7] V. Majer, V. Svoboda, M. Lencka, J. Chem. Thermodyn. 16 (1984) 1019–1024. [8] M.A. Mikhailenko, J. Crystal Growth 265 (2004) 616. [9] E.V. Boldyreva, V.A. Drebushchak, I.E. Paukov, Y.A. Kovalevskaya, T.N. Drebushchak, J. Therm. Anal. Calorim. 77 (2004) 607. [10] E.V. Boldyreva, V.A. Drebushchak, T.N. Drebushchak, I.E. Paukov, Y.A. Kovalevskaya, E.S. Shutova, J. Therm. Anal. Calorim. 73 (2003) 419. [11] E. Marti, E. Kaisersberger, G. Kaiser, W.Y. Ma, Thermoanalytical characterization of pharmaceuticals, NETZSCH Annual Report 2000, NETZSCH, Selb, 2000, p. 38–40.