Methods of amorphization and investigation of the amorphous state

Open access


The amorphous form of pharmaceutical materials represents the most energetic solid state of a material. It provides advantages in terms of dissolution rate and bioavailability. This review presents the methods of solid- -state amorphization described in literature (supercooling of liquids, milling, lyophilization, spray drying, dehydration of crystalline hydrates), with the emphasis on milling. Furthermore, we describe how amorphous state of pharmaceuticals differ depending on the method of preparation and how these differences can be screened by a variety of spectroscopic (X-ray powder diffraction, solid state nuclear magnetic resonance, atomic pairwise distribution, infrared spectroscopy, terahertz spectroscopy) and calorimetry methods.

1. B. C. Hancock and G. Zografi, Characteristics and significance of the amorphous state in pharmaceutical systems, J. Pharm. Sci. 86 (1997) 1-12; DOI: 10.1021/js9601896.

2. L. Yu, Amorphous pharmaceutical solids: preparation, characterization and stabilization, Adv. Drug Delivery Rev. 48 (2001) 27-42; DOI: 10.1016/S0169-409X(01)00098-9.

3. G. L. Amidon, H. Lennernäs, V. P. Shah and J. R. Crison, A theoretical basis for a biopharmaceutic drug classification: the correlation of in vitro drug product dissolution and in vivo bioavailability, Pharm. Res. 12 (1995) 413-420; DOI: 10.1023/A:1016212804288.

4. P. Poole, T. Grande, C. Angell and P. McMillan, Polymorphic phase transitions in liquids and glasses, Science 275 (1997) 322-323; DOI: 10.1126/science.275.5298.322.

5. A. Saleki-Gerhardt, J. G. Stowell, S. R. Byrn and G. Zografi, Hydration and dehydration of crystalline and amorphous forms of raffinose, J. Pharm. 84 (1995) 318-323.

6. L. R. L. Hilden and K. R. K. Morris, Physics of amorphous solids, J. Pharm. 93 (2003) 3-12; DOI: 10.1002/jps.10489.

7. K. A. Graeser, C. J. Strachan, J. E. Patterson, K. C. Gordon and T. Rades, Physicochemical properties and stability of two differently prepared amorphous forms of simvastatin, Cryst. GrowthDes. 8 (2008) 128-135; DOI: 10.1021/cg700913m.

8. P. Karmwar, K. Graeser, K. C. Gordon, C. J. Strachan and T. Rades, Investigation of properties and recrystallisation behaviour of amorphous indomethacin samples prepared by different methods, Int. J. Pharm. 417 (2011) 94-100; DOI: 10.1016/j.ijpharm.2010.12.019.

9. M. Otsuka, J.-I. Nishizawa, N. Fukura and T. Sasaki, Characterization of poly-amorphous indomethacin by terahertz spectroscopy, J. Infrared Milli. Terahz. Waves 33 (2012) 953-962; DOI: 10. 1007/s10762-012-9910-1.

10. R. Lefort, A. De Gusseme, J. F. Willart, F. Danède and M. Descamps, Solid state NMR and DSC methods for quantifying the amorphous content in solid dosage forms: an application to ball- -milling of trehalose, Int. J. Pharm. 280 (2004) 209-219; DOI: 10.1016/j.ijpharm.2004.05.012.

11. D. Kivelson, J. Pereda, K. Luu, M. Lee, H. Sakai, A. Ha, I. Cohen and G. Tarjus, Facts and speculation concerning low-temperature polymorphism in glass formers, Symp. Ser. 676 (1997), 224-232; DOI: 10.1021/bk-1997-0676.ch017.

12. J. E. Patterson, M. B. James, A. H. Forster, R. W. Lancaster, J. M. Butler and T. Rades, The influence of thermal and mechanical preparative techniques on the amorphous state of four poorly soluble compounds, J. Pharm. Sci. 94 (2005) 1998-2012; DOI: 10.1002/jps.20424.

13. D. Q. D. Craig, V. L. V. Kett, J. R. J. Murphy and D. M. D. Price, The measurement of small quantities of amorphous material-should we be considering the rigid amorphous fraction, Pharm. Res. 18 (2001) 1081-1082.

14. D. Turnbull, Under what conditions can a glass be formed?, Contemp. Phys. 10 (1969) 473-488; DOI: 10.1080/00107516908204405.

15. C. Angell, Structural instability and relaxation in liquid and glassy phases near the fragile liquid limit, J. Non-Cryst. Solids 102 (1988) 205-221; DOI: 10.1016/0022-3093(88)90133-0.

16. J. Liu, D. Rigsbee, C. Stotz and M. Pikal, Dynamics of pharmaceutical amorphous solids: The study of enthalpy relaxation by isothermal microcalorimetry, J. Pharm. Sci. 91 (2002) 1853-1862; DOI:10.1002/jps.10181.

17. D. Grant, Polymorphism in Pharmaceutical Solids, Marcel Dekker, Basel 1999, pp. 183-227.

18. K. A. Graeser, J. E. Patterson, J. A. Zeitler, K. C. Gordon and T. Rades, Correlating thermodynamic and kinetic parameters with amorphous stability, Eur. J. Pharm. Sci. 37 (2009) 492-498; DOI: 10.1016/j.ejps.2009.04.005.

19. J. W. Lee, L. C. Thomas and S. J. Schmidt, Effects of heating conditions on the glass transition parameters of amorphous sucrose produced by melt-quenching, J. Agric. Food Chem. 59 (2011) 3311-3319; DOI: 10.1021/jf104853s.

20. H. Miyanishi, T. Nemoto, M. Mizuno, H. Mimura, S. Kitamura, Y. Iwao, S. Noguchi and S. Itai, Evaluation of crystallization behavior on the surface of nifedipine solid dispersion powder using inverse gas chromatography, Pharm. Res. 30 (2013) 502-511; DOI: 10.1007/s11095-012-0896-0.

21. M. G. Abiad, D. C. Gonzalez, B. Mert, O. H. Campanella and M. T. Carvajal, A novel method to measure the glass and melting transitions of pharmaceutical powders, Int. J. Pharm. 396 (2010) 23-29; DOI: 10.1016/j.ijpharm.2010.06.001.

22. H. Takeuchi, S. Nagira, H. Yamamoto and Y. Kawashima, Solid dispersion particles of tolbutamide prepared with fine silica particles by the spray-drying method, Powder Technol. 141 (2004) 187-195; DOI: 10.1016/j,powtec.2004.03.007.

23. R. C. Rowe, P. J. Sheskey, W. G. Cook and M. F. Fenton, Colloidal Silicon Dioxide, in Handbook ofPharmaceutical Excipients, Pharmaceutical Press, London 2000, pp. 143-145.

24. H. Takeuchi, T. Handa and Y. Kawashima, Spherical solid dispersion containing amorphous tolbutamide embedded in enteric coating polymers or colloidal silica prepared by spray-drying technique, Chem. Pharm. Bull. 35 (1987) 3800-3806.

25. I. Chuang and G. Maciel, Probing hydrogen bonding and the local environment of silanols on silica surfaces via nuclear spin cross polarization dynamics, J. Am. Chem. Soc. 118 (1996) 401-406; DOI: 10.1021/ja951550d.

26. J. Broadhead, S. K. E. Rouan and C. T. Rhodes, The spray drying of pharmaceuticals, Drug. Dev. Ind. Pharm. 18 (1992) 11-12; DOI: 10.3109/03639049209046327.

27. R. Vehring, Pharmaceutical particle engineering via spray drying, Pharm. Res. 25 (2008) 999-1022; DOI: 10.1007/s11095-007-9475-1.

28. K. Haque and Y. H. Roos, Crystallization and X-ray diffraction of spray-dried and freeze-dried amorphous lactose, Carbohyd. Res. 340 (2005) 293-301; DOI: 10.1016/j.carres.2004.11.026.

29. D. Chiou, T. A. G. Langrish and R. Braham, The effect of temperature on the crystallinity of lactose powders produced by spray drying, J. Food Eng. 86 288-293; DOI: 10.1016/j.jfoodeng.2007. 10.005.

30. S. P. Bhardwaj, K. K. Arora, E. Kwong, A. Templeton, S. D. Clas and R. Suryanarayanan, Correlation between molecular mobility and physical stability of amorphous itraconazole, Mol. Pharm. 10 (2013) 694-700; DOI: 10.1021/mp300487u.

31. M. Vogt, K. Kunath and J. B. Dressman, Dissolution enhancement of fenofibrate by micronization, cogrinding and spray-drying: comparison with commercial preparations, Eur. J. Pharm. Biopharm. 68 (2008) 283-288; DOI: 10.1016/j.ejpb.2007.05.010.

32. D. Q. Craig, P. G. Royall, V. L. Kett and M. L. Hopton, The relevance of the amorphous state to pharmaceutical dosage forms: glassy drugs and freeze dried systems, Int. J. Pharm. 179 (1999) 179-207; DOI: 10.1016/S0378-5173(98)00338-X.

33. J. Liu, Physical characterization of pharmaceutical formulations in frozen and freeze-dried solid states: techniques and applications in freeze-drying development, Pharm. Dev. Technol. 11 (2006) 3-28; DOI: 10.1080/10837450500463729.

34. S. P. Bhardwaj and R. Suryanarayanan, Molecular mobility as an effective predictor of the physical stability of amorphous trehalose, Mol. Pharm. 9 (2012) 3209-3217; DOI: 10.1021/mp300302g.

35. K. P. O’Donnell, Z. Cai, P. Schmerler and R. O. I. Williams, Atmospheric freeze drying for the reduction of powder electrostatics of amorphous, low density, high surface area pharmaceutical powders, Drug Dev. Ind. Pharm. 39 (2013) 205-217; DOI: 10.3109/03639045.2012.669385.

36. Y. Li, J. Han, G. G. Zhang, D. J. Grant and R. Suryanarayanan, In situ dehydration of carbamazepine dihydrate: a novel technique to prepare amorphous anhydrous carbamazepine, Pharm. Dev. Technol. 5 (2000) 257-266; DOI: 10.1081/PDT-100100540.

37. F. Sussich and A. Cesaro, Trehalose amorphization and recrystallization, Carboh. Res. 343 2667-2674; DOI: 10.1016/j.carres.2008.08.008.

38. B. Bennett and G. Cole, Secondary Pharmaceutical Production: An Engineering Guide, IChemE 2003, pp. 111-201.

39. D. M. Parikh, Handbook of Pharmaceutical Granuation Technology, Taylor and Francis, London 2005, pp. 491-512.

40. R. Liu, Water-InsolubleDrug Formulation, Taylor and Francis, London 2008, pp. 88-455.

41. R. Price and P. M. Young, On the physical transformations of processed pharmaceutical solids, Micron. 36 (2005) 519-524; DOI: 10.1016/j.micron.2005.04.003.

42. G. Zhang, C. Gu, M. Zell, R. Burkhardt, E. Munson and D. Grant, Crystallization and transitions of sulfamerazine polymorphs, J. Pharm. Sci. 91 (2002) 1089-1100; DOI: 10.1002/jps.10100.

43. P. Thanatuksorn, K. Kawai, K. Kajiwara and T. Suzuki, Effects of ball-milling on the glass transition of wheat flour constituents, J. Sci. Food Agric. 89 (2009) 430-435; DOI: 10.1002/jsfa.3463.

44. J. F. Willart and M. Descamps, Solid state amorphization of pharmaceuticals, Mol. Pharmaceutics5 (2008) 905-920; DOI: 10.1021/mp800092t.

45. A. Revesz, Melting behavior and origin of strain in ball-milled nanocrystalline Al powders, J. Mater. Sci. 40 (2005) 1643-1646; DOI: 10.1007/s10853-005-0664-1.

46. S. Karki, T. Friscic, W. Jones and W. D. S. Motherwell, Screening for pharmaceutical cocrystal hydrates via neat and liquid-assisted grinding, Mol. Pharmaceutics 4 (2007) 347-354; DOI: 10. 1021/mp0700054.

47. K. Chadwick, R. Davey and W. Cross, How does grinding produce co-crystals? Insights from the case of benzophenone and diphenylamine, CrystEngComm 9 (2007) 732-734; DOI: 10.1039/ b709411f.

48. T. Shakhtshneider, Phase transformations and stabilization of metastable states of molecular crystals under mechanical activation, Solid State Ionics 101 (1997) 851-856; DOI: 10.1016/S0167-2738(97)00224-5.

49. E. Dudognon, J. Willart, V. Caron, F. Capet, T. Larsson and M. Descamps, Formation of budesonide/ alpha-lactose glass solutions by ball-milling, Solid State Commun. 138 (2006) 68-71; DOI: 10.1016/j.ssc.2006.02.007.

50. I. Tsukushi, O. Yamamuro and T. Matsuo, Solid state amorphization of organic molecular crystals using a vibrating mill, Solid State Commun. 94 (1995) 1013-1013; DOI: 10.1016/0038-1098 (95)00161-1.

51. J. Font, J. Muntasell and E. Cesari, Amorphization of organic compounds by ball milling, Mater. Res. Bull. 32 (1997) 1691-1696; DOI: 10.1016/S0025-5408(97)00162-1.

52. J. Willart, V. Caron, R. Lefort, F. Danède, D. Prevost and M. Descamps, Athermal character of the solid state amorphization of lactose induced by ball milling, Solid State Commun. 132 (2004) 693-696; DOI: 10.1016/j.ssc.2004.09.007.

53. M. Otsuka, H. Ohtani, N. Kaneniwa and S. Higuchi, Isomerization of lactose in solid-state by mechanical stress during grinding, J. Pharm. Pharmacol. 43 (1991) 148-153; DOI: 10.1111/j.2042-7158.1991.tb06656.x.

54. J. Willart, A. De Gusseme, S. Hemon, G. Odou, F. Danède and M. Descamps, Direct crystal to glass transformation of trehalose induced by ball milling, Solid State Commun. 119 (2001) 501-505; DOI: 10.1016/S0038-1098(01)00283-6.

55. A. J. Megarry, J. Booth and J. Burley, Amorphous trehalose dihydrate by cryogenic milling, Carbohyd. Res. 346 (2011) 1061-1064; DOI: 10.1016/j.carres.2011.03.011.

56. J. F. Willart, N. Dujardin, E. Dudognon, F. Danède and M. Descamps, Amorphization of sugar hydrates upon milling, Carbohyd. Res. 345 (2010) 1613-1616; DOI: 10.1016/j.carres.2010.04.014.

57. P. Okamoto and N. Lam, Physics of crystal-to-glass transformations, Solid State Phys. 52 (1999) 1-135; DOI: 10.1016/S0081-1947(08)60018-1.

58. H. Fecht, Defect-induced melting and solid-state amorphization, Nature 356 (1992) 133-135; DOI: 10.1016/S0081-1947(08)60018-1.

59. M. Descamps, J. F. Willart, E. Dudognon and V. Caron, Transformation of pharmaceutical compounds upon milling and comilling: the role of Tg, J. Pharm. Sci. 96 (2007) 1398-1407; DOI: 10. 1002/jps.20939.

60. J. Willart, N. Descamps, V. Caron, F. Capet, F. Danède and M. Descamps, Formation of lactose- -mannitol molecular alloys by solid state vitrification, Solid State Commun. 138 (2006) 194-199; DOI: 10.1016/j.ssc.2006.02.034.

61. G. Martin and P. Bellon, Driven alloys, Solid State Phys. 50 (1997) 189-331.

62. S. Qi, I. Weuts, S. De Cort, S. Stokbroekx, R. Leemans, M. Reading, P. Belton and D. Q. M. Craig, An investigation into the crystallisation behaviour of an amorphous cryomilled pharmaceutical material above and below the glass transition temperature, J. Pharm. Sci. 99 (2010) 196-208; DOI: 10.1002/jps.21811.

63. K. J. Crowley and G. Zografi, Cryogenic grinding of indomethacin polymorphs and solvates: assessment of amorphous phase formation and amorphous phase physical stability, J. Pharm. Sci. 91 (2002) 492-507; DOI: 10.1002/jps.10028.

64. J. Carstensen, Advanced Pharmaceutical Solids, Marcel Dekker, New York 2001, pp. 107-117.

65. C. Sun and D. J. Grant, Influence of crystal shape on the tableting performance of L-lysine monohydrochloride dihydrate, J. Pharm. Sci. 90 (2001) 569-579; DOI: 10.1002/1520-6017(200105)90: 5<569::AID-JPS1013>3.0.CO;2-4.

66. V. Chikhalia, R. T. Forbes, R. A. Storey and M. Ticehurst, The effect of crystal morphology and mill type on milling induced crystal disorder, Eur. J. Pharm. Sci. 27 (2006) 19-26; DOI: 10.1016/ j.ejps.2005.08.013.

67. T. Watanabe, S. Hasegawa, N. Wakiyama, A. Kusai and M. Senna, Comparison between polyvinylpyrrolidone and silica nanoparticles as carriers for indomethacin in a solid state dispersion, Int. J. Pharm. 250 (2003) 283-286; DOI: 10.1016/S0378-5173(02)00549-5.

68. A. Ali, K. Yamamoto, A. Elsayed, F. Habib and Y. Nakai, Molecular behavior of flufenamic acid in physical and ground mixtures with florite, Chem. Pharm. Bull. 40 (1992) 1289-1294.

69. H. Sekizaki, K. Danjo, H. Eguchi, Y. Yonezawa, H. Sunada and A. Otsuka, Solid-state interaction of ibuprofen with polyvinylpyrrolidone, Chem. Pharm. Bull. 43 (1995) 988-993.

70. V. Boldyrev, T. Shakhtshneider, L. Burleva and V. Severstev, Preparation of the disperse systems of sulfathiazole-polyvinylpyrrolidone by mechanical activation, Drug Dev. Ind. Pharm. 20 (1994) 1103-1114.

71. N. Kaneniwa and A. Ikekava, Solubilization of Water-insoluble organic powders by ball-milling in the presence of polyvinylpyrrolidone, Chem. Pharm. Bull. 23 (1975) 2973-2986.

72. N. Kaneniwa, A. Ikekava and M. Sumi, A decrease in crystallinity of amobarbital by mechanical treatment in presence of diluents, Chem. Pharm. Bull. 26 (1978) 2734-2743.

73. H. Takeuchi, S. Nagira, H. Yamamoto and Y. Kawashima, Solid dispersion particles of amorphous indomethacin with fine porous silica particles by using spray-drying method, Int. J. Pharm. 293 (2005) 155-164; DOI: 10.1016/j.ijpharm.2004.12.019.

74. M. Fujii, H. Okada, Y. Shibata, H. Teramachi, M. Kondoh and Y. Watanabe, Preparation, characterization, and tableting of a solid dispersion of indomethacin with crospovidone, Int. J. Pharm.293 (2005) 145-153; DOI: 10.1016/j.ijpharm.2004.12.018.

75. Y. Nakai, E. Fukuoka, S. Nakajima and Y. Iida, Effect of grinding on physical and chemical properties of crystalline medicinals with microcrystalline cellulose. 2. Retention of volatile medicinals in ground mixture, Chem. Pharm. Bull. 26 (1978) 2983-2989.

76. M. Cirri, F. Maestrelli, S. Furlanetto and P. Mura, Solid-state characterization of glyburide-cyclodextrin co-ground products, J. Therm. Anal. Calorim. 77 (2004) 413-422; DOI: 10.1023/B: JTAN.0000038982.40315.8f.

77. T. Shakhtshneider, M. Vasiltchenko, A. Politov and V. Boldyrev, The mechanochemical preparation of solid disperse systems of ibuprofen-polyethylene glycol, Int. J. Pharm. 130 (1996) 25-32; DOI: 10.1016/0378-5173(95)04244-X.

78. D. Bahl and R. H. Bogner, Amorphization of indomethacin by co-grinding with Neusilin US2: Amorphization kinetics, physical stability and mechanism, Pharm. Res. 23 (2006) 2317-2325; DOI: 10.1007/s11095-006-9062-x.

79. U. Zimper, J. Aaltonen, C. M. McGoverin, K. C. Gordon, K. Krauel-Goellner and T. Rades, Quantification of process induced disorder in milled samples using different analytical techniques, Pharmaceutics 2 (2010) 30-49; DOI: 10.3390/pharmaceutics2010030.

80. V. Caron, J. F. Willart, R. Lefort, P. Derollez, F. Danède and M. Descamps, Solid state amorphization kinetic of alpha lactose upon mechanical milling, Carbohyd. Res. 346 (2011) 2622-2628; DOI: 10.1016/j.carres.2011.09.004.

81. J. P. Bøtker, P. Karmwar, C. J. Strachan, C. Cornett, F. Tian, Z. Zujovic, J. Rantanen and T. Rades, Assessment of crystalline disorder in cryo-milled samples of indomethacin using atomic pair- -wise distribution functions, Int. J. Pharm. 417 (2011) 112-119; DOI: 10.1016/j.ijpharm.2010.12. 018.

82. K. Terada, H. Kitano, Y. Yoshihashi and E. Yonemochi, Quantitative correlation between initial dissolution rate and heat of solution of drug, Pharm. Res. 17 (2000) 920-924; DOI: 10.1023/A: 1007514902161

83. Z. Lavrič, J. Pirnat, J. Lužnik, J. Seliger, V. Žagar, Z. Trontelj and S. Srcic, Application of 14N NQR to the study of piroxicam polymorphism, J. Pharm. Sci. 99 (2010) 4857-4865; DOI: 10.1002/ jps.22186.

84. C. J. Strachan, T. Rades and K. C. Gordon, A theoretical and spectroscopic study of gamma- -crystalline and amorphous indomethacin, J. Pharm. Pharmacol. 59 (2007) 261-269; DOI: 10.1211/ jpp.59.2.0012.

85. M. Savolainen, A. Heinz, C. Strachan, K. C. Gordon, J. Yliruusi, T. Rades and N. Sandler, Screening for differences in the amorphous state of indomethacin using multivariate visualization, Eur. J. Pharm. Sci. 30 (2007) 113-123; DOI: 10.1016/j.ejps.2006.10.010.

86. C. Rawle, C. Lee, C. Strachan, K. Payne, P. Manson and T. Rades, Towards characterization and identification of solid state pharmaceutical mixtures through second harmonic generation, J. Pharm. Sci. 95 (2006) 761-768; DOI: 10.1002/jps.20575.

87. G. G. Buckton and P. P. Darcy, Assessment of disorder in crystalline powders - a review of analytical techniques and their application, Int. J. Pharm. 179 (1999) 141-158; DOI: 10.1016/S0378-5173(98)00335-4.

88. B. Shah, V. K. Kakumanu and A. K. Bansal, Analytical techniques for quantification of amorphous/ crystalline phases in pharmaceutical solids, J. Pharm. Sci. 95 (2006) 1641-1665; DOI: 10. 1002/jps.20644.

89. N. Chieng, Z. Zujovic, G. Bowmaker, T. Rades and D. Saville, Effect of milling conditions on the solid-state conversion of ranitidine hydrochloride form 1, Int. J. Pharm. 327 (2006) 36-44; DOI: 10.1016/j.ijpharm.2006.07.032.

90. C. Gustafsson, H. Lennholm, T. Iversen and C. Nyström, Comparison of solid-state NMR and isothermal microcalorimetry in the assessment of the amorphous component of lactose, Int. J. Pharm. 174 (1998) 243-252; DOI: 10.1016/S0378-5173(98)00272-5.

91. M. Mirmehrabi, S. Rohani, K. S. K. Murthy and B. Radatus, Characterization of tautomeric forms of ranitidine hydrochloride: thermal analysis, solid-state NMR, X-ray, J. Cryst. Growth 260 (2004) 517-526; DOI: 10.1016/j.jcrysgro.2003.08.061.

92. D. C. Apperley, R. A. Fletton, R. K. Harris, R. W. Lancaster, S. Tavener and T. L. Threlfall, Sulfathiazole polymorphism studied by magic-angle spinning NMR, J. Pharm. Sci. 88 (1999) 1275-1280; DOI: 10.1021/js990175a.

93. D. C. Apperley, R. K. Harris, T. Larsson and T. Malmstrom, Quantitative nuclear magnetic resonance analysis of solid formoterol fumarate and its dihydrate, J. Pharm. Sci. 92 (2003) 2487-2494; DOI: 10.1002/jps.10500.

94. P. A. Tishmack, D. E. Bugay and S. R. Byrn, Solid-state nuclear magnetic resonance spectroscopy- pharmaceutical applications, J. Pharm. Sci. 92 (2003) 441-474; DOI: 10.1002/jps.10307.

95. A. Gombás, I. Antal, P. Szabó-Révész, S. Marton and I. Erõs, Quantitative determination of crystallinity of alpha-lactose monohydrate by near Infrared Spectroscopy (NIRS), Int. J. Pharm. 256 (2003) 25-32; DOI: 10.1016/S0378-5173(03)00059-0.

96. P. Debenedetti, Metastable Liquids: Concepts and Principles, Princeton University Press, Chichester 1996.

97. G. P. Johari, S. Ram, G. Astl and E. Mayer, Characterizing amorphous and microcrystalline solids by calorimetry, J. Non-Cryst Solids 116 (1990) 282-285; DOI: 10.1016/0022-3093(90)90703-O.

98. S. Bates, G. Zografi, D. Engers, K. Morris, K. Crowley and A. Newman, Analysis of amorphous and nanocrystalline solids from their X-ray diffraction patterns, Pharm. Res. 23 (2006) 2333-2349; DOI: 10.1007/s11095-006-9086-2.

99. S. J. L. Billinge and M. G. Kanatzidis, Beyond crystallography: the study of disorder, nanocrystallinity and crystallographically challenged materials with pair distribution functions, Chem. Commun. 7 (2004) 749-760; DOI: 10.1039/b309577k..

100. A. S. Masadeh, E. S. Bozin, C. L. Farrow, G. Paglia, P. Juhas, S. J. L. Billinge, A. Karkamkar and M. G. Kanatzidis, Quantitative size-dependent structure and strain determination of CdSe nanoparticles using atomic pair distribution function analysis, Phys. Rev. B 76 (2007); DOI: 10. 1103/PhysRevB.76.115413.

101. T. Egami and S. J. L. Billinge, Underneath the Bragg Peaks, Pergamon Press, Oxford 2003, pp. 25-101.

102. T. Proffen, S. Billinge, T. Egami and D. Louca, Structural analysis of complex materials using the atomic pair distribution function - a practical guide, Z. Kristallogr. 218 (2003) 132-143; DOI: 10.1524/zkri.

103. L. Tarasov and B. E. Warren, X-ray diffraction study of liquid sodium, J. Chem. Phys. 4 (1936) 236-238; DOI: 10.1063/1.1749828.

104. B. Warren, H. Krutter and O. Morningstar, Fourier-analysis of X-ray-patterns of vitreous SiO2 and B2O3, J. Am. Ceram. Soc. 75 (1992) 11-15.

105. F. Zernike and J. A. Prins, Die Beugung von Röntgenstrahlen in Flüssigkeiten als Effekt der Molekülanordnung, Z. Physik 41 (1927) 184-194; DOI: 10.1007/BF01391926.

106. F. Atassi, C. Mao, A. S. Masadeh and S. R. Byrn, Solid-state characterization of amorphous and mesomorphous calcium ketoprofen, J. Pharm. Sci. 99 (2009) 3684-3697; DOI: 10.1002/jps.21925.

107. S. Bates, R. C. Kelly, I. Ivanisevic, P. Schields, G. Zografi and A. W. Newman, Assessment of defects and amorphous structure produced in raffinose pentahydrate upon dehydration, J. Pharm. Sci. 96 (2007) 1418-1433; DOI: 10.1002/jps.20944.

108. A. Heinz, C. J. Strachan, F. Atassi, K. C. Gordon and T. Rades, Characterizing an amorphous system exhibiting trace crystallinity: A case study with saquinavir, Crys. Growth Des. 8 (2008) 119-127; DOI: 10.1021/cg700912q.

109. A. Sheth, S. Bates, F. Muller and D. Grant, Polymorphism in piroxicam, Cryst. Growth Des. 4 (2004) 1091-1098; DOI: 10.1021/cg049876y.

110. A. Sheth, S. Bates, F. Muller and D. Grant, Local structure in amorphous phases of piroxicam from powder X-ray diffractometry, Cryst. Growth Des. 5 (2005) 571-578; DOI: 10.1021/cg049757i.

111. M. D. Moore, A. M. Steinbach, I. S. Buckner and P. L. Wildfong, A structural investigation into the compaction behavior of pharmaceutical composites using powder X-ray diffraction and total scattering analysis, Pharm. Res. 26 (2009) 2429-2437; DOI: 10.1007/s11095-009-9954-7.

112. A. Newman, D. Engers, S. Bates, I. Ivanisevic, R. C. Kelly and G. Zografi, Characterization of amorphous API: Polymer mixtures using X-ray powder diffraction, J. Pharm. Sci. 97 (2008) 4840-4856; DOI: 10.1002/jps.21352.

113. K. Nollenberger, A. Gryczke, C. Meier, J. Dressman, M. U. Schmidt and S. Brühne, Pair distribution function X-ray analysis explains dissolution characteristics of felodipine melt extrusion products, J. Pharm. Sci. 98 (2009) 1476-1486; DOI: 10.1002/jps.21534.

114. P. Robinson, HyperDSC, Speed DSC Technique, ESTAC8 Abstract Book, Barcelona (August 25-29, 2002), p. 101.

115. Y. Roos, Melting and glass transitions of low molecular weight carbohydrates, Carbohyd. Res.238 (1993) 39-48; DOI: 10.1016/0008-6215(93)87004-C.

116. M. Brown, Introduction to Thermal Analysis: Techniques and Applications, Kluwer Academic Publishers, Amsterdam 2001.

117. Perkin Elmer, Thermal Analysis Newsletter, Application Example PETAN-51, Norwalk 2000.

118. P. Claudy, M. Siniti and J. El Hajri, Thermodynamic study of the glass relaxation phenomena - DSC study of annealing of maltitol glass, J. Therm. Anal. Calorim. 68 (2002) 251-264.

119. M. J. Pikal, A. L. Lukes, J. E. Lang and K. Gaines, Quantitative crystallinity determinations for b-lactam antibiotics by solution calorimetry: Correlations with stability, J. Pharm. Sci. 67 (1978) 767-773; DOI: 10.1002/jps.2600670609.

120. D. Gao and J. Rytting, Use of solution calorimetry to determine the extent of crystallinity of drugs and excipients, Int. J. Pharm. 151 (1997) 183-192; DOI: 10.1016/S0378-5173(97)04895-3.

121. S. E. Hogan and G. Buckton, The quantification of small degrees of disorder in lactose using solution calorimetry, Int. J. Pharm. 207 (2000) 57-64; DOI: 10.1016/S0378-5173(00)00527-5.

122. K. C. Thompson, J. P. Draper, M. J. Kaufman and G. S. Brenner, Characterization of the crystallinity of drugs: B02669, a case study, Pharm. Res. 11 (1994) 1362-1365; DOI: 10.1023/A:101 8919201058.

123. G. H. Ward and R. K. Schultz, Process-induced crystallinity changes in albuterol sulfate and its effect on powder physical stability, Pharm. Res. 12 (1995) 773-779; DOI: 10.1023/A:1016232230 638.

124. P. Harjunen, V. P. Lehto, M. Koivisto, E. Levonen, P. Paronen and K. Järvinen, Determination of amorphous content of lactose samples by solution calorimetry, Drug Dev. Ind. Pharm. 30 (2004) 809-815; DOI: 10.1081/DDC-200030302.

125. R. W. Douglas and G. A. Jones, An apparatus for the determination of small changes in density, J. Sci. Instrum. 24 (1947) 72; DOI: 10.1088/0950-7671/24/3/304.

126. J. Pelsmaekers and S. Amelinckx, Simple apparatus for comparative density measurements, Rev. Sci. Instr. 32 (1961) 828-830; DOI: 10.1063/1.1717522.

127. R. Suryanarayanan, Evaluation of two concepts of crystallinity using calcium gluceptate as a model compound, Int. J. Pharm. 24 (1985) 1-17; DOI: 10.1016/0378-5173(85)90140-1.

128. G. M. Venkatesh, M. E. Barnett, C. Owusu-Fordjour and M. Galop, Detection of low levels of the amorphous phase in crystalline pharmaceutical materials by thermally stimulated current spectrometry, Pharm. Res. 18 (2001) 98-103, DOI: 10.1023/A:1011087012826.

129. R. Huttenrauch, Molecular galenics as the basis of modern drug formation, Acta Pharm. Technol. (Suppl.) 6 (1978) 55-127.

130. A. Salekigerhardt, C. Ahlneck and G. Zografi, Assessment of disorder in crystalline solids, Int. J. Pharm. 101 (1994) 237-247; DOI: 10.1016/0378-5173(94)90219-4.

131. P. M. Young, H. Chiou, T. Tee, D. Traini, H.-K. Chan, F. Thielmann and D. Burnett, The use of organic vapor sorption to determine low levels of amorphous content in processed pharmaceutical powders, Drug Dev. Ind. Pharm. 33 (2007) 91-97; DOI: 10.1080/03639040600969991.

132. J. Vollenbroek, G. A. Hebbink, S. Ziffels and H. Steckel, Determination of low levels of amorphous content in inhalation grade lactose by moisture sorption isotherms, Int. J. Pharm. 395 (2010) 62-70; DOI: 10.1016/j.ijpharm.2010.04.035.

133. M. Kunaver, J. Zadnik and O. Planinsek, Inverse gas chromatography-A different approach to characterization of solids and liquids, Acta Chim. Slov. 51 (2004) 373-394.

134. A. Voelkel, B. Strzemiecka, K. Adamska and K. Milczewska, Inverse gas chromatography as a source of physicochemical data, J. Chromatogr. A 1216 (2009) 1551-1566; DOI: 10.1016/j.chroma. 2008.10.096.

135. S. P. Chamarthy and R. Pinal, The nature of crystal disorder in milled pharmaceutical materials, Colloid. Surfaces A 331 (2008) 68-75; DOI: 10.1016/j.colsurfa.2008.06.040.

136. O. Planinsek, J. Zadnik, M. Kunaver, S. Srcic and A. Godec, Structural evolution of indomethacin particles upon milling: time-resolved quantification and localization of disordered structure studied by IGC and DSC, J. Pharm. Sci. 99 (2010) 1968-1981; DOI: 10.1002/jps.21986.

137. M. Otsuka and N. Kaneniwa, Effect of environment on crystallinity and chemical stability in solid-state of ground cephalotin sodium during storage, Drug Dev. Ind. Pharm. 17 (1990) 909-918; DOI: 10.3109/03639049109040828.

138. H. Konno and L. S. Taylor, Influence of different polymers on the crystallization tendency of molecularly dispersed amorphous felodipine, J. Pharm. Sci. 95 (2006) 2692-2705; DOI: 10.1002/ jps.20697.

139. X. C. Tang, M. J. Pikal and L. S. Taylor, The effect of temperature on hydrogen bonding in crystalline and amorphous phases in dihydropyrine calcium channel blockers, Pharm. Res. 19 (2002) 484-490; DOI: 10.1023/A:1015199713635.

140. L. Mackin, S. Sartnurak, I. Thomas and S. Moore, The impact of low levels of amorphous material, Int. J. Pharm. 231 (2002) 213-226; DOI: 10.1016/S0378-5173(01)00880-8.

141. J. J. Seyer, P. E. Luner and M. S. Kemper, Application of diffuse reflectance near-infrared spectroscopy for determination of crystallinity, J. Pharm. Sci. 89 (2000) 1305-1316; DOI: 10.1002/ 1520-6017(200010)89:10<1305::AID-JPS8>3.0.CO;2-Q.

142. S. J. Bai, M. Rani, R. Suryanarayanan, J. F. Carpenter, R. Nayar and M. C. Manning, Quantification of glycine crystallinity by near-infrared (NIR) spectroscopy, J. Pharm. Sci. 93 (2004) 2439-2447; DOI:10.1002/jps.20153.

143. P. Aldridge, C. Evans, H. Ward, S. Colgan, N. Boyer and P. Gemperline, Near-IR detection of polymorphism and process-related substances, Anal. Chem. 68 (1996) 997-1002; DOI: 10.1021/ ac950993x.

144. S. Hogan and G. Buckton, The application of near infrared spectroscopy and dynamic vapor sorption to quantify low amorphous contents of crystalline lactose, Pharm. Res. 18 (2001) 112-116; DOI: 10.1023/A:1011091113734.

145. G. Buckton, E. Yonemochi, J. Hammond and A. Moffat, The use of near infra-red spectroscopy to detect changes in the form of amorphous and crystalline lactose, Int. J. Pharm. 168 (1998) 231-241; DOI: 10.1016/S0378-5173(98)00095-7.

146. M. Otsuka and H. Tanabe, Stability test for amorphous materials in humidity controlled 96- -well plates by near-infrared spectroscopy, Drug Dev. Ind. Pharm. 38 (2012) 380-385; DOI: 10. 3109/03639045.2011.608680.

147. M. Otsuka, F. Kato and Y. Matsuda, Comparative evaluation of the degree of indomethacin crystallinity by chemoinfometrical Fourier-transformed near-infrared spectroscopy and conventional powder X-ray diffractometry, AAPS PharmSci 2 (2000) E9; DOI: 10.1208/ps020109.

148. P. Vandenabeele, Practical Raman Spectroscopy, Wiley, Chichosten 2013, pp. 23-80.

149. P. Karmwar, K. Graeser, K. C. Gordon, C. J. Strachan and T. Rades, Effect of different preparation methods on the dissolution behaviour of amorphous indomethacin, Eur. J. Pharm. Biopharm.80 (2012) 459-464; DOI: 10.1016/j.ejpb.2011.10.006.

150. J. P. Boetker, V. Koradia, T. Rades and J. Rantanen, Atomic pairwise distribution function analysis of the amorphous phase prepared by different manufacturing routes, Pharmaceutics 4 (2012) 93-103 DOI: 10.3390/pharmaceutics4010093.

151. M. Savolainen, K. Kogermann, A. Heinz, J. Aaltonen, L. Peltonen, C. Strachan and J. Yliruusi, Better understanding of dissolution behaviour of amorphous drugs by in situ solid-state analysis using Raman spectroscopy, Eur. J. Pharm. Biopharm. 71 (2009) 71-79; DOI: 10.1016/j.ejpb. 2008.06.001.

152. S. Hasegawa, T. Hamaura, N. Furuyama, S. Horikawa, A. Kusai, E. Yonemochi and K. Terada, Uniformity and physical states of troglitazone in solid dispersions determined by electron probe microanalysis and microthermal analysis, Int. J. Pharm. 280 (2004) 39-46; DOI: 10.1016/j. ijpharm.2004.04.024.

153. K. Kawakami, T. Numa and Y. Ida, Assessment of amorphous content by microcalorimetry, J. Pharm. Sci. 91 (2002) 417-423; DOI: 10.1002/jps.10017.

154. G. Buckton, P. Darcy, D. Greenleaf and P. Holbrook, The use of isothermal microcalorimetry in the study of changes in crystallinity of spray-dried salbutamol sulphate, Int. J. Pharm. 116 (1995) 113-118; DOI: 10.1016/0378-5173(94)00322-V.

155. L. E. Briggner, G. Buckton, K. Bystrom and P. Darcy, The use of isothermal microcalorimetry in the study of changes in crystallinity induced during the processing of powders, Int. J. Pharm.105 (1994) 125-135; DOI: 10.1016/0378-5173(94)90458-8.

156. D. Giron, P. Remy, S. Thomas and E. Vilette, Quantitation of amorphicity by microcalorimetry, J. Therm. Anal. 48 (1997) 465-472; DOI: 10.1007/BF01979493.

157. J. Nishizawa, N. G. Hadjiconstantinou, G. Dimonte, P. S. Lomdahl, B. L. Holian and B. J. Alder, Pioneering work of THz wave and its application for molecular sciences, AIP Conference Proceedings708 (2004) 369-375.

Acta Pharmaceutica

The Journal of Croatian Pharmaceutical Society

Journal Information

IMPACT FACTOR 2017: 1.071
5-year IMPACT FACTOR: 1.623

CiteScore 2017: 1.46

SCImago Journal Rank (SJR) 2017: 0.362
Source Normalized Impact per Paper (SNIP) 2017: 0.642

Cited By


All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 843 819 57
PDF Downloads 252 247 28