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Understanding the Behavior of Amorphous Pharmaceutical Systems during Dissolution

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Abstract

Purpose

To investigate the underlying physical processes taking place during dissolution of amorphous pharmaceuticals and correlate them to the observed solution concentration-time profiles. Felodipine and indomethacin were used as model hydrophobic compounds.

Methods

Concentration-time profiles were monitored during dissolution of the model amorphous compounds using in situ fiber-optic ultraviolet spectroscopy. Crystallization of the solid exposed to an aqueous environment was monitored using Raman spectroscopy and/or powder X-ray diffraction. Polarized light microscopy was used to provide qualitative information about crystallization processes.

Results

For felodipine, a small extent of supersaturation was generated via dissolution at 25°C but not at 37°C. The amorphous solid was found to crystallize rapidly at both temperatures upon exposure to the dissolution medium. Addition of low concentrations of polymers to the dissolution medium was found to delay crystallization of the amorphous solid, leading to the generation of supersaturated solutions. Amorphous indomethacin did not crystallize as readily in an aqueous environment; hence, dissolution resulted in supersaturated solutions. However, crystallization from these supersaturated solutions was rapid. Polymeric additives were able to retard crystallization from supersaturated solutions of both indomethacin and felodipine for up to 4 h.

Conclusions

The dissolution advantage of amorphous solids can be negated either by crystallization of the amorphous solid on contact with the dissolution medium or through rapid crystallization of the supersaturated solution. Polymeric additives can potentially retard both of these crystallization routes, leading to the generation of supersaturated solutions that can persist for biologically relevant timeframes.

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References

  1. Leuner C, Dressman J. Improving drug solubility for oral delivery using solid dispersions. Eur J Pharm Biopharm. 2000;50:47–60.

    Article  CAS  PubMed  Google Scholar 

  2. Lipinski CA, Lombardo F, Dominy BW, Feeney PJ. Experimental and computational approaches to estimate solubility and permeability in drug discovery and development settings. Adv Drug Delivery Rev. 1997;23:3–25.

    Article  CAS  Google Scholar 

  3. Ambike AA, Mahadik KR, Paradkar A. Spray-dried amorphous solid dispersions of simvastatin, a low Tg drug: in vitro and in vivo evaluations. Pharm Res. 2005;22:990–8.

    Article  CAS  PubMed  Google Scholar 

  4. Six K, Verreck G, Peeters J, Brewster M, Van den Mooter G. Increased physical stability and improved dissolution properties of itraconazole, a class II drug, by solid dispersions that combine fast- and slow-dissolving polymers. J Pharm Sci. 2004;93:124–31.

    Article  CAS  PubMed  Google Scholar 

  5. Yamashita K, Nakate T, Okimoto K, Ohike A, Tokunaga Y, Ibuki R, et al. Establishment of new preparation method for solid dispersion formulation of tacrolimus. Int J Pharm. 2003;267:79–91.

    Article  CAS  PubMed  Google Scholar 

  6. Kennedy M, Hu J, Gao P, Li L, Ali-Reynolds A, Chal B, et al. Enhanced bioavailability of a poorly soluble vr1 antagonist using an amorphous solid dispersion approach: a case study. Mol Pharm. 2008;5:981–93.

    Article  CAS  PubMed  Google Scholar 

  7. Kim MS, Jin SJ, Kim JS, Park HJ, Song HS, Neubert RHH, et al. Preparation, characterization and in vivo evaluation of amorphous atorvastatin calcium nanoparticles using supercritical antisolvent (SAS) process. Eur J Pharm Biopharm. 2008;69:454–65.

    Article  CAS  PubMed  Google Scholar 

  8. Law D, Schmitt EA, Marsh KC, Everitt EA, Wang WL, Fort JJ, et al. Ritonavir-PEG 8000 amorphous solid dispersions: in vitro and in vivo evaluations. J Pharm Sci. 2004;93:563–70.

    Article  CAS  PubMed  Google Scholar 

  9. Vaughn JM, McConville JT, Crisp MT, Johnston KP, Williams RO. Supersaturation produces high bioavailability of amorphous danazol particles formed by evaporative precipitation into aqueous solution and spray freezing into liquid technologies. Drug Dev Ind Pharm. 2006;32:559–67.

    Article  CAS  PubMed  Google Scholar 

  10. Marsac PJ, Konno H, Taylor LS. A comparison of the physical stability of amorphous felodipine and nifedipine systems. Pharm Res. 2006;23:2306–16.

    Article  CAS  PubMed  Google Scholar 

  11. Shamblin SL, Tang XL, Chang LQ, Hancock BC, Pikal MJ. Characterization of the time scales of molecular motion in pharmaceutically important glasses. J Phys Chem B. 1999;103:4113–21.

    Article  CAS  Google Scholar 

  12. Wu T, Yu L. Surface crystallization of indomethacin below T-g. Pharm Res. 2006;23:2350–5.

    Article  CAS  PubMed  Google Scholar 

  13. Yu L. Amorphous pharmaceutical solids: preparation, characterization and stabilization. Adv Drug Delivery Rev. 2001;48:27–42.

    Article  CAS  Google Scholar 

  14. Zhou D, Zhang GGZ, Law D, Grant DJW, Schmitt EA. Thermodynamics, molecular mobility and crystallization kinetics of amorphous griseofulvin. Mol Pharm. 2008;5:927–36.

    Article  CAS  PubMed  Google Scholar 

  15. Hancock BC, Parks M. What is the true solubility advantage for amorphous pharmaceuticals? Pharm Res. 2000;17:397–404.

    Article  CAS  PubMed  Google Scholar 

  16. Chikaraishi Y, Otsuka M, Matsuda Y. Dissolution phenomenon of the piretanide amorphous form involving phase change. Chem Pharm Bull. 1996;44:2111–5.

    CAS  Google Scholar 

  17. Fukuoka E, Makita M, Yamamura S. Glassy state of pharmaceuticals. 2. Bioinequivalence of glassy and crystalline indomethacin. Chem Pharm Bull. 1987;35:2943–8.

    CAS  PubMed  Google Scholar 

  18. Savolainen M, Kogermann K, Heinz A, Aaltonen J, Peltonen L, Strachan C, et al. Better understanding of dissolution behaviour of amorphous drugs by in situ solid-state analysis using Raman spectroscopy. Eur J Pharm Biopharm. 2009;71:71–9.

    Article  CAS  PubMed  Google Scholar 

  19. Windbergs M, Jurna M, Offerhaus HL, Herek JL, Kleinebudde P, Strachan CJ. Chemical imaging of oral solid dosage forms and changes upon dissolution using coherent anti-stokes Raman scattering microscopy. Anal Chem. 2009;81:2085–91.

    Article  CAS  PubMed  Google Scholar 

  20. Konno H, Taylor LS. Influence of different polymers on the crystallization tendency of molecularly dispersed amorphous felodipine. J Pharm Sci. 2006;95:2692–705.

    Article  CAS  PubMed  Google Scholar 

  21. Matsumoto T, Zografi G. Physical properties of solid molecular dispersions of indomethacin with poly(vinylpyrrolidone) and poly(vinylpyrrolidone-co-vinylacetate) in relation to indomethacin crystallization. Pharm Res. 1999;16:1722–8.

    Article  CAS  PubMed  Google Scholar 

  22. Van den Mooter G, Wuyts M, Blaton N, Busson R, Grobet P, Augustijns P, et al. Physical stabilisation of amorphous ketoconazole in solid dispersions with polyvinylpyrrolidone K25. Eur J Pharm Sci. 2001;12:261–9.

    Article  PubMed  Google Scholar 

  23. Weuts I, Kempen D, Decorte A, Verreck G, Peeters J, Brewster M, et al. Physical stability of the amorphous state of loperamide and two fragment molecules in solid dispersions with the polymers PVP-K30 and PVP-VA64. Eur J Pharm Sci. 2005;25:313–20.

    Article  CAS  PubMed  Google Scholar 

  24. Hoffman JD. Thermodynamic driving force in nucleation and growth processes. J Chem Phys. 1958;29:1192–3.

    Article  CAS  Google Scholar 

  25. Konno H, Handa T, Alonzo DE, Taylor LS. Effect of polymer type on the dissolution profile of amorphous solid dispersions containing felodipine. Eur J Pharm Biopharm. 2008;70:493–9.

    Article  CAS  PubMed  Google Scholar 

  26. Taylor LS, Zografi G. Spectroscopic characterization of interactions between PVP and indomethacin in amorphous molecular dispersions. Pharm Res. 1997;14:1691–8.

    Article  CAS  PubMed  Google Scholar 

  27. Towler CS, Taylor LS. Spectroscopic characterization of intermolecular interactions in solution and their influence on crystallization outcome. Cryst Growth Des. 2007;7:633–8.

    Article  CAS  Google Scholar 

  28. Marsac PJ, Konno H, Rumondor ACF, Taylor LS. Recrystallization of nifedipine and felodipine from amorphous molecular level solid dispersions containing poly(vinylpyrrolidone) and sorbed water. Pharm Res. 2008;25:647–56.

    Article  CAS  PubMed  Google Scholar 

  29. Sato T, Okada A, Sekiguchi K, Tsuda Y. Difference in physico-pharmaceutical properties between crystalline and noncrystalline 9, 3″-diacetylmidecamycin. Chem Pharm Bull. 1981;29:2675–82.

    CAS  Google Scholar 

  30. Zhu L, Wong L, Yu L. Surface-enhanced crystallization of amorphous nifedipine. Mol Pharm. 2008;5:921–6.

    Article  CAS  PubMed  Google Scholar 

  31. Ishida H, Wu TA, Yu LA. Sudden rise of crystal growth rate of nifedipine near T-g without and with polyvinylpyrrolidone. J Pharm Sci. 2007;96:1131–8.

    Article  CAS  PubMed  Google Scholar 

  32. Wu T, Sun Y, Li N, de Villiers MM, Yu L. Inhibiting surface crystallization of amorphous indomethacin by nanocoating. Langmuir. 2007;23:5148–53.

    Article  CAS  PubMed  Google Scholar 

  33. Andronis V, Yoshioka M, Zografi G. Effects of sorbed water on the crystallization of indomethacin from the amorphous state. J Pharm Sci. 1997;86:346–51.

    Article  CAS  PubMed  Google Scholar 

  34. Bhugra C, Pikal MJ. Role of thermodynamic, molecular, and kinetic factors in crystallization from the amorphous state. J Pharm Sci. 2008;97:1329–49.

    Article  CAS  PubMed  Google Scholar 

  35. Lachman L, Lieberman HA, Kanig JL. The theory and practice of industrial pharmacy. Stipes Publishing LLC, 1986.

  36. Mullin JW. Crystallization. 4th ed. Oxford: Elsevier Butterworth-Heinemann; 2001.

    Google Scholar 

  37. Garside J, Mersmann A, Nyvlt J. Measurement of Crystal Growth and Nucleation Rates. 2nd ed. Rugby: Institute of Chemical Engineers; 2002.

    Google Scholar 

Download references

Acknowledgments

We would like to acknowledge the PhRMA foundation for providing a pre-doctoral fellowship to David Alonzo, as well as funding from Abbott Labs. A special thanks to Davor Gusak and Sajeda Abdo for their help in the laboratory.

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Correspondence to Yi Gao or Lynne S. Taylor.

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Alonzo, D.E., Zhang, G.G.Z., Zhou, D. et al. Understanding the Behavior of Amorphous Pharmaceutical Systems during Dissolution. Pharm Res 27, 608–618 (2010). https://doi.org/10.1007/s11095-009-0021-1

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  • DOI: https://doi.org/10.1007/s11095-009-0021-1

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