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The Use of Inverse Phase Gas Chromatography to Study the Glass Transition Temperature of a Powder Surface

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Abstract

Purpose. To measure the glass transition temperature (Tg) at the surface of a hydrophobic particle at different temperatures and humidities, on the hypothesis that the surface may be plasticized to a different extent to the bulk due to slow water sorption giving a concentration gradient of water through the particles.

Methods. Amorphous indomethacin was exposed to a range of relative humidities (RH) and temperatures in an inverse gas chromatograph (IGC). The retention volumes of decane were calculated at all conditions using center of mass (Vcom) and peak height (Vmax) methods. The extent of water sorption was determined gravimetrically.

Results. The Vcom retention volumes were found to deviate from Vmax results at certain critical humdities at each temperature. This was taken as a novel method for determining the Tg of the sample surface at different experimental conditions. Extrapolating the critical RH to lower the Tg to experimental temperature to 0% RH yeilded a Tg similar to literature values. Water sorption data provided valuable information on changes in mobility of the amorphous form as a function of temperature and RH.

Conclusions. It is possible to use IGC to determine the Tg of the surface of particles at defined conditions. This overcomes the problems of conventional methods of assessing Tg, relating to disruption of water sorption on heating. This helps in the understanding of the physical form of the surface of hydrophobic particles and how and when the surface will start to crystallize.

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REFERENCES

  1. H. E. Newell, G. Buckton, D. A. Butler, F. Thielmann, and D. R. Williams. The use of inverse phase gas chromatography to study the change of surface energy of amorphous lactose as a function of relative humidity and the process of collapse and crystallization. Int. J. Pharm. 217:45-56 (2001).

    Google Scholar 

  2. S. E. Hogan and G. Buckton. Water sorption/desorption-near IR and calorimetric study of crystalline and amorphous raffinose. Int. J. Pharm. 227:57-69 (2001).

    Google Scholar 

  3. V. Andronis, M. Yoshioka, and G. Zografi. Effect of sorbed water on the crystallization of indomethacin from the amorphous state. J. Pharm. Sci. 86:346-351 (1997).

    Google Scholar 

  4. G. Buckton and P. Darcy. Water mobility in amorphous lactose below and close to the glass transition temperature. Int. J. Pharm. 135:141-146 (1996).

    Google Scholar 

  5. F. Thielmann. iGC analysis software manual, Version 1.2 (Standard), Surface measurement systems. London. Page 12. June (2002).

  6. T. Mastumato and G. Zografi. Physical properties of solid molecular dispersions of indomethacin with poly(vinylpyrrolidone) and poly(vinylpyrrolidone-co-vinyl-acetate) in relation to indomethacin crystallization. Pharm. Res. 16:1722-1728 (1999).

    Google Scholar 

  7. P. Tong and G. Zografi. Solid state characteristics of amorphous sodium indomethacin relative to its free acid. Pharm. Res. 16: 1186-1192 (1999).

    Google Scholar 

  8. M. Yoshioka, B. C. Hancock, and G. Zografi. Crystallization of Indomethacin from the amorphous state below and above its glass transition temperature. J. Pharm. Sci. 83:1700-1705 (1994).

    Google Scholar 

  9. M. Yoshioka, B. C. Hancock, and G. Zografi. Inhibition of indomethacin crystallization in poly(vinylpyrrolidone) coprecipitate. J. Pharm. Sci. 84:983-986 (1995).

    Google Scholar 

  10. B. C. Hancock, S. Shamblin, and G. Zografi. Molecular mobility of amorphous pharmaceutical solids below their glass transition temperature. Pharm. Res. 12:799-806 (1995).

    Google Scholar 

  11. P. Tong and G. Zografi. A study of amorphous molecular dispersions of Indomethacin and its Sodium salts. J. Pharm. Sci. 90:1991-2004 (2001).

    Google Scholar 

  12. M. Gordon and J. S. Taylor. Ideal co-polymers and the second order transitions of synthetic rubbers. 1. Non-crystalline co-polymers. J. Appl. Chem. 2:493-500 (1952).

    Google Scholar 

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Authors and Affiliations

  1. Department of Pharmaceutics, School of Pharmacy, University of London, London, WC1N 1AX, UK

    Graham Buckton & Ameet Ambarkhane

  2. World Wide Physical Properties, GlaxoSmithKline Research & Development Limited, Kent, TN11 9AN, UK

    Kim Pincott

Authors
  1. Graham Buckton
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  2. Ameet Ambarkhane
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  3. Kim Pincott
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Buckton, G., Ambarkhane, A. & Pincott, K. The Use of Inverse Phase Gas Chromatography to Study the Glass Transition Temperature of a Powder Surface. Pharm Res 21, 1554–1557 (2004). https://doi.org/10.1023/B:PHAM.0000041447.15874.f7

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  • DOI: https://doi.org/10.1023/B:PHAM.0000041447.15874.f7

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