X-Ray Diffractometry and Other Analytical Techniques

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We are interested in the material science of pharmaceutical solids, with a particular emphasis on their physical characterization.  Specifically, we investigate the polymorphic form, degree of crystallinity, and the nature and extent of interaction with other components. We employ a battery of analytical techniques, specifically, differential scanning calorimetry, thermogravimetric analysis, gravimetric water sorption, powder X-ray diffractometry (both laboratory and synchrotron sources), microscopy, and spectroscopy (IR, NMR and dielectric) for comprehensive material characterization. A recent addition is low temperature small angle neutron scattering. The overall objective is to identify and resolve the problems associated with phase transformations.

Further Reading

  1. K.K. Amponsah-Efah, B. Demeler, R. Suryanarayanan. Characterizing Drug-Polymer Interactions in Aqueous Solution with Analytical Ultracentrifugation. Mol Pharm, 18(1), 246-256 (2020).
  2. S. Thakral, N.K. Thakral, R. Suryanarayanan. Estimation of drug particle size in intact tablets by two dimensional X-ray diffractometry. J Pharm Sci, 107(1), 231-238 (2018).
  3. S. Koranne, R. Govindarajan, R. Suryanarayanan. Investigation of spatial heterogeneity of salt disproportionation in tablets by synchrotron X-ray diffractometry. Mol Pharm, 14(4), 1133-1144 (2017).
  4. S. Thakral, M.W. Terban, N.K. Thakral, R. Suryanarayanan. Recent advances in the characterization of amorphous pharmaceuticals by X-ray diffractometry. Adv Drug Deliv Rev, 100, 183-193 (2016).
  5. R. Govindarajan, M. Landis, B. Hancock, L.A. Gatlin, R. Suryanarayanan, E.Y. Shalaev. Surface acidity and solid-state compatibility of excipients with an acid-sensitive API: Case study of atorvastatin calcium. AAPS PharmSciTech, 16(2), 1-10 (2014).
  6. V. Ragoonanan, R. Suryanarayanan. Ultrasonication as a potential tool to predict solute crystallization in freeze-concentrates. Pharm Res, 31(6), 1512-1524 (2014).
  7. S. Bhardwaj, R. Suryanarayanan. Use of dielectric spectroscopy to monitor molecular mobility in glassy and supercooled trehalose. J Phys Chem, 116(38), 11728-11736 (2012).
  8. P. Chakravarty, S. Bhardwaj, L. King, R. Suryanarayanan. Monitoring Phase Transformations in Intact Tablets of Trehalose by FT-Raman Spectroscopy. AAPS PharmSciTech, 10, 1420-1426 (2009).
  9. R. Surana, R. Suryanarayanan. Quantification of crystallinity in substantially amorphous pharmaceuticals and study of crystallization kinetics by X-ray powder diffractometry. Powder Diffr, 15, 2-6 (2000).