International E-publication: Publish Projects, Dissertation, Theses, Books, Souvenir, Conference Proceeding with ISBN.  International E-Bulletin: Information/News regarding: Academics and Research

Molecular Dynamics in Amorphous Atropine and Tolnaftate

    , , ,

Author Affiliations

  • 1Department of Physics, University of Calicut, Kerala, India
  • 2MES Ponnani College, Ponnani, India
  • 3Department of Physics, University of Calicut, Kerala, India
  • 4Departmento di Fisica, Università di Pisa, Italy

Res. J. Recent Sci., Volume 5, Issue (3), Pages 40-44, March,2 (2016)

Abstract

During the development of new pharmaceutical products in amorphous form, the molecular mobility of amorphous active ingredients has to be characterized in detail. Here, using broadband dielectric spectroscopy, the molecular mobility in supercooled liquid and glassy states of two pharmaceuticals namely atropine and tolnaftate have been studied. The dielectric permittivity and loss spectra of glassy and ultraviscous states of the above two pharmaceuticals have been measured for some test frequencies over a wide temperature range. Above the glass transition temperature Tg, the presence of the structural α- relaxation peak was observed which shifts towards lower frequencies as the temperature decreases and kinetically freezes at Tg. The secondary relaxations perceivable below the glass transition temperature is due to intramolecular modes and are usually designated as β, γ and δ etc. are clearly observed in the ε” spectra of atropine, while in tolnaftate no secondary relaxation processes is observed in the loss spectra, but an excess contribution to the high- frequency tail of the α-peak, called excess wing is observed. The α- process shows non-Arrhenius behavior for both the samples. The dielectric relaxation time increases on cooling according to the Vogel-Fulcher-Tammann equation. The secondary relaxation process shows Arrhenius behavior.

References

  1. Hancock B.C. and Parks M. (2000). , What is the True Solubility Advantage for Amorphous Pharmaceuticals?, , Pharm. Res., 17(4), 397-404.
  2. Alie J., Menegotto J., Cardon P., Dupla H., Caron A., Lacabanne C. and Bauer M. (2003). , Dielectric Study of the Molecular Mobility and the Isothermal Crystallization Kinetics of an Amorphous Pharmaceutical Drug Substance,, J.Pharm. Sci., 93, 218-233.
  3. Kirchhoff C., Bitar Y., Ebel S. and Holzgrabe U. (2004). , Analysis of Atropine, Its Degradation Products and Related Substances of Natural Origin by means of Reversed-phase High-performance Liquid Chromatography, , J. Chromatography A., 1046(1-2), 115-20.
  4. Lanfranchi D.A., Tomi F. and Casanova J. (2010), , Enantiomeric Differentiation of Atropine/Hyoscyamine by 13C NMR Spectroscopy and its Application to Datura stramonium extract, , Phytochemical Analysis., 21(6), 597–601.
  5. Budavari S. (1996). , The Merck index: An Encyclopedia of Chemicals, Drugs, and biological, 12th ed, Merck and Company, , 148-149.
  6. Fukuoka E, Makita M and Yammura S. (1989). , Glassy State of Pharmaceuticals. III. Thermal Properties and Stability of Glassy Pharmaceuticals and Their Binary Glass Systems, , Chem. Pharm. Bull., 37(4), 1047-1050.
  7. Dash A.K. (1994). , Analytical Profiles of Drug Substances and Excipients: Edited by H. Brittain, ed. Academic Press, San Diego, CA, , 23, 543-570.
  8. Gupta P and Garg S. (2002). , Recent Advances in Semisolid Dosage Form for Dermatological Application. , Pharmaceutical Technology, 144-162.
  9. Fukuoka E., Makita M. and Nakamura Y. (1991). , Glassy State of Pharmaceuticals. V. Relaxation during Cooling and Heating of Glass by Differential Scanning Calorimetry, , Chem. Pharm. Bull., 39(94), 2087-2090.
  10. Sailaja U., Thayyil M.S., Krishna Kumar N.S and Govindraj G. (2013). , Molecular Dynamics in Liquid and Glassy State of Non-steroidal Anti-inflammatory Drug: Ketoprofen, , Eur. J. Pharm. Sci., 49, 333-340.
  11. Johari J.P. and Goldstein M. (1971). , Viscous Liquids and the Glass Transition. III. Secondary relaxation in aliphatic alcohols and other non rigid molecules, , J. Chem. Phys., 55, 4245-4252.
  12. Rault J. (2000). , Origin of the Vogel-Fulcher-Tammann law in Glass-forming Materials: α-β Bifurcation, , J. Non-Cryst. Solids., 271, 177-217.
  13. Hancock B.C. (1998). , Christensen K and Shamblin S. L., Estimating the Critical Molecular Mobility Temperature (TK) of Amorphous Pharmaceuticals, , Pharm. Res., 15(11), 1649-1651.
  14. Patkowski A., Paluch M. and Gapinski J. (2003). , Relationship between T0, Tg and their Pressure Dependence for Supercooled Liquids, , J. Non-Cryst. Solids., 330, 259-263.