1 / 15

„ The und is covered life is not worth for living !“

„ The und is covered life is not worth for living !“. Socrates. Brno University of Technology Faculty of Chemistry – Institute of Physical and Applied chemistry. Surface Tension and Flow Properties of Hyaluronic Solutions. Ing. Martin Chytil doc. Ing. Miloslav Pekař, CSc. 2004 - 2005.

shanon
Download Presentation

„ The und is covered life is not worth for living !“

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. „The undiscovered life is not worth for living!“ Socrates

  2. Brno University of Technology Faculty of Chemistry – Institute of Physical and Applied chemistry Surface Tension and Flow Properties of Hyaluronic Solutions Ing. Martin Chytil doc. Ing. Miloslav Pekař, CSc. 2004 - 2005

  3. 1) What was the study about?

  4. 1) What was the study about? • Hyaluronic acid (HA) - widely occurred polysaccharide • Unique properties of HA predict its huge range of applications (pharmacy, cosmetics, medicine etc.) • Hydrophobic modification of HA – change in some properties (hydrophilic/hydrophobic character)  possibility in solubilization and drug carrier delivery • Research focused on rheological and surface active properties of these compounds in aq. solutions • Studied compounds produced by

  5. Studied compounds 1) What was the study about? • Hyaluronic acid (HA); Mw: • 183.9×103 • HALW 0.56×106 • HAHW 1.63× 106 • HA derivates: hydrophobically modified HA by N-alkyl • Derivates with ether (epoxy) bond • Derivates with carbamate bond • R – butyl, hexyl, octyl, decyl, dodecyl • Mr of derivates: cca 90-840 kDa

  6. 1) What was the study about? Shortened Scheme of HA Derivatives Synthesis HA + ( ) R1: C4 –C12

  7. 2) Experimental

  8. 2) Experimental • Samples for measurements: • Solutions of HA and HA derivates in 0.1 M phosphate bufferwith NaCl (0.15 M); pH ~ 7 • Rheology of samples studied deformation τ,γ˙,γ, n, M, ω material loading Response – resistence against deformation η, C, G Cone-Plate sensor

  9. 2) Experimental • Surface active properties and association ability studied by the surface tension measurements of the samples solutions at lab. temperature ( ca 75 °F; ca 23 °C) • Measurements performed using the Pt-ring method Demonstration of surface tension measurement; F represents force of thering tearing off the liquid surface; R means ring radius

  10. 3) Results and discussions

  11. 3) Results and discussions Flow Behavior of HA and HA Derivates Flow and viscosity curves of HA (Mw 1.63×106) aq. solution Various settings of measurements for C6-EP-HA (Mw 130 000; SD 8.7%)

  12. concentration Concentration, alkyl chain length and SD influences of HA derivatives 3) Results and discussions The influence of an alkyl chain length

  13. 3) Results and discussions The Surface Tension Measurement Results: Comparison of the HA Derivates with SDS formation of a gel CMC SD(OK-NH-HA7) = 18.82%; γs represents surface tension of a sample, γ – surface tension of buffer, w – weight concentration in % w/w. Comparison of the surface activity of the OK-NH-HA7 with HA LW

  14. 3) Results and discussions The surface Tension Measurement Results: The Alkyl Chain Length and SD Influences The alkyl chain length influencefor the epoxy HA derivates

  15. 4) Conclusions • The poorer rehological behavior of HA derivates in aq. solutions in comparison to HA • The hexyl derivates displayed the most advantageous rheologicalbehavior • A HA derivate could be built into HA gel/solution and solubilize poorly soluble ( ophthalmic) drugs • The most convenient derivates for solubilization: hexyl, and octyl even with the middle low SD (ca 30%) and octyl carbamate derivates with the highest SD

More Related