Diffusion and Swelling Measurements in Pharmaceutical Powder Compacts Using Terahertz Pulsed Imaging

Samy Yassin, Ke Su, Hungyen Lin, Lynn F. Gladden andJ. Axel Zeitler

Abstract

Tablet dissolution is strongly affected by swelling and solvent penetration into its matrix. A terahertz-pulsed imaging (TPI) technique, in reflection mode, is introduced as a new tool to measure one-dimensional swelling and solvent ingress in flat-faced pharmaceutical compacts exposed to dissolution medium from one face of the tablet. The technique was demonstrated on three tableting excipients: hydroxypropylmethyl cellulose (HPMC), Eudragit RSPO, and lactose. Upon contact with water, HPMC initially shrinks to up to 13% of its original thickness before undergoing expansion. HPMC and lactose were shown to expand to up to 20% and 47% of their original size in 24 h and 13 min, respectively, whereas Eudragit does not undergo dimensional change. The TPI technique was used to measure the ingress of water into HPMC tablets over a period of 24 h and it was observed that water penetrates into the tablet by anomalous diffusion. X-ray microtomography was used to measure tablet porosity alongside helium pycnometry and was linked to the results obtained by TPI. Our results highlight a new application area of TPI in the pharmaceutical sciences that could be of interest in the development and quality testing of advanced drug delivery systems as well as immediate release formulations. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci

This study was performed using TeraView's Spectra 3000 system. (TeraView, Cambridge, UK)

Full Article: http://onlinelibrary.wiley.com/doi/10.1002/jps.24376/full

Polymorphism of Resorcinol Explored by Complementary Vibrational Spectroscopy (FT-RS, THz-TDS, INS) and First Principles Solid-State Computations (Plane-Wave DFT)

Kacper Druzbicki , Edward Mikuli , Norbert Pałka , Sławomir Zalewski , and Mirosława Danuta Ossowska-Chruściel

Abstract

The polymorphism of resorcinol has been complementary studied by combining Raman, time-domain terahertz and inelastic neutron scattering spectroscopy with modern solid-state density functional theory (DFT) calculations. The spectral differences, emerging from the temperature-induced structural phase transition, have been successfully interpreted with an emphasis on the low-wavenumber range. The given interpretation is based on the plane-wave DFT computations, providing an excellent overall reproduction of both wavenumbers and intensities and revealing the source of the observed spectral differences. The performance of the generalized gradient approximation (GGA) functionals in prediction of the structural parameters and the vibrational spectra of the normal-pressure polymorphs of resorcinol has been extensively examined. The results show that standard PBE along with its ‘hard’ revised form tend to be superior if compared to the ‘soft’ GGA approximation.

This study was performed using TeraView's Spectra 3000 system. (TeraView, Cambridge, UK)

Full Article: http://pubs.acs.org/doi/abs/10.1021/jp507241j

TeraView announces being a proud sponsor of this year’s IRMMW-THz conference

TeraView are glad to announce its continued support of the terahertz research community by being a proud sponsor of this year’s IRMMW-THz conference hosted by Professor Emma MacPherson in Hong Kong! 

The International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), is the oldest and largest continuous forum devoted to the science and technology of long-wavelength radiation. The scope of the conference includes all scientific and technological activities from millimeter-waves to the THz regime and on to the far-infrared region of the electromagnetic spectrum. This covers a very wide range of disciplines, encompassing everything from micro- and nano-scale devices and structures to large-scale accelerators and tokamaks and their applications. Presentations at this conference address issues ranging from basic physics, chemistry, electrical engineering and materials science to problems in high frequency circuits and systems, communications, antennas and optics, imaging and spectroscopy, and much, much more.

The conference will be held 23-28 August 2015 at the Chinese University of Hong Kong. For more information please visit: http://bme.ee.cuhk.edu.hk/thzgroup/irmmw2015/

Positions at TeraView

TeraView Limited is the world's leader in the design and manufacture of terahertz (THz) products to the pharmaceutical, security, medical and materials characterisation markets. Our products continue to yield many ground-breaking applications such as tablet coating thickness and uniformity, cracks, defect analysis, foreign materials and analysis of solid-state structure to be exploited by our customers. Based in Cambridge UK, we have a global client base and a highly-skilled workforce.

We are seeking a applicants
to join our team; an individual who is able to meet the existing operational needs of the company, as well as planning for the future needs of the company as we grow.

For a full job description and more information on the role, please visit: http://www.teraview.com/about/careers-jobs.html

TeraHertz: New opportunities for industry - 3-5 February 2015

TeraHertz (THz), the frequencies between electronics and optics,
was until recently the last unexploited part of the electro-
magnetic spectrum. The harnessing of THz-based technologies has the potential of impacting globally a vast number of industries, like both electronics in the 70’s and optics in the 80’s did.

THz applications span over a wide array of fields, including:

Quality Control and Non-destructive testing

Surface analysis

Security

Chemical and Bio-Medical analysis

Telecommunications

Filling the TeraHertz “gap” has led to unprecedented creativity in the development and commercialization of TeraHertz sources, transmission components and detectors.

This year’s edition will focus on THz materials measurements and applications.

- See more at: http://www.formation-continue-unil-epfl.ch/thz#sthash.87N5prmt.dpuf

Registration deadline: 23 January 2015