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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Preparation of hydrocortisone nanosuspension through a bottom-up nanoprecipitation technique using microfluidic reactors.

Ali, Hany S.M., York, Peter, Blagden, Nicholas 22 June 2009 (has links)
No / In this work, the possibility of bottom-up creation of a relatively stable aqueous hydrocortisone nanosuspension using microfluidic reactors was examined. The first part of the work involved a study of the parameters of the microfluidic precipitation process that affect the size of generated drug particles. These parameters included flow rates of drug solution and antisolvent, microfluidic channel diameters, microreactors inlet angles and drug concentrations. The experimental results revealed that hydrocortisone nano-sized dispersions in the range of 80¿450nm were obtained and the mean particle size could be changed by modifying the experimental parameters and design of microreactors. The second part of the work studied the possibility of preparing a hydrocortisone nanosuspension using microfluidic reactors. The nano-sized particles generated from a microreactor were rapidly introduced into an aqueous solution of stabilizers stirred at high speed with a propeller mixer. A tangential flow filtration system was then used to concentrate the prepared nanosuspension. The nanosuspension produced was then characterized using photon correlation spectroscopy (PCS), Zeta potential measurement, transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and X-ray analysis. Results showed that a narrowsized nanosuspension composed of amorphous spherical particles with a mean particle size of 500±64 nm, a polydispersity index of 0.21±0.026 and a zeta potential of ¿18±2.84mVwas obtained. Physical stability studies showed that the hydrocortisone nanosuspension remained homogeneous with slight increase in mean particle size and polydispersity index over a 3-month period.
2

Polymorphs of Curcumin and Its Cocrystals With Cinnamic Acid

Rathi, N., Paradkar, Anant R, Gaikar, V.G. 2019 March 1921 (has links)
Yes / We report formation of polymorphs and new eutectics and cocrystals of curcumin, a sparingly water-soluble active component in turmeric, structurally similar to cinnamic acid. The curcumin polymorphs were formed using liquid antisolvent precipitation, where acetone acted as a solvent and water was used as the antisolvent. The metastable form 2 of curcumin was successfully prepared in varied morphology over a wide range of solvent-to-antisolvent ratio and under acidic pH conditions. We also report formation of new eutectics and cocrystals of curcumin with cinnamic acid acting as a coformer. The binary phase diagrams were studied using differential scanning calorimetry and predicted formation of the eutectics at the curcumin mole fraction of 0.15 and 0.33, whereas a cocrystal was formed at 0.3 mole fraction of curcumin in the curcumin–cinnamic acid mixture. The formation of the cocrystal was supported with X-ray powder diffraction, the enthalpy of fusion values, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The hydrogen bond interaction between curcumin and cinnamic acid was predicted from Fourier-transform infrared spectra, individually optimized curcumin and cinnamic acid structures by quantum mechanical calculations using Gaussian-09 and their respective unit cell packing structures.
3

Utilization of Carbon Dioxide in Separation Science: Fabrication of a Solid Phase Extraction Sorbent and Investigation of the Greenness of Supercritical Fluid Chromatography

GIbson, Rebekah January 2021 (has links)
No description available.

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