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The Characterization of Dry Powder Magnesium Hydroxide Suspensions Using Sedimentation, Thermal Analysis and Other Techniques

Wang, Yingzhe
http://rave.ohiolink.edu/etdc/view?acc_num=mco1322075364

Abstract Details

2011, Master of Science in Pharmaceutical Science (MSP), University of Toledo, College of Pharmacy.
Dry powder magnesium hydroxide suspensions in various media were characterized by their settling behavior as determining their particle size in the dispersed phase by sedimentation and other techniques, as well as thermal analysis. Several different methods were used for the particle size determination, including sieve analysis, sedimentation, scanning electron microscopy (SEM), and laser diffraction (LD). The settling behavior of the concentrated flocculated suspensions is termed hindered settling, where Stokes' law cannot be applied. Several different theories were utilized for the interpretation of the hindered settling phenomenon by correlating the observed rate of fall of the interface and Stokes' limiting velocity. The best matches for the case of dry powder magnesium hydroxide suspensions were the theories of Steinour, Richardson and Zaki, and Dollimore and McBride. The particle size determined by sieve analysis was much greater than that determined by sedimentation due to the clustered porous nature of the dry powder magnesium hydroxide. Thus, sieve analysis is not a suitable method for particle size determination for suspensions since the vehicle associates with the dry powder to cause it to break apart into its individual granules. Sedimentation methods were verified to be more consistent with both SEM and LD results although the un-spherical shape of the particles casued the precision of the sedimentation results to vary to some extent. The unbound and bound water associated with the suspensions in various media were determined by thermal techniques such as differential scanning calorimetry (DSC) and thermogravimetry (TG). The thermal results showed that the dried sediments decomposed after heating at temperatures above 350 °C, which made it difficult to determine the interstitial water content. X-ray powder diffraction (PXRD) was used to verify the decomposition of magnesium hydroxide as the dry powder and dried sediments before and after heating by comparing the peak patterns with standards.
Kenneth Alexander (Committee Chair)
Jerry Nesamony (Committee Member)
Kenneth Alexander (Committee Member)
Sai Hanuman Sagar Boddu (Committee Member)
201 p.
Pharmaceuticals
Sedimentation; Suspensions; Thermal Analysis

Recommended Citations

Citations

  • Wang, Y. (2011). The Characterization of Dry Powder Magnesium Hydroxide Suspensions Using Sedimentation, Thermal Analysis and Other Techniques [Master's thesis, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=mco1322075364

    APA Style (7th edition)

  • Wang, Yingzhe. The Characterization of Dry Powder Magnesium Hydroxide Suspensions Using Sedimentation, Thermal Analysis and Other Techniques. 2011. University of Toledo, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=mco1322075364.

    MLA Style (8th edition)

  • Wang, Yingzhe. "The Characterization of Dry Powder Magnesium Hydroxide Suspensions Using Sedimentation, Thermal Analysis and Other Techniques." Master's thesis, University of Toledo, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=mco1322075364

    Chicago Manual of Style (17th edition)

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© 2011, all rights reserved.
This open access ETD is published by University of Toledo Health Science Campus and OhioLINK.