In spite of the vast research on polymer-based tissue regeneration, extensive studies to develop an elastic and cell-promoting polymer biomaterial are still ongoing. However, using a renewable resource and a simple, environment-friendly synthesis route to synthesize an elastic polymer has not been successfully achieved yet. The objective of this work was to develop an elastic polymer for tissue engineering and drug delivery applications by using non-toxic, inexpensive and renewable monomers. A new nature-derived renewable material, xylitol, was used to synthesize an elastic polymer with the presence of a crosslinking agent, dodecanedioic acid. Here a simple melt condensation polymerization method was used to synthesize the poly(xylitoldodecanedioic acid)(PXDDA). The physicochemical and biological properties of the new PXDDA polymer were characterized. Fourier transform infrared (FTIR) confirmed the formation of ester bonding in the polymer structure, and thermal analysis demonstrated that the polymer was completely amorphous. The polymer shows high elasticity. Increasing the molar ratio of dodecanedioic acid resulted in higher hydrophobicity and lower glass transition temperature. Further, the polymer degradation and in vitro dye release studies revealed that the degradation and dye release from the polymer became slower when the amount of dodecanedioic acid in the composite increased. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

Purpose: The aim of this thesis was to investigate a novel method of preparing crosslinked alginate matrices. Current methods use large quantities of water and hence are not suitable for large scale manufacturing of drug alginate particulate systems. Moreover, the current processes offer little scope for control of the crosslinking process. The aim was to overcome these problems through studies of paracetamol alginate granular matrices prepared by the novel method and to explore if these granules could be used to improve the taste of paracetamol. Methods: The novel method involves preparation of dried drug alginate granules (moisture content: <5-6 %) using conventional granulation followed by crosslinking treatment of the dried granules with calcium chloride or a combination of calcium and magnesium ion solution in a crosslinking bath. The effect of the process (shear rate, binder quantity) to prepare untreated granules, composition of the raw materials (drug particle size and type of alginate) and subsequently the crosslinking treatment process variables (Ca�⁺ ion concentration, agitation rate, time and temperature of Ca�⁺ solution) on the physicochemical properties of granule systems were studied using factorial designs together with supporting studies. The granules were characterized using sodium and calcium content analysis, drug release studies (mainly sub-60s release) matrix swelling rate and equilibrium swelling studies, tensile strength studies, ion permeation studies, SEM and X Ray analysis and gravimetric studies. Sensory studies correlating sub-60 s drug release (determined using a specially designed apparatus) and human taste scores (measured using an analogue scale) were then undertaken. Selected formulations were evaluated for taste improvement and to determine if mucoadhesion led to an increased unpalatability of paracetamol. Results: Of the crosslinking treatment factors, the calcium concentration had the greatest effect on crosslinked granules. Although other treatment factors also affected the granule properties, alteration of the salt concentration allowed considerable control over the crosslinking process (not possible in the conventional method) in addition to providing a mechanistic understanding of the crosslinking process in the dried state. The use of low calcium concentrations (< 20 mg/ml, CaCl₂. 2H₂O) during treatment led to granule erosion (hence drug loss) due to overall incomplete crosslinking but led to a reduction in the short-term drug release compared to the granules treated with intermediate (100- 250 mg/ml) or high calcium concentrations (>400 mg/ml) due to reduction in the granule porosity after crosslinking. Although intermediate calcium concentrations led to complete crosslinking and longer release times (T 85 %: 25 min) high calcium crosslinking restricted the crosslinking to the surface of the granules leading to faster drug release (T 85 %: 8 min) with low calcium granules showing intermediate crosslinking and drug release rates (T 85 %: 18 min). High calcium treatment limited drug loss during crosslinking (95 % recovered compared to 83 % recovery at intermediate calcium concentration) without affecting the short-term drug release much. Low calcium granules showed the lowest drug recovery (< 70 %) and slowest sub-60s drug release followed closely by intermediate and high calcium treated granules. The granule preparation factors (shear rate, binder quantity) and type of alginate used, considerably affected the sub-60s drug release by affecting surface porosity especially when a low shear rate was used. However, these factors only slightly reduced the drug loss during crosslinking treatment phase (about 4 % increase in drug recovery). Smaller drug particle size had a slightly larger incremental effect on drug recovery (about 8 % increase in the drug recovery) during crosslinking treatment due to better embedding of the drug particles inside the untreated granule matrix. This was true as long as the particle size of the drug was > 98 [mu]m. Below this size drug recovery remained unaffected by changes in drug particle size. Although granule surface porosity considerably affected the sub-60s drug release, its effect on drug release (long-term) was much less. A linear correlation was observed between the sub-60s drug release and sensory scores despite high individual variability. Both granule formulations evaluated showed taste improvement and mucoadhesion did not lead to an increase in the bitter taste of the uncrosslinked paracetamol alginate granules. Conclusions: Unlike the traditional method, the new technique of preparation of crosslinked drug alginate particulate systems uses very little water and allows greater control over the the crosslinking process compared to the swollen state crosslinking. The novel process of preparation is versatile, and should be scalable. It offers the formulator a platform to prepare a matrix, reservoir or a combination of these two systems using alginates and other drugs and polymers as well. Adequate short-term control over paracetamol release, very little loss of paracetamol during treatment (< 5 % loss), reduction in mucoadhesion of the granules and lastly improvement of the taste of paracetamol is possible using alginate based systems especially if high calcium is used during the crosslinking treatment. Hence, it is likely that these taste-improved granules could be used to prepare tablets without the need for a protective film coating to improve taste. Finally, this research established the utility of short-term drug release in taste improvement research and characterization of solid controlled release dosage forms.

Thesis (Ph. D.)--Ohio State University, 2006. / Full text release at OhioLINK's ETD Center delayed at author's request

Thesis (Ph. D.)--University of Akron, Dept. of Chemistry, 2006. / "May, 2006." Title from electronic dissertation title page (viewed 10/11/2006). Advisor, Daniel J. Smith; Committee members, Michael J. Taschner, Wiley J. Youngs, Kim C. Calvo, Darrell H. Reneker; Department Chair, Michael J. Taschner; Dean of the College, Ronald F. Levant; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Thesis (M.S.)--Rutgers University, 2009. / "Graduate Program in Chemistry and Chemical Biology." Includes bibliographical references.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Chemistry and Chemical Biology." Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 2001. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on Jan. 27, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical Engineering, [Department of] Chemical and Materials Engineering, University of Alberta. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

Thesis (Ph.D.)--Virginia Commonwealth University, 2009. / Prepared for: Dept. of Pharmaceutics. Title from title-page of electronic thesis. Bibliography: leaves 123-135.