Chemical & Biomolecular Engineering

Permanent URI for this communityhttp://hdl.handle.net/1903/2219

Formerly known as the Department of Chemical Engineering.

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    Effect of Carbon Chain Length, Ionic Strength, and pH on the In Vitro Release Kinetics of Cationic Drugs from Fatty-Acid-Loaded Contact Lenses
    (MDPI, 2021-07-10) Torres-Luna, Cesar; Hu, Naiping; Domszy, Roman; Fan, Xin; Yang, Jeff; Briber, Robert M.; Wang, Nam Sun; Yang, Arthur
    This paper explores the use of fatty acids in silicone hydrogel contact lenses for extending the release duration of cationic drugs. Drug release kinetics was dependent on the carbon chain length of the fatty acid loaded in the lens, with 12-, 14- and 18-carbon chain length fatty acids increasing the uptake and the release duration of ketotifen fumarate (KTF) and tetracaine hydrochloride (THCL). Drug release kinetics from oleic acid-loaded lenses was evaluated in phosphate buffer saline (PBS) at different ionic strengths (I = 167, 500, 1665 mM); the release duration of KTF and THCL was decreased with increasing ionic strength of the release medium. Furthermore, the release of KTF and THCL in deionized water did not show a burst and was significantly slower compared to that in PBS. The release kinetics of KTF and THCL was significantly faster when the pH of the release medium was decreased from 7.4 towards 5.5 because of the decrease in the relative amounts of oleate anions in the lens mostly populated at the polymer–pore interfaces. The use of boundary charges at the polymer–pore interfaces of a contact lens to enhance drug partition and extend its release is further confirmed by loading cationic phytosphingosine in contact lenses to attract an anionic drug.
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    Defining Critical Parameters for Producing and Modulating Inflammation Caused by Cell Encapsulating Alginate Microspheres
    (2007-09-11) Breger, Joyce Catherine; Wang, Nam Sun; Lyle, Dan B; Chemical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Minimizing induced inflammation, particularly nitric oxide (NO) production, is critical to optimal function or failure of implanted encapsulated cells. The purpose of this study is to define critical factors that affect toxic NO production from the macrophage cell line RAW264.7 in response to alginate microcapsules. The effects of the following were determined: 1) concentration of endotoxin (LPS) contamination; 2) presence of interferon-gamma (IFN-γ); 3) bead diameter and alginate volume; and 4) anti-inflammatory drugs in the alginate. A higher concentration (5 X) of LPS was required in alginate to produce the effect seen by LPS free in medium, sensitivity was enhanced by IFN-γ, bead diameter was inversely proportional to NO2 under low inflammatory conditions, and parthenolide in alginate significantly reduced inflammation. These results suggest that survival of implanted encapsulated cells may be improved by using highly purified alginate, avoiding ancillary inflammation, controlling surface area presentation, and incorporating anti-inflammatory drugs into the capsule matrix.
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    A Novel Cyclic Acetal Biomaterial and Its Use in Cleft Palate Repair
    (2006-05-04) Moreau, Jennifer Lynn; Fisher, John P; Chemical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Cleft lip and/or palate are the most prevalent congenital craniofacial birth defect in humans. While myriad surgical techniques have been described to repair orofacial clefts, several complications have been associated with the repair techniques. To overcome these complications, a tissue engineering strategy may be employed. In particular, we are investigating strategies for regenerating the alveolar bone that is often missing as a result of cleft palates. Numerous materials have been explored as biomaterials for bone tissue engineering, however there are disadvantages to these, including compromised mechanical properties and harmful degradation products. To overcome this issue, a novel class of biomaterials has been created. These materials are crosslinked networks of monomers of 5-ethyl-5-(hydroxymethyl)-beta,beta-dimethyl-1,3-dioxane-2-ethanol diacrylate. The study presented here was designed to determine the effects of the material's formulation scheme on several of its physical properties, so as to develop a novel bone tissue engineering material suitable for cleft palate repair.