Arabic-speaking Americans.

Mode of access: Internet.

Sefer ʻEn Yaʻakov.

The last four sedarim of the work were edited after Ibn Habib's death by his son Levi.

Analysis of pedestrian crosswalk safety on one-way street networks. Final report.

Transportation Department, Research and Special Programs Administration, Washington, D.C.

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Mode of access: Internet.

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Hat ve hattatan /

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An Arabic-English dictionary on a new system /

v. 1. Arabic-English.--v. 2. English index.

Türkisch : praktische Türkische Sprachlehre für Anfänger /

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School of Nursing Class of 1998

Top Row: Kathleen S. Allen, Elizabeth Anderson, Mary Assenmacher, Deana Barrett, Laurie Barringer, Linda Baty, Holidae Bauman, Leila Beach, Liesha Beachum, Jacquline S. Bean, Jane Betten, Melanie Black, Kari Blouin, Kelly Bottger, Nancy Bowman, JoAnn Britenfeld, Ruth C. Brower

Row 2: Melanie Mai Brown, Estera Carp, Christine Haveman, Kimberly Webster, Rebecca Amo, Tina K. Ciricola, Gerard A. Castaneda, Steven J. Bednarski, Michelle Kuo, Kathleen Szymanski, Alissa Enriquez, Kristin Snow, Jennifer Berk, Erica Reese, Angela Cassadime, Lynn Chacko

Row 3: Anne chambers, Mechele Chau, Marcy Christensen, Regi Colthorp, Kellie Conover, Jenny Cwiek, Michele DeMaagd, Kristin Diotte, Amanda Dressel, Kimberly Dunlap, Esther DuRussel, Katrina Ehr

Row 4: Holly M. Greenough, Eileen Gumayagay, Sheila Habib, Allison Hale, Kristi Hale, Amy Hollis, Rebecca Hostman, Marilynn Huizinga, Jennifer Ivinson, Christine Jodoin, Christine Kaetz, Kimberly Kenny-Sherlock, Andrea Latva, Kathleen Levin

Row 5: Shawna Mangan, Sofia Marquez, Paul Mazurek, Charla McMichael, Tina Marie Meeks, Richard W. Redman, Beverly Jones, Ada Sue Hinshaw, Susan Boehm, Nola Pender, Jeffrey Mendoza, Melissa Meulenberg, Cheryl Milekovich, Amanda Miller, Amy Miller

Row 6: Nicole Miller, Bonnie Mobley, Kara More, Cherylann Mortzfield, Leslie Nance, Ruby Nzoma, Megan Oleszek, Larah Faye Ostonal, Jean C. Palad, Danielle Pankowski, Nancy Penrose, Laurie Pierce, Heather Polsen, Julie Marie Postma, Amy Prielipp, Martha Quigley, Aimee Racette

Row 7: Marty Rauser, Nekia Robinson, Kimberly Rowe, Janice Rybski, Ricardo Salazar, Marie Sanderson, Kimberly Scholma, Bonnie Schweitzer, Veena Shewakramani, Julie Showers, Olga Simanovskaya, Emily Simon, Lakeeta Smith, Amy Stewart, Robert Strudgeon, Jaime Sulek

Row 8: Charity Sutherland, William Ten Haaf, Mark Thomas, Nichole Thomas, Donna Thompson, Tonya Tomski, Michele Uller, Celina Uranga, Sarah Volkhardt, Larna Welch, Melanie White, Michelle White, Britt Williams, Stephanie Windisch, Brian Wright, Christina Wyrybkowski, Lisa Ziegelmann

Solubilisation of drugs within liposomal bilayers:alternatives to cholesterol as a membrane stabilising agent

Objectives The aim of this work was to investigate the effect of cholesterol on the bilayer loading of drugs and their subsequent release and to investigate fatty alcohols as an alternative bilayer stabiliser to cholesterol. Methods The loading and release rates of four low solubility drugs (diazepam, ibuprofen, midazolam and propofol) incorporated within the bilayer of multilamellar liposomes which contained a range of cholesterol (0–33 mol/mol%) or a fatty alcohol (tetradecanol, hexadecanol and octadecanol) were investigated. The molecular packing of these various systems was also investigated in Langmuir monolayer studies. Key findings Loading and release of drugs within the liposome bilayer was shown to be influenced by their cholesterol content: increasing cholesterol content was shown to reduce drug incorporation and inclusion of cholesterol in the bilayer changed the release profile of propofol from zero-order, for phosphatidyl choline only liposomes, to a first-order model when 11 to 33 total molar % of cholesterol was present in the formulation. At higher bilayer concentrations substitution of cholesterol with tetradecanol was shown to have less of a detrimental impact on bilayer drug loading. However, the presence of cholesterol within the liposome bilayer was shown to reduce drug release compared with fatty alcohols. Monolayer studies undertaken showed that effective mean area per molecule for a 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) : cholesterol mixture deviated by 9% from the predicted area compared with 5% with a similar DSPC : tetradecanol mixture. This evidence, combined with cholesterol being a much more bulky structure, indicated that the condensing influence of tetradecanol was less compared with cholesterol, thus supporting the reduced impact of tetradecanol on drug loading and drug retention. Conclusions Liposomes can be effectively formulated using fatty alcohols as an alternative bilayer stabiliser to cholesterol. The general similarities in the characteristics of liposomes containing fatty alcohols or cholesterol suggest a common behavioural influence for both compounds within the bilayer.

Environmental scanning electron microscope imaging of vesicle systems

The structural characteristics of liposomes have been widely investigated and there is certainly a strong understanding of their morphological characteristics. Imaging of these systems, using techniques such as freeze-fracturing methods, transmission electron microscopy, and cryo-electron imaging, has allowed us to appreciate their bilayer structures and factors that influence this. However, there are a few methods that study these systems in their natural hydrated state; commonly, the liposomes are visualized after drying, staining and/or fixation of the vesicles. Environmental scanning electron microscopy (ESEM) offers the ability to image a liposome in its hydrated state without the need for prior sample preparation. We were the first to use ESEM to study the liposomes and niosomes, and have been able to dynamically follow the hydration of lipid films and changes in liposome suspensions as water condenses onto, or evaporates from, the sample in real-time. This provides an insight into the resistance of liposomes to coalescence during dehydration, thereby providing an alternative assay for liposome formulation and stability.

The application of monolayer studies in the understanding of liposomal formulations

The study of surfactant monolayers is certainly not a new technique, but the application of monolayer studies to elucidate controlling factors in liposome design remains an underutilised resource. Using a Langmuir-Blodgett trough, pure and mixed lipid monolayers can be investigated, both for their interactions within the monolayer, and for interfacial interactions with drugs in the aqueous sub-phase. Despite these monolayers effectively being only half a bilayer, with a flat rather than curved structure, information from these studies can be effectively translated into liposomal systems. Here we outline the background, general protocols and application of Langmuir studies with a focus on their application in liposomal systems. A range of case studies are discussed which show how the system can be used to support its application in the development of liposome drug delivery. Examples include investigations into the effect of cholesterol within the liposome bilayer, understanding effective lipid packaging within the bilayer to promote water soluble and poorly soluble drug retention, the effect of alkyl chain length on lipid packaging, and drug-monolayer electrostatic interactions that promote bilayer repackaging.

Engineering liposomal systems to develop solubility enhancing technology

This research primarily focused on identifying the formulation parameters which control the efficacy of liposomes as delivery systems to enhance the delivery of poorly soluble drugs. Preliminary studies focused on the drug loading of ibuprofen within vesicle systems. Initially both liposomal and niosomal formulations were screened for their drug-loading capacity: liposomal systems were shown to offer significantly higher ibuprofen loading and thereafter lipid based systems were further investigated. Given the key role cholesterol is known to play within the stability of bilayer vesicles. the optimum cholesterol content in terms of drug loading and release of poorly soluble drugs was then investigated. From these studies a concentration of 11 total molar % of cholesterol was used as a benchmark for all further formulations. Investigating the effect of liposomc composition on several low solubility drugs, drug loading was shown to be enhanced by adopting longer chain length lipids. cationic lipids and. decreasing drug molecular weight. Drug release was increased by using cationic lipids and lower molecular weight of drug; conversely, a reduction was noted when employing longer chain lipids thus supporting the rational of longer chain lipids producing more stable liposomes, a theory also supported by results obtained via Langmuir studies· although it was revealed that stability is also dependent on geometric features associated with the lipid chain moiety. Interestingly, reduction in drug loading appeared to be induced when symmetrical phospholipids were substituted for lipids constituting asymmetrical alkyl chain groups thus further highlighting the importance of lipid geometry. Combining a symmetrical lipid with an asymmetrical derivative enhanced encapsulation of a hydrophobic drug while reducing that of another suggesting the importance of drug characteristics. Phosphatidylcholine liposornes could successfully be prepared (and visualised using transmission electron microscopy) from fatty alcohols therefore offering an alternative liposomal stabiliser to cholesterol. Results obtained revealed that liposomes containing tetradecanol within their formulation shares similar vesicle size, drug encapsulation, surface charge. and toxicity profiles as liposomes formulated with cholesterol, however the tetradecanol preparation appeared to release considerably more drug during stability studies. Langmuir monolayer studies revealed that the condensing influence by tetradecanol is less than compared with cholesterol suggesting that this reduced intercalation by the former could explain why the tetradecanol formulation released more drug compared with cholesterol formulations. Environmental scanning electron microscopy (ESEM) was used to analyse the morphology and stability of liposomes. These investigations indicated that the presence of drugs within the liposomal bilayer were able to enhance the stability of the bilayers against collapse under reduced hydration conditions. In addition the presence of charged lipids within the formulation under reduced hydration conditions compared with its neutral counterpart. However the applicability of using ESEM as a new method to investigate liposome stability appears less valid than first hoped since the results are often open to varied interpretation and do not provide a robust set of data to support conclusions in some cases.