Near-Surface and Bulk Behavior of Bicontinuous Microemulsions under High-Pressure Conditions

Confined microemulsions: pore diameter induced change of the phase behavior

In the present work, the temperature-dependent phase behavior of a C10E4 based microemulsion is studied in different meso-macroporous glasses, as a function of their pore diameter. The phase behavior in these pores is investigated by small-angle X-ray scattering (SAXS). The crucial parameter we discuss based on the SAXS results is the domain size of the bicontinuous phase. Using a simplified model to fit the scattering data, we can observe the microemulsion inside the pores. These experiments reveal a temperature-dependent change in domain sizes of the bicontinuous microemulsion only for large pores.

Basic principles of drug delivery systems - the case of paclitaxel

Cancer is the second cause of death worldwide, exceeded only by cardiovascular diseases. The prevalent treatment currently used against metastatic cancer is chemotherapy. Among the most studied drugs that inhibit neoplastic cells from acquiring unlimited replicative ability (a hallmark of cancer) are the taxanes. They operate via a unique molecular mechanism affecting mitosis. In this review, we show this mechanism for one of them, paclitaxel, and for other (non-taxanes) anti-mitotic drugs. However, the use of paclitaxel is seriously limited (its bioavailability is <10%) due to several long-standing challenges: its poor water solubility (0.3 μg/mL), its being a substrate for the efflux multidrug transporter P-gp, and, in the case of oral delivery, its first-pass metabolism by certain enzymes. Adequate delivery methods are therefore required to enhance the anti-tumor activity of paclitaxel. Thus, we have also reviewed drug delivery strategies in light of the various physical, chemical, and enzymatic obstacles facing the (especially oral) delivery of drugs in general and paclitaxel in particular. Among the powerful and versatile platforms that have been developed and achieved unprecedented opportunities as drug carriers, microemulsions might have great potential for this aim. This is due to properties such as thermodynamic stability (leading to long shelf-life), increased drug solubilization, and ease of preparation and administration. In this review, we define microemulsions and nanoemulsions, analyze their pertinent properties, and review the results of several drug delivery carriers based on these systems.

Properties of Hydrogen-Bonded Liquids at Interfaces

Effects of interfaces on hydrogen-bonded liquids play major roles in nature and technology. Despite their importance, a fundamental understanding of these effects is still lacking. In large parts, this shortcoming is due to the high complexity of these systems, leading to an interference of various interactions and effects. Therefore, it is advisable to take gradual approaches, which start from well designed and defined model systems and systematically increase the level of intricacy towards more complex mimetics. Moreover, it is necessary to combine insights from a multitude of methods, in particular, to link novel preparation strategies and comprehensive experimental characterization with inventive computational and theoretical modeling. Such concerted approach was taken by a group of preparative, experimentally, and theoretically working scientists in the framework of Research Unit FOR 1583 funded by the Deutsche Forschungsgemeinschaft (German Research Foundation). This special issue summarizes the outcome of this collaborative research. In this introductory article, we give an overview of the covered topics and the main results of the whole consortium. The following contributions are review articles or original works of individual research projects.

Generalized skew-symmetric interfacial probability distribution in reflectivity and small-angle scattering analysis

Generalized skew-symmetric probability density functions are proposed to model asymmetric interfacial density distributions for the parameterization of any arbitrary density profiles in the `effective-density model'. The penetration of the densities into adjacent layers can be selectively controlled and parameterized. A continuous density profile is generated and discretized into many independent slices of very thin thickness with constant density values and sharp interfaces. The discretized profile can be used to calculate reflectivitiesviaParratt's recursive formula, or small-angle scatteringviathe concentric onion model that is also developed in this work.