Claudia Menzel

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BACKGROUND Bacteriorhodopsin (bR) from Halobacterium salinarum is a proton pump that converts the energy of light into a proton gradient that drives ATP synthesis. The protein comprises seven transmembrane helices and in vivo is organized into purple patches, in which bR and lipids form a crystalline two-dimensional array. Upon absorption of a photon,(More)
AIM It was the aim of this study to synthesize pectin (PEC) with sulfhydryl groups and evaluate its suitability in buccal application. MATERIALS & METHODS Native PEC was chemically modified by covalent attachment of sulfhydryl-bearing cysteine (CYS). Stability assays in form of water uptake behavior and erosion study were performed. Additionally,(More)
The objective of this study was to develop a novel thiomer with enhanced mucoadhesive properties using a highly mucoadhesive polymeric backbone. Fixomer™ A-30 (poly(methacrylic acid-co-sodium acrylamidomethyl propane sulfonate)), exhibiting a mucoadhesive strength superior to that of all other polymers, was thiolated by conjugation with l-cysteine and(More)
The use of mucus permeating drug carrier systems being able to overcome the mucus barrier can lead to a remarkable enhancement in bioavailability. One promising approach is the design of mucolytic enzyme decorated carrier systems (MECS). These systems include micro- and nanoparticles as well as self-emulsifying drug delivery systems (SEDDS) decorated with(More)
The aim of the present study was to establish a novel polymeric excipient for liquid nasal dosage forms exhibiting viscosity increasing properties, improved mucoadhesion and stability towards oxidation in solution. In order to achieve this goal, 2-mercaptonicotinic acid was first coupled to l-cysteine by disulfide exchange reaction and after purification(More)
This study aimed to screen the stability, disintegration, and swelling behavior of chemically modified anionic polymers. Investigated polymers were well-known and widely used staples of the pharmaceutical and medical field, namely, alginate (AL), carboxymethyl cellulose (CMC), polycarbophil (PC), and hyaluronic acid (HA). On the basis of amide bond(More)
Within this study a novel form of mucoadhesive nanoparticles (NPs) exhibiting a prolonged residence time on mucosal tissues was developed. In order to achieve this goal a new thiomer was synthesized by the covalent attachment of the amino acid l-cysteine ethyl ester to poly(acrylic acid) (100 kDa). The free thiol groups were in the following preactivated(More)
FecI, an extracytoplasmic-function sigma factor, is required for initiation of transcription of the ferric citrate transport genes. A mutational analysis of the fecA promoter revealed that the nonconserved -10 region and a downstream regulatory element are important for fecA promoter activity. However, nucleotide substitutions in the well-conserved -35(More)
The aim of this study was to establish a novel type of preactivated thiomers exhibiting a comparatively higher reactivity with mucus and consequently improved mucoadhesive properties. In order to achieve this goal, the dimeric form of 2-mercaptonicotinic acid (MNA-MNA) was directly attached to the polymeric backbone of chitosan (CHI) via amide bond(More)
INTRODUCTION Minor surgical interventions in children are often at times challenging due to the lack of cooperation by the child. Procedural sedation and analgesia is often appropriate, but unpleasant or painful applications of medication add additional discomfort to the child. A mixture of nitrous oxide (N2O)/oxygen (O2) in a ratio of 50:50, functioning as(More)