English
norskBlar i forfatter "Brandl, Martin"
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Drug permeability across a phospholipid vesicle based barrier: 3. Characterization of drug-membrane interactions and the effect of agitation on the barrier integrity and on the permeability
(Journal article; Tidsskriftartikkel; Peer reviewed, 2007)Recently, we reported on the development and structural characterization of a phospholipid vesicle based barrier useful for medium throughput screening of passive drug permeability. Here, we investigate the physical and functional integrity of the phospholipid vesicle based barriers to agitation by stirring or shaking, and whether agitation affects drug permeability of sulpiride, metoprolol and ... -
Drug permeability across a phospholipid vesicle based barrier: A novel approach for studying passive diffusion
(Journal article; Tidsskriftartikkel; Peer reviewed, 2005-10)The aim of this study was to develop a novel predictive medium-throughput screening method for drug permeability, with use of a tight barrier of liposomes on a filter support. To our knowledge no one has succeeded in depositing membrane barriers without the use of inert solvent such as hexadecane. The first part of the study involved development of a protocol for preparation of these barriers, which ... -
Drug permeability across a phospholipid vesicle-based barrier - 2. Characterization of barrier structure, storage stability and stability towards pH changes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2006-04-18)Recently we reported on the development of a phospholipid vesicle-based barrier as a medium throughput method for screening of drug permeability. The aim of this present study is to characterize the barrier structure, including an estimation of the amount of phospholipid within it, its storage stability and its stability over various pH ranges found in different parts of the gastrointestinal tract. ... -
Drug permeability across a phospholipid vesicle-based barrier: 4. The effect of tensides, co-solvent and pH changes on barrier integrity and on drug permeability
(Journal article; Tidsskriftartikkel; Peer reviewed, 2008-07-03)In this study the integrity of the recently developed phospholipid vesicle-based permeability barrier in the presence of a variety of co-solvents and tensides has been investigated. Also included are studies of the influence of these additives on drug permeation and the effect of pH changes on the permeability of ionogenic drug compounds. Permeability experiments using the hydrophilic model ... -
Drug permeability profiling using cell-free permeation tools: Overview and applications
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-04-13)Cell-free permeation systems are gaining interest in drug discovery and development as tools to obtain a reliable prediction of passive intestinal absorption without the disadvantages associated with cell- or tissue-based permeability profiling. Depending on the composition of the barrier, cell-free permeation systems are classified into two classes including (i) biomimetic barriers which are ... -
How docetaxel entrapment, vesicle size, zeta potential and stability change with liposome composition–A formulation screening study
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-21)Limitations of the anticancer drug product Taxotere® have encouraged researchers to entrap the active ingredient docetaxel (DTX) into nanocarriers such as liposomes. However, until now no DTX-liposome formulation has reached the clinic. Hence, in the present study, different Soy-PC based DTX-liposome formulations were screened in an attempt to identify lipid-compositions with promising DTX-entrapment ... -
Insight into the mechanism behind oral bioavailability-enhancement by nanosuspensions through combined dissolution/permeation studies
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-02)As numerous new drug candidates are poorly water soluble, enabling formulations are needed to increase their bioavailability for oral administration. Nanoparticles are a conceptually simple, yet resource consuming strategy for increasing drug dissolution rate, as predicting in vivo oral absorption using in vitro dissolution remains difficult. The objective of this study was to obtain insight into ... -
Liposomal formulations of poorly soluble camptothecin: drug retention and biodistribution
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012-12-05)Context: Camptothecin (CPT) represents a potent anticancer drug. Its therapeutic use however is impaired by both drug solubility, hydrolysis and protein interactions in vivo. Use of liposomes as drug formulation approach could overcome some of these challenges. <p>Objective: The objective of this study was to perform a mechanistic study of the incorporation and retention of the lipophilic parent ... -
The Phospholipid Vesicle-Based Drug Permeability Assay: 5. Development Toward an Automated Procedure for High-Throughput Permeability Screening
(Journal article; Tidsskriftartikkel; Peer reviewed, 2009-02)In-vitro screening for oral absorption has become an essential part of drug discovery and development. Recently, a new phospholipid vesicle-based permeation assay was developed which has shown to satisfyingly predict passive absorption of drugs in humans. The purpose of the current study was to investigate whether the assay may be further developed into a high-throughput tool by automating its ... -
The relative spatial positions of tryptophan and cationic residues in helical membrane-active peptides determines their cytotoxicity
(Journal article; Tidsskriftartikkel; Peer reviewed, 2011-11-04)Background: Tryptophan side chains can influence the binding of amphipathic peptides to biological membranes. <p>Results: The cytotoxic activity of model helical amphipathic peptides was markedly influenced by the positions of tryptophan residues in the sequence. <p>Conclusion: Tryptophan residues located adjacent to a hydrophobic helical portion created the most potent cytotoxic peptides. <p> ... -
Sonosensitive dioleoylphosphatidylethanolamine-containing liposomes with prolonged blood circulation time of doxorubicin
(Journal article; Tidsskriftartikkel; Peer reviewed, 2011)Ultrasound sensitive (sonosensitive liposomes) are drug delivery systems designed for releasing their drug load upon exposure to ultrasound (US). Inclusion of dioleoylphosphatidylethanolamine (DOPE) in liposome membranes was previously shown to induce sonosensitivity. For efficient US mediated drug delivery to solid tumours, a long blood circulation time of the liposomal drug providing high tumour ... -
Ultrasound-mediated destabilization and drug release from liposomes comprising dioleoylphosphatidylethanolamine
(Journal article; Tidsskriftartikkel; Peer reviewed, 2011)Novel sonosensitive doxorubicin-containing liposomes comprising dioleoylphosphatidylethanolamine (DOPE) as the main lipid constituent were developed and characterized in terms of ultrasound-mediated drug release in vitro. The liposome formulation showed high sonosensitivity; where approximately 95% doxorubicin was released from liposomes after 6 min of 40 kHz US exposure in buffered sucrose solution. ...
