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Jesper Østergaard

University of Copenhagen

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Henrik Jensen

Biosyntia (Denmark)

Susan Weng Larsen

University of Copenhagen

Claus Larsen

Aalborg University

Anan Yaghmur

University of Copenhagen

Anette Müllertz

University of Copenhagen

Bente Gammelgaard

University of Copenhagen

Niels H. H. Heegaard

Statens Serum Institut

Stefan Stürup

University of Copenhagen

Steen Honoré Hansen

University of Copenhagen

Jukka Rantanen

University of Copenhagen

Cooperative Institutions

University of Copenhagen

142

Technical University of Denmark

Schools of Visual Arts, The Royal Danish Academy of Fine Arts

Novo Nordisk (Denmark)

University of Helsinki

Centre National de la Recherche Scientifique

Lundbeck (Denmark)

University of Southern Denmark

Copenhagen University Hospital

University of Huddersfield

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Dissolution enhancement of griseofulvin from griseofulvin-sodium dodecyl sulfate discs investigated by UV imaging

Journal of Drug Delivery Science and Technology (2017)

Peter Madelung Poul Bertelsen Jette Bredahl Jacobsen Anette Müllertz Jesper Østergaard

Griseofulvin

Sodium dodecyl sulfate

10.1016/j.jddst.2017.05.010

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Citations (6)

Performance characteristics of UV imaging instrumentation for diffusion, dissolution and release testing studies

Journal of Pharmaceutical and Biomedical Analysis (2016)

Sabrine S. Jensen Henrik Jensen David M. Goodall Jesper Østergaard

Collimated light

Instrumentation

Agarose

10.1016/j.jpba.2016.08.018

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Citations (13)

Ghrelin–liposome interactions: Characterization of liposomal formulations of an acylated 28‐amino acid peptide using CE

Electrophoresis (2009)

Jesper Østergaard Eva Horn Moeller

Ghrelin is a pharmacologically interesting peptide hormone due to its effects on appetite and metabolism. The cationic, octanoylated 28 amino acid peptide has a short biological half-life; thus, prolonged release formulations are of interest. Acylated peptides have been suggested to bind to or be incorporated into liposomes. Formulations based on neutral dipalmitoylphosphatidylcholine (DPPC) liposomes and phosphatidylcholine:cholesterol (70:30 mol%) liposomes, and negatively charged dipalmitoylphosphatidylcholine:dipalmitoylphosphatidylserine (DPPC:DPPS) (70:30 mol%) liposomes (2 mM total lipid concentration) were characterized using ACE. Pre-equilibrium CZE and frontal analysis CE methods circumventing capillary wall adsorption of the peptide and the liposomes and suitable for characterizing ghrelin-liposome interactions were developed. The cationic peptide exhibited low affinity (<10% bound) for DPPC and phosphatidylcholine:cholesterol (70:30 mol%) liposomes whereas electrostatic interactions caused a higher affinity for DPPC:DPPS (70:30 mol%) liposomes. Studies on desacyl ghrelin instead of ghrelin demonstrated the significance of the n-octanoyl side chain as an affinity providing moiety towards DPPC:DPPS liposomes (48 and 73% bound peptide, respectively). CE experiments showed that the binding was characterized by rapid dissociation kinetics.

Dipalmitoylphosphatidylcholine

10.1002/elps.200900394

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Citations (17)

Characterization of the complexation of tauro- and glyco-conjugated bile salts with γ-cyclodextrin and 2-hydroxypropyl-γ-cyclodextrin using affinity capillary electrophoresis

Journal of inclusion phenomena and molecular recognition in chemistry (2008)

René Holm Rune A. Hartvig Henrik V. Nicolajsen Peter Westh Jesper Østergaard

Binding constant

10.1007/s10847-008-9409-5

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Citations (22)

Microenvironmental pH modifying films for buccal delivery of saquinavir: Effects of organic acids on pH and drug release in vitro

International Journal of Pharmaceutics (2020)

Shaolong He Jesper Østergaard Madina Ashna Carsten Uhd Nielsen Jette Bredahl Jacobsen

Saquinavir

Malic acid

10.1016/j.ijpharm.2020.119567

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Citations (16)

Mechanistic Studies of the Effect of Bile Salts on Rhodamine 123 Uptake into RBE4 Cells

Molecular Pharmaceutics (2011)

Lin Yang J. Paul Fawcett Jesper Østergaard Hu Zhang Ian G. Tucker

To examine the ability of bile salts (BS) to act as permeation enhancers at the blood brain barrier, the effect of four BS (cholate, deoxycholate, monoketocholate and taurocholate) on accumulation of rhodamine 123 (R123) in rat brain endothelial (RBE4) cells was investigated. Experiments were performed using BS concentrations shown to be noncytotoxic to RBE4 cells. Uptake and efflux of R123 in the absence and presence of BS were studied by fluorescence spectroscopy and confocal microscopy. Changes in RBE4 cell membrane fluidity in the presence of BS were evaluated using fluorescence anisotropy. The direct interaction between BS and R123 (ion pairing) and the effect of BS on distribution of R123 into liposomes were studied by capillary electrophoresis. All BS influenced R123 uptake in a concentration-dependent manner and increased cell membrane fluidity. Monoketocholate produced the greatest increase in uptake and also significantly reduced R123 efflux probably by inhibition of P-glycoprotein (P-gp). Direct interaction of BS and R123 was weak, but distribution of R123 into liposomes was increased by BS. The results suggest that BS increase R123 uptake by increasing cell membrane fluidity and, in the case of MKC, by inhibiting P-gp.

Rhodamine 123

P-glycoprotein

Rhodamine

10.1021/mp200201y

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Citations (39)

Characterization of a liposome-based formulation of oxaliplatin using capillary electrophoresis: Encapsulation and leakage

Journal of Pharmaceutical and Biomedical Analysis (2011)

Ulrik Franzen Tam T. T. N. Nguyen Charlotte Vermehren Bente Gammelgaard Jesper Østergaard

Sonication

Pharmaceutical formulation

10.1016/j.jpba.2010.12.037

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Citations (47)

Investigation of diclofenac release and dynamic structural behavior of non-lamellar liquid crystal formulations during in situ formation by UV–Vis imaging and SAXS

International Journal of Pharmaceutics (2022)

Nina Mertz Frederik Bock Jesper Østergaard Anan Yaghmur Susan Weng Larsen

In situ formation of high viscous inverse lyotropic non-lamellar liquid crystalline phases is a promising approach for sustained drug delivery in the joint. The in situ forming process on exposure of two diclofenac-loaded preformulations to aqueous media was characterized with respect to depot size and shape, initial release and structural transitions using UV-Vis imaging and spatially and time-resolved synchrotron small-angle X-ray scattering (SAXS). The preformulations consisted of 10 % (w/w) ethanol, 10 % (w/w) water and a binary lipid mixture of glycerol monooleate (GMO):1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DOPG) or GMO:medium chain triglycerides (MCT). Upon injection of preformulations into an employed injection-cell containing excess of bio-relevant medium, rapid generation of liquid crystalline depots was observed. UV-Vis images and constructed 2D SAXS maps of the injection-cell showed depots with different shapes and sizes, and features with high nanostructural heterogeneity. More extensive swelling of the GMO:DOPG-based preformulation was observed compared to the GMO:MCT-based preformulation. The UV image analysis found that a higher amount of diclofenac was released in the image area after 20 h from the GMO:MCT depot compared to the GMO:DOPG depot. The injection-cell setup employing UV-Vis imaging and synchrotron SAXS constitutes an attractive approach for evaluating the in situ forming processes of liquid crystalline depots.

Small-angle X-ray scattering

Lyotropic

10.1016/j.ijpharm.2022.121880

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Citations (5)

Monitoring lidocaine single‐crystal dissolution by ultraviolet imaging

Journal of Pharmaceutical Sciences (2011)

Jesper Østergaard Fengbin Ye Jukka Rantanen Anan Yaghmur Susan Weng Larsen

10.1002/jps.22532

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Citations (52)

PEGylation of Phytantriol-Based Lyotropic Liquid Crystalline Particles—The Effect of Lipid Composition, PEG Chain Length, and Temperature on the Internal Nanostructure

Langmuir (2014)

Christa Nilsson Jesper Østergaard Susan Weng Larsen Claus Larsen Arto Urtti

Poly(ethylene glycol)-grafted 1,2-distearoyl-sn-glycero-3-phosphoethanolamines (DSPE-mPEGs) are a family of amphiphilic lipopolymers attractive in formulating injectable long-circulating nanoparticulate drug formulations. In addition to long circulating liposomes, there is an interest in developing injectable long-circulating drug nanocarriers based on cubosomes and hexosomes by shielding and coating the dispersed particles enveloping well-defined internal nonlamellar liquid crystalline nanostructures with hydrophilic PEG segments. The present study attempts to shed light on the possible PEGylation of these lipidic nonlamellar liquid crystalline particles by using DSPE-mPEGs with three different block lengths of the hydrophilic PEG segment. The effects of lipid composition, PEG chain length, and temperature on the morphology and internal nanostructure of these self-assembled lipidic aqueous dispersions based on phytantriol (PHYT) were investigated by means of synchrotron small-angle X-ray scattering and Transmission Electron Cryo-Microscopy. The results suggest that the used lipopolymers are incorporated into the water-PHYT interfacial area and induce a significant effect on the internal nanostructures of the dispersed submicrometer-sized particles. The hydrophilic domains of the internal liquid crystalline nanostructures of these aqueous dispersions are functionalized, i.e., the hydrophilic nanochannels of the internal cubic Pn3m and Im3m phases are significantly enlarged in the presence of relatively small amounts of the used DSPE-mPEGs. It is evident that the partial replacement of PHYT by these PEGylated lipids could be an attractive approach for the surface modification of cubosomal and hexosomal particles. These PEGylated nanocarriers are particularly attractive in designing injectable cubosomal and hexosomal nanocarriers for loading drugs and/or imaging probes.

PEGylation

Lyotropic

Nanocarriers

10.1021/la501411w

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Citations (57)