Application of Asymmetrical Flow Field-Flow Fractionation for Characterizing the Size and Drug Release Kinetics of Theranostic Lipid Nanovesicles.

Liposome size and in vitro release of the active substance belong to critical quality attributes of liposomal carriers. Here, we apply asymmetric flow field-flow fractionation (AF4) to characterize theranostic liposomes prepared by thin lipid film hydration/extrusion or microfluidics. The vesicles' size was derived from multi-angle laser light scattering following fractionation (AF4) and compared to sizes derived from dynamic light scattering measurements.

Insight into theranostic nanovesicles prepared by thin lipid hydration and microfluidic method.

Liposomes are phospholipid-based self-assembled nanoparticles. Various components can be solubilized in the lipid bilayer, encapsulated in the aqueous core or attached to the surface, making liposomes attractive platforms for multimodality functionalization. Here we describe theranostic liposomes delivering a magnetic resonance contrast agent (lipid derivative of gadopentetic acid) and a hydrophobic photosensitizer (zinc phthalocyanine, ZnPc) for photodynamic therapy of cancer.

(Sub)micron particles forming in aqueous dispersions of amorphous solid dispersions of the poorly soluble drug ABT-199: A combined particle optical counting and field-flow fractionation study.

The dispersive behavior of three different amorphous solid dispersion (ASD) formulations of the poorly soluble ABT-199 (Venetoclax) were studied in aqueous and biomimetic media and spontaneously forming supramolecular associates and particles analysed. To this end, the aqueous dispersions were fractionated into a submicron (colloidal) and micrometer-sized particle-fraction by bench-top centrifugation. The submicron fraction was characterized by Asymmetric Flow Field-Flow Fractionation in conjunction with Multi-angle Laser Light Scattering (AF4-MALLS), Dynamic Light Scattering (DLS) and zeta potential analysis.

Co-existing colloidal phases of human duodenal aspirates: Intraindividual fluctuations and interindividual variability in relation to molecular composition.

We investigated the ultrastructural pattern of colloidal phases in human duodenal fluids. Aspirates were collected from three volunteers in both fasted and fed nutritional states. Analysis methods comprised the combination of asymmetric flow field-flow fractionation (AF4) and multi-angle laser light scattering (MALLS).

A dynamic in vitro permeation study on solid mono- and diacyl-phospholipid dispersions of celecoxib.

The current study documents enhanced apparent solubility of the BCS class II drug celecoxib (CXB) when formulated as solid phospholipid dispersion (SPD) with either mono- or diacyl-phospholipids by freeze drying from hydro-alcoholic solvent. The enhanced solubility upon dispersion in buffer or fasted state simulated intestinal fluid (FaSSIF) is interpreted to be due to two effects: (1) amorphization of CXB, inducing supersaturation, which is also observed when CXB is freeze dried in the absence of phospholipids and (2) association of CXB with spontaneously forming colloidal structures, such as vesicles and/or micelles, promoting solubilization. The latter effect depended on the CXB-to-phospholipid ratio, where monoacyl-phospholipid was a more efficient solubilizer than diacyl-phospholipid.

Co-existing colloidal phases in artificial intestinal fluids assessed by AF4/MALLS and DLS: A systematic study into cholate & (lyso-) phospholipid blends, incorporating celecoxib as a model drug.

Colloidal phases (self-assemblies) in aqueous dispersions of selected binary bile salt/phospholipid blends were studied utilizing the combined analytical approach of asymmetrical flow field-flow fractionation (AF4) and multi-angle laser light scattering (MALLS) in order to resolve the co-existence of different colloidal assemblies. The binary blends were prepared by freeze-drying from tert-butanol/water co-solvent solutions. The blends contained one of two bile salts (sodium taurocholate (TC) or sodium glycodeoxycholate (GDX)) and a mono- or di-acyl phospholipid (lyso-phosphatidylcholine (L-PC) and phosphatidylcholine (PC), respectively).

Bile Salt Micelles and Phospholipid Vesicles Present in Simulated and Human Intestinal Fluids: Structural Analysis by Flow Field-Flow Fractionation/Multiangle Laser Light Scattering.

Knowledge about colloidal assemblies present in human intestinal fluids (HIFs), such as bile salt micelles and phospholipid vesicles, is regarded of importance for a better understanding of the in vivo dissolution and absorption behavior of poorly soluble drugs (Biopharmaceutics Classification System class II/IV drugs) because of their drug-solubilizing ability. The characterization of these potential drug-solubilizing compartments is a prerequisite for further studies of the mechanistic interplays between drug molecules and colloidal structures within HIFs. The aim of the present study was to apply asymmetrical flow field-flow fractionation (AF4) in combination with multiangle laser light scattering in an attempt to reveal coexistence of colloidal particles in both artificial and aspirated HIFs and to determine their sizes.