(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. The micron particle fraction was characterized by Single Particle Optical Sensing (SPOS) and light microscopy. Furthermore, drug contents were monitored in terms of total dispersed drug and apparently dissolved drug in the submicron fraction. Despite the fact, that all three formulations showed decent dispersive behavior with almost the complete drug content rapidly dispersed, substantial differences were identified between two of the formulations and the third one: ABT-199/12 and ABT-199/20 showed pronounced precipitation of the drug in form of micrometer particles, a phenomenon described as glass liquid phase separation (GLPS) and only a marginal fraction of the drug was found in the submicron-fraction, i.e. associated with 3 to 4 different supramolecular assemblies (micelles), irrespective whether buffer or fasted state simulated intestinal fluid (FaSSIF) were used as dispersion media. In contrast, ABT-199/40 showed pronounced formation of a wide variety of supramolecular assemblies (micelles) along with substantial association of the drug with all of these, but reduced glass liquid phase separation.

High-throughput quantitative and qualitative analysis of microsomal incubations by cocktail analysis with an ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometer system.

BACKGROUND: Metabolite identification studies are very resource intensive and also are rarely performed in early discovery. Here, we report the validation of an ultraperformance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS) platform for generating high-throughput stability data with structure elucidation in a single injection. MATERIALS & METHODS: Tandem mass spectrometry spectra were obtained for quantitative analysis using a generic information-dependent acquisition method from pooled microsomal samples incubated at low compound concentrations. RESULTS: A good correlation was observed between clearance determined using UPLC-HRMS and UPLC-triple-quadrupole analysis. Structural elucidation performed with MassMetaSite™ (Molecular Discovery, Perugia, Italy) software identified 85% of the major metabolites of eight marketed drugs and over 100 internal compounds under these conditions. CONCLUSION: For the first time, a high-throughput quantitative-qualitative workflow was established using a cocktail approach for sample analysis with UPLC-HRMS in order to enable metabolite identification in early discovery projects.