Analytical & Biological Chemistry Research Facility - Journal Articles
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Item Mechanistic investigation into the phase separation behavior of soluplus in the presence of biorelevant media(ACS American Chemical Society, 2025) Lange, Justus Johann; Senniksen, Malte Bøgh; Wyttenbach, Nicole; Page, Susanne; Bateman, Lorraine M.; O’Dwyer, Patrick J.; Saal, Wiebke; Kuentz, Martin; Griffin, Brendan T.; Horizon 2020More than a decade since its introduction, the polymeric excipient Soluplus continues to receive considerable attention for its application in the development of amorphous solid dispersions (ASDs) and its utility as a solubilizer for drugs exhibiting solubility limited absorption. While it is well-recognized that Soluplus forms micelles, the impact of its lower critical solution temperature of approximately 40 °C remains an underexplored aspect. This study investigated the phase behavior of Soluplus in fasted-state simulated intestinal fluid (FaSSIF-V1). It was demonstrated that Soluplus forms a dispersed polymer-rich coacervate phase, which coexists with Soluplus micelles at 37 °C. This behavior was confirmed by cloud point measurements, visually discernible phases after centrifugation, as well as multi-angle dynamic light scattering (MADLS) measurements, and quantitative 1H-nuclear magnetic resonance (NMR) spectroscopy of Soluplus concentrations in the supernatant pre- and post-centrifugation. The practical relevance of these findings was contextualized by solvent shift experiments and dissolution testing of spray-dried ASD. The results demonstrated that the poorly water-soluble drug RO6897779 resided in a polymer-rich coacervate phase and was spun down during centrifugation, which resulted in an amorphous pellet exhibiting the characteristics of a viscous liquid. The entrapment of the drug within the polymer-rich phase was further analyzed by temperature- and time-dependent MADLS experiments. The findings of this study are of particular relevance for a mechanistic understanding, relevant to comprehending in vitro-in vivo relationships of Soluplus-based ASDs. Low sampled drug concentrations in FaSSIF-V1 at 37 °C may originate not only from limited drug release and precipitation but also from the formation of a drug-containing, polymer-rich Soluplus phase. Therefore, a liquid–liquid phase separation occurring from Soluplus-based formulations in a biorelevant medium can be excipient-driven, which is different from the common perception that phase separation in the solution state is triggered primarily by high drug concentrations exceeding their amorphous solubility.Item Variations in crystals of flufenamic acid of its methyl and tert-butyl analogues as impurities as determined by partial dissolutions(Royal Society of Chemistry, 2024-11-22) Bourke, Timothy; Chiarella, Renato A.; Moynihan, Humphrey A.; Irish Research Council; Science Foundation IrelandAchieving specified levels of impurities is one the key goals of crystallisation processes in manufacturing. The mode of impurity incorporation and the variation of impurity levels throughout crystal batches are key factors affecting the performance of crystallisations in terms of achieving purity specifications. Evaluation of the distribution of impurities in crystals of flufenamic acid (FFA) using a controlled partial dissolution approach is described. 2-(3-Tolylamino)benzoic acid (MeFA) and 2-((3-(tert-butyl)phenyl)amino)benzoic acid (tBuFA), analogues of FFA in which the trifluoromethyl group has been replaced by a methyl group or by a tert-butyl group respectively, were selected as the impurities. Thermal analysis suggests formation of a solid solution between FFA and MeFA isostructural to FFA form III. The stepwise dissolution approach was initially demonstrated on samples of pure FFA crystals and was then extended to evaluate the distribution of levels of MeFA and tBuFA impurities. The impurity levels are shown as varying with dissolution midpoint. Stepwise dissolution was usefully applied to FFA crystal of various morphologies, while for crystals with extremely needle-like morphology, a segmentation analysis approach was more practical. The work presented outlines a method for evaluating the distribution of impurities in crystalline materials using commonly available analytical and particle sizing methods.Item Exploring the crystal landscape of mandelamide and chiral resolution via cocrystallization(American Chemical Society, 2025) Huang, Shan; Fitzgerald, Deirbhile; Koledoye, Samuel A.; Collins, Stuart G.; Maguire, Anita R.; Lawrence, Simon E.; Science Foundation Ireland; Irish Research CouncilThe crystal structures of (±)-mandelamide, S-mandelamide, and enantioenriched mandelamide (94 S : 6 R) were determined. Diastereomeric cocrystal pairs of S-mandelamide with both enantiomers of mandelic acid and proline were synthesized. The diastereomeric cocrystal pairs of S-mandelamide with S/R-mandelic acid form 1:1 cocrystals in each case, while the diastereomeric cocrystal pairs of S-mandelamide with proline have different stoichiometries. Preliminary investigation of this diastereomeric cocrystal system for chiral resolution shows promise.Item Synthesis, evaluation and mechanistic insights of novel IMPDH inhibitors targeting ESKAPEE bacteria(Elsevier Ltd., 2024-10-05) Ayoub, Nour; Upadhyay, Amit; Tête, Arnaud; Pietrancosta, Nicolas; Munier-Lehmann, Hélène; O'Sullivan, Timothy P.; Irish Research Council; Science Foundation Ireland; Université Sorbonne Paris CitéAntimicrobial resistance poses a significant threat to global health, necessitating the development of novel therapeutic agents with unique mechanisms of action. Inosine 5′-monophosphate dehydrogenase (IMPDH), an essential enzyme in guanine nucleotide biosynthesis, is a promising target for the discovery of new antimicrobial agents. High-throughput screening studies have previously identified several urea-based leads as potential inhibitors, although many of these are characterised by reduced chemical stability. In this work, we describe the design and synthesis of a series of heteroaryl-susbtituted analogues and the evaluation of their inhibitory potency against IMPDHs. Our screening targets ESKAPEE pathogens, including Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. Several analogues with submicromolar inhibitory potency are identified and show no inhibitory potency on human IMPDH nor cytotoxic effects on human cells. Kinetic studies revealed that these molecules act as noncompetitive inhibitors with respect to the substrates and ligand virtual docking simulations provided insights into the binding interactions at the interface of the NAD+ and IMP binding sites on IMPDH.Item Synthesis and reactivity of α-diazo-β-keto sulfonamides(Georg Thieme Verlag KG, 2024-06-19) Maguire, Anita R.; Judge, Evan; O'Shaughnessy, Keith A.; Lawrence, Simon E.; Collins, Stuart G.; Science Foundation Ireland; Irish Research Council; Higher Education Authority; Synthesis and Solid State Pharmaceutical Centre; European Regional Development FundCopper mediated reactions of α-diazo-β-keto sulfonamides 1 leads to a range of products including the alkyne sulfonamides 5, the enamines 6, and the α-halosulfonamides 7 and 11 with no evidence for intramolecular C–H insertion in any of the reactions, in contrast to the reactivity of the comparable α-diazo-β-keto sulfones. Use of copper(II) triflate (5 mol%) led to isolation of a series of alkyne sulfonamides 5 (up to 12%) and enamines 6 (up to 64%). Use of copper(II) chloride (5 mol%) formed, in addition, the α-halosulfonamides 7; use of stoichiometric amounts of copper(II) chloride/bromide enables facile halogenation of the β-keto sulfonamide to form the α-halosulfonamides 7 and 11 (up to 63%).