Anti-SACS (C-terminal) polyclonal antibody

Amorphous and co-amorphous formulations have been used to enhance the solubility and bioavailability of poorly water-soluble drugs. However, during handling and/or storage amorphous solids present inherent instability and overtime recrystallize back into their crystalline counterpart. The development of tools capable of quantifying and monitoring the recrystallization of amorphous materials is required to ensure the delivery of solid dosage forms with improved performance. This work describes the development and validation of a computational model for simple measurement of amorphous and co-amorphous olanzapine (OLZ) fractions in tablets. Amorphous OLZ produced by quench cooling and co-amorphous OLZ by solvent evaporation using saccharin (SAC) as a co-former were characterized by calorimetry (DSC), diffractometry (XRPD) and spectroscopy (FTIR and NIR). Spectral differences were used to predict the fraction of amorphous OLZ in samples containing different fractions of powdered amorphous and co-amorphous OLZ:SAC. The models were shown to be linear, accurate and reproducible. Blends of (co)amorphous OLZ and excipients were directly compacted at different pressures and dwell times to impose physical stress on the systems. Data collected from the analysis of the tablets was used in the model to monitor the stability of amorphous and co-amorphous OLZ demonstrating the applicability and validity of the model.

Single-atom catalysts (SACs) have quickly emerged as a new class of catalytic materials. When confronted with classical carbon-supported nanoparticulated catalysts (Pt/C), SACs are often claimed to have superior electrocatalytic properties, e.g., stability. In this study, we critically assess this statement by investigating S-doped carbon-supported Pt SACs as a representative example of noble-metal-based SACs. We use a set of complementary techniques, which includes online inductively coupled plasma mass spectrometry (online ICP-MS), identical location transmission electron microscopy (IL-TEM), and X-ray photoelectron spectroscopy (XPS). It is shown by online ICP-MS that the dissolution behavior of as-synthesized Pt SACs is significantly different from that of metallic Pt/C. Moreover, Pt SACs are, indeed, confirmed to be more stable toward Pt dissolution. When cycled to potentials of up to 1.5 V-RHE, however, the dissolution profiles of Pt SACs and Pt/C become similar. IL-TEM and XPS show that this transition is due to morphological and chemical changes caused by cycling. The latter, in turn, is a consequence of the relatively poor stability of S ligands. As monitored by online ICP-MS and XPS, significant amounts of sulfur leave the catalyst during oxidation. Hence, in case catalysts with improved stability in the anodic potential region are desired, more robust supports and ligands must be developed.