Primary clarification of mammalian cell culture fluid using enhanced sedimentation on inclined surfaces inside the single-use disposable Sudhin BioSettler150.

The first downstream processing step in the purification of a biopharmaceutical protein secreted into mammalian cell culture fluid is the primary clarification of the culture fluid. As cell densities in the fed-batch and increasingly more common perfusion bioreactors have increased over last two decades through intensified upstream bioreactor production processes, the traditional primary clarification unit operations of centrifugation and/or microfiltration become more challenging with issues like frequent desludging, cell disruption due to shear damage and quick fouling of membranes. We have developed a novel compact cell settler device exploiting the enhanced sedimentation on inclined surfaces and demonstrated that this settler device can be adapted easily to remove and contain cells or cell clumps from the clarified supernatant collected via the top effluent of the settler. In this work, we present high product recovery results during primary clarification of mammalian cell culture supernatant using our novel single-use disposable BioSettler150 while processing about 10 L of cell culture broth within short processing times of about 4 h.

Screening and identification of a novel class of TGF-ß type 1 receptor kinase inhibitor.

Transforming growth factor ß (TGF-ß) type I receptor (activin receptor-like kinase 5, ALK5) has been identified as a promising target for fibrotic diseases. To find a novel inhibitor of ALK5, the authors performed a high-throughput screen of a library of 420,000 compounds using dephosphorylated ALK5. From primary hits of 1521 compounds, 555 compounds were confirmed. In total, 124 compounds were then selected for follow-up based on their unique structures and other properties. Repeated concentration-response testing and final interference assays of the above compounds resulted in the discovery of a structurally novel ALK5 inhibitor (compound 8) (N-(thiophen 2-ylmethyl)-3-(3,4,5 trimethoxyphenyl)imidazo[1,2ß]pyridazin 6-amine) with a low IC(50) value of 0.7 µM. Compound 8 also inhibited the TGF-ß-induced nuclear translocation of SMAD with an EC(50) value of 0.8 µM. Kinetic analysis revealed that compound 8 inhibited ALK5 via mixed-type inhibition, suggesting that it may bind to ALK5 differently than other published adenosine triphosphate site inhibitors.

Darusentan is a potent inhibitor of endothelin signaling and function in both large and small arteries.

Endothelin is a potent vasoconstrictor often up-regulated in hypertension. Endothelin vasoconstriction is mediated via the G-protein coupled endothelin A (ETA) receptor present on vascular smooth muscle. Endothelin receptor antagonists (ERAs) have been shown to antagonize ET-induced vasoconstriction. We describe the primary pharmacology of darusentan, a propanoic acid based ERA currently in phase 3 clinical trials for resistant hypertension. Darusentan was tested in membrane-, cell-, and tissue-based assays to determine its biochemical and functional potency. Rat aortic vascular smooth muscle cells (RAVSMs) were characterized using flow cytometry. RAVSM membrane fractions tested in saturation experiments exhibited moderate endothelin receptor density. Receptor counting revealed that >95% of the endothelin receptors in these fractions were the ETA subtype. (S)-Darusentan competed for radiolabeled endothelin binding in RAVSM membranes with single-site kinetics, exhibiting a Ki = 13 nmol/L. (R)-Darusentan exhibited no binding activity. In cultured RAVSMs, endothelin induced increases in inositol phosphate and Ca2+ signaling, both of which were attenuated by (S)-darusentan in a concentration-dependent manner. In isolated endothelium-denuded rat aortic rings, (S)-darusentan inhibited endothelin-induced vascular contractility with a pA2 = 8.1 +/- 0.14 (n = 4 animals; mean +/- SD). (R)-Darusentan had no effect. The vasorelaxant potency of (S)-darusentan did not change when determined in isolated denuded rat mesenteric arterioles, suggesting a similar mode of action in both conductance and resistance arteries. In vascular smooth muscle, (S)-darusentan is an ERA with high affinity for the ET receptor, which in this preparation is predominantly ETA receptors. (S)-Darusentan inhibits endothelin-induced signaling related to pro-contractile activity and is a potent inhibitor of vasoconstriction in large and small arteries.