Bio-Inspired Robust Membranes Nanoengineered from Interpenetrating Polymer Networks of Polybenzimidazole/Polydopamine.

Marine mussel inspired polydopamine (PDA) has received increased attention due to its good thermal and chemical stability as well as strong adhesion on most materials. In this work, high-performance nanofiltration membranes based on interpenetrating polymer networks (IPN) incorporating PDA and polybenzimidazole (PBI) were developed for organic solvent nanofiltration (OSN). Generally, in order to obtain solvent stability, polymers need to be covalently cross-linked under harsh conditions, which inevitably leads to losses in permeability and mechanical flexibility. Surprisingly, by in situ polymerization of dopamine within a PBI support, excellent solvent resistance and permeance of polar aprotic solvents were obtained without covalent cross-linking of the PBI backbone due to the formation of an IPN. The molecular weight cutoff and permeance of the membranes can be fine-tuned by changing the polymerization time. Robust membrane performance was achieved in conventional and emerging green polar aprotic solvents (PAS) in a wide temperature range covering -10 °C to +100 °C. It was successfully demonstrated that the in situ polymerization of PDA-creating an IPN-can provide a simple and green alternative to covalent cross-linking of membranes. To elucidate the nature of the solvent stability, a detailed analysis was performed that revealed that physical entanglement along with strong secondary interaction synergistically enable solvent resistance with as low as 1-3% PDA content.

Biomimetic Synthesis of Drug Metabolites in Batch and Continuous-Flow Reactors.

A medium-throughput screening (MTS) of biomimetic drug metabolite synthesis is developed by using an iron porphyrin catalyst. The microplate method, in combination with HPLC-MS analysis, was shown to be a useful tool for process development and parameter optimization in the production of targeted metabolites and/or oxidation products of forty-three different drug substances. In the case of the biomimetic oxidation of amiodarone, the high quantity and purity of the isolated products enabled detailed HRMS and NMR spectroscopic studies. In addition to identification of known metabolites, several new oxidation products of the drug that was studied were characterized. Fast degradation and poor recovery of the catalyst under batch conditions was overcome by immobilization of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin iron(III) chloride (FeTSPP) on the surface of 3-aminopropyl-functionalized silica by electrostatic interaction. The supported catalyst was successfully applied in a packed-bed reactor under continuous-flow reaction conditions for the large-scale synthesis of amiodarone metabolites.