Purification of ADCs by Hydrophobic Interaction Chromatography.

Antibody-drug conjugate (ADC) in vitro potency has been shown to be dependent on drug load, with higher drug load providing lower IC values. However, in vivo potency is affected by intrinsic biological effects as well, such as plasma clearance, dose-limiting toxicity, etc. Developing a preparative HIC process for ADC purification to isolate species with a specific drug loading involves several steps including conjugation optimization, resin selection, solubility studies gradient screening, and step gradient development (buffer selection).

Potassium tert-Amylate: A Cautionary Tale.

Potassium tert-amylate ( t-AmylOK) is a well-known, commercially available base and generally regarded as a more solvent-soluble form of potassium tert-butoxide ( t-BuOK). However, despite the structural similarity between the tert-butyl and amyl moieties, potassium tert-amylate in toluene can undergo distinct physical property changes in the presence of protic solvents that warrant further consideration. This is particularly surprising given that t-AmylOH is a byproduct of deprotonation with t-AmylOK, as well as the fact that its structurally similar relative, t-BuOK, is commercially available in t-BuOH.

Microwave-assisted Piloty-Robinson synthesis of 3,4-disubstituted pyrroles.

The synthesis of N-acyl 3,4-disubstituted pyrroles can be accomplished directly from hydrazine and an aldehyde via a Piloty-Robinson pyrrole synthesis. The use of microwave radiation for the cyclization and pyrrole formation greatly reduces the time necessary for this process and facilitates moderate to good yields from hydrazine for the corresponding 3,4-disubstituted products (5-12). By simple hydrolysis, the free N-H pyrroles can be accessed after the Piloty-Robinson reaction and then used directly in the synthesis of octaethylporphyrin (H2OEP, 14) and octaethyltetraphenylporphyrin (H2OETPP, 15).