Application of Fast Reversed Phase Liquid Chromatography for Analysis of Pharmaceutical Related Boronic Acid and Boronic Pinacol Ester Functionalized Compounds

A fluorescent probe for selective detection of boric acids and its application for screening the conversion of the Suzuki-Miyaura coupling reaction

Boric acid (B(OH)3) plays an important physiological role and is widely used as a food preservative and an antiseptic. Various colorimetric, fluorescent probes have been developed to detect boric acid; however, most of them could not discriminate boric acid over boronic acids (R-B(OH)2) or are limited to boronic acid sensors. Therefore, the development of boric acid-selective probes is necessary. Herein, a salicylimine-based fluorophore, Di-OH, was designed that showed selective fluorescence response to boric acid over boronic acid. Its fluorescence response to boric acid showed a large fluorescence turn-on signal up to 140 fold and excellent selectivity with various analytes. Furthermore, since boric acid is generated in proportion to the consumed boronic acid derivatives during reactions involving oraganoboron compounds, Di-OH allowed the determination of the conversion of the Suzuki-Miyaura coupling reaction using fluorescence spectroscopy and its correlation with the GC conversion was confirmed.

Limiting degradation of reactive antibody drug conjugate intermediates in HPLC method development

The development of an accurate HPLC method for a reactive linker drug intermediate for antibody drug conjugates (ADCs) is challenging as the linker drug is designed to be reactive. This reactivity can lead to the generation of artifact peaks in the chromatograms and deliver inaccurate impurity content results. In this study, the linker drug contains an amine reactive tetrafluorophenyl (TFP) ester that readily undergoes hydrolysis and internal succinimide cyclization in aqueous solution. While complete elimination of the on-column degradation was nearly impossible, optimization of the critical chromatography conditions guided by chemical kinetics minimizes the degree of on-column degradation enabling an accurate assay and purity method for this reactive linker drug intermediate. Kinetics of the linker drug reactions were studied in different solution pHs and temperatures while the reaction rates were used to guide the selection of the optimum diluent, mobile phase pH, and column temperature to minimize the on-column degradation. An UHPLC column was used to achieve fast analysis to further reduce the degree of on-column degradation. The actual amount of on-column degradation of the final HPLC method was determined to be <0.1%, lower than the ICH reporting limit of, therefore demonstrate the effectiveness of the strategy.