Raman and Terahertz Spectroscopic Characterization of Solid-state Cocrystal Formation within Specific Active Pharmaceutical Ingredients

Abstract

Cocrystallization of specific active pharmaceutical ingredients (APIs) in the solid-state phase is becoming a feasible way to improve their corresponding physicochemical properties and ultimate bioavailability without making and breaking any covalent bonds within them. Many recent reports deal with the characterization and analysis topics of pharmaceutical APIs-based cocrystals. In this mini-review, we will focus on the recent steady-state and time-dependent spectroscopic investigation into the cocrystallization of specific APIs based on both Raman and emerging terahertz spectroscopy in pharmaceutical fields. Distinctive spectral, structural and also kinetic information of pharmaceutical APIs-based cocrystals are obtained and discussed, which would highlight the potential of vibrational spectroscopy as an attractive technique for various drug research and development during cocrystallization of specific APIs.

Keywords: Cocrystallization; Raman spectroscopy; active pharmaceutical ingredients (APIs); covalent; kinetic; solid-state APIs-based cocrystals; terahertz time-domain spectroscopy (THz-TDS).