Characterization and monitoring of pseudo-polymorphs in manufacturing process by NIR.

Moisture-sensitive pseudo-polymorphs with different stabilities were characterized, and their polymorphisms were monitored in the process of tableting and film coating by near-infrared (NIR) spectroscopy. In this study, we proved that we could successfully maintain the crystal form ratio in the tablet by controlling the moisture profile during the manufacture to sufficiently stabilize the drug product. Mitemcinal fumarate is an erythromycin derivative with two pseudo-polymorphic forms, hydrate and anhydrate.

Microscopic molecular mobility of amorphous AG-041R measured by solid-state 13C NMR.

Purpose: AG-041R is characterized to be stable in amorphous state and difficult to crystallize at normal period of time. In order to investigate the molecular mobility in microscopically, the spin-lattice relaxation time (T1) of AG-041R was investigated by solid-state CP/MAS 13C NMR at temperature below and above glass transition temperature (Tg).

Method: CP/MAS measurement and T1 measurement were performed by means of 13C NMR, where the measurement temperatures were 60, 70, 80, 100, and 110 degrees C.

A study of the substrate specificity of Na+-dependent and Na+-independent neutral amino acid transport systems in dog intestinal brush-border membrane vesicles using L-alanine analogues.

Neutral amino acids are mainly transported across the intestinal brush-border membrane by two Na+-dependent systems (system B0 and system B0+) and one Na+-independent system (system b0,+). To investigate potential differences in substrate specificity between these systems, we screened ten different alanine analogues for their ability to inhibit the transport of L-alanine in dog intestinal brush-border membrane vesicles. The results suggested that a phenyl group directly attached to the alpha-carbon has different effects on the Na+-dependent and Na+-independent transport systems, with an increased affinity for the former and a decreased affinity for the latter.