In situ photoacoustic analysis of near-infrared absorption of rhodium-doped strontium titanate photocatalyst powder.

Near-infrared absorption of strontium titanate (SrTiO) doped with rhodium (Rh) was investigated by photoacoustic (PA) Fourier transform infrared spectroscopy. In the absence of an electron acceptor and the presence of a hole scavenger, the largest absorption change in the Rh valence state from tetravalent to trivalent was observed in Rh-doped SrTiO prepared at 1473 K, which showed the highest activity for hydrogen evolution. PA measurements revealed the effective redox cycle mechanism between tetravalent and trivalent Rh ions in Rh-doped SrTiO.

Mid-infrared absorption of trapped electrons in titanium(iv) oxide particles using a photoacoustic FTIR technique.

Mid-infrared absorption of titanium(iv) oxide (TiO2) under ultraviolet (UV) irradiation was studied by Fourier transform infrared spectroscopy using a photoacoustic (PA) technique. UV irradiation induced an upward shift of the PA spectra, which is due to the trivalent titanium (Ti3+) species produced by electron accumulation. The PA spectra under UV irradiation mainly depend on the crystal structure, indicating that the energy levels of Ti3+ are largely determined by crystal structures.

Evaluating tamsulosin hydrochloride-released microparticles prepared using single-step matrix coating.

The objective of the present study was to determine the optimum composition for sustained-release of tamsulosin hydrochloride from microparticles intended for orally disintegrating tablets. Microparticles were prepared from an aqueous ethylcellulose dispersion (Aquacoa®), and an aqueous copolymer based on ethyl acrylate and methyl methacrylate dispersion (Eudragit®) NE30D), with microcrystalline cellulose as core particles with a fluidized bed coating process. Prepared microparticles were about 200 μm diameter and spherical.

Characteristics of the gastric pH profiles of unfed and fed cynomolgus monkeys as pharmaceutical product development subjects.

Gastric pH is an important factor which significantly affects the dissolution of drugs, and therefore their bioavailability. In this study, the gastric pHs were measured directly with a miniature pH electrode inserted through the nostril into the body of the stomach of cynomolgus monkeys. Results from three separate sets of measurements using the same male monkeys indicated that the median gastric pH profiles of unfed monkeys were low, fluctuating between pH 1 and pH 3.