Ammonio Methacrylate Copolymer (Type B)-Diltiazem Interactions in Solid Dispersions and Drug-Delivery Systems.

This paper presents a complex analytical study on the distribution, solubility, amorphization, and compatibility of diltiazem within the composition of Eudragit RS 100-based particles of microspongeous type. For this purpose, a methodology combining attenuated total reflectance Fourier transform infrared (ATR-FTIR) absorption spectroscopy, differential scanning calorimetry (DSC), scanning electron microscopy with energy-dispersive X-ray microanalysis (SEM-EDX), and in vitro dissolution study is proposed. The correct interpretation of the FTIR and drug-dissolution results was guaranteed by the implementation of two contrasting reference models: physical drug-polymer mixtures and casting-obtained, molecularly dispersed drug-polymer composites (solid dispersions).

A QCM-based assay of drug content in Eudragit RS 100-based delivery systems.

A specific version of the quartz crystal microbalance method has been proposed for quantitative evaluation of drug content in polymeric drug carrier systems. In this study, ammonio methacrylate copolymer (type B) microparticles and their standard solutions have been prepared and loaded with set amounts of the medications diltiazem (base) and lidocaine. The analytes have been segregatim deposited on the surface of the resonator and the drug content in them has been derived from the downshift of the resonance frequency produced by irreversible interaction of the drug molecules with irradiating hydrochloric gas.

Growth and toxic gas sensing properties of poly(urethaneimide) thin films.

In this work we present a study on the growth and the gas sensing properties of poly(urethane imide) thin films. We first deeply characterized by atomic force microscopy (AFM) the nanostructuration of the poly(urethane imide) holding different amine groups. We further studied the interaction between highly toxic gases such as hexamethyleneimine (HMI) and pyridine and the polymer by using an unconventional method based on Quartz Crystal Microbalance (QCM) measurement.