A Nicolet 380 FTIR Spectrometer equipped with deuterated triglycine sulphate detector and Smart Orbit single reflection diamond ATR sampling accessory was employed for all experiments. Measurements were made in absorption mode on a small amount of sample deposited on the ATR crystal. No sample treatment was necessary for measurement: the internal content of capsules was homogenized by milling and a sample portion was directly placed on the ATR element. Each mixture was sampled in triplicate. Identical pressure was used for all measurements. Each spectrum consists of 16 co-added scans measured at a spectral resolution of 4 cm1 in the 4000–525 cm1 range. Spectral data were acquired with EZ OMNIC software, version 7.2a (Nicolet Instrument Co.)