N-alpha-benzoyl-L-argininate ethyl ester chloride (BAEEH(+)center dot Cl-) has been used as a model drug in the development of polymeric delivery systems for peptides and proteins. In this study, crystalline BAEEH(+)center dot Cl- was characterized by different thermoanalytical techniques. The main thermal events were identified by modulated differential scanning calorimetry (MDSC). Polarized light thermomicroscopy (PLTM) showed that no phase transitions but fusion occur before thermal decomposition. A crystalline phase could not be obtained from the melt in cooling/heating cycles between 150 degrees C and -150 degrees C. at 10 degrees C min(-1) scanning rate. The thermal stability and the non-isothermal kinetic analysis of the thermal decomposition were studied by conventional and high resolution modulated thermogravimetric analysis (HiRes-MTGA). Depending on the conditions of the study, the decomposition starts in the range from 197 C(HiRes-MTGA at phi = 2 degrees C min(-1)) to 261 degrees C (TGA at 20 degrees C min(-1)). It was found that the first stage of the decomposition process can be described by the kinetic triplet E-a = 142 kJ mol(-1), A = 1.86 x 10(11) s(-1), and f(alpha)= (1 - alpha)(2.78). (C) 2011 Elsevier B.V. All rights reserved.