Thermal Analysis of Peptide and Carbohydrate Formulations

Using conditions similar to previously reported [24 (link),28 (link),29 (link),30 (link),46 (link),47 (link),48 (link),49 (link)], thermal analysis and phase transition measurements of Ang (1—7), PNA5, and Trehalose (all unprocessed), SD, and co-SD formulations were studied. The thermograms were obtained using the TA Q1000 differential scanning calorimeter (DSC) (TA Instruments, New Castle, Delaware). A mass of 3–5 mg of each sample was weighed into hermetic anodized aluminum DSC pan. DSC measurements were performed at the heating rates of 5.00 °C/min and 40.0 °C/min from 0.00–300 °C. As a reference, an empty, hermetically sealed aluminum pan was used. The purging gas was nitrogen at a rate of 50 mL/min. Phase transition parameters including the glass transition temperature (T_g), melting point (T_m) main phase transition, enthalpy (ΔH), and heat capacity (ΔC_p) were measured and calculated using TA Universal Analysis (TA Instruments). Moreover, to ensure reproducibility, each experiment was repeated three times.