Creams, samples A and B
Inactive ingredient
Measuring cell: DSC821e with IntraCooler
Pan: Aluminum 40 µl, hermetically sealed
Sample preparation: As received, no preparation
DSC measurement: Heating from 5 °C to 70 °C at 5 K/min
Atmosphere: Nitrogen, 50 cm3/min
The inactive ingredients such as fatty acid esters and mono-, di- and tri-glycerides that are used for the manufacture of O/W creams, can form three dimensional structures of different types and strengths with the addition of water. On heating, the composition melts or undergoes specific transformations. This results in a DSC curve that is characteristic of a particular mixture.
The peak maxima or onset temperatures (in °C) and integral ΔH (in J/g) of all the peaks are determined. For integration, the baseline types ‘spline’ or ‘line’ are used, depending on the shape of the peak.
Effect | 1 | 1 | 2 | 2 | 3 | 3 | 4 | 4 |
Sample | Peak, °C | ΔH, J/g | Peak, °C | ΔH, J/g | Peak, °C | ΔH, J/g | Onset, °C | ΔH, J/g |
A | 27.1 | 1.1 | 32.5 | 0.4 | 39.4 | 1.9 | 58.1 | 2.8 |
B | 60.4 | 3.9 |
Characteristic transformation temperatures and energies can be measured by DSC. Even if the effects observed are quite weak, they can still be used as a ‘fingerprint’ to characterize O/W emulsions.
DSC 'Fingerprint', O/W Cream | Thermal Analysis Application No. HB807 | Application published in METTLER TOLEDO TA Application Handbook Pharmaceuticals