Structural analysis of w/o/w multiple emulsions by means of DSC

Abstract

The properties of the inner and the external aqueous phases, were studied in w/o/w multiple emulsions with light microscopic image analysis and differential scanning calorimetry (DSC).The importance of multiple emulsions lies in the presence of these aqueous phases, making them available for sustained, controlled drug delivery systems. Differentiation of these two aqueous phases, studying the effect of manufacturing technology on droplet structure, quantitative determination of phase volumes and any changes occurring during storage are essential when planning w/o/w emulsions. The present study uses microscopic observations combined with DSC measurements in order to identify the formed structure, at developmental stage in case of different components, preparation methods, and stirring rates. These tools are beneficial during manufacturing as in process controls, or to ensure product quality.

Optimization and development of stable w/o/w cosmetic multiple emulsions by means of the Quality by Design approach

“…Based on the results of the rheological investigations, it can be concluded that in conformity with the results from the former structural analytical methods, the characteristics of the flow and viscosity curves represent the structural changes (swelling, breakup) during storage. These results correlate with the microscopic observation (previous chapter) and the thermoanalytical measurements as described in the previous study [27].…”

“…In one of our previous studies, the DSC method was used to characterize these systems , mirroring also the results of other authors .…”

Influence of the second emulsification step during production of W/O/W multiple emulsions: Comparison of different methods to determine encapsulation efficiency in W/O/W emulsions

“…On the contrary, differential scanning calorimetry (DSC) allows the direct determination of the amount of water in the inner water phase of a W/O/W double emulsion. [22,25,26] A small sample of the multiple emulsion is frozen applying a constant temperature rate. Inner and outer water phases freeze at different temperatures and can therefore be distinguished.…”

Stability evaluation of tocopheryl acetate and ascorbyl tetraisopalmitate in isolation and incorporated in cosmetic formulations using thermal analysis

“…These authors found that the multiple emulsions prepared with non-polar lipophilic agents contained less multiple droplets than those containing polar agents at the same surfactant concentration (Kovács et al, 2005).…”