Title: Emulsions and Emulsifications Methods and Processes | LLS Health CDMO
Headings: Emulsions and Emulsifications
Emulsions and Emulsifications
Table Of Contents hide
Emulsification
Stabilization
Addition of API
Conclusions

Content: Therefore, they remain at the droplet interface where they can provide a barrier to droplet coalescence. Emulsification
The Gibb’s free energy change, ΔG, on forming an emulsion from two bulk liquids is given by the familiar equation: ΔG=ΔH–TΔS, where ΔH is enthalpy change, T is temperature, and ΔS is entropy change. 100 ml of an o/w emulsion containing 10% w/w of oil in the form of 1 µm droplets, contains 2 x 1013 droplets, having a combined surface area of 60 m2
Without going deeply into the relative energetic contributions, the free energy of emulsification is positive. The first corollary of this is that emulsification is rarely a spontaneous process, and hence requires the input of energy. This energy usually comes from mechanical shear provided by various types of mixers, and the final droplet size of the emulsion is dependent on not only the chemistry but also the amount of energy applied. Simple paddle-type mixers are suitable when the required droplet size is above ~10 µm but to make smaller droplets, higher shear is generally required. High shear rotor-stator mixers are commonly used. These operate by pumping the emulsion phases through the narrow gap between a perforated cylinder (the stator) and the blades of a rapidly rotating stirrer housed inside it (the rotor) where the forces are sufficient to make droplets as small as around 1 µm (Figure 2). To make even smaller nano-sized droplets, at small scale, ultrasonic devices can be used, but they are generally not practical to scale up.