2.4.2. Heating–cooling cycle
This study was performed to check the effect of temperature variations on the stability of microemulsion formulations. Samples were stored between 4 and 40 °C temperature each for a period of 48 h. The heating–cooling cycle was repeated four times. The microemulsion formulations that did not show any instability such as cracking, creaming and phase separation were chosen and subjected to freeze–thaw stress.