Accelerated stability testing of a water-in-oil emulsion

Non-optimal or non-predictable stability properties of emulsions can be lim iting for the applications of emulsions. Therefore, it is of general intere st to predict stability behavior. In the present study, accelerated stabili ty testing employing elevated temperatures with good accuracy predicted lon g-term stability of a w/o emulsion stabilized with polyglycerol polyricinol eate (PG PR) kept at 4 degreesC It is argued that elevated temperature test ing may successfully be applied to w/o emulsions provided that the phase in version temperature is not crossed during the accelerated study. Furthermor e, some qualitative effects of temperature on chemical stability could be o bserved. It was found that triglycerol polyricinoleate-6 provided the highe st physical stability of four qualities of PG PR. Release characteristics of two entrapped hydrophilic markers, glucose and p olyethylene glycol (m.w.4000) showed different sensitivities towards therma l stressing. The high releasing compound, glucose, showed a significant red uction in release rate in contrast to polyethylene glycol.