ABSTRACT:
Silicone oils owe their versatility and biocompatibility to their unique properties due to which they are being widely applied in the cosmetic and pharmaceutical industries today. One of the possible formulations by which these oils can be used is in the form of micro and nanoemulsions. Kinetic stability of these emulsions has been addressed in terms of thermodynamic concepts. Various simple and advanced methods exist for their preparation which are of the oil in water and water in oil types. Double emulsions have demonstrated superiority over the single ones and can be prepared by traditional two step and novel single step processes. Emulsion formulations require the incorporation of suitable emulsifiers into the system and studies on biocompatibility of such emulsifiers have revealed the non ionic ones to be more suitable than ionic types. Pronounced emulsifier activity has also been noticed with multifunctional polymeric silicone based emulsifiers, due to their strong absorption at oil in water interface. Toxicity studies have proved that silicone oil systems exhibit low order toxicity, except in very few cases. Biocompatibility can additionally be improved by the usage of bio based surfactants. Applications of silicone oil emulsions in cosmetics, medicine and pharmaceutics have been discussed here.