Microemulsions have gained interest from the pharmaceutical industry due to their ability to co-solubilize hydrophilic and lipophilic drugs, and to provide enhanced drug penetration. In this work, thermosensitive gelatin- and poloxamer 407-stabilized microemulsion-based gels (MBGs) were formulated using alcohol-free, low toxicity and low viscosity lecithin-based linker microemulsions. The addition of gelatin to water-rich bicontinuous microemulsions induced the formation of clear viscoelastic gels containing an oil-rich microemulsion as the gelatin seemed to dehydrate the original microemulsion. The addition of poloxamer 407 to water-continuous microemulsions produced MBGs with different gelation temperatures. High concentrations of lipophilic components in the microemulsion, particularly the oil, reduced sol-gel transition temperature, while hydrophilic components increased sol-gel transition temperature. Gelatin and poloxamer MBGs provided desirable viscoelastic properties for ophthalmic and transdermal applications with minimal impact on the transport properties of the original microemulsions.

Microemulsions have gained interest from the pharmaceutical industry due to their ability to co-solubilize hydrophilic and lipophilic drugs, and to provide enhanced drug penetration. In this work, thermosensitive gelatin- and poloxamer 407-stabilized microemulsion-based gels (MBGs) were formulated using alcohol-free, low toxicity and low viscosity lecithin-based linker microemulsions. The addition of gelatin to water-rich bicontinuous microemulsions induced the formation of clear viscoelastic gels containing an oil-rich microemulsion as the gelatin seemed to dehydrate the original microemulsion. The addition of poloxamer 407 to water-continuous microemulsions produced MBGs with different gelation temperatures. High concentrations of lipophilic components in the microemulsion, particularly the oil, reduced sol-gel transition temperature, while hydrophilic components increased sol-gel transition temperature. Gelatin and poloxamer MBGs provided desirable viscoelastic properties for ophthalmic and transdermal applications with minimal impact on the transport properties of the original microemulsions.