In Vitro Comparison of O/W Type Emulsion Gel and Liposome Gel for Cosmetic Application of Kinetin

Kinetin is a highly potent growth factor that is capable of delaying or preventing age-related changes of human skin fibroblasts. The purpose of this study was to develop and characterize topical kinetin-loaded emulsion gel and liposome gel formulations. Emulsion formulation was prepared using the spontaneous emulsification method. Pseudoternary phase diagram for oil/water (o/w) type emulsion was constructed using caprylic/capric/linoleic triglyceride (Miglyol®818), surfactant [egg lecithin (phosphatidyl choline content 80%)], cosurfactant (absolute ethanol), poloxamer 188 (Lutrol®F68) and water. Poloxamer 188 and water were used as the aqueous phase. Liposome was prepared by conventional film hydration method using 9:1 w/w phosphatidylcholine:cholesterol as lipophilic phase. The encapsulation efficiency of liposome was found to be 84.5%. The droplet/vesicle sizes were 3.88 μm and 5.30 μm for o/w type emulsion and liposome systems, respectively. Emulsion and liposome formulations were incorporated in hydroxypropyl methylcellulose (HPMC®K15M) and carbomer (Carbopol®974) gels for improving the viscosity for topical administration, respectively. The reograms exhibited a non-Newtonian behavior. Kinetin release from emulsion and liposome gels were evaluated through artificial membrane (cellulose acetate membrane with molecular cut-off 12000 Dalton, D-0405). The results of the study indicated that the emulsion and liposome gels may be promising vehicles for topical delivery of kinetin.