title: Terpene microemulsions for transdermal curcumin delivery: effects of terpenes and cosurfactants.
abstract: Microemulsion systems composed of terpenes, polysorbate 80, cosurfactants, and water were investigated as transdermal delivery vehicles for curcumin. Pseudoternary phase diagrams of three terpenes (limonene, 1,8-cineole, and α-terpineol) at a constant surfactant/cosurfactant ratio (1:1) were constructed to illustrate their phase behaviors. Limonene combined with cosurfactants like ethanol, isopropanol, and propylene glycol were employed as microemulsion ingredients to study their potential for transdermal curcumin delivery. The transdermal delivery efficacy and skin retention of curcumin were evaluated using neonate pig skin mounted on a Franz diffusion cell. The curcumin permeation rates in the limonene microemulsion studied were 30- and 44-fold higher than those of 1,8-cineole and α-terpineol microemulsions, respectively. Significant effects on the skin permeation rates were observed from microemulsions containing different limonene/water contents. Histological examination of treated skin was performed to investigate the change of skin morphologies. Characteristics such as droplet size, conductivity, interfacial tension, and viscosity were analyzed to understand the physicochemical properties of the transdermal microemulsions. In conclusion, microemulsions loaded with curcumin were successfully optimized for transdermal delivery after screening various terpenes, cosurfactants, and limonene/water ratios. These results indicate that the limonene microemulsion system is a promising tool for the percutaneous delivery of curcumin.
authors.affiliation: Graduate Institute of Biochemical and Biomedical Engineering, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Taoyuan 333, Taiwan. chl@mail.cgu.edu.tw
authors.forename: Chi-Hsien
authors.initials: CH
authors.lastname: Liu
authors.forename: Fu-Yen
authors.initials: FY
authors.lastname: Chang
authors.forename: De-Kai
authors.initials: DK
authors.lastname: Hung
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D003474:Curcumin / Q000008:administration & dosage* / Q000494:pharmacology*; D053138:Cyclohexenes / Q000008:administration & dosage / Q000494:pharmacology; D020405:Dermis / Q000166:cytology / Q000187:drug effects*; D016503:Drug Delivery Systems; D004553:Electric Conductivity; D004655:Emulsions; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D000077222:Limonene; D009822:Oils, Volatile / Q000008:administration & dosage / Q000494:pharmacology; D010316:Particle Size; D010539:Permeability / Q000187:drug effects; D044367:Phase Transition / Q000187:drug effects; D011136:Polysorbates / Q000494:pharmacology; D012869:Skin Absorption / Q000187:drug effects; D013500:Surface Tension / Q000187:drug effects; D013501:Surface-Active Agents / Q000008:administration & dosage / Q000494:pharmacology*; D034421:Sus scrofa; D013729:Terpenes / Q000008:administration & dosage* / Q000494:pharmacology*; D014783:Viscosity / Q000187:drug effects; D014867:Water / Q000737:chemistry
chemical_list: D053138:Cyclohexenes; D004655:Emulsions; D009822:Oils, Volatile; D011136:Polysorbates; D013501:Surface-Active Agents; D013729:Terpenes; D014867:Water; D000077222:Limonene; D003474:Curcumin