title: Microemulsion: a novel transdermal delivery system to facilitate skin penetration of indomethacin.
abstract: In this study, we aimed to develop thermodynamically stable microemulsion formulations of indomethacin with lower surfactant and cosurfactant contents, to improve drug permeability. Formulations were based on the oil/water microemulsion region of pseudo-ternary phase diagrams. The characteristic parameters (viscosity, diameter, and polydispersity) of the microemulsion formulations were then determined. In vitro permeation studies were performed using Franz diffusion cells. Permeation through mouse skin and skin retention of indomethacin microemulsions and ointment were tested. The cumulative amount of permeated indomethacin and its skin retention were significantly higher in microemulsion formulations compared with ointment. Drug flux and skin retention improved with decreasing droplet diameter of the microemulsions. On the basis of these results, we suggest some possible mechanisms for the enhanced transdermal permeation of drugs in microemulsions, including high drug-loading capacity, permeation enhancement by surfactants and cosurfactants, and smaller droplet diameter. In conclusion, microemulsions represent a novel transdermal delivery vehicle for increasing the solubility and permeability of indomethacin.
authors.affiliation: Tianjin Key Laboratory of Modern drug Delivery and High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, PR China. cliangmei@gmail.com
authors.forename: Liangmei
authors.initials: L
authors.lastname: Chen
authors.forename: Fengping
authors.initials: F
authors.lastname: Tan
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D002626:Chemistry, Pharmaceutical; D002851:Chromatography, High Pressure Liquid; D004655:Emulsions; D005079:Excipients; D066298:In Vitro Techniques; D007213:Indomethacin / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D008297:Male; D051379:Mice; D012869:Skin Absorption / Q000502:physiology*; D013024:Soybean Oil; D013056:Spectrophotometry, Ultraviolet; D013501:Surface-Active Agents
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004655:Emulsions; D005079:Excipients; D013501:Surface-Active Agents; D013024:Soybean Oil; D007213:Indomethacin