title: Characterization and in vitro permeation study of microemulsions and liquid crystalline systems containing the anticholinesterase alkaloidal extract from Tabernaemontana divaricata.
abstract: The aims of the present study were to characterize the microstructure and study the skin permeation enhancement of formulations containing the alkaloidal extract from Tabernaemontana divaricata. The extract was loaded in the formulations composed of Zingiber cassumunar oil, Triton X-114, ethanol and water with the oil:surfactant ratios of 1:5 and 2:5. The formulations were characterized by photon correlation spectroscopy, polarizing light microscopy, differential scanning calorimetry, and viscosity measurement. A reverse micellar phase, w/o microemulsions, liquid crystalline systems, liquid crystal in microemulsion systems and coarse emulsions were formed along the aqueous dilution line of both oil:surfactant ratios. Formulations with the ratio of 1:5 containing 0.1 μg/ml extract showed a significantly higher acetylcholinesterase inhibition than those with the ratio of 2:5. The skin of stillborn piglet was used in the permeation study. The liquid crystalline and microemulsion systems significantly increased the transdermal delivery of the extract within 24h. It was concluded that the alkaloidal extract from T. divaricata stem loaded in liquid crystalline or microemulsion systems comprising Z. cassumunar oil/Triton X-114/ethanol/water may act as an alternative percutanous formulations for enhancing the acetylcholine level in Alzheimer's patients.
authors.affiliation: Department of Pharmaceutical Science, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: Wantida
authors.initials: W
authors.lastname: Chaiyana
authors.forename: Thomas
authors.initials: T
authors.lastname: Rades
authors.forename: Siriporn
authors.initials: S
authors.lastname: Okonogi
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000470:Alkaloids / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D002800:Cholinesterase Inhibitors / Q000737:chemistry / Q000378:metabolism*; D004655:Emulsions; D000431:Ethanol / Q000737:chemistry / Q000378:metabolism; D066298:In Vitro Techniques; D017830:Octoxynol; D009822:Oils, Volatile / Q000737:chemistry / Q000378:metabolism*; D010539:Permeability; D010936:Plant Extracts / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry / Q000378:metabolism; D018547:Plant Stems; D011092:Polyethylene Glycols / Q000737:chemistry / Q000378:metabolism; D027343:Rhizome; D012867:Skin / Q000378:metabolism*; D012869:Skin Absorption; D013501:Surface-Active Agents / Q000737:chemistry / Q000378:metabolism; D013552:Swine; D030014:Tabernaemontana; D013729:Terpenes / Q000737:chemistry / Q000378:metabolism; D030521:Zingiberaceae
chemical_list: D000470:Alkaloids; D002800:Cholinesterase Inhibitors; D004655:Emulsions; D009822:Oils, Volatile; D010936:Plant Extracts; D010938:Plant Oils; D013501:Surface-Active Agents; D013729:Terpenes; D000431:Ethanol; D011092:Polyethylene Glycols; C052901:lemongrass oil; D017830:Octoxynol; C010615:Nonidet P-40; D000110:Acetylcholinesterase