Carriers for skin delivery of trihexyphenidyl HCl: ethosomes vs. liposomes.
The purpose of this work was to characterize a novel ethosomal carrier containing trihexyphenidyl HCl (THP) and to investigate the delivery of THP from ethosomes versus classic liposomes. THP-ethosomal systems were shown by electron microscopy to contain small, phospholipid vesicles. As the THP concentration was increased from 0 to 3%, the size of the vesicles decreased from 154 to 90 nm. This is most likely due to the surface activity of THP (critical micelle concentration of 5.9 mg/ml), as measured in this work. In addition, the ethosome zeta potential value increased as a function of THP concentration, from -4.5 to +10.4 when the THP concentration was increased from 0 to 3%. In contrast, THP liposomes were much larger and their charge was not affected by THP. When compared with standard liposomes, ethosomes had a higher entrapment capacity and a greater ability to deliver entrapped fluorescent probe to the deeper layers of skin. The flux of THP through nude mouse skin from THP ethosomes (0.21 mg/cm2 h) was 87, 51 and 4.5 times higher than from liposomes, phosphate buffer and hydroethanolic solution, respectively (p < 0.01). The quantity of THP remaining in the skin at the end of the 18-h experiment was statistically significantly greater from the ethosomal system than from liposomes or a control hydroethanolic solution. Our results indicate that the ethosomal THP system may be a promising candidate for transdermal delivery of THP.
Department of Pharmaceutics, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jeriusalem, Israel.
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Dayan
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Touitou
D000818:Animals; D002152:Calorimetry, Differential Scanning; D004337:Drug Carriers; D004355:Drug Stability; D007271:Injections, Intradermal; D007700:Kinetics; D008081:Liposomes; D051379:Mice; D008819:Mice, Nude; D008823:Micelles; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D010713:Phosphatidylcholines / Q000737:chemistry; D012867:Skin / Q000378:metabolism*; D014282:Trihexyphenidyl / Q000008:administration & dosage* / Q000493:pharmacokinetics
D004337:Drug Carriers; D008081:Liposomes; D008823:Micelles; D010713:Phosphatidylcholines; D014282:Trihexyphenidyl