Percutaneous Absorption Study of Small Peptides Encapsulated in Liposomes

• Main Authors: LAN CHEN-JUNG, 藍陳鎔
• Other Authors: Muh-Hwan,Su
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/90589523158616896038

碩士 === 國防醫學院 === 藥學類 === 86 === It was found in this study that the content of amino acids of the human epidermal membrane (HEM) were increased as the incubation time increased which can interfere the diffusion of cold ( exogenous ) amino acids through HEM. When benzoic acid was used as the model drug, its permeability coefficient in pH 7.4 phosphate buffer saline through HEM was about 2.408~6.512×10-8, in pH 4.0 phosphate buffer saline through HEM was about 4.25~8.683×10-6. These results further proved that the permeation mechanism of polar compounds or amino acids and/or peptides through HEM followed the pore pathway. Due to the low permeability of peptides, we have tried seven different formulations (SL : Dppc : Chol, SL : Dppe : Chol, SL : Dppc : Dppe : Chol, SL : Dppc : SA : Chol, SL : Dppe : SA : Chol, SL : Dppc : PA : Chol, SL:Dppe:PA:Chol) to obtain liposomes entraped with six different amino acids or sodium fluorescein. A series of stability studies were performed for these liposomes based on their particle size homogeneity after the change of phospholipids, surface charge, pH, temperature and ionoc strength etc. The most stable formulation was chosen to encapsulate dansyl-dialanine, tetraalanine and hexaalanine which were synthesized by simple chemical reaction in this laboratory. The obtained liposomal peptides were found to have beter (3~5 folds better) penetration through HEM than those without liposomes. It was also suggested that the higher the molecular weight is the smaller the flux will be.