Non-ionic surfactant vesicles to carry peptides and proteins

In the present study the preparation, characterization and activity of Non-ionic surfactants vesicles (NiSV) containing three aminoacid based molecules were described. NiSV have been largely proposed as drug delivery systems. This class of vesicles, structurally very similar to liposomes, was chosen as alternative to liposomes for the possible administration of aminoacid based molecules via mucosal (nasal or vaginal) route. NiSV were introduced to overcome the problems due to the chemical instability of phospholipids, such as easy hydrolysis of esters bonds or the peroxidation of unsaturated bonds, as compared to that of surfactants. Niosomes based on polyglycerol alkyl ethers and on sorbitan monoalkyl ethers were produced by direct hydration and sonication. As model compounds trypsin, bovine basic pancreatic inhibitor (BBPI) and a polylysine rich peptide (PLP), derived from the glycoprotein B of Herpes Simplex Virus type 1, were employed. As determined by PCS, niosomes containing trypsin are characterized by a mean diameter around 260 nm, whilst those carrying BBPI or PLP were respectively around 140 nm and 220 nm. The in vitro release kinetics of the three molecules from NiSV (as determined by dialysis) showed that after 8 hours trypsin was released for the 87%, BBPI inhibitor for the 52% and PLP for the 75-80%. Our study indicates that the produced NiSV (i) are able to encapsulate the model drugs over 49%, (ii) are characterized by dimensions compatible with applications on the mucous membrane, (iii) remain stable in size for at least 3 months and (iv) can release the peptide following the same behaviour of the corresponding free solution. Further studies are in progress in order to evaluate the ability of the different NiSV to interact to the cells at the mucosal site and efficiently release the encapsulated peptide.