Abstract
“Onion-type” multilamellar micro-vesicles of phospholipids (spherulites) were doped with different amounts of a cationic cosurfactant ((-)N-dodecyl-N-methylephedrinium bromide) for the purpose of controlling the sustained release of anionic drugs. Three weak acid probes (methyl red, chlorophenol red, and ibuprofen) were encapsulated in the vesicles as drug models. The kinetics and rate of release were studied by absorption spectroscopy and HPLC. The effect of probe charge (pH above and below pKa of the probes), of cosurfactant concentration and of added salt was investigated. It was found that, above pKa (i.e., when the probes are anionic), the release can be almost totally inhibited by doping the vesicles with 2.4 wt% of cationic cosurfactant. The release properties can even be finely tuned by controlling the amounts of the cosurfactant. Salt and pH effects demonstrate the role of electrostatic interactions in sustaining the release.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
