Physicochemical and in-vitro release studies of liponanocapsules

• Main Author: Tan, Dulcia Wei Ni.
• Other Authors: Subramanian Venkatraman
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Materials::Biomaterials
• Online Access: http://hdl.handle.net/10356/48445
• Institution: Nanyang Technological University

The objective of this project is to optimize and study the formulation of stable polyelectrolyte coated liposomes called liponanocapsules. They are formed using the layer-by-layer (lbl) technique. This technique applies the alternating adsorption of oppositely charged polyelectrolyte ions via electrostatic interactions. Liposome were fabricated from 1, 2-Dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1, 2-Dimyristoyl-sn-glycero-3[Phospho-rac-(1-glycerol)] (sodium salt, DMPG-Na) in 80:20 wt%. Subsequent deposition of positively charged poly(allylamine hydrochloride) (PAH) and negatively charged sodium poly(styrene sulfonate) (PSS) were alternatively coated onto these liposomes. Two different approaches were carried out in the formulation of liponanocapsules. In the first approach formulation and coating of 100 nm liposomes were carried in a PBS (pH 7.4) buffer system; while the other approach involved in the coating of larger size liposomes, formulated through 800 nm filter membrane in ultrapure water. From long term storage stability study, liponanocapsules have better stability as compared to DMPC/DMPG-Na (80:20 wt%) liposomes. Liponanocapsules had smaller size increment and smaller drop in zeta potential. On the other hand, DMPC/DMPG-Na liposomes showed signs of aggregation with increase in size. Avastin is used as a model drug and successfully loaded into the PSS-PAH coated liposomes by simple mixing (wrapping up). It is believed that avastin was coated on the liposomes since it was added after the formation of liponanocapsules. In the drug release studies, avastin was showed to have a complete release within a day, suggesting that the adsorption of avastin was weak and quickly released upon release. In conclusion, liponanocapsules increase the stability of the liposomes but further studies are warranted to improve its sustainability during release.