Studies of bioactivity of proteins encapsulated in liposomes

One of the leading causes for blindness in the developed world is Age-related macular degeneration (AMD). The eye has a unique structure with barriers which pose challenges for drug delivery, especially to the posterior segment of the eye. As such, drug delivery systems such as liposomes have recently been investigated. The main objective of this study was to study and understand the loading and release of Avastin from liposomes in vitro. In addition, the characterization of liposomes and proteins were also carried out. Negatively charged liposomes 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) and cholesterol in 60:20:20 wt%. Liposome samples were characterized prior to the start of the drug release study and standard calibration curves for the determination of unknown concentrations of the samples were also plotted. It was found that Triton X-100, which breaks the lipid bilayer, had an effect on the quantification of proteins. From storage stability studies, Avastin was found to be stable at temperatures 4 oC and 37 oC in BSA coated tubes. In the drug release studies, Avastin was loaded into the fabricated liposomes by passive loading. Different sized liposome samples were being investigated. The drug release rate of the smaller sized liposome sample was found to be slower than the larger sized liposome sample. In addition, the measurement of active proteins in the drug release samples was carried out. However, the amount of active proteins as compared to the total amount of proteins in the sample was significantly low. In conclusion, liposomes of smaller size seemed to have better sustained release but further studies should be conducted to improve its sustained drug release.Bachelor of Engineering (Materials Engineering