Journal of Pharmaceutical Care & Health Systems
Open Access

Novel cholesterol based siRNA lipoplexes with and without PEG-modification: Characterization and in vitro cytotoxicity studies

4^th African Pharma Congress

June 20-21, 2016 Cape Town, South Africa

Saffiya Habib, Mario Ariatti and Moganavelli Singh

University of KwaZulu-Natal, South Africa

Posters & Accepted Abstracts: J Pharma Care Health Sys

Abstract :

Cationic liposomes have potential in carrying small interfering RNA (siRNA) molecules as gene medicines. However, unfavorable liposome-serum interactions often limit their efficacy. In order to address this concern, liposome-stabilizing agents, cholesterol (Chol) and polyethylene glycol (PEG) were incorporated in the design of new liposome-siRNA systems. The helper lipid, Chol, was combined in equimolar quantities with the cytofectin, N,N-dimethylaminopropylamidosuccinylc holesterylformylhydrazide (MS09), to give unilamellar vesicles. For PEG-modification, distearoylphosphatidylethanolamine poly(ethylene glycol) 2000 was added at 2 mol %. Electrostatic association of liposomes with siRNA was followed in band shift and fluorescence quenching assays. Liposome-siRNA complexes (lipoplexes) were observed as globular aggregates by cryotransmission electron microscopy. Characterization of lipoplexes by Zeta-potential Nanoparticle Tracking Analysis (Z-NTA) showed that lipoplex size and zeta potential were dependent on both liposome composition and the MS09: siRNA (w/w) mixing ratio. siRNA within lipoplexes resisted serum-induced damage at MS09:siRNA (w/w) ratios of 12:1-32:1. The effects of lipoplexes on cell growth were evaluated with a non-targeting siRNA sequence in transformed and non-transformed human cell lines. MTT and alamarBlue�® assays showed that MCF-7 and HEK293 cells retained at least 78% viability at final siRNA and lipid concentrations of 57 nM and 29-60 �¼M, respectively. In general, cell survival profiles of MS09/Chol and MS09/ Chol/PEG liposomes compared favorably with that of Lipofectamineâ�¢ 3000 and control formulations which contained the conventional helper lipid, dioleoylphosphatidylethanolamine (DOPE). At present, the siRNA delivery capability of liposomes is under assessment and the most promising formulations will be applied to the delivery of oncogene-specific siRNA in gene silencing experiments.

Biography :

Email: saffiya.habib@gmail.com