Investigation on the stability of saquinavir loaded liposomes: Implication on stealth, release characteristics and cytotoxicity

Although anti-retroviral therapy is the most efficient disease management strategy for HIV-AIDS, its applications are limited by several factors including the low bioavailability and first pass metabolism of the drugs. Nanocarriers such as liposomes have been developed to circumvent some of these problems. We report here preparation of novel liposome formulations for efficient delivery of anti-retroviral drugs to mammalian cells in culture. The liposomes were prepared and surface was modified using poly (ethylene glycol). Encapsulation efficiency of the anti-retroviral drug saquinavir was found to be approximately 33% and also exhibited sustained release of the drug. Although PEGylated liposomes were more stable in protein-supplemented media, had better colloidal stability and exhibited lesser sonochemical stability due to lower cavitation threshold. The cell viability studies using Jurkat T-cells revealed that the PEGylated liposomes loaded with saquinavir were less cytotoxic as compared to the non-PEGylated liposomes or free drug confirming the potential of the liposomes as a sustained drug-release system. The drug delivery potential of the liposomes loaded with Alexa flour 647 was evaluated using Jurkat T-cells and flow cytometry showing uptake upto 74%. Collectively, our data demonstrate efficient targeting of mammalian cells using novel liposome formulations with insignificant levels of cytotoxicity. (C) 2012 Elsevier B.V. All rights reserved.