An Engineered Specificity Of Tamoxifen Loaded Stealth Liposomes Design And Characterization

Abstract

The present study deals with the formulation and in-vitro characterization of tamoxifen loaded stealth liposomes and was carried out to evaluate and compare the tissue distribution profile of tamoxifen citrate, when administered intravenously as a non-formulated tamoxifen citrate or when encapsulated into stealth liposomes with an average diameter of 479 nm. Passive targeting by stealth liposomes, once combined with efficient intracellular delivery, may be a very useful strategy to improve the antitumor efficacy for the anticancer agents. Stealth liposomes were prepared by using cholesterol, DMPC, DSPC and polyethylene glycol 4000 (PEG-4000) in order to achieve prolonged circulation time and sustained release. The prepared liposomes were evaluated for size, shape, profile, degree of drug entrapment, and in-vitro release efficiency. The effect of various formulation and drug release was investigated. In-vivo tissue distribution study was carried out in Sprague-Dawley rats having mammary tumor induced by chemical carcinogen DMBA (7, 12-dimethylbenz(a)anthracene). Natural ability of liposomes to target cancer cells (tumor) due to EPR effect and PEG coating of stealth liposomes which is inert in the body, allows longer circulatory life for the drug delivery mechanism resulting in enhanced accumulation of tamoxifen citrate in tumor site. After intravenous administration, the primary site of accumulation for the tamoxifen loaded stealth liposomes was a tumor accounting up to 36% after 6 h post injection compared to 6% observed with non-formulated tamoxifen citrate. The results indicate that, tamoxifen loaded stealth liposomes may present a promising delivery system to achieve preferential tumor-targeting newline