Abstract 5531: Preparation and cellular delivery of doxorubicin nanoemulsion for cancer therapy

Abstract

Abstract Purpose: The aim of this study is to formulate a novel nanoemulsion of doxorubicin to enhance the therapeutic efficacy of the drug. Method: Four different multiple emulsions (W1/O/W2) were prepared (A, B, C, and D) by homogenization of a mixture of aqueous and oil phases. The resultant primary emulsions were later pass through a high pressure homogenization to further reduce the globules size to nanometer range. The formulation A is a control nanoemulsion, consisted of only deionized water as W1 phase. The W1 phase of the other three formulations (B, C, and D) consisted of aqueous solution of BSA (as an emulsion stabilizer), doxorubicin, and a mixture of BSA and doxorubicin, respectively. For all four formulations, the oil phase (O) consisted of a 2:1 mixture of soyabean oil and Span 80, and the outer aqueous phase (W2) consisted of prolaxamer P-85 and Vitamin E TPGS. The nanoemulsions were evaluated for stability, polydispersity index, size, and viscosity. Anticancer efficacy of these formulations was evaluated by Alamar Blue Assay and Colony Forming Assay using MCF-7 cells as a model malignant breast cancer cell line. Results: The stability of nanoemulsions was found to be significantly better for the formulations containing BSA. Presence of BSA or doxorubicin resulted in a significant increase in viscosity from 2.09 to 10.6 cP. Cell culture studies showed that doxorubicin nanoemulsions had higher localization in cytoplasm as compared to the nucleus. In regard to cellular uptake (intracellular quantification of doxorubicin), the following results were obtained at 2h, 24h, 48h, and 120h post-incubation, respectively: 42%, 30%, 37%, and 22% with doxorubicin solution; 12%, 19%, 21%, 33% with formulation C; and 0.25%, 6%, 10%, 19% with formulation D. The results of Alamar Blue Assay showed IC50 values of 0.97μM (solution), 1.62μM (formulation C) and 1.91μM (formulation D). The results of Colony Forming Assay (12days-post-treatment with equivalent to 0.86 μM doxorubicin) showed 74% (solution), 86% (formulation C) and 92.6% (formulation D) growth inhibitions. Conclusions: The presence of BSA within the aqueous phase enhances the stability of nanoemulsions. In comparison to doxorubicin solution, the nanoemulsions produce higher anticancer efficacy. This exploratory study will be followed by more detailed studies to confirm this preliminary finding. Acknowledgements: This work was funded in part by the NASA grant # NCC3-946-S4, Louisiana Board of Regents RC/EEP (2007-10), NIH grant# 5P20CA118768-02, and Louisiana Cancer Research Consortium. We are thankful to Dr. Thomas Wiese of the College of Pharmacy, XULA, for providing the Cell culture lab facilities. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5531.