J. Biomedical Science and Engineering, 2011, 4, 352-356 doi:10.4236/jbise.2011.45044 Published Online May 2011 (http://www.SciRP.org/journal/jbise/ JBiSE ). Published Online May 2011 in SciRes. http://www.scirp.org/journal/JBiSE Enhanced stability of nano-emulsified paclitaxel Ju Young Lee 1a , Da Yeon Kim 1a , Gyeong Hae Kim 1 , Kkot Nim Kang 1 , Byoung Hyun Min 1 , Bong Lee 2 , Jae Ho Kim 1 , Moon Suk Kim 1 1 Department of Molecular Science and Technology, Ajou University, Suwon, Korea; 2 Department of Polymer Engineering, Pukyong National University, Busan, Korea. Email: moonskim@ajou.ac.kr Received 9 February 2011; revised 28 March 2011; accepted 4 April 2011. ABSTRACT The main goal of this work was to develop an optimal self-microemulsifying paclitaxel prepared with PLGA and solubilizer such as tetraglycol, Cremophor ELP, and Labrasol. The prepared PTx-loaded SMES showed the size of the range of 80-130 nm by dynamic light scattering and a spherical shape by atomic force mi- croscopy. In experiment of storage stability in deion- ized water (DW) or blood condition, PTx-loaded SMES showed good stability in DW and comparable stability in blood condition at 37˚C for 7 days. In ad- dition, PTx-loaded SMES showed a significant in- hibitory effect on B16F10 melanoma proliferation. In conclusion, we confirmed that the formulations tried in this study could be used as administration form for animal trials of PTx. Keywords: Self-Microemulsifying; Paclitaxel; Stability; Anti-Tumor Activity 1. INTRODUCTION Paclitaxel (PTx), a major anticancer drug isolated from the bark of Taxus brevifolia, has significant activity in clinical trials against a variety of tumors such as breast cancer, advanced ovarian carcinoma, lung cancer, head and neck carcinoma [1,2]. PTx is a hydrophobic drug with poor aqueous solubility. To enhance its solubility and allow parenteral administration, PTx is currently formulated with solution of Cremophor® EL and ethanol as dosage-form of PTx (Taxol®) for clinical application [3,4]. Recently, numerous investigations have been focused on the development of various PTx delivery systems such as liposomes, emulsions, micelles, microspheres, and polymeric nanoparticles [5-9]. Among these, self- microemulsifying systems (SMES) may be a promising way to load PTx in delivery system because it provides high concentration of PTx in the aqueous media system [10,11]. SMES are isotropic mixtures of oil, a surfactant, and possibly one or more hydrophilic solvents or cosur- factants, which form fine oil-in-water emulsions when exposed to aqueous media under condition of gentle agitation [12]. At present, many studies have highlighted the devel- opment of PTx-loaded SMES with optimal condition for blood circulation in effective concentration [13]. How- ever, the major obstacle that limits the use of SMES is due to the physical and/or to the chemical instability by absorption of biological compounds such as protein dur- ing drug circulation time in blood after intravenous ad- ministration [14]. To improve stability of SMES, various formulations of SMES is needed that can extend PTx circulation time in blood. Our understanding is that the formulations of SMES could examine under the blood condition. Thus, the aim of this study was to examine various formula- tions of PTx-loaded SMES to increase systemic clear- ance through extending of the circulation time of PTx. 2. MATERIALS AND METHODS 2.1. Materials Poly(d,l-lactide-co-glycolide) (PLGA, molecular weight, 8000, 20,000 and 90,000 g/mole) were purchased from Boerhinger Ingelheim (Ingelheim, Germany). Paclitaxel was purchased from Samyang Genex Co. (Seoul, Korea). Caprylocaproyl macrogol-8 glyceride (Labrasol®) was obtained from Gattefosse (Westwood, NJ, USA). Cre- mophor ELP was purchased from BASF (Germany). Tetraglycol was purchased from Sigma Chemical Co. (St. Louis, MO, USA). All other chemicals were of reagent grade. Deionized water (DW) was prepared by a Milli-Q purification system from Millipore (Molsheim, France). 2.2. Preparation of PTx-Loaded SMES A series of SMES was prepared in each of the various formulas with various ratios of PLGA, paclitaxel, solu- a Ju Young Lee and Da Yeon Kim are equal first authors in this work.