194 Current Drug Delivery, 2011, 8, 194-202 1567-2018/11 $58.00+.00 © 2011 Bentham Science Publishers Ltd. Paclitaxel Loaded Nanosponges: In-Vitro Characterization and Cytotoxic- ity Study on MCF-7 Cell Line Culture Khalid A. Ansari 1,3 , Satyen J. Torne 1 , Pradeep R. Vavia 1,* , Francesco Trotta 2 and Roberta Cavalli 3 1 Centre for Novel Drug Delivery System, Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology Mumbai, India; 2 Dip. Di Chemica IFM, Università di Torino, via P. Giuria 7, 10125 Torino, Italy; 3 Dip. di Scienza e Tecnologia del Farmaco ,Università di Torino, via P. Giuria 9, 10125, Torino, Italy Abstract: Beta cyclodextrin (-CD) based nanosponges were synthesized and paclitaxel inclusion complex with nano- sponges were prepared using techniques of inclusion complex formation. The paclitaxel nanosponge’s complexes were evaluated for their release. The nanosponges complexes were also evaluated using DSC, FTIR, and NMR techniques for confirmation of inclusion complex formation between paclitaxel and nanosponges. Particle size and morphology of pacli- taxel nanosponge’s complex were estimated using SEM, TEM and dynamic light scattering techniques. The particle sizes were found out to be in range of 400 to 600 nm. Cytotoxic efficacy of paclitaxel nanosponge complex was determined against MCF-7 cells and paclitaxel nanosponge’s complex was found to be cytotoxic and more effective against this cell line. Keywords: Nanosponges, paclitaxel, cyclodextrin, complexation, cytotoxicity. INTRODUCTION Paclitaxel is a natural chemotherapeutic agent, effective against several types of cancers, such as ovarian and breast cancer. It works by stabilizing cellular microtubules through polymerization [1, 2]. The drug has very limited aqueous solubility and is currently formulated in the commercial product (Taxol, Bristol-Myers Squibb, New York, NY, USA) as a nonaqueous concentrate containing 6 mg/mL pa- clitaxel in 1:1 v/v mixture of Cremophor EL (BASF, Mount Olive, NJ, USA) and ethanol. Before intravenous administra- tion, Taxol ® must be diluted 5 to 20 fold in normal saline or 5% dextrose solution. Despite the dilution, the amount of Cremophor EL necessary to deliver the required doses of paclitaxel is significantly higher than that administered with any other marketed pharmaceutical injectable drugs and causes serious or fatal hypersensitivity episodes in humans [3]. Once diluted, the formulation only has limited physical stability because drug particles tend to precipitate out over 12-24 h [1, 2]. An in-line filter is typically used for the infu- sion line to remove any precipitated particulates [1, 4]. Cre- mophor EL is a mixture of hydrogenated castor oils that can cause severe anaphylactic reactions in patients [1, 4]. To avoid these side effects, a pretreatment of corticosteroids and an antihistamine is required before the administration of Taxol. Over the past few decades, there has been consider- able effort in the development of non-Cremophor EL formu- lations for paclitaxel using traditional approaches, such as the use of co-solvents, cyclodextrins, liposomes and oil-in- *Address correspondence to this author at the Department of Pharmaceuti- cal Sciences and Technology, Centre of Drug Delivery Systems, Institute of Chemical Technology, University of Mumbai, Matunga, Mumbai-400019, India; Tel : +912224145616; Fax: +912224145614; E-mail: vaviapradeep@yahoo.com water emulsions [5]. The main challenge in all of these ap- proaches is the difficulty of maintaining paclitaxel in solu- tion after diluting the concentrate into intravenous infusion fluids for at least 24 h and preferably 48 h. The poor aqueous solubility of hydrophobic drugs is a challenging formulation problem, particularly for intravenous delivery [6]. It is esti- mated that 40% of new chemical entities have poor aqueous solubility [7]. Poor aqueous solubility is, in particular, a common property of compounds identified using combinato- rial chemistry and high-throughput screening [7]. Thus, cre- ating intravenous formulations of such compounds is of sig- nificant value. In the present work we have used a novel excipient which is essentially a polymeric derivative of -CD we have devel- oped earlier [8-10]. The polymeric derivative of -CD more commonly called ‘Nanosponge’ takes its name by its prop- erty of forming sponge like structure when lyophilized and high capacity to entrap small molecules in its matrix. The nanosponge is highly capable of rapidly forming suspension when dispersed in water thereby forming a matrix like struc- ture in aqueous media and allowing a free transfer of en- trapped drug molecules earlier [8-12]. The formulation discussed in this paper is a paclitaxel nanosponge’s lyophilized complex for reconstitution in a similar way as that of Taxol. The present formulation was developed with the aim of creating Ethanol and Cremophor EL free formulation, which can be used for IV administra- tion without any difficulties of sedimentation during admini- stration. MATERIALS Paclitaxel was a generous gift of Indena (Milan, Italy). - CD was a kind gift from Wacker Chemie Germany. Saline (0.9% NaCl injectable solution) was obtained from Choong-