Improvement of curcumin solubility by polyethylene glycol/chitosan-gelatin nanoparticles (CUR-PEG/CS-G-nps). Poopak Farnia 1,2 , Saeed Mollaei 3 , Afshin Bahrami 1 , Alireza Ghassempour 4 , Ali Akbar Velayati 1 , Jalaledin Ghanavi 1,2* 1 Mycobacteriology Research Center, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran 2 Experimental Medicine and Tissue Engineering Center, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran 3 Department of Chemistry, Faculty of Science, Azarbaijan Shahid Madani University, Tabriz, Iran 4 Department of Phytochemistry, Medicinal Plant and Drug Research Institute, Shahid Beheshti University, G. C., Evin, Tehran, Iran Abstract Curcumin (CUR), a yellow polyphenol compound is reportedly associated with a diverse therapeutic potential. Despite all curative properties of CUR, its usage in oral administration is restricted due to low bioavailability, low aqueous solubility and poor absorption rate. The aim of this study was to develop a nontoxic nanocurcumin (CUR-NPs) with enhanced bioavailability. For this reason, the CUR was first capped by polyethylene glycol (PEG) and then encapsulated into chitosan-gelatin nanoparticles (CS-G NPs). The PEG act as a co-solvent and CS-G act as a drug carrier biodegradable polymer. The efficiency and solubility of nanocurcumin were determined by transmission electron microscopy (TEM), fourier transformed infrared spectroscopy (FT-IR), dynamic light scattering (DLS) and high liquid chromatography (HPLC). Under TEM, the nanocurcumin were spherical in shape with average size of 300-400 nm. Zeta potential was 43.23 mV with 69.29% entrapment at 17.11% loading capacity. The solubility rate increased up to 2000 fold. The in-vitro drug release profile at PH 3.4 and PH 7.2 indicated a slow and controlled release at a constant rate. The release-rate is affected by size and loading capacity of NPs. In summary, the bioavailability of CUR-NPs was improved. Additionally, our procedure represents a mild and safety process for synthesizing efficient CUR-NPs, as we have not use any organic or toxic solvents. Keywords: Chitosan, Curcumin, Gelatin, Nanoparticle, Slow release, Polyethylene glycol. Accepted on February 22, 2016 Introduction Curcumin (CUR), a bioactive component of turmeric (Curcuma longa L.) can interact with multiple targets to prevent diseases progression safely and inexpensively. They exhibit a wide range of pharmacological activities such as anti- inflammatory [1], anti-carcinogenic [2], anti-diabetic [3], antifungal and antiviral properties [4]. CUR is very effective against cancer cells like breast, prostate, head and neck cancers [5-7]. Although CUR reported to have many medicinal qualities, but due to poor aqueous solubility and poor bioavailability, its clinical application has been restricted [8-10]. To overcome the CUR limitations, researchers proposed the use of co solvency and nano drug carrier, which may represent the most practical approaches for improving the solubility of CUR in pharmaceutical liquid formulations [11-15]. Generally, co solvents are the mixtures of miscible solvents that enhance the solubility of nonpolar solutes [12]. Among studied solvents that used as a co-solvent mixture, the polyethylene glycol (PEG), and propylene glycol (PG) gained more scientific attention. The polyethylene glycol (PEG) is a biocompatible, biodegradable, hygroscopic, stable, non-toxic and water-soluble liquid with bacteriostatic and fungistatic properties. Because of very low toxicity of PEG, it is an ideal medium for the topical delivery of many oral and parenteral drugs in animals and humans, as well as the formulations of fragrances, cosmetics and personal care products [13]. In recent years, nanotechnology-based drug delivery systems have aimed to transfer the drugs directly into target cells with more systematic and release control profile [14,15]. In this regards, many studies underline the importance of using chitosan (CS) and gelatin (G) as a nanodrugs carriers. Chitosan (CS) is a ISSN 0970-938X www.biomedres.info Biomed Res- India 2016 Volume 27 Issue 3 659 Biomedical Research 2016; 27 (3): 659-665