International Journal of Biological Macromolecules 72 (2015) 1020–1026 Contents lists available at ScienceDirect International Journal of Biological Macromolecules j ourna l ho me pa g e: www.elsevier.com/locate/ijbiomac Characterization and evaluation of smart starch from Kyllinga nemoralis N. Paramakrishnan, S. Jha, K. Jayaram Kumar ∗ Department of Pharmaceutical Sciences & Technology, Birla Institute of Technology, Mesra, Ranchi 835215, Jharkhand, India a r t i c l e i n f o Article history: Received 14 August 2014 Received in revised form 10 September 2014 Accepted 26 September 2014 Available online 22 October 2014 Keywords: Smart starch Kyllinga nemoralis Thermogravimetric analysis In vitro release a b s t r a c t Starch from Kyllinga nemoralis (KNSS) rhizomes was investigated for its morphological, chemical and func- tional properties in order to utilize its potential as a pharmaceutical adjuvant. Rhizomes of K. nemoralis yielded an appreciable amount of starch that is 19.77% (w/w). Amylose content was measured as of 28.66%. The shapes of starch granules were mostly round, disc like, flat and the size varied from 3.93 to 9.45 m. Further polysaccharide nature of KNSS was confirmed by FTIR spectra. The solubility and swelling power was found to be increased with the increase in the temperature. Micromeritic properties of the isolated starch showed unique feasibility of KNSS being used as a pharmaceutical excipient. The TGA data revealed that KNSS is thermally stable with less bound water. In vitro release study confirmed that KNSS in pH 6.8 slows down the release of the drug smartly compared to pH 1.2, due its ability to respond to the external pH-stimuli. Release profile proved that KNSS could find an application as a smart polymer for its stimuli-responsive and bio-related applications such as drug delivery. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Explosive growth in the era of biopolymer from last two or three decades revealed the emerging of polymers with special properties. These polymers coined the term “Smart polymers” or “intelligent polymers” [1]. The property which makes them smart is the capabil- ity to respond the changing environment or external stimuli. This transition may be due to change in the temperature, pH, shape, surface characteristics, solubility, etc. Smart polymers offer a drug delivery platform that can be employed to deliver the pharmaceu- tical active ingredients at a controlled rate and in a stable form [2]. Out of the smart polymers; starches could provide a good scope in this regard. The variety of stimuli to which the starch can respond makes them particularly attractive as components of drug delivery systems as these are conceived to release the drug according to a pre-established pattern, smart or intelligent manner and specifically releases the drug according to certain physiologi- cal events [3]. The expanding market of starch ranked it as a vital biopolymer among all others for various industrial purposes. With wide applications in pharmaceutical and food industries, it plays the prominent role in formulation developments [4]. An ample amount of starches extracted from maize, potato, wheat, etc. for the ∗ Corresponding author. Tel.: +91 06512276247; fax: +91 06512275290. E-mail address: jayarampharm@gmail.com (K. Jayaram Kumar). aforementioned purposes. An extended effort is still needed to dis- cover alternative sources of starch for industrial uses [5]. In view of the prime advantage in terms of safety, there is demand for natural polysaccharide in the pharmaceutical sector. Among underutilized plants that could be an alternative source of starch is ‘sedge’ belonging to the family Cyperaceae. Plants of the Cyperaceae family grow naturally in tropical, subtropical, and temperate regions. This is one of the earliest known and most important edible herbs, and has been reported to exhibit wide spectrum activity in biological systems, including antioxidant and anti-inflammatory effects [6–8]. Research on Cyperaceae sedge like Cyperus esculentus, Cyperus rotundus showed that starch could be isolated from these tubers [9,10]. Kyllinga nemoralis is one of the Cyperus sedge, which has not been studied yet for its starch. So, keeping all the points under consideration, we shall study extrac- tion of the smart starch from K. nemoralis rhizomes to establish its suitability as pharmaceutical adjuvant. 2. Materials and methods 2.1. Raw materials The plant species K. nemoralis (KN) and its rhizomes were collected from Kerala, India and were authenticated (Sheet No. CNH/56/2013/Tech.II/22, specimen No. C-05) by Dr. V.P. Prasad, Botanical Survey of India, Kolkata, West Bengal, India. http://dx.doi.org/10.1016/j.ijbiomac.2014.09.065 0141-8130/© 2014 Elsevier B.V. All rights reserved.