Modification of chitosan by using samarium for potential use in drug delivery system Eny Kusrini a,⇑ , Rita Arbianti a , Nofrijon Sofyan b , Mohd Aidil A. Abdullah c , Fika Andriani a a Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus Baru UI, 16424 Depok, Indonesia b Department of Metallurgical and Materials Engineering, Faculty of Engineering, Universitas Indonesia, Kampus Baru UI, 16424 Depok, Indonesia c Department of Chemical Sciences, Faculty of Science and Technology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu Darul Iman, Malaysia highlights  Chitosan–Sm complexes were synthesized by the impregnation method.  Chitosan combined with Sm 3+ ions produced a drug carrier material with fluorescence properties.  The addition of Sm 3+ ions into chitosan affects its physical and chemical properties.  The Sm 3+ ion is used as an indicator of drug release with ibuprofen as a model drug.  Chitosan–Sm 25 wt.% showed the highest efficiency of ibuprofen adsorption (33.04%). graphical abstract article info Article history: Received 15 November 2012 Received in revised form 16 September 2013 Accepted 29 September 2013 Available online 7 October 2013 Keywords: Chitosan Drug delivery Ibuprofen Fluorescence Samarium abstract In the presence of hydroxyl and amine groups, chitosan is highly reactive; therefore, it could be used as a carrier in drug delivery. For this study, chitosan–Sm complexes with different concentrations of samar- ium from 2.5 to 25 wt.% have been successfully synthesized by the impregnation method. Chitosan com- bined with Sm 3+ ions produced a drug carrier material with fluorescence properties; thus, it could also be used as an indicator of drug release with ibuprofen (IBU) as a model drug. We evaluated the spectroscopic and interaction properties of chitosan and Sm 3+ ions, the interaction of chitosan–Sm matrices with IBU as a model drug, and the effect of Sm 3+ ions addition on the chitosan ability to adsorb the drug. The result showed that the hypersensitive fluorescence intensity of chitosan–Sm (2.5 wt.%) is higher than the oth- ers, even though the adsorption efficiency of chitosan–Sm 2.5 wt.% is lower (29.75%) than that of chito- san–Sm 25 wt.% (33.04%). Chitosan–Sm 25 wt.% showed the highest efficiency of adsorption of ibuprofen (33.04%). In the release process of ibuprofen from the chitosan–Sm–IBU matrix, the intensity of orange fluorescent properties in the hypersensitive peak of 4 G 5/2 ? 6 H 7/2 transition at 590 nm was observed. Fluorescent intensity increased with the cumulative amount of IBU released; therefore, the release of IBU from the Sm-modified chitosan complex can be monitored by the changes in fluorescent intensity. Ó 2013 Elsevier B.V. All rights reserved. Introduction Indonesia produces large amount of biological wastes, including shrimp waste, crab shells, and ox bones. Shrimp waste is promising material having a high sales value because it contains protein, carotenoids, and chitin [1]. Chitin compounds in biological waste are part of a class of polysaccharides that can be converted to chitosan by deacetylation. Chitosan shows excellent potential as a biomaterial because of its biocompatibility in the mammalian body; it is a polymer biomaterial that is biodegradable and non- toxic to mammalian cells [2]. Due to these properties, therefore, 1386-1425/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.saa.2013.09.132 ⇑ Corresponding author. Tel.: +62 21 7863516x6207; fax: +62 21 7863515. E-mail address: ekusrini@che.ui.ac.id (E. Kusrini). Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 120 (2014) 77–83 Contents lists available at ScienceDirect Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa