Recent advances in hydrogel based drug delivery systems for the human body Arti Vashist, a Atul Vashist, b Y. K. Gupta c and Sharif Ahmad * a The upsurge in the need of targeted controlled drug delivery (TCDD) has led to the invention of remarkable biomaterials with improved biocompatibility and biodegradability. In recent years, “Smart Polymers” have emerged as a potential candidate, competing with the existing hydrogel systems used for controlled drug delivery. This article is an effort to highlight the diverse applications of hydrogels for revolutionizing the present research on drug delivery systems. This article summarizes the role of hydrogels as delivery vehicles for drugs used in various disorders related to the brain and other distinct parts of the human body. The clinical application and toxicological aspects of hydrogels are also highlighted. Their potential for diagnostics and various therapeutic interventions against tuberculosis have been reviewed. In addition, the limitations and future prospectives in the development of biopolymeric hydrogels are discussed. 1. Introduction During the past few decades, hydrogels have been in use for biomedical applications such as drug delivery systems, 1 in situ gels, 2 and tissue scaffolds. 3 Hydrogels have a unique three dimensional cross linked network of natural polymers, which have the ability to imbibe large amounts of water. 4 As an intriguing material, hydrogels are smart, environmentally sensitive and compatible with biological systems, and can be made degradable and responsive to various stimuli. 5–7 Hydro- gels are designed to exhibit a signicant volume change in response to small changes in their environmental factors, such as pH, ionic strength, temperature, electric eld, solvent or magnetic eld. 8–12 Depending on the type of bonds formed during the fabrication process hydrogels may be classied as physical or chemical hydrogels. Physical hydrogels are formed due to the weak forces involved in the formation of molecular entanglements and secondary forces, including ionic and H- bonding. They are reversible in nature due to the presence of Arti Vashist, Senior Research Fellow, CSIR, New Delhi, India at the Dept of Chemistry, Jamia Millia Islamia, New Delhi, India. She joined the Materials Research Laboratory at Jamia as a PhD student in Chemistry in 2009 under the supervision of Prof. Sharif Ahmad and co- supervision of Prof. Y. K. Gupta. Her research interests focus on biodegradable polymers and biopolymeric hydrogels for drug delivery systems. Atul Vashist, Senior Research Fellow, ICMR at the Department of Biotechnology, All India Institute of Medical Sciences is pursuing a PhD in Biotechnology from the National JALMA Insti- tute of Leprosy and Other Mycobacterial Diseases affili- ated to Dr B. R. Ambedkar University, Agra under the supervision of Dr U. D. Gupta and co-supervision of Prof. J. S. Tyagi. He is presently working on the DevR-DevS two component signal transduction system involved in the dormancy of Mycobacterium tuberculosis (M.tb). DevR has also been suggested as a potential drug target against dormant M.tb. a Materials Research Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi, India. E-mail: sharifahmad_jmi@yahoo.co.in; arti_vashist_19@yahoo.com; Fax: +91 11 26840229; Tel: +91 11 26827508; +91 9711401540 b Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India. E-mail: atulvashist1980@gmail.com; Tel: +91 9310286188 c Department of Pharmacology, All India Institute of Medical Sciences, India. E-mail: yk. ykgupta@gmail.com; Tel: +91 11 26593282 Cite this: J. Mater. Chem. B, 2014, 2, 147 Received 23rd July 2013 Accepted 3rd October 2013 DOI: 10.1039/c3tb21016b www.rsc.org/MaterialsB This journal is © The Royal Society of Chemistry 2014 J. Mater. Chem. B, 2014, 2, 147–166 | 147 Journal of Materials Chemistry B FEATURE ARTICLE Published on 03 October 2013. Downloaded by Jamia Millia Islamia University on 03/03/2014 04:44:59. View Article Online View Journal | View Issue