1. Introduction 2. Therapeutics 3. Conclusion and perspectives 4. Expert opinion Review Guar gum as platform for the oral controlled release of therapeutics Tejraj M Aminabhavi † , Mallikarjuna N Nadagouda, Shrinivas D Joshi & Uttam A More S.E.T’s College of Pharmacy, Department of Pharmaceutical Engineering and Chemistry, Dharwad, India Introduction: The past decade of research has witnessed a huge advancement in research efforts on guar gum (GG)-based polymers as controlled release (CR) formulations for the delivery of therapeutics. Areas covered: The unique structure and beneficial properties of GG makes it an attractive biomaterial in CR applications. Current status on GG-based polymers has been addressed as a CR formulation in the form of microspheres, nanoparticles, hydrogels and matrix tablets for the delivery of various types of therapeutics having a wide range of physicochemical properties. Majority of literature on GG as a platform technology has dealt with oral route of drug administration as it is the most convenient, patient-compliant and preferred approach. Recent reports on GG-based polymers are summarized and critically discussed to narrate their usefulness as oral delivery systems. Expert opinion: The research on GG-based formulations has been focused on optimization of the therapy by designing CR dosage forms with a minimum number of excipients. In this context, GG-based polymers are quite attractive. The present review summarizes published reports on these systems and offers expert opinion relevant to oral delivery of therapeutics. Keywords: colon delivery, controlled release, guar gum, oral route, therapeutics Expert Opin. Drug Deliv. (2014) 11(5):753-766 1. Introduction In the past decades, drug release in a controlled manner had been the greatest challenge faced by the pharmaceutical scientists. The active drug in a formulation has to be delivered to the desired region of the body system. For more than five decades, pharmaceutical scientists have been working on optimization of the ther- apy by designing suitable delivery systems to increase bioavailability, minimize side effects and overcome solubility barriers, while controlling the duration of the drug action [1-5]. Accordingly, innumerable delivery systems have been developed by utilizing appropriate polymer--drug conjugates in dosage forms with a minimum number of excipients. In this sense, guar gum (GG), a water-soluble polysaccharide, extracted from the seeds of Cyamopsis tetragonoloba belonging to Leguminosae family, has been widely explored in drug delivery area as a platform technology [6-8]. GG, also called guaran, is a non-ionic natural polysaccharide derived from the ground endosperm of guar bean, whose chemical structure is shown in Figure 1. GG consists of a linear chain of b-D-mannopyranosyl units linked (1!4) with sin- gle member a-D-galactopyranosyl units occurring as side branches. The galacto- mannan residues, which cannot be digested by humans and animals, are well fermented by microbes in the gastrointestinal (GI) tract, which produces large amounts of short chain fatty acids [9]. Continuing research efforts in developing GG-based drug-loaded controlled release (CR) oral formulations with ensured safety, quality and efficacy to treat human diseases have lead to numerous applications. Recently, more efficient, 10.1517/17425247.2014.897326 © 2014 Informa UK, Ltd. ISSN 1742-5247, e-ISSN 1744-7593 753 All rights reserved: reproduction in whole or in part not permitted Expert Opin. Drug Deliv. Downloaded from informahealthcare.com by Nandini Loganathan on 05/15/14 For personal use only.