138 ISSN 0326-2383 KEY WORDS: Buoyancy, Drug release, Encapsulation efficiency, Gellan gum, Low molecular weight chitosan, Polyelectrolyte complex, Rifabutin. * Author to whom correspondence should be addressed. E-mail: anuragverma_iftm@yahoo.co.in Latin American Journal of Pharmacy (formerly Acta Farmacéutica Bonaerense) Lat. Am. J. Pharm. 31 (1): 138-46 (2012) Regular Article Received: January 28, 2012 Revised version: February 5, 2012 Accepted: February 8, 2012 Preparation and Characterization of Floating Gellan-Chitosan Polyelectrolyte Complex Beads Anurag VERMA * 1 , Ramesh C. NAGARWAL 3 , Suresh D. SHARMA 2 , Jayant K. PANDIT 3 1 School of Pharmaceutical Sciences, IFTM University, Moradabad, 244001, India 2 School of Sciences, IFTM University, Moradabad, 244001, India 3 Department of Pharmaceutics, Institute of Technology, Banaras Hindu University, Varanasi, India SUMMARY. The objective of the present investigation was to evaluate the potential of gellan gum- low molecular weight chitosan (GG-LMCH) polyelectrolyte complex (PEC) in the form of beads as prolonged release stomach specific floating drug delivery system. PEC beads were prepared in one step, without us- ing any chemical crosslinker, by dropwise addition of GG to a solution of LMCH in acetic acid. Buoyancy to the beads was attributed to the use of CaCO 3 . The % buoyancy, encapsulation efficiency and drug re- lease from PEC beads were compared with Ca ++ crosslinked GG floating beads prepared under same con- ditions using rifabutin as model drug. Our finding showed that the PEC beads remained buoyant for up to 8 h and showed significantly better (p < 0.05) control over drug release compared to Ca ++ crosslinked GG beads and, therefore, possess great potential for the stomach specific sustained delivery of drugs like ri- fabutin for the treatment of Helicobacter pylori infection. INTRODUCTION During the last 25 years GG beads has been extensively experimented for oral sustained/ controlled/ stomach specific delivery of drugs 1-7 . However, these beads often show poor drug en- capsulation efficiency and/or rapid drug release in acidic medium 2,4,6 . A number of efforts have been made by various workers in past to over- come these disadvantages by employing various modifications such as replacing Ca ++ with other divalent or trivalent cations, changing the pH of gelation medium, modification of physical prop- erties of gellan gum including use of chemical crosslinker 7 , but these modifications often leads to the systems which are difficult to reproduce or scale up or not acceptable for human use due to presence of traces of chemical crosslink- er. In an effort to search techniques to over- come the demerits of GG beads, we did exten- sive experimentation in our laboratory and ex- plored the potential of PECs of GG with LMCH in the form of beads for drug delivery applica- tions. Briefly, PECs are association complexes formed between oppositely charged polymers due to electrostatic interactions, although other space oriented inter macromolecular interac- tions, such as hydrogen bonding and non-ori- ented ones, such as hydrophobic and/or charge- transfer and/or van der Waals interactions, can also play a critical role 8-11 . Their (PECs) forma- tion avoids the use of toxic chemical crosslink- ers, thereby preventing the possible toxicity and other undesirable effects of crosslinking agents. Further, the PECs formed between a poly acid and poly base are little affected by pH variation of the dissolution medium. It is also reported that, the PECs so formed exhibit a very high de- gree of ordering and crystal like properties, and have quite compact structures 12 . Keeping this in view, it is expected that, if these complexes in