Bera H.,AIMST University |
Sarkar S.,Dr. Reddys Laboratory Ltd
Materials Science and Engineering C | Year: 2016
Novel alginate-fenugreek gum (FG) gel membrane coated hydroxypropylmethylcellulose (HPMC) based matrix tablets were developed for intragastric quetiapine fumarate (QF) delivery by combining floating and swelling mechanisms. The effects of polymer blend ratios [HPMC K4M:HPMC E15] and citric acid contents on time taken for 50% drug release (t50%, min) and drug release at 8 h (Q8 h, %) were studied to optimize the core tablets by 32 factorial design. The optimized tablets (F-O) exhibited t50% of 247.67 ± 3.51 min and Q8 h of 71.11 ± 0.32% with minimum errors in prediction. The optimized tablets were coated with Ca+ 2 ions crosslinked alginate-FG gel membrane by diffusion-controlled interfacial complexation technique. The biopolymeric-coated optimized matrices exhibited superior buoyancy, preferred swelling characteristics and slower drug release rate. The drug release profiles of the QF-loaded uncoated and coated optimized matrices were best fitted in Korsmeyer-Peppas model with anomalous diffusion driven mechanism. The uncoated and coated tablets containing QF were also characterized for drug-excipients compatibility, thermal behaviour and surface morphology by FTIR, DSC and SEM analyses, respectively. Thus, the newly developed alginate-FG gel membrane coated HPMC matrices are appropriate for intragastric delivery of QF over a prolonged period of time with greater therapeutic benefits. © 2016 Elsevier B.V. All rights reserved.
Prasad A.S.,Dr. Reddys Laboratory Ltd |
Prasad A.S.,Jawaharlal Nehru University |
Satyanarayana B.,Dr. Reddys Laboratory Ltd
Asian Journal of Chemistry | Year: 2012
An efficient method is described for the direct amination of alcohols with sulfonamides using magnetically separable Pd/Fe 3O 4 as a catalyst without using any additives. Various alcohols such as benzylic alcohol and allylic alcohol underwent sulfamidation with sulfonamides gave the corresponding products in good to excellent yields. This effective catalyst requires no preactivation of the hydroxy group of alcohols and the reaction is environmentally benign with water as a by-product. The catalyst is completely recoverable with the simple application of an external magnetic field and the efficiency of the catalyst remains unaltered even after five cycles.