A new intragastric delivery system for the treatment of Helicobacter pylori associated gastric ulcer: in vitro evaluation

A new strategy is proposed for the triple drug treatment (tetracycline, met ronidazole and bismuth salt) of Helicobacter pylori associated peptic ulcer s. The design of the delivery system was based on the swellable asymmetric triple layer tablet approach, with floating feature in order to prolong the gastric retention time of the delivery system. Hydroxypropylmethyl-cellulo se and poly(ethylene oxide) were the major rate-controlling polymeric excip ients. Tetracycline and metronidazole were incorporated into the core layer of the triple-layer matrix for controlled delivery, while bismuth salt cou ld be included in one of the outer layers for instant release. The concentr ation of tetracycline and metronidazole released over time was determined s imultaneously on a gradient high-performance liquid chromatography system. Results demonstrated that sustained delivery of tetracycline and metronidaz ole over 6-8 h can be easily achieved while the tablet remained afloat. The floating aspect was envisaged to extend the gastric retention time of the designed system to maintain effective localized concentration of tetracycli ne and metronidazole. Additionally, the developed HPLC method for the concu rrent determination of tetracycline and metronidazole was proved to be rapi d and accurate. The developed delivery system has potential to increase the efficacy of the therapy and improve patient compliance. (C) 1999 Elsevier Science B.V. All rights reserved.