Alaa A. Abdulrasool

The aim of this study is to prepare gastroretentive dosage form based on the super porous hydrogel (SPH) composites using metronidazole as a model drug for eradication of H pylori.Blowing technique was used to prepare SPH composites. The latter was used as a body for the drug delivery system. The core was made from matrix granules. Four types of retardants (Beeswax, carnauba wax, ethylcellulose, and Eudragit®RS) were used to prepare the granules by fusion for waxes and wet granulation methods for other polymers. For each retardants, two ratios (1:1 and 1:0.5 of drug: retardant) were used. Simple new method for insertion of core inside the SPH composite by using syringe with wide end opening without use of glue to close the insertion site was applied. The system was characterized by scanning electron microscopy, FT-IR. Also swelling, mechanical, and dissolution properties were studied. Scanning electron microscopic images clearly show highly porous structure and interconnected channels. FT-IR study confirmed the formation of crosslinking poly (acrylamide- sulfopropyl acrylate) SPH composites. The delivery system achieved the equilibrium swelling in about 3 minutes with swelling ratio of 10.45 ± 0.9 and penetration pressure of 483.34 ± 48.0 cm H2O. The results showed non-significant (p > 0.05) difference between loaded and unloaded SPH composites regarding mechanical and swelling properties. A significant difference (P < 0.05) was found among the cumulative amount of metronidazole released with time depending on the nature and ratio of each retardant. It can be concluded that the proposed drug delivery system based on superporous hydrogel composite is promising for gastroretentive stomach specific delivery of metronidazole. Key words: Superporous hydrogel composites, Gastroretentive dosage form, metronidazole