Formulation and evaluation of intragastric buoyant tablets of amoxicillin trihydrate

Intragastric buoyant tablets, i.e., gastro retentive drug delivery systems of Amoxycillin trihydrate were prepared with the objective to obtain site-specific drug delivery for the stomach and to extend its duration of action. The sustained release of amoxicillin is desired because of its short biological half-life. Part icularly to treat Helicobacter pylori infections, the sustained release is desired to be confined to the stomach. The intragastric buoyant tablets of amoxicillin will provide site-specific drug delivery and thereby extend its duration of action. The dosage form was designed by using HPMC K15M and HPMC K100 polymers as gelling agents, sodium bicarbonate as gas generating agent and other excipients. Init ially granules were prepared by wet granulat ion tech nique and compressed into tablets. The pharmaceutical properties of formulations, their buoyancy lag time and total floatation time and in vitro drug release were evaluated. It is found that the hardness of the tablet will affect the buoyancy characteristics of the dosage form. The in vitro release studies indicated that the floating dosage forms containing higher concentration of HPMC K100 showed slower release. The % drug release profile was in the order of F6 > F5 > F4 > F3 > F2 > F1. The in vitro release data was treated with mathemat ical equations, and it was concluded that Amoxicillin released from the tablet followed Peppas model with non-Fickian d iffusion. Hence gastro retentive drug delivery system of Amoxycillin trihydrate is a promising approach as it can lead to decrease in the frequency of administration and ultimately lead to better patient compliance. Key-Words: Gastro retentive, amoxicillin, Helicobacter pylori, in vitro drug release.