A preliminary investigation on the estimation of the sustained-release of indomethacin from agar beads part I

In this study agar beads containing indomethacin were prepared at different polymer-drug ratios. It was found that the release rate of indomethacin from agar beads was inversely related to the drug content. Lactose was added to the formulations in order to investigate its effect on the release of indomethacin from agar beads. Lactose increased the release rate of indomethacin and in vitro release studies exhibited a ?t dependence indicating a diffusion controlled process from a matrix formulation. All of the prepared formulations gave prolonged release. The release profiles of the formulations were compared with Indocid-R available in the market. The release criteria of all the formulations and Indocid-R were examined according to USP criteria given for indomethacin and general release criteria. At the end of the study, the obtained data were evaluated mathematically. Two equations to be used in the preparation of agar-indomethacin beads with or without lactose for optimum formulation were estimated. It was found that the estimated equations were in good agreement with the observed release results. In addition, in this study the in vivo distribution of agar beads prepared with barium sulfate as a contrast substance in the gastro-intestinal tract was also examined.