Improved Dissolution Rate of Poorly Soluble Drug by Incorporation of Buffers

Abstract

This study focused on comparing dissolution rates of indomethacin after cocompressing with three different buffers (calcium carbonate, sodium carbonate, and sodium citrate) at pH 2 and 7. Factors affecting the dissolution rate were also examined, such as type and particle size of buffer and weight-to-weight ratio of drug to buffer. It was found that, at pH 7, the release rates of indomethacin with sodium carbonate (<74 μm, all proportions) and sodium citrate (<74 μm, 75% loading) at a 20-min test time were about 10-fold and 6-fold greater, respectively, than that of indomethacin alone. When the drug and buffer were compressed into tablets using a tableting machine, the release rates of indomethacin for the control, sodium carbonate incorporated (25% and 75% buffer loading), and sodium citrate incorporated (75% buffer loading) at a 15-min test time were 50%, 90%, 66%, and 67%, respectively.