X-RAY DIFFRACTION STUDIES ON TOLBUTAMIDE SOLID DISPERSION

D860 (tolbutamide)solid dispersions prepared with urea, polyvinylpyrrolidone (PVP), and polyethylene glycal (PEG) 6000 as carriers were studied byX- ray diffraction, relating to their dissolution rates. D860 in D860- PVP dispersion wasshown to be in an amorphous state and to have greater dissolution rate. D860- urea andD860-PEG melts were found to be partly in miscible solid solution state and partlyin microcrystal state and possess higher activity and greater dissolution rate. D860- PEGcoprecipitate was a physical mixture and its dissolution rate is slower than its melt. No va-riation in the crystal structure of the D860 dispersions was observed during the ageingtest.