title: Increasing the dissolution rate of a low-solubility drug through a crystalline-amorphous transition: a case study with indomethacin [correction of indomethicin].
abstract: The purpose of this research is to further the understanding of the crystalline to amorphous phase transition (amorphization) that occurs when some crystalline drugs are dry blended with porous adsorbents. Indomethacin (IMC) and three grades of silica gel (SGs) were used in the study. Amorphization of crystalline IMC occurs rapidly during dry mixing with SG and was independent of mixing intensity and time. Extent of amorphization increases with lower ratios of IMC:SG and with decreased IMC and SG particle size. Blocking H-bonding silanol groups on SG by chemical modification reduced the extent of amorphization. IMC-SG mixtures showed improved dissolution rates over crystalline IMC, the improvement being directly related to the extent of amorphization. To preserve the improved dissolution rate, mixtures should be protected from moisture and heat. This approach holds promise as a mean of improving the dissolution rate of sparingly soluble drugs such as IMC.
authors.affiliation: School of Pharmacy, University of Maryland, Baltimore, MD 21201, USA. laugsbur@rx.umaryland.edu
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Pan
authors.forename: Thomas
authors.initials: T
authors.lastname: Julian
authors.forename: Larry
authors.initials: L
authors.lastname: Augsburger
mesh_terms: D003460:Crystallization; D004355:Drug Stability; D006358:Hot Temperature; D007213:Indomethacin / Q000737:chemistry*; D010316:Particle Size; D044367:Phase Transition; D058428:Silica Gel; D012822:Silicon Dioxide / Q000737:chemistry*; D012995:Solubility; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D058428:Silica Gel; D012822:Silicon Dioxide; D007213:Indomethacin