title: A new hydrate form of diflunisal precipitated from a microemulsion system.
abstract: Three microemulsion systems were applied as solvents for polymorph screening of seven active pharmaceutical ingredients (APIs): carbamazepine, piroxicam, sulfaguanidine, nitrofurantoin, theophylline, quercetin, and diflunisal. All the recrystallized compounds were examined by using powder X-ray diffractometry, differential scanning calorimetry, elemental analysis, Karl Fischer titration and dissolution rate. A new crystal form of diflunisal hydrate was discovered by the cooling method of recrystallization in a water-in-oil microemulsion system, composed of water, alkane and dioctyl sodium sulfosuccinate. The new hydrate form of diflunisal was characterized and confirmed to be a stoichiometry of diflunisal:water of 1:1. The other two microemulsion systems were able to convert the anhydrous diflunisal Form I to Form III. The dissolution rate of diflunisal hydrate is unexpectedly much higher than that of anhydrous ones (Forms I and III). All the other six APIs (carbamazepine, piroxicam, sulfaguanidine, nitrofurantoin, theophylline and quercetin) recrystallized from the microemulsion systems were all converted into hydrate form.
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan.
authors.forename: Hsuan-Lei
authors.initials: HL
authors.lastname: Sung
authors.forename: Yueh-Lin
authors.initials: YL
authors.lastname: Fan
authors.forename: Kimberly
authors.initials: K
authors.lastname: Yeh
authors.forename: Yen-Fu
authors.initials: YF
authors.lastname: Chen
authors.forename: Li-Jen
authors.initials: LJ
authors.lastname: Chen
mesh_terms: D004061:Diflunisal / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry; D010316:Particle Size; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D004655:Emulsions; D014867:Water; D004061:Diflunisal