title: Amorphous drug nanosuspensions. 2. Experimental determination of bulk monomer concentrations.
abstract: A simple turbidimetric method was developed to measure the bulk concentration of drug in nanosuspensions. The bulk concentrations measured were in the range from 1 microM to 1 mM. The accuracy of the method was checked by determination of the bulk concentration of crystalline nanosuspensions, i.e., the crystalline solubility, which compared favorably to solubilities measured by a conventional method. Results obtained for amorphous nanosuspensions agreed with predictions using a theory describing the relative solubility between a supercooled liquid and a crystal. Further, it was found that the bulk concentration in Ostwald ripening inhibited amorphous nanosuspensions and could be lowered by incorporation of higher amounts of the inhibitor, in agreement with predictions using the Bragg-Williams theory of nonideal solutions.
authors.affiliation: Pharmaceutical and Analytical R&D, AstraZeneca R&D Mölndal, Sweden. lennart.lindfors@astrazeneca.com
authors.forename: Lennart
authors.initials: L
authors.lastname: Lindfors
authors.forename: Sara
authors.initials: S
authors.lastname: Forssén
authors.forename: Pia
authors.initials: P
authors.lastname: Skantze
authors.forename: Urban
authors.initials: U
authors.lastname: Skantze
authors.forename: Anna
authors.initials: A
authors.lastname: Zackrisson
authors.forename: Ulf
authors.initials: U
authors.lastname: Olsson
mesh_terms: D002121:Calcium Channel Blockers / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D003460:Crystallization; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology; D009543:Nifedipine / Q000737:chemistry*; D012995:Solubility; D013696:Temperature
chemical_list: D002121:Calcium Channel Blockers; D009543:Nifedipine