Thermodynamic Stability and Crystal Structures for Polymorphs and Solvates of Formoterol Fumarate

NMR characterisation of dynamics in solvates and desolvates of formoterol fumarate

“…Results (and associated error bars) were averaged where repeat measurements were taken at a single temperature. In most cases, good fits to single exponential behaviour were obtained, with the exception of data measured at estimated sample temperatures above 115 C; this is close to the melting point of the material, 120-125 C [4], and so atypical behaviour might be expected. The potential effects of cross-relaxation were investigated by measuring relaxation decays at +30 C in the presence of a train of 90 1 H pulses (duration 4.2 s, interpulse delay of 1 ms) during the recovery period.…”

“…[4] for its preparation), with some excess of solvent to maintain its integrity. Form C was produced by allowing the solvate to dry in air for 2 days [4]. The preparation of selectively 2 H-labelled form C is described in Ref.…”

“…Figure 1(a) gives its chemical structure and shows the labelling used herein for the carbon nuclei. The forms of formoterol fumarate have been investigated by a variety of techniques [4,5]. Of particular interest here are the isomorphous diformoterol fumarate disolvates, where the solvent is ethanol or isopropanol, and formoterol fumarate form C which is obtained by desolvation of these solvates.…”

Introduction to the Solid State – Physical Properties and Processes

“…The procedure is then repeated for all organic solvents of interest. More information about this procedure can be described by Jarring et al (2006) and Harris et al (2008).…”

Polymorphism and Solvatomorphism 2006

“…133 During the conduct of a crystal form screening study for formoterol fumarate, three nonsolvated polymorphs and four solvatomorphs (the dihydrate, diethanol solvate, diisopropanol solvate, and dibenzyl alcohol solvate) were obtained. 134 Isolation of solids was performed using 12 solvent systems multiplexed with three different crystallization protocols, and subsequently the products were subjected to the usual panel of physical testing. Crystallographic grade products were obtained for anhydrate Form-B, the dihydrate, and the di-solvatomorphs with ethanol and isopropanol, so structural determinations were also performed on these.…”