Theophylline formulation by supercritical antisolvents

Transmission Electron Microscopy of Pharmaceutical Materials

“…The inset is an electron diffraction pattern from this crystal, in the correct relative orientation. The diffraction pattern was a match for the polymorph of theophylline reported by Roy et al32…”

“…However, the imaging mode also revealed a small number of crystals that were morphologically different to the bulk sample. The associated diffraction pattern recorded from one of these crystals was a match for the theophylline polymorph reported by Roy et al32 This result demonstrates how TEM can identify phases that are undetectable by XRPD. It also suggests that TEM could be an important tool for investigating samples which contain a mixture of phases.…”

“…Despite repeated attempts to index the pattern on the basis of form II of theophylline, no successful indexing was possible. Likewise, comparison of the diffraction pattern reflections with PXRD peak positions of other reported polymorphic forms of theophylline, for which there is no reported crystal structure (form I, and a form recently reported by Roy et al),31, 32 did not give a match. The two possible explanations for this result are the presence of an unknown impurity phase or the existence of a previously unknown polymorph.…”

Properties of PLA/PCL particles as vehicles for oral delivery of the androgen hormone 17α-methyltestosterone

“…A specific modality, in which the supercritical fluid is used as an anti-solvent (SAS method), has been increasingly used in the production of particles [12] and even of fibers with potential use in the pharmaceutical industry field [22]. PLA particles containing theophylline [23], lutein [24] and rifampicin [25] were successfully produced by SAS methodology, as well as PCL particles containing Rosmarinus officinalis extract [26]. In the SAS method, the supercritical fluid and the polymer solution are supplied separately and continuously fed into the precipitation vessel through a nozzle [27].…”

Investigation of an Amide-Pseudo Amide Hydrogen Bonding Motif within a Series of Theophylline:Amide Cocrystals

“…Form II is the most commonly observed theophylline polymorph, whereas Form V is a seldom observed crystal form that has been previously isolated during supercritical antisolvent crystallisations of theophylline, 35 and in trace amounts during crystallisations from methanol. 36 Here, thermal dissociation of the acetamide cocrystal has provided an alternative route to observing this unusual crystal form of theophylline, albeit as a minor phase in a mixture with Form II.…”