Thermal Behavior of Benzoic Acid/Isonicotinamide Binary Cocrystals

YesA comprehensive study of the thermal behavior of the 1:1 and 2:1 benzoic acid/isonicotinamide cocrystals is reported. The 1:1 material shows a simple unit cell expansion followed by melting upon heating. The 2:1 crystal exhibits more complex behavior. Its unit cell first expands upon heating, as a result of C–H···π interactions being lengthened. It then is converted into the 1:1 crystal, as demonstrated by significant changes in its X-ray diffraction pattern. The loss of 1 equiv of benzoic acid is confirmed by thermogravimetric analysis–mass spectrometry. Hot stage microscopy confirms that, as intuitively expected, the transformation begins at the crystal surface. The temperature at which conversion occurs is highly dependent on the sample mass and geometry, being reduced when the sample is under a gas flow or has a greater exposed surface area but increased when the heating rate is elevated

Emergence of 3D Printed Dosage Forms: Opportunities and Challenges

The recent introduction of the first FDA approved 3D-printed drug has fuelled interest in 3D printing technology, which is set to revolutionize healthcare. Since its initial use, this rapid prototyping (RP) technology has evolved to such as extent that it is currently being used in a wide range of applications including in tissue engineering, dentistry, construction, automotive and aerospace. However, in the pharmaceutical industry this technology is still in its infancy and its potential yet to be fully explored. This paper presents various 3D printing technologies such as stereolithographic, powder based, selective laser sintering, fused deposition modelling and semi-solid extrusion 3D printing. It also provides a comprehensive review of previous attempts at using 3D printing technologies on the manufacturing dosage forms with a particular focus on oral tablets. Their advantages particularly with adaptability in the pharmaceutical field have been highlighted, including design flexibility and control and manufacture which enables the preparation of dosage forms with complex designs and geometries, multiple actives and tailored release profiles. An insight into the technical challenges facing the different 3D printing technologies such as the formulation and processing parameters is provided. Light is also shed on the different regulatory challenges that need to be overcome for 3D printing to fulfil its real potential in the pharmaceutical industry

3D printed tablets loaded with polymeric nanocapsules: an innovative approach to produce customized drug delivery systems

The generation of multi-functional drug delivery systems, namely solid dosage forms loaded with nano-sized carriers, remains little explored and is still a challenge for formulators. For the first time, the coupling of two important technologies, 3D printing and nanotechnology, to produce innovative solid dosage forms containing drug-loaded nanocapsules was evaluated here. Drug delivery devices were prepared by fused deposition modelling (FDM) from poly(ε-caprolactone) (PCL) and Eudragit® RL100 (ERL) filaments with or without a channelling agent (mannitol). They were soaked in deflazacort-loaded nanocapsules (particle size: 138nm) to produce 3D printed tablets (printlets) loaded with them, as observed by SEM. Drug loading was improved by the presence of the channelling agent and a linear correlation was obtained between the soaking time and the drug loading (r2=0.9739). Moreover, drug release profiles were dependent on the polymeric material of tablets and the presence of the channelling agent. In particular, tablets prepared with a partially hollow core (50 infill) had a higher drug loading (0.27 w/w) and faster drug release rate. This study represents an original approach to convert nanocapsules suspensions into solid dosage forms as well as an efficient 3D printing method to produce novel drug delivery systems, as personalised nanomedicines

Polymorphism in 2‑Chlorobenzamide: Run of the Mill or Not?

Structures of two very similar polymorphic forms of 2-chlorobenzamide have been obtained at low temperature. The metastable α-form is very susceptible to grinding, a property not initially realized considering the polymorphs have been reported in the literature for many years. Systematic milling studies have been carried out in a search for other polymorphic forms and to assess the rate of any polymorphic change(s). No new polymorphs were found, though a computational search for low energy structures suggested a complex crystal-energy landscape. An experimental polymorph screen was also carried out

Are Oxygen and Sulfur Atoms Structurally Equivalent in Organic Crystals?

New guidelines for the design of structurally equivalent molecular crystals were derived from structural analyses of new cocrystals and polymorphs of saccharin and thiosaccharin, aided by a computational study. The study shows that isostructural crystals may be obtained through an exchange of >CO with >CS in the molecular components of the solids, but only if the exchanged atom is not involved in hydrogen bonding

Continuous cocrystallization for dissolution rate optimization of a poorly water-soluble drug

A continuous manufacturing process, hot melt extrusion (HME), was employed for the development of high quality carbamazepine–saccharin (CBZ–SCH) cocrystals. The produced cocrystals were compared with a prototype prepared by a solvent method. It was found that processing parameters such as temperature, screw speed, and screw configuration were the critical processing parameters. In-line near-infrared analysis demonstrated that cocrystallization takes place gradually during the process along the extruder’s mixing zones. Further characterization of the extruded cocrystals proved that the manufactured highly crystalline cocrystals were similar to the prototype but had improved CBZ dissolution rates. Continuous manufacturing of cocrystals of water-insoluble drugs is a novel and robust approach

Expanding the Solid-State Landscape of l

To date, only one crystal structure of l-phenylalanine has been reported, with no confirmed report of polymorphism of this material. In the present work, we report the discovery of a new polymorph of l-phenylalanine, with the structural properties determined directly from powder X-ray diffraction data. The new polymorph of l-phenylalanine is stable only under rigorously dry conditions. In addition, two new solid hydrate phases of l-phenylalanine have been discovered: a monohydrate and a hemihydrate. The hemihydrate is susceptible to partial water deficiency. The crystal structures of the monohydrate and hemihydrate phases have also been determined directly from powder X-ray diffraction data. On the basis of results from dynamic vapor sorption and other experiments, we demonstrate that the three new solid forms are readily interconvertible as a function of relative humidity