Despite the abundant use of polyethylene oxides (PEOs) and their integration as an excipient in numerous pharmaceutical products, there have been no previous reports of applying this important thermoplastic polymer species alone to fused deposition modelling (FDM) 3D printing. In this work, we have investigated the manufacture of oral doses via FDM 3D printing by employing PEOs as a backbone polymer in combination with polyethylene glycol (PEG). Blends of PEO (molecular weight 100K, 200K, 300K, 600K or 900K) with PEG 6K (plasticiser) and a model drug (theophylline) were hot-melt extruded. The resultant filaments were used as a feed for FDM 3D printer to fabricate oral dosage forms (ODFs) with innovative designs. ODFs were designed in a radiator-like geometry with connected paralleled plates and inter-plate spacing of either 0.5, 1, 1.5 or 2 mm. X-ray diffraction patterns of the filaments revealed the presence of two distinctive peaks at 2θ = 7° and 12°, which can be correlated to the diffraction pattern of theophylline crystals. Varying blends of PEO and PEG allowed the formation of mechanically resistant filaments (maximum load at break of 357, 608, 649, 882, 781 N for filament produced with PEO 100K, 200K, 300K, 600K or 900K, respectively). Filaments of PEO at a molecular weight of 200-600K were compatible with FDM 3D printing process. Further increase in PEO molecular weight resulted in elevated shear viscosity (>10 4 Pa.S) at the printing temperature and hindered material flow during FDM 3D printing process. A minimal spacing (1 mm) between parallel plates of the radiator-like design deemed essential to boost drug release from the structure. This is the first report of utilising this widely used biodegradable polymer species (PEOs and PEG) in FDM 3D printing.

p K a is an important property of a molecule which impacts many fields, such as drug design, catalysis, reactivity, and environmental toxicity. It is often necessary to measure p K a in nonaqueous media due to the poor solubility of an analyte in water, for example, many compounds of pharmaceutical interest. Although NMR methods to measure p K a in water are well established, determining p K a in organic solvents is laborious and problematic. We present an efficient one-shot method to determine the p K a of an analyte in an organic solvent in a single measurement. Diffusion of an acid into a basic solution of the analyte and a set of pH indicators establishes a pH gradient in the NMR tube. The chemical shift of a pH sensitive resonance of the analyte and the pH of the solution are then determined simultaneously as a function of position along the pH gradient by recording a chemical shift image of the NMR tube. The p K a of the analyte is then determined using the Henderson–Hasselbalch equation. The method can be implemented in any laboratory with a gradient equipped NMR high-field spectrometer and is demonstrated for a range of pharmaceutical compounds and inorganic phosphazene bases.

BackgroundDespite regulatory advances, lack of age-appropriate formulations (AAFs) remains a challenge in paediatric practice. 3D-printing of oral dosage forms (ODFs) offers potential for AAFs for children. Optimising drug release from 3D-printed ODFs is an important technological step. Despite the abundant use of polyethylene oxides (PEOs) and their extensive use as an excipient, there have been no previous reports of applying this thermoplastic polymer species alone to fused deposition modelling (FDM) 3D printing. We assessed the impact of polymer molecular weight (MW) on the mechanical properties of the resultant filaments and their rheological properties. In the FDM 3D printing process, we also tested the effect of an innovative radiator-like design of the ODF on the acceleration of drug release patterns.MethodsBlends of PEO (MW: 100K, 200K, 300K, 600K or 900K) with PEG 6K (plasticiser) and a model drug (theophylline) were prepared by hot-melt extrusion. The resultant filaments were used as a feed for a FDM 3D printer to fabricate innovative designs of ODFs in a radiator-like geometry with inter-connected paralleled plates and inter-plate spacing of either 0.5mm, 1mm, 1.5mm or 2mm.ResultsVarying blends of PEO and PEG allowed formation of mechanically resistant filaments (maximum load at break of 357, 608, 649, 882, 781 N for filament produced with 100K, 200K, 300K, 600K or 900K, respectively). Filaments of PEO at a MW of 200K-600K were compatible with FDM 3D printing. Further increase in PEO MW resulted in elevated shear viscosity (>104 Pa.S) at the printing temperature and hindered material flow during FDM 3D printing. A minimum spacing (1 mm) between parallel plates of the radiator-like design was essential to boost drug release from the structure.ConclusionThese findings are essential in the development of next-generation personalised drug delivery doses using specialised polymer/polymer blends purposely optimised for FDM 3D printing.Disclosure(s)Nothing to disclose

Bridged amides and anilines display interesting properties owing to perturbation of conjugation of the nitrogen lone-pair with the adjacent π-system. A convergent approach to diazabicyclic scaffolds which contain either twisted amides or anilines is described, based on the photocatalysed hydroamination of cyclic enecarbamates and subsequent cyclisation. The modular nature of the synthesis allows for variation of the degree of ‘twist’ and hence the properties of the amides and anilines.

Bridged amides and anilines display interesting properties owing to perturbation of conjugation of the nitrogen lone-pair with the adjacent π-system. A convergent approach to diazabicyclic scaffolds which contain either twisted...