Johan Peter Boetker

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Traditional dissolution testing determines drug release to the bulk, but does not enable an understanding of the events happening close to the surface of a solid or a tablet. UV imaging is a new imaging approach that can be used to study the dissolution behavior of chemical compounds. The UV imaging instrumentation offers recording of absorbance maps with a(More)
The current work reports the simultaneous use of UV imaging and Raman spectroscopy for detailed characterization of drug dissolution behavior including solid-state phase transformations during dissolution. The dissolution of drug substances from compacts of sodium naproxen in 0.1 HCl as well as theophylline anhydrate and monohydrate in water was studied(More)
Future manufacturing of pharmaceuticals will involve innovative use of polymeric excipients. Hot melt extrusion (HME) is an already established manufacturing technique and several products based on HME are on the market. Additionally, processing based on, e.g., HME or three dimensional (3D) printing, will have an increasingly important role when designing(More)
The aim of the present work was to investigate the potential of three-dimensional (3D) printing as a manufacturing method for products intended for personalized treatments by exploring the production of novel polylactide-based feedstock materials for 3D printing purposes. Nitrofurantoin (NF) and hydroxyapatite (HA) were successfully mixed and extruded with(More)
This work describes an approach to modify the release of active compound from a 3D printed model drug product geometry intended for flexible dosing and precision medication. The production of novel polylactic acid and hydroxypropyl methylcellulose based feed materials containing nitrofurantoin for 3D printing purposes is demonstrated. Nitrofurantoin,(More)
Amorphous forms of indomethacin have previously been prepared using various preparation techniques and it could be demonstrated that the way the material was prepared influenced the physicochemical properties of the amorphous form of the drug. The aim of this study was to use one preparation technique (transformation via the melt) to prepare amorphous(More)
Most dissolution testing systems rely on analyzing samples taken remotely from the dissolving sample surface at different time points with poor time resolution and therefore provide relatively unresolved temporally and spatially information on the dissolution process. In this study, a flexible numerical model was combined with a novel UV imaging system,(More)
The purpose of this study was to investigate the in vitro release of 5-aminosalicylic acid from single extrudates by UV imaging and to explore the technique as a visualization tool for detecting film coating defects on extrudates coated with a thin ethyl cellulose layer. 5-Aminosalicylic acid extrudates were film coated with ethyl cellulose in a typical lab(More)
Transformation of the solid-state form of a drug compound in the lumen of the gastrointestinal tract may alter the drug bioavailability and in extreme cases result in patient fatalities. The solution-mediated anhydrate-to-hydrate phase transformation was examined using an in vitro model with different biorelevant media, simulated fasted and fed state(More)
In situ elucidation of kinetics of solution-mediated phase transformations using direct structural determination has been achieved using synchrotron SAXS/WAXS radiation. Using theophylline as a model drug with known phase transformation from anhydrate to monohydrate form in aqueous conditions within a few minutes, the kinetics of the structural transition(More)