A ceramic thick film humidity sensor, produced from MnZn ferrite, is presented. The proposed sensing mechanism is a combination of proton hopping, hydronium diffusion, and vacancy donor traps releasing electrons into the conduction band. The sensor structure comprises a two-layer device; the first layer is an interdigitated conductor and the second layer is a 30µm thick sensing layer. The effects of sintering the sensing pastes in air and vacuum have been reported. The air-fired sample exhibits the highest humidity sensitivity (1.54%/RH%) and the lowest temperature sensitivity (0.37%/ o C). The vacuum-fired sample has the lowest humidity sensitivity (0.043%/RH) and the highest temperature sensitivity (0.77%/ o C). The sensitivity results indicate that the air-fired sample has the best potential for use in humidity sensing applications.

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Real-time process monitoring using process analytical technology (PAT) tools can augment process understanding, enable improved process control, and hence facilitate the production of high-quality pharmaceutical products. While beneficial for batch processes, the availability of PAT tools to monitor continuous processes in real time is required to ensure product quality. This paper presents the application of novel process analytical technology (PAT) tools in combination with off-line analytical techniques for the study of a laboratory-scale roller compaction dry granulation process. An experiment whereby roll pressure was linearly increased and the effects thereof on roller compacted ribbon and granule properties of a placebo formulation is described. Analysis of the ribbons and granules was performed using both in-line and off-line techniques. Ribbon envelope density was measured using the GeoPyc, and the results were compared to off-line near-infrared (NIR) measurements and a novel in-line NIR tool, the Multieye. Particle size analysis of roller compacted granules was assessed with traditional sieve analysis, Camsizer and a novel technique, the Eyecon. Both Camsizer and Eyecon have the potential of being used as PAT tools in-line. Additionally the compressibility of the granules was determined using in-die Heckle analysis and the hardness of the resultant compacts was assessed. The compacts were subsequently analysed using off-line Raman spectroscopy to investigate the surface smoothness which was shown to indicate crushing strength for compacts prepared. The results of this initial study demonstrate a good relationship between in-line and off-line measurement of key in-process material attributes. The findings thus support the further exploitation of these new in-line PAT methods in monitoring of continuous unit operations at a commercial scale.

Miniaturised solvent casting (MSC) has been developed as a method for screening the stability of amorphous solid dispersions (ASD) of BCS class II drugs. The aim of the work was to further develop a rapid screening technique for drug-polymer amorphous dispersions made by solvent removal techniques. A second aim was to assess the impact of varying dissolution solvent on the resultant ASD stability. The technique was rapid, repeatable and practically straightforward. Storage stability of resultant ASD films was monitored over 4 weeks. The method is suited to preformulation as a risk-reduction tool during the formulation of drug product. Four drugs, seven polymers and five solvents have been examined. The resultant ASD films were monitored for stability and homogeneity over a four week period using polarised light microscopy (PLM), X-ray powder diffraction (XRD) and photography. A qualitative scoring system indicating the approximate proportion of amorphous and crystalline content of the films was developed. Results were rationalised against the physiochemical properties of the drugs, the functionality of the polymeric excipients and the physical properties of the solvents.