Publications by authors named "Patrick S Wray"

Sticking to tablet punches is a major issue during drug product manufacturing. Research has shown that sticking involves the interrelationship of powder properties, compression force, length of manufacturing runs and punch quality. Here, we present a novel non-destructive methodology to study the surface metrology of punches to monitor them over their lifetime.

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The onset of Covid-19 pandemic has resulted in the exponential growth of alcohol-based hand rub (ABHR)/hand sanitizer use. Reports have emerged of ABHR products containing methanol, a highly toxic compound to humans, exposing users to acute and chronic medical illnesses. While gas chromatography-mass spectrometry (GC-MS) remains the gold-standard method for the detection and identification of impurities in ABHRs, there exist limitations at widespread volume testing.

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Form changes during drug product processing can be a risk to the final product quality in terms of chemical stability and bioavailability. In this study, online Raman spectroscopy was used to monitor the form changes in real time during high shear wet granulation of Compound A, a highly soluble drug present at a high drug load in an extended release formulation. The effect of water content, temperature, wet massing time and drying technique on the degree of drug transformation were examined.

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The aim of this study was to assess the impact of unit processes on the de-aggregation of a cohesive micronised API within a pharmaceutical formulation using near-infrared chemical imaging. The impact on the primary API particles was also investigated using an image-based particle characterization system with integrated Raman analysis. The blended material was shown to contain large, API rich domains which were distributed in-homogeneously across the sample, suggesting that the blending process was not aggressive enough to disperse aggregates of micronised drug particles.

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NIR imaging and Raman mapping of the dissolution of model pharmaceutical formulations containing the HCl salt of a developmental compound, were carried out using a custom designed flow through cell. The results of this work have shown that NIR imaging and Raman mapping are capable of monitoring the distribution of the components in a formulation during dissolution while also revealing any form changes which may occur in real time. The NIR and Raman data revealed that the drug underwent conversion to the free base when water was used as the dissolution medium.

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Two different vibrational spectroscopic approaches, ATR-FTIR spectroscopic imaging and Raman mapping, were used to investigate the components within a tablet containing an ionised drug during dissolution experiments. Delivering certain drugs in their salt form is a method that can be used to improve the bioavailability and dissolution of the poorly aqueous soluble materials. However, these ionised species have a propensity to covert back to their thermodynamically favourable free acid or base forms.

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This work uses ATR-FTIR spectroscopic imaging to study the dissolution of delayed release and pH resistant compressed coating pharmaceutical tablets. Tablets with an inner core and outer shell were constructed using a custom designed compaction cell. The core of the delayed release tablets consisted of hydroxypropyl methylcellulose (HPMC) and caffeine.

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This work presents the novel application of attenuated total reflection-Fourier transform infrared spectroscopic (ATR-FTIR) imaging to study the dissolution of ibuprofen form tablets in which the internal pH of the matrix has been modified by addition of acidic and basic powders to the formulations. Acidic additives to the matrix retarded the dissolution of crystalline ibuprofen domains. Basic additives formed both soluble and insoluble salts with the ibuprofen depending on the pH modifier added.

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