Publications by authors named "Richard Elkes"

Process intensification involves the miniaturization of equipment while retaining process throughput and performance. The pharmaceutical industry can benefit from this approach especially during drug product development, where the availability of active pharmaceutical ingredients (API) is often limited. It reduces the need for process scale up, as equipment used during product development and commercial production is identical.

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This study systematically evaluated the predictive accuracy of common empirical models for pharmaceutical powder compaction. A dataset of nine placebo and twelve active pharmaceutical ingredient (API) loaded blend formulations (four APIs at three drug loadings) was fitted to the widely used empirical tablet compression (Gurnham, Heckel, and Kawakita) and compaction (Ryshkewitch-Duckworth and Leuenberger) models. At low API loadings (<20w/w%), all models achieved R above 90 % and RRMSE (relative root mean squared error) below 0.

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Continuous Direct Compaction (CDC) has emerged as a promising route towards producing solid dosage forms while reducing material, development time and energy consumption. Understanding the response of powder processing unit operations, especially blenders, is crucial. There is a substantial body of work around how lubrication via batch blender operation affects tablet critical quality attributes such as hardness and tensile strength.

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Recent years have seen the advent of Quality-by-Design (QbD) as a philosophy to ensure the quality, safety, and efficiency of pharmaceutical production. The key pharmaceutical processing methodology of Direct Compression to produce tablets is also the focus of some research. The traditional Design-of-Experiments and purely experimental approach to achieve such quality and process development goals can have significant time and resource requirements.

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Due to the complexity in the interactions of variables and mechanisms leading to blend segregation, quantifying the segregation propensity of an Active Pharmaceutical Ingredient (API) has been challenging. A high-throughput segregation risk prediction workflow for early drug product development has been developed based on the dispensing mechanism of automated powder dispensing technology. The workflow utilized liquid handling robots and high-performance liquid chromatography (HPLC) with a well-plate autosampler for sample preparation and analysis.

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A new approach is proposed to support prediction of tablet tensile strength as a function of both solid fraction (and/or compression pressure) and extent of lubrication by using empirical data to parameterise the model. This is a pre-requisite for simulation of the compaction unit operation where a linkage from tablet press operating parameters and formulation material properties to output tensile strength is required. The approach extends the previously published Kushner and Moore model to allow calculation across a range of solid fractions.

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Successful implementation of Continuous Manufacturing technology requires real time product quality monitoring that can result into rejection strategies for material manufactured outside process control limits. In a twin screw granulation process, parameters like water content, powder feed rate, and granulator screw speed can influence granule quality. Deviations in any of these parameters from the set-point may affect granule quality.

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The forces experienced by the particles inside a twin screw granulator (TSG) are one of the most difficult parameters to measure quantitatively. However, it is possible to perform accurately this measurement through the use of dye containing calibrated microencapsulated sensors (CAMES) whose rupture is directly dependant on their experienced shear stress. The current study measures the extent of local stresses in the transformation from powder to granules at different channel fills during TSG processing.

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Gastric retention is postulated as an approach to improve bioavailability of compounds with narrow absorption windows. To elucidate the role of image size on gastric retention and pharmacokinetics, formulations with different image sizes and swelling kinetics but similar dissolution rates were designed and imaged in dogs. Diet had a clear effect, with increasing calorific intake prolonging retention in the dog model.

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