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Dive into the research topics where Stephen V. Hammond is active.

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Featured researches published by Stephen V. Hammond.


Journal of Pharmaceutical and Biomedical Analysis | 2008

Non-invasive quantitative assessment of the content of pharmaceutical capsules using transmission Raman spectroscopy.

Charlotte Eliasson; Neil A. Macleod; Linda Jayes; Fiona C. Clarke; Stephen V. Hammond; Mark R. Smith; Pavel Matousek

This study demonstrates how transmission Raman spectroscopy can be used in the quantitative, non-invasive probing of the bulk content of production line relevant pharmaceutical products contained within capsules with a strong interfering Raman signal (principally TiO(2)). This approach is particularly beneficial in situations where the conventional Raman backscattering method is hampered or fails due to excessive Raman or fluorescence signals emanating from surface layers (capsule or coating) that pollute the much weaker subsurface Raman signals. In these feasibility experiments the interfering surface Raman signal was effectively suppressed, relative to the Raman signal of the internal content, by a factor of 33, in the transmission geometry in comparison with the conventional backscattering Raman approach. In conjunction with the superior bulk probing ability of the transmission Raman geometry, which effectively removes the sub-sampling problem inherent to conventional Raman spectroscopy, and multivariate analysis (principal component analysis (PCA), partial least squares (PLS) and classical least squares (CLS) regression), this provides an analytical tool well suited for rapid control monitoring applications in the pharmaceutical industry. The measured relative root mean square error of prediction (RMSEP) of the concentration of the active pharmaceutical ingredient (API) was 1.2 and 1.8% with 5 and 1s acquisition times, respectively.


Applied Spectroscopy | 2002

Determination of the Information Depth and Sample Size for the Analysis of Pharmaceutical Materials Using Reflectance Near-Infrared Microscopy

Fiona C. Clarke; Stephen V. Hammond; Roger D. Jee; Anthony C. Moffat

The depth near-infrared (NIR) radiation penetrates into a sample during spectral acquisitions in NIR reflectance microscopy was investigated for pharmaceutical materials. Cellulose and its derivatives are widely used as excipients for pharmaceuticals and hence, were the basis for this study. The evaluation of the depth of sample contributing to the measured reflected radiation (information depth) was achieved using varying thicknesses of cellulose placed on top of a substrate. Analyzing the change in the absorption profile of the substrate showed the relationship between thickness and absorption to be exponential. The information depth was evaluated using the point where the substrate signal was reduced by 50%, termed the DP50 value. The DP50 value ranged from 39 to 61 μm at ∼1675 nm, but was found to have an exponential relationship with wavelength. Longer wavelengths had less penetration into the sample; at 2380 nm the DP50 was ∼27 μm but this increased to ∼180 μm at 1100 nm. The sample size was determined using the information depth and an approximate model for the contributing sample volume. Sample size was found to be within the range of 0.03–418 μg of sample per NIR spectrum depending on the wavelength used.


Journal of Pharmaceutical and Biomedical Analysis | 2011

Characterisation of transmission Raman spectroscopy for rapid quantitative analysis of intact multi-component pharmaceutical capsules.

Michael D. Hargreaves; Neil A. Macleod; Mark R. Smith; Darren Andrews; Stephen V. Hammond; Pavel Matousek

A detailed characterisation of the performance of transmission Raman spectroscopy was performed from the standpoint of rapid quantitative analysis of pharmaceutical capsules using production relevant formulations comprising of active pharmaceutical ingredient (API) and 3 common pharmaceutical excipients. This research builds on our earlier studies that identified the unique benefits of transmission Raman spectroscopy compared to conventional Raman spectroscopy. These include the ability to provide bulk information of the content of capsules, thus avoiding the sub-sampling problem, and the suppression of interference from the capsule shell. This study demonstrates, for the first time, the techniques insensitivity to the amount of material held within the capsules. Different capsules sizes with different overall fill weights (100-400 mg) and capsule shell colours were assayed with a single calibration model developed using only one weight and size sample set (100 mg) to a relative error of typically <3%. The relative root mean square error of prediction of the concentration of API for the main sample set (nominal content 75%, w/w) was 1.5% with a 5s acquisition time. Models built using the same calibration set also predicted the 3 low level excipients with relative errors of 5-15%. The quantity of API was also predicted (with a relative error within ∼3%) using the same model for capsules prepared with different generations of API (i.e. API manufactured via different processes). The study provides further foundation blocks for the establishment of this emerging technique as a routine pharmaceutical analysis tool, capitalising on the inherently high chemical specificity of Raman spectroscopy and the non-invasive nature of the measurement. Ultimately, this technique has significant promise as a Process Analytical Technology (PAT) tool for online production application.


Journal of Near Infrared Spectroscopy | 1998

Focusing near infrared spectroscopy on the business objectives of modern pharmaceutical production

Tony Graham Axon; R. Brown; Stephen V. Hammond; S. J. Maris; F. Ting

The early use of near infrared (NIR) spectroscopy in the pharmaceutical industry was for raw material identification, later moving on to some conventional “calibrations” for various ingredients in a variety of sample types. The approach throughout this development process has always been “conventional” with one measurement by NIR directly replacing some other slower method, be it Mid-IR identification, or determinations by Karl Fischer, high performance liquid chromatography (HPLC)etc. A significant change in approach was demonstrated by Plugge and Van der Vlies1 in 1993, where a qualitative system was used to provide “quantitative like” answers for potency of a drug substance. Following on from that key paper, there has been a realisation that the qualitative analysis ability of NIR, has the potential to be a powerful tool for process investigation, control and validation. The final step has been to develop “model free” approaches, that consider individual data sets as unique systems, and present the opportunity for NIR to escape the shackles of “calibration” in one form or another. The use of qualitative, or model free, approaches to NIR spectroscopy provides an effective tool for satisfying many of the demands of modern pharmaceutical production. “Straight through production,” “right first time,” “short cycle time” and “total quality management” philosophies can be realised. Eventually the prospect of parametric release may be materialised with a strong contribution from NIR spectroscopy. This paper will illustrate the above points with some real life examles.


Journal of Pharmaceutical and Biomedical Analysis | 2018

Development and validation of an in-line NIR spectroscopic method for continuous blend potency determination in the feed frame of a tablet press

Fien De Leersnyder; Elisabeth Peeters; Hasna Djalabi; Valérie Vanhoorne; Bernd Van Snick; Ke Hong; Stephen V. Hammond; Angela Yang Liu; Eric Ziemons; Chris Vervaet; Thomas De Beer

Graphical abstract Figure. No caption available. HighlightsNIR as a PAT tool for in‐line monitoring in the feed frame of a tablet press.Notches made inside paddle wheel fingers to avoid the use of mathematical filters.API concentration model developed using PLS and ratio models.Method validation and uncertainty analysis through the accuracy profile approach.PLS models showed best predictive performance. ABSTRACT A calibration model for in‐line API quantification based on near infrared (NIR) spectra collection during tableting in the tablet press feed frame was developed and validated. First, the measurement set‐up was optimised and the effect of filling degree of the feed frame on the NIR spectra was investigated. Secondly, a predictive API quantification model was developed and validated by calculating the accuracy profile based on the analysis results of validation experiments. Furthermore, based on the data of the accuracy profile, the measurement uncertainty was determined. Finally, the robustness of the API quantification model was evaluated. An NIR probe (SentroPAT FO) was implemented into the feed frame of a rotary tablet press (Modul™ P) to monitor physical mixtures of a model API (sodium saccharine) and excipients with two different API target concentrations: 5 and 20% (w/w). Cutting notches into the paddle wheel fingers did avoid disturbances of the NIR signal caused by the rotating paddle wheel fingers and hence allowed better and more complete feed frame monitoring. The effect of the design of the notched paddle wheel fingers was also investigated and elucidated that straight paddle wheel fingers did cause less variation in NIR signal compared to curved paddle wheel fingers. The filling degree of the feed frame was reflected in the raw NIR spectra. Several different calibration models for the prediction of the API content were developed, based on the use of single spectra or averaged spectra, and using partial least squares (PLS) regression or ratio models. These predictive models were then evaluated and validated by processing physical mixtures with different API concentrations not used in the calibration models (validation set). The &bgr;‐expectation tolerance intervals were calculated for each model and for each of the validated API concentration levels (&bgr; was set at 95%). PLS models showed the best predictive performance. For each examined saccharine concentration range (i.e., between 4.5 and 6.5% and between 15 and 25%), at least 95% of future measurements will not deviate more than 15% from the true value.


Journal of Pharmaceutical Innovation | 2018

Evaluation of a Dry Coating Technology as a Substitute for Roller Compaction for Dry Agglomeration Applications in the Pharmaceutical Industry

Sophie Hudon; Pierre-Philippe Lapointe-Garant; Jean-Sébastien Simard; Albert Pichieri; Stephen V. Hammond; George Sienkiewicz; Nicolas Abatzoglou; Michel Perrier

PurposeA dry coating technology has been evaluated as a dry agglomeration technique for a typical pharmaceutical formulation. Its efficiency was compared with that of the more commonly used roller compaction dry granulation.MethodsA commercially available system was selected as a representative technology. The selection was based on batch size, processing time, unit size, vendor support, preventive maintenance requirements, development stage, and maturity for pharmaceutical industry requirements. The comparison targets the behavior of the resulting materials in terms of flowability, compressibility, mixing efficiency, and prevention of segregation. Particle size distribution, bulk density, scanning electron microscopy, FT4 powder rheometer, and hardness were used for the characterization of the powders. A design of experiment was used to evaluate the impact of the dry coating equipment operating parameters (rotor speed and processing time) as well as the impact of formulation (grade of microcrystalline cellulose and ratio between dibasic calcium phosphate and lactose).ResultsThe tested dry coating technology shows (1) an improved compressibility, (2) that the powders are homogenous, and (3) that they do not have a tendency to segregate in downstream process steps and during handling and storage. The impact of the rotor speed is proven statistically not significant, but it seems that a lower rotor speed might lead to less attrition and better flow properties. Processing time does not seem to have an impact for the range of processing times evaluated. Compared to roller compaction, the main advantages of the tested technology are the shape and surface enhancement and the absence of work hardening.ConclusionsThis work has shown that the blends produced by the targeted dry coating equipment has equal or better results than the powders processed by roller compaction for all the critical quality attributes that were evaluated.


Analytical Chemistry | 2001

Chemical Image Fusion. The Synergy of FT-NIR and Raman Mapping Microscopy To Enable a More Complete Visualization of Pharmaceutical Formulations

Fiona C. Clarke; Matthew J. Jamieson; Donald A. Clark; Stephen V. Hammond; Roger D. Jee; Anthony C. Moffat


International Journal of Pharmaceutics | 2007

Effect of moisture and magnesium stearate concentration on flow properties of cohesive granular materials.

Abdul Mobeen N. Faqih; Amit Mehrotra; Stephen V. Hammond; Fernando J. Muzzio


Powder Technology | 2009

An observed correlation between flow and electrical properties of pharmaceutical blends

Kalyana C. Pingali; Troy Shinbrot; Stephen V. Hammond; Fernando J. Muzzio


International Journal of Pharmaceutics | 2009

Use of a static eliminator to improve powder flow

Kalyana C. Pingali; Stephen V. Hammond; Fernando J. Muzzio; Troy Shinbrot

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Neil A. Macleod

Science and Technology Facilities Council

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Pavel Matousek

Rutherford Appleton Laboratory

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