SubscribeThere is no longer a need to open bags, sacks, drums and other containers of incoming raw materials to remove a sample for identity testing in the laboratory.
The new and portable LabSpec® VIS-NIR spectroscopy systems enable fast and efficient measurements through-the-bag to confirm or otherwise the identity of incoming raw materials.
Each measurement and identity confirmation typically takes just one second. The LabSpec® instruments are specifically designed for portability and have an extremely rugged and compact design.
They also feature completely independent battery operation, wireless connectivity, fibre-optic measuring probe and remote trigger device, making LabSpec® ideal for use in a raw material goods inwards environment. In a World where regulatory bodies and more stringent quality measures continuously demand more testing of raw materials, the new LabSpec® machines offer a simple, fast and convenient way to perform more raw materials testing.
The inconvenience of breaking into packaging (possibly having already moved material into a dedicated sampling area), taking a sample, resealing the packaging, transporting sample to the laboratory, sample preparation, analysis and reporting, can often be reduced dramatically or completely removed.
LabSpec® VIS-NIR spectroscopy systems can work through the majority of typical packaging materials because they use a High Intensity Contact Probe with built-in light source and a unique post dispersive optical system.
Four basic models of LabSpec® are currently available depending on resolution requirements and requirement for a built in light source. Each LabSpec® model can be specified with up to three spectrometers installed depending on wavelength range required.
Typically a High Intensity Contact Probe is used for through-the-bag measurements, however an almost limitless range of fibre optic measurement probes can also be used for other applications, for example a dip probe for measurement of liquids.
LabSpec®2500 - Measuring Tablets
The requirement was for a simple to use and portable VIS-NIR spectroscopy system that could operate conveniently within the raw materials goods inwards area of a pharmaceutical manufacturing unit.
GoLab Workstation
Fast, easy and reliable spectral measurement and identification of a variety of raw materials, preferably without having to open their containers (mainly laminated paper and plastic sacks) was a key objective of the customer.
LabSpec®2500 - Backpack Operation
They wanted to be able to perform 100% testing of raw materials without having a dramatic increase in workload. Therefore measurements needed to be made through-the-packaging. It was anticipated that the LabSpec®2500 system would have an excellent chance of success with this application, as it has been with many other through-the-container applications.
This is mainly due to the LabSpec®'s unique post-dispersive optical system, excellent signal-to-noise performance, extended wavelength range and the light sources close proximity to the sampling interface by way of it being built-in to the head of a High Intensity Contact Probe.
Measurement Method
A LabSpec®2500 system covering the wavelength range 350-2500nm and coupled to a High Intensity Contact Probe via fibre optic cable was used to make the measurements. The High Intensity Contact Probe is a hand held reflectance probe with built in light source, it illuminates an 18mm diameter sample area and reflected radiation is collected internally by a fibre optic cable which then feeds back to the spectrophotometer.
A notepad PC with IndicoPro control and data collection software was used to collect the spectra, and the integral Rapid Classifier identification package to create calibration models and subsequently analyse and identify unknown samples.
The notepad PC communicated wirelessly with the LabSpec®2500. IndicoPro can also interface seamlessly with other qualitative and quantitative chemometric calibration models created with other commonly used and commercially available packages such as Grams (Thermo Galactic) and Unscrambler (Camo).
High Intensity Contact Probe
The instrument was referenced and optimised before commencing any measurement. Referencing and optimisation was carried out using a clean white Spectralon tile. Sample measurements were taken by pressing the High Intensity Contact Probe firmly into a non-printed area of the bag to reduce the air gap inside the bag or laminate to a minimum. Spectra take only 100 milliseconds to collect and normally between 10 and 20 were collected and averaged for each complete measurement, hence analysis time for each sample was between just 1 and 2 seconds.
LabSpec® 2500
Multiple spectral measurements were taken at different points of the known samples, which were automatically saved. These were all then added into the Rapid Classifier identification software to create a calibration model. The model was then used to predict the identity of unknown samples. The threshold at which the Rapid Classifier algorithm identifies a sample from the model will always require some optimisation depending on the robustness of the calibration model, variation of the sample, nature and magnitude of the spectral differences it is attempting to distinguish.
Measured Results
Data had been collected on a range of the customers raw material samples, initially by measuring these directly and later by measuring the same samples through-the-bag. This included a variety of different actives and excipients, including the following commonly used excipients: Lactose (two different granulation sizes), other pharmaceutical (tablet) grades of Lactose, Sucrose, Talc, Microcrystalline Cellulose, Water-soluble Methylcellulose and Calcium Dihydrate. A whole host of customer specific actives had also been measured.
A simple model was created using Rapid Classifier consisting of all the above spectral data. No pre-treatment of the data was performed (derivitisation, smoothing etc.). Having loaded the model, further measurements were made on the same samples to validate that the model was working correctly and the threshold was adjusted to find a level appropriate for the model being used.
Despite the very close spectral similarities of the pharmaceutical (tablet) grades of Lactose and the two different particle size variants of Lactose, Rapid Classifier was very easily able to distinguish between all of these samples and provide a positive identification.
The same procedure was then applied to the samples again, however this time measuring through-the-bag. This would normally be a very tough test due to the spectral similarities of some of the samples already mentioned above combined with the fact that measurements were being made through bags/sacks each consisting of three layers of dense brown paper/card as well an inner plastic liner.
However, as already mentioned, due to the unique post-dispersive optical design of the LabSpec®2500, the excellent signal-to-noise performance from its electrothermally cooled InGaS detectors and having a light source built in to the head of a High Intensity Contact Probe, this instrument had the best possible chance faced with such a demanding application. Once again, after slight further modification of threshold parameters in the model, Rapid Classifier was very easily able to distinguish between all samples.
It was suggested that due to the even closer similarity in the spectra from the through-the-bag measurements it could perhaps have been possible that we might be simply identifying different bag types rather than the product contained within! (Maybe this was all just too good to be true!) In order to further verify this, a sample of the bag laminate material was taken and multiple measurements were taken through-the-bag with only the Spectralon reference panel behind.
Visibly one could easily see that plenty of light was penetrating through all the combined layers of the packaging material. These spectra were then added to the existing model and a simple and clear distinction was then made of the blank bag samples on measuring back. Hence it was confirmed conclusively that what was being measured was indeed real product differences and not simply differences in bag types.
In order to illustrate and verify further that there were real spectral differences between the several Lactose variants, spectral data measured through-the-bag from these were exported into Grams PLS Plus 3D Viewer and displayed as single points in 3-dimensional space. Clear separation could be seen between the different groups of data. None of the data required pre-treatment before exporting. A model was also therefore developed using Grams PLS Plus and used to make predictions. Models created using Grams PLS Plus work seamlessly with the IndicoPro software.
From the measured data, observations and evaluations, it can be concluded that all the objectives of the pharmaceutical company could be met by the LabSpec®2500. Even at the time of demonstration and before having collected a significant quantity of spectral information and hence using relatively small and therefore at that stage relatively un-robust models, it was already clear that working through-the-bag would still enable reliable identification of all this customer's actives and excipients with ease.
The unique capability to measure through-the-bag, plus the portability and ruggedness of the LabSpec®2500 system, in particular when combined with the new GoLab mobile workstation, would be a great asset in any Raw Materials Good Inwards and possibly other working areas within a pharmaceutical company.
For more information about the unique new LabSpec® instruments and application details of their use in raw materials identification please contact:
Analytik Ltd
Unit 4 The Acorn Centre
Chestnut Avenue
Biggleswade
Beds SG18 0RA
Tel: +44 (0)870 991 4044
Fax: +44 (0)870 135 2488
Email: ian.laidlaw@analytik.co.uk
Web: www.analytik.co.uk