PROCESSING TECHNOLOGY 39
which includes the universities of Leeds, Heriot-Watt and Newcastle, along with ten key industrial partners. It is primarily concerned with optimal design of batch reactors using in-process measurement and advanced modelling techniques, and works in measurement and modelling across the length scales relevant to pharmaceutical and organic fine chemical production. This is the latest in a raft of new quality by design
(QBD) tools being developed for the pharmaceutical manufacturing sector as part of a drive for increased understanding of drug processing fundamentals. “By developing tools to increase knowledge about,
and monitor, batch process systems, we’re providing practical solutions to problems faced by industry on a daily basis,” says Mahmud. “This sort of technological approach to manufacture will help reduce waste – and therefore costs – and could have a significant role to play in increasing the competitiveness of the pharmaceutical sector.”
Monitoring supersaturation
The Leeds research is published in a paper entitled “In situ Measurement of Solution Concentration during the Batch Cooling Crystallisation of L-Glutamic Acid using ATR-FTIR Spectroscopy Coupled with Chemometrics” and has been published online in Crystal Growth & Design. In it, the authors give details of the in situ
measurement of solution supersaturation associated with the batch cooling crystallisation of LGA at both 500 ml and 20 l scale sizes. This is assessed via ATR-FTIR spectroscopy.
A partial least-squares chemometric calibration
model was developed for the online prediction of LGA concentration from measured FTIR absorbance spectra overcoming some significant challenges related to the low sensitivity of LGA in the mid-IR frequency range, its low solubility in water, and its complex speciation chemistry. According to the authors, the solubility data of LGA
in water over the temperature range from 40-80˚C, using ATR-FTIR, reveals excellent agreement with that obtained both from using a gravimetric method and literature data. The metastable zone width determined using the turbidimetric methods as a function of heating/cooling rates and solute concentration is found to increase with increasing cooling rate while it decreases with increasing solution concentration. Monitoring online crystallisation via both spontaneous and seeded in 500 mL and 20 L crystallisers reveals good concentration predictions for seeded crystallisation, while fouling of the ATR crystal prevents its routine use for unseeded crystallisation studies. Higher supersaturation levels are found for the larger
crystalliser scale-size, consistent with enhancement of secondary nucleation at the smaller scale-size. u
'SILVER BULLET' KILLS CONTAMINATING BUGS IN THE LAB
BioCote antimicrobial protection, an integral feature of all Stuart benchtop laboratory equipment, reduces bacterial contamination of instrument surfaces by over 96 per cent. Details of the study, carried out
A
at the University of Birmingham in a laboratory conducting research for Cancer Research UK, are published by Bibby Scientific. Bacterial surface contamination of six BioCote-treated Stuart instruments, such as hotplate stirrers and a mixer, was compared with untreated instruments in the same laboratory. All items included in the study had been in routine use for around 18 months. Swabs from touchpads, switches, casings etc. were collected fortnightly for two months and Total Viable Counts (TVC) were obtained after inoculation and incubation of plate count agar. Results were, according to Bibby
Scientific, dramatic: there was a mean reduction in excess of 96 per cent in
two-month environmental study has shown that silver-based
the TVC of bacteria contaminating the BioCote-treated equipment, compared with untreated control items in the same environment. According to Rob Skehens, Marketing
Director, Bibby Scientific: "This important study suggests that BioCote antimicrobial protection has a vital role to play, complementing established GLP and GMP
protocols, in ensuring that laboratory environments comply with the highest health and safety standards. While surface disinfection in the laboratory will always
www.scientistlive.com
be essential, permanent antimicrobial surfaces of instruments represent a powerful weapon against the hazards of lab-acquired infection and contamination of precious experimental or test samples. This is particularly true for surfaces subjected to physical contact with reagents, or repeated hand contact by multiple users." Laboratory evidence suggests that BioCote technology, in the form of silver ions, disrupts the bacterial cell membrane function and causes denaturing of vital enzymes within the cell, leading to rapid cell death. Silver ions are slowly released from an inorganic matrix via an ion exchange mechanism, maintaining an effective concentration on or near the surface of the material. Active throughout the useful life of each instrument, BioCote kills a wide range of bacteria and fungi, including MRSA, E. coli, Legionella, Staphylococcus aureus and Aspergillus niger. u
For more information, visit
www.bibby-scientific.com
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