Near-infrared (NIR) spectroscopy was employed as a process analytical technique in three steps of tabletting process: to monitor the blend homogeneity, evaluate the content uniformity of tablets and determine the tablets coating thickness.
A diode-array spectrometer mounted on a lab blender (SP15 NIR lab blender) was used to monitor blend uniformity using a calibration-free model with drug concentration ranging from 2.98 to 9.25% (w/w). The method developed accurately depicted the changes in concentration of the drug during blending and the positive effect of a delumping step in the production process. Blend homogeneity was reached within 2 min of the blending step post-delumping, with relative standard deviation (R.S.D.) values varying from 1.0 to 2.5% depending on the drug concentration of the blend.
A Fourier-transform spectrometer (Bruker MPA) was used to analyze content uniformity and coating thickness with calibration based models. Prediction of a validation set with tablets compacted at pressures not present in the calibration set yielded an root mean square error of cross validation (RMSEP) of 1.94%; prediction of tablets compacted at pressures present in the calibration set yielded a RMSEP of 1.48%. Performance of the model was influenced by several physical tablet properties, which could be reduced by spectral pre-processing.
A model based on reflectance spectra predicted coating thickness and its variation more accurately than the model based on transmission spectra. Inter-tablet coating variation was predicted with NIR and compared to reference thickness measurements. Both methods gave comparable results. Initial inter-tablet variation of tablets sampled in-process during coating was high, but stabilized after 30 min into the process. 相似文献
In this study, we describe the use of an innovative imaging system to measure and control the effect of nozzle operating parameters
on the characteristics of a spray. These characteristics, including spray pattern, droplet size distribution, and droplet
velocity, define the quality of the spray. They can have significant impact on the efficiency of the pan coating process and
the quality of the coat. Suspensions of different composition were used in this study, and the authors demonstrated that the
spray characteristics can be controlled with this approach.
The main conclusions from this study were:
1.
The AA/Spray (atomization air/spray rate) and AA/PA (atomization air/pattern air) mass flow ratios were the key parameters
that affect spray characteristics. Although viscosity can impact the spray, there was minimal impact within the viscosity
range tested in this study.
2.
With proper selection of the AA/Spray and AA/PA mass flow ratios, it was possible to generate sprays with consistent spatial
distributions of volume flux with minimal variations of mean droplet size over the range of coating suspensions and spray
rates studied.
Spray characterization can be a powerful tool for exploring and establishing the design space of nozzles operation in the
pan coating process. When scaling or transferring a spray coating process, the focus should be on maintaining consistent spray
qualities rather than limiting nozzle operating parameters to a range. This approach embraces the FDA concept of process analytical
technology (PAT) and design space (FDA, Guidance for industry PAT—A framework for innovative pharmaceutical development, manufacturing,
and quality assurance, 2004) for science-based operation flexibility.
The authors describe an imaging device that can be used to characterize the pattern, droplet velocities, and droplet size
distribution of a spray. This device, used at-line as a process analytical technology (PAT) tool, ensures the consistent performance
of spray nozzles used for coating processes. 相似文献
Carbon fiber reinforced polymer (CFRP) composites are integral to today’s industries. Curing or consolidation are vital processes for manufacturing CFRP components. Microwave processing has many advantages compared with conventional processing technologies using ovens or autoclaves; however, the uneven temperature distribution caused by the non-uniform microwave field has a significant influence on the quality of the cured products. In this study, we propose a new idea to solve this problem, i.e., limiting the absorption of hot areas. Under such circumstances, cold ones can catch up with them more easily. To adjust the absorbing capability of the CFRP laminate, periodically arranged metallic resonance structures supported by a dielectric spacer are introduced on its surface. The dielectric spacer, made of epoxy matrix and strontium titanate particles, is designed to possess a dielectric constant positively related to temperatures. In this situation, the microwave absorption (2.45 GHz) of the metal-dielectric-CFRP configuration is changed from 97.6% at room temperature to 55.9% at 150 °C continuously. As a result, a reduction of 43.1% in maximum temperature difference and 89% in standard deviation has been achieved. 相似文献
