New pilot-scale research in the Pharmacy Department of the National University of Singapore is demonstrating the value of the Insitec in-line particle size analyzer from Malvern Instruments for monitoring and control of spray drying processes. Process Analytical Technology (PAT) options, such as the Insitec, are used increasingly in the pharmaceutical manufacturing industry at the pilot plant stage to enable Quality by Design. Here the analyzer was installed to monitor the performance of a spray dryer producing oil-loaded microspheres in the size range 10–35 microns.

Spray-drying is a technique that is commonly used by the industry to modify product properties. The particle size of the resulting material is typically a key performance variable, routinely measured by off-line analysis. The microspheres produced in this study by Professor Heng’s research group were oily and prone to agglomeration, making measurement challenging.

Using the Insitec laser diffraction in-line continuous analyzer, the complete product stream was measured, optimizing the statistical relevance of the data. Produced in real time, the measurement data provided insight into the process dynamics allowing, for example, start-up time to be accurately determined, so that no in-specification material was wasted. The research team found the technique preferable to light microscopy, which although useful for off-line measurement, is tedious and time-consuming, and ill-suited to the process environment. 

Insitec technology can be used at-, in-, or on-line to measure both wet and dry systems containing particles in the size range 0.1 to 1000 microns. At- and on-line analyses both provide the opportunity for sample treatment, prior to measurement, which can be especially valuable for the accurate characterization of materials that are prone to agglomeration. Data acquisition rates are as high as four complete measurements per second, so the analyzer can monitor even the most rapidly changing processes. The real-time measurements produced are ideal for monitoring -- and for the automated control -- of a wide range of processes.

To view the full research paper, visit www.malvern.com/common/downloads/campaign/MRK1110-01.pdf.