One of those vendors is Brightwell Technologies, which will also be present at the IBC meeting. Deepak Sharma, Ph.D., senior research scientist, will host a workshop that describes how Micro-Flow Imaging™ (MFI) applies to biopharmaceutical formulations.
Particle characterization is a standard method for measuring the stability of biotech products, particularly for protein aggregates and other species indicative of degradation, oxidation, or other undesirable chemical events.
Conventional particle-analyzing instrumentation works best with opaque, spherical particles, but protein-based particles are highly irregular in shape, transparent to light, and usually unstable. For example, manual light microscopy and light obscuration, the default techniques for analyzing particulates in parenteral drug formulations, both have drawbacks that are becoming obvious as more biotech products hit the market.
Manual methods are tedious, error-prone, and slow. Moreover, they consistently undercount protein-based particles that are almost always transparent and gel-like. Developed in the 1970s, light obscuration (LO) was designed to detect extrinsic particulates (e.g., glass, fibers, metal) larger than about 10 microns, in drug formulations. “Since LO was not designed to study intrinsic particles originating in bioformulations, its performance for these particle types is limited,” explains Dr. Sharma. Scattering and obscuration do poorly in sizing nonspherical or optically transparent species. When particles are detected, the information gleaned from them is limited.
MFI, which was developed by Brightwell, and is currently under investigation at Wyeth, analyzes images of particles captured in succession as a sample stream passes through a flow cell. Size, shape, and intensity of each individual particle are measured, as well as the count and concentration of the entire particle population. MFI can also operate in a time-resolved mode to monitor dynamic processes.
Maintaining a correlation between each particle’s morphological parameters and its image, aids in the classification of unique particle species, which may be isolated and characterized through software. MFI’s strength is monitoring protein aggregation or precipitation during formulation development, stability testing, production processes, and final-lot validation. It also detects and characterizes extrinsic particles such as air bubbles, silicone oil droplets, and foreign particles like glass, rubber, or metal.
“The technology is already widely employed as an orthogonal technique in the formulation development phase of drug discovery by big pharmaceutical companies,” notes Dr. Sharma. “FDA has also started showing interest in MFI as an orthogonal technique.”
Protein aggregation is a fundamental problem with implications in diseases, as well as biopharmaceutical formulations. One hallmark of Alzheimer’s disease, for example, is aggregation of amyloid plaques. Jennifer Laurence, Ph.D., professor of pharmaceutical chemistry at the University of Kansas, is planning to discuss her group’s investigations into factors and conditions that affect stability and aggregation, including mechanisms implicit in the formation of amorphous protein aggregates. “It’s an area where not a lot is known at the molecular level,” Dr. Laurence says.