Confocal stability

The first fluorescence correlation spectroscopy experiments were carried out several decades ago,62 64 but the general use of the technique was made possible with the introduction of lasers with high beam quality and long-term temporal stability, low noise detectors, and high-quality microscope objectives with high numeric apertures.58,63 The most common set-up is using a confocal inverted epi-fluorescence... 

An early example of Raman mapping by Breitenbach et al. [52] showed that when crystalline ibuprofen is formulated in a hot melt extrudate the API changes to the amorphous form. Ibuprofen is a sparingly water-soluble compound, so this formulation provides a route to better bioavailability via the more soluble amorphous form. Using confocal Raman mapping the form of the API was determined at the time of manufacture and under stress conditions and was used to assess the stability of the amorphous form. These studies also showed that the API was homogeneously distributed throughout the formulation based on the relative band intensities of the amorphous API and a formulation excipient, polyvinylpyrrolidone (PVP). 

Figure 4.6 Panel (a) depicts the subject restrainer and the skinfold chamber that is bolted to a stainless steel stabilizing plate. Panel (b) shows the subject holder mounted onto the stage of a confocal microscope.

Macnaughton S. J., Booth T., Embley T. M., and O Donnell A. G. (1996) Physical stabilization and confocal microscopy of bacteria on roots using 16S rRNA targeted, fluorescent-labeled oligonucleotide probes. J. Microbiol. Meth. 26(3), 279-285. 

The lack of any further Raman shifts during a stability study indicated that the ibuprofen in the melt extrudate is stable and that there were no crystallization processes that could affect the dissolution and bioavailability. Therefore, one use of confocal Raman spectroscopy could be to optimize various formulations and quickly determine their likely long-term stability. 

Fig. 8 Confocal laser scanning micrograph of polymer-stabilized blue phase I [16]...

Perfusion chamber such as the Sykes-Moore chamber see Subheading 2.3, item 2). This chamber works well in confocal or multiphoton microscopy when used with quartz coverslips (SPI Supplies Division of Structure Probe Inc., West Chester PA http //www.2spi.com) for improved stability during perfusion and the NE-1000 Multiphase Programmable Pump (New Era Pump Systems, Farmingdale, NY) see Subheading 2.3, item 3). 

A certain body of recent research has focused on the microstructural stability of protein stabilized oil-in-water emulsions that are structurally similar to recently developed foodstuffs (e.g., dairy alternative or fresh cheese type products, etc.). - The image of such an emulsion has been visualized by the use of Confocal Laser Scanning Microscopy (CSLM). However, not much research has been done yet on the oxidative destabilization of these emulsion systems. A better understanding of the factors monitoring the oxidative deterioration of emulsions would offer antioxidant strategies to improve the organoleptic and nutritional value of the related products. 

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