Applications, microscopy emulsions

Other recent applications of FT-IR in pharmaceutical analysis include reaction monitoring by fiberoptic FT-IR/ATR spectroscopy140 and stability studies of pharmaceutical emulsions using FT-IR microscopy.141 A novel equipment cleaning verification procedure using grazing angle fiberoptic FT-IR reflection-absorption spectroscopy was described by Perston et al.142... 

Jenkins EC. Wire-loop application of liquid emulsion to slides for autoradiography in light microscopy. Stain Technol 1972 47 23-26. 

Emulsion stability can be assessed by a great num ber of techniques which are generally based on the analysis of the droplet size distribution. Most of these techniques are easily applicable to diluted oil-in-water (0/W) emulsions (e.g. light scattering. Coulter counter, and microscopy), but they are unfortunately not adaptable to opaque W/0 emulsions. Even optical microscopy, which is considered as a universal technique in the field of emulsions, is very... 

The major structural unit of interest in emulsions, microemulsions, colloids and latexes is the particle. It is well known that the particle shape, size and distribution of a latex controls the properties and end use applications. Many latexes are manufactured with a controlled and sometimes monodisperse distribution of particle sizes. Polymer liquids, in the form of emulsions and adhesives, are wet and sticky, and therefore specimen preparation for electron microscopy is very difficxilt. As a result of the importance of the determination of particle size distribution, microscopy techniques have focused on specimen preparations which do not alter this distribution or which alter it as little as possible. Methods have included special cryotechniques (Section 4.9), staining-fixation methods (Section 4.4), microtomy (Section 4.3) and some simple methods (Section 4.1) such as dropping a solution onto a specimen holder. This section is meant to provide a brief survey of the types of microscopy applications which have been foimd useful in the evaluation of emulsions and latexes. 

Techniques such as microscopy or the use of a Coulter counter are common techniques to study O/W emulsion stability, but they are applicable only to dilute systems. DSC represents a suitable technique to characterize a W/O emulsion without disturbing the system. Characterization of a water-in-crude oil emulsion has been studied in the laboratory. The degree of undercooling and the probable temperature obtained from a cooling thermogram allows the determination of the distribution size of dispersed droplets. By knowing the latent heat of solidification, it is also possible to determine the number of droplets crystallized at temperature T. ... 

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