Characterization of polyox ® granules using environmental scanning electron microscopy

Abstract

Summary:The scanning electron microscope (SEM) has been frequently used in the pharmaceutical industry for studying pharmaceutical products. However, the technique does not allow for the continuous characterization of a product in both dry and hydrated states without processing the product. Through the recent advent of the environmental scanning electron microscope (ESEM), it is now possible to observe a sample in both the dry and hydrated states without extensive product preparation. The ESEM also allows for continual observation during the hydration process from the dry state until the sample is dissolved. In this study, the ESEM was used to characterize the morphologic differences and hydration patterns of granules formulated with a water-soluble hydrophilic swelling polymer, Polyox ® . Two molecular weights (1,000,000 and 7,000,000) of the polymer were used in concentrations ranging from 10 to 25% w/w. Visual differences in granule surface morphology and differences in hydration patterns were seen in granules prepared from different polymer concentrations. The morphologic data were corroborated by surface area measurements taken on a surface area analyzer. The rate at which the granule dissolved in the ESEM also correlated with the drug dissolution times determined by the standard USP dissolution method.

ESEM Characterization of Grafoil Flow Field Plates

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Environmental scanning electron microscopy (ESEM) has allowed the examination of specimens in a gaseous environment [1]. ESEM has been used to study hydration of pharmaceuticals [2] as well as, imaging of biological specimens [3,4]. A research field in which ESEM imaging would be beneficial is that of proton exchange membrane (PEM) fuel cell (FC) components.

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