Near-Infrared Spectroscopic Determination of Residual Moisture in Lyophilized Sucrose Through Intact Glass Vials

Abstract
A rapid, noninvasive, and nondestructive method for determining moisture in sealed freeze-drying vials is described. The method, based on near-infrared spectrometry, used a novel fiber-optic diffuse-reflectance probe to make remote reflectance measurements from 1100 to 2500 nm through the bottom of glass vials. The correlation of the method to results obtained by Karl Fischer analysis was good (r2 = 0.97). The moisture content of sucrose, a common cryoprotectant, was determined with an error of 0.27% using a single sample scan.