Determination of moisture content of lyophilized allergen vaccines by NIR spectroscopy

Moisture content is an important parameter for lyophilized vaccines. Currently, Karl Fischer titration is widely used for moisture determination in routine analysis. However, this method is time-consuming, sample destructive and requires environment polluting reagents, as well as the results rely on the random samplings. In this study, near infrared spectroscopy was used as a fast, non-invasive and non-destructive method to determine the moisture content in lyophilized allergy vaccines. Five different vaccine products were investigated, which contained water in the range of 0.17-1.51% (w/w, KF). Different data pre-treatments, wavelength selection and partial least squares regression were applied to construct calibration models. Multi-products model and product-specific models were obtained, which show the possibility of NIR as a rapid method to discriminate whether moisture content fit into the specifications of a pharmaceutical company.