Fluorescence spectroscopy for the determination of reconstitution time of an in-vial lyophilised product.

Lyophilisation is a prominent technique used to create stabilised, dried forms of biopharmaceutical formulations. Reconstitution of lyophilised parenteral formulations is a key step prior to patient administration. The accurate determination of reconstitution time is a necessity to aid formulation development and support product quality control. Traditional methods for quantifying reconstitution time involve the visual identification of the endpoint, which has led to variable values reported across studies. In this work, the use of ultra-violet (UV) excited fluorescence spectroscopy as an alternative to the visual quantification of the reconstitution time was investigated. Spectrographic information was collected via a bespoke setup that allowed the measurement of the reconstitution time in a standard sealed lyophilisation vial. The spectra were analysed via principal component analysis (PCA) to obtain a time-based representation of the changes in a reconstituting formulation. The analysis was followed by the identification of an endpoint using three techniques ranging from fully automated to manual with regards to the required level of user input. At high protein concentration, the variability of the reconstitution time measurements was reduced from 80.4% relative standard deviation obtained via the traditional method to 8.2% for the instrumental method presented in.