Combined semi-empirical screening and design of experiments (DOE) approach to identify candidate formulations of a lyophilized live attenuated tetravalent viral vaccine candidate.

A combination experimental approach, utilizing semi-empirical excipient screening followed by statistical modeling using design of experiments (DOE), was undertaken to identify stabilizing candidate formulations for a lyophilized live attenuated Flavivirus vaccine candidate. Various potential pharmaceutical compounds used in either marketed or investigative live attenuated viral vaccine formulations were first identified. The ability of additives from different categories of excipients, either alone or in combination, were then evaluated for their ability to stabilize virus against freeze-thaw, freeze-drying, and accelerated storage (25°C) stresses by measuring infectious virus titer. An exploratory data analysis and predictive DOE modeling approach was subsequently undertaken to gain a better understanding of the interplay between the key excipients and stability of virus as well as to determine which combinations were interacting to improve virus stability. The lead excipient combinations were identified and tested for stabilizing effects using a tetravalent mixture of viruses in accelerated and real time (2-8°C) stability studies. This work demonstrates the utility of combining semi-empirical excipient screening and DOE experimental design strategies in the formulation development of lyophilized live attenuated viral vaccine candidates.