Following our research efforts, in collaboration with the international non-profit organization PATH, we formulated and developed an improved measles vaccine that is stable for at least 8 weeks at 37 °C.1
Developing a stable formulation
The stable formulations, which comprised all excipients that are approved for human use, consisted of a mixture of sugars (trehalose and sucrose) in potassium phosphate buffer as base excipients. We then incorporated our patented plasticisation technology to further enhance the storage stability of the measles vaccine. Other components that we found to stabilize the vaccine included Larginine, human serum albumin and a mixture of divalent cations.
The challenges we faced with the measles vaccine were the same as those encountered with other virus and bacteriabased vaccines, which we have worked on previously: to minimize the process loss; and to maintain the vaccine titre during storage.
The measles vaccine comprises live attenuated measles virus and, as such, we could not employ traditional spray drying conditions (i.e., high atomization pressure, high drying temperature, etc.); we observed process loss resulting in > 1 Log10 in vaccine titre under traditional spray drying conditions. With optimization in atomization pressure, drying temperature and solution feed rate, we minimized the process loss to < 0.2 Log10. The formulation components do have an impact on process recovery; with certain formulation mixtures, we were able to see no process loss from spray drying.