Design of the lyophilization process of a L-leucyl-L-alanine dipeptide formulation based on its thermal properties
Abstract
The system for phenylketonuria diagnostic in newborns (UMTEST® PKU) is produced at the Center for Immunoassay (Havana, Cuba). L-leucyl-L-alanine is one of the kit components and requires lyophilization due to its limited aqueous solution stability. Results from Diffferential Thermal Analysis/Impedance (DTA/ Zsinφ) and lyomicroscopy determinations, identify that during the freezing step product temperature must be below –30 ºC, while throughout the primary drying process product temperature at sublimation front cannot exceed –18.9 ºC. The use of a procedure based on the critical variables determinations, allow the lyophilization of three industrial batches that finally fulfilled the quality specifications and achieve a reduction of 32 % in the cycle total time.
