Mixing process operating variables

For a given experiment and configuration, the mixing time will depend upon the process and operating variables as follows ... 

Based on the analysis of the preformulation data, likely excipients are selected and small batches may be produced. The number and size of the batches depend on the availability of the drug substance. The batches are intended to assess the feasibility of the formulation, including the types and levels of excipients, as well as the process and its operational variables, such as order of addition, mixing times, compression force, granulation time, etc. The goal is to develop a formulation and process that meets the criteria set forth earlier under Objectives. 

All SFC processes operate at above the critical temperature (Tc) of supercritical fluids. Temperature is a critical controlling variable of the SFC process based on both thermodynamic and kinetic considerations. First, solubility is a function of temperature, and this will determine the supersaturation ratio or the driving force for the crystallization of individual polymorphs. Second, the kinetics of polymorphic transformation is governed by the Arrhenius law and is also temperature dependent. The rate constant of the conversion is related to the activation energy and the mass transfer process involved (i.e., diffusion, evaporation, or mixing in supercritical fluids). 

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