Physicochemical characterization solution stability

Although the physicochemical stability of these lipid-based formulations may be well characterized, the impact on the physiological factors of drug adsorption and metabolism can vary dramatically. As such, lipid-based formulations may require more extensive BE/BA studies than simple oral liquids such as solutions or syrups. 

It is important to characterize the physicochemical properties of the suspensions well, so that the PK data can be interpreted appropriately. Typical characterization of the drug substance includes purity, residual solvents, aqueous solubility pro Lie (pH 2, FaSSIF), crystallinity (XRPD/DSC), particle size, pl and logP. For solution formulations at various stages of discovery studies, dose analysis is essential, and for efLcacy assessment and toxicology studies, chemical stability for the... 

Water/oil (W/0) emulsions are thermodynamically unstable aggregates. Similar to the reversed surfactant systems, the electrolyte solutions are encapsulated but in this case merely mechanically. However, the stability can usually be controlled from seconds (destabilization) to months (stabilization). The size of the emulsion droplets and the stability are sensitively dependent on the physicochemical processing conditions. The emulsion systems are best characterized by phase diagrams. 

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