The API (i.e. loteprednol etabonate )has poor solubility in water but has excellent solubility in Transcutol P which serves as cosurfactant in my microemulsion formulation. But when I added water in finished formulation, the drug substance precipitated. I was preplexed. Could you help me understand the problem? I also gave a glance at google scholar search results, and could not find any research on loteprednol etabonate microemulsion or nanoemulsion. Would you be so kind as to help me get some? Thank you very much.
Xiangyang Fang
You dissolve ether( loteprednol etabonate) in alcohol( Transcutol P). Then add water. Ether and alcohol are poorly soluble in water. Therefore, the drug is precipitated. You can get a water-in-drug microemulsion. To do this, water must be added dropwise to the medicine (solution) in order to see the appearance of a microemulsion.
Poor solubility in water must be driving the precipitation
suggestions -
Typically, emulsions are a ternary phase system and it is important to find the right amounts of each phase (water, oil and surfactant) and a phase diagram may be necessary through an appropriate DOE.
Drop wise addition with High energy sonication and high speed homogenization can help as well.
Select some ionic/nonionic emulsifiers like ethoxylate/ polysorbate and dissolved in water followed by adding of glycol/glycerol as a co-surfactant -prepare aqueous phase
Dissolve loteprednol elaborate in minimum alcohol, optional addition of low quantity Span emulsifier- form oil phase.
Transparent emulsion will be form my adding oil phase into water phase by drop wise under magnetic stirrer @>2000 rpm at 30-40C temp.
Hope this will be works,
Thanks
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