What is the best way to orally administer a water insoluble powdered drug to macaque monkeys?
If it is not water-soluble (lipophobic or hydrophilic), the only other alternative would be that it is fat-soluble (lipophilic or hydrophobic). Consider adding the powder to fatty solids or liquids which can be absorbed from the GI tract into the vascular system, if that is where you'd like the drug to go to be distributed throughout the body. Ideally, you would need to look up the target concentration of the drug within the blood in order to be effective, its volume of distribution, its bioavailability, its half-life, mechanism of metabolism, and calculate from there how much you would really need in order to last the full 2 weeks.