I am working on a pilot study giving rats IP injections daily with a target dosage of 60mg/kg of a drug (BLZ-945). According to product sheet, soluble in organic solvents like ethanol/DMSO/etc. and sparingly soluble in aqueous buffers.

A previous person on the project said to dissolve in 0.5% methylcellulose and 0.1% Tween-20, however, this has been largely unsuccessful and drug keeps precipitating out, making it difficult to guarantee we are dosing correctly. We are looking to avoid using DMSO/DMF, but looking for some advice on increasing solubility of this drug in physiological saline. Currently I heat around 40-50C in the aforementioned vehicle for 1-2H, then I am leaving in 4C overnight due to the properties of methylcellulose.

Others on this forum have had success diluting the drug in a more concentrated stock of their non-aqueous buffer and then diluting to a working concentration in the aqueous one (60mg/mL) after, wanted to see if this is applicable. Most applications do DMSO/DMF followed by PBS. How could I modify this with the current substrates? Or are there better ones like oils/ethanol? What final working concentrations are safe for these?

TLDR: Any suggestions on how to dissolve a difficult drug for daily IP injection using physiological saline as the main component? Should we increase our concentration of Tween/MC? Should I make it in a stock solution first and dilute after? Do you recommend something alternatively, like corn oil/ethanol? Thank you in advance for the help!