Literature says that the dosage of trigonelline is 50mg/kg for mice and is to be administered through drinking water. I am unsure how to make the trigonelline water solution - how much to add? In general, how to prepare water solutions of drugs whose dosage is known in terms of mg/kg for mice?
If we were to assume the kg refers to water, and not the weight of the mice, 1 kg of water is 1000 g or one liter. So 50 mg trigonelline per liter of water. If it was by weight of the mouse, and an example mouse weighed 100 mg, which is equal to 0.1 kg, you would add 5 mg trigonelline to its drinking water. It would not be hard to develop a spreadsheet if the weight of the individual mouse is to be considered.
Why not start your experiment without dosing, and see how much water the mice drink? Assume that the amount is equal per mouse, if they are caged together - you get better control if they are caged separately.
Once you know what they drink and how much they weigh the dose levels in water are straightforward.
This seems easier and better defined than a literature search for the typical water consumption of mice.
Well, I don't know the nature of your experiment. But literally, to dissolve a drug at a dosage of 50mg/kg simply means dissolving 50mg of the drug in 1litre of water which is also 1kg of water.
But what is important is that you need to know whether it is a stock solution you are preparing or a graded or serial solution.