Hi! I'm doing a study with Wistar Rats and the concentration in humans is 30g/day. I used an average human weight of 60Kg, therefore, that makes the concentration in humans 500mg/Kg/day.
When i use the "Km ratio rule" to calculate the dose in rats it results in a very high dose to be diluted in a short amout of water, since the rats can only have maxium of 3 mL per gavage.
I was wondering if someone could help me find alternatives methods to administrat substance in rats... or if there is other calculations that i can use besides "Km ratio rule".
It depends on the nature of the substance you want to apply and the exact quantity. Maybe you could do it i.p.
Hi Alain Bousquet-Melou, the "Km ratio rule" is the one who uses the Km ratio.
Km (ratio) = rat Km (200g) / human Km (60Kg) = 0,16
Rat equivalent dose (mg/Kg) = Human Dose x Km (ratio)
Hello @Elizabeth i couldn't give it i.p ... the substance is WHEY PROTEIN.
Hi, OK it is the scaling of doses according to the surface area ; I suppose that you mean that the rat dose was equal to the human dose divided (not multiplied) by 0.16. I rapidly calculated that the dose was 625 mg for a 200g rat.
If the total volume is too high, per haps you can split the dose in two or three gavages per day ?
Alain Bousquet-Melou yes! You right, i'm sorry haha. I thought of that idea... giving one dose in the morning and another in late afternoon. So in that case i can use the " maximum of 3 mL per gavage" in the animal two times a day without causing any harm for it?
The maximum volume is mainly to avoid distension of the stomach ; so after gastric emptying, it should be possible to repeat the gavage at the time interval you suggest. Per haps there are specific recommendations for repeated dosage during the day.
You can find information on this page and on the cited guidelines :
https://www.nature.com/articles/6605642/tables/4
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