Rat to Human Dose Conversion Calculator (HED)
Conversion Results:
Human Equivalent Dose (HED): 0 mg/kg
Total Human Dose for 60kg Adult: 0 mg
*Conversion based on FDA guidelines for Body Surface Area (BSA) normalization using Km factor 6 for rats and 37 for humans.
How to Convert Rat Dose to Human Dose
In pharmacological research, translating animal doses to human equivalent doses (HED) is a critical step. Simply adjusting by body weight (mg/kg) is often inaccurate because metabolic rates and physiological processes vary significantly between species. Instead, researchers use Body Surface Area (BSA) normalization.
The HED Formula
The standard method for dose translation follows the FDA guideline formula:
HED (mg/kg) = Animal Dose (mg/kg) × (Animal Km / Human Km)
For a rat to human conversion:
- Rat Km factor = 6
- Human (Adult) Km factor = 37
- Conversion Ratio = 6 / 37 ≈ 0.162
| Species | Average Weight (kg) | Km Factor |
|---|---|---|
| Human (Adult) | 60.0 | 37 |
| Rat | 0.15 | 6 |
| Mouse | 0.02 | 3 |
| Rabbit | 1.5 | 12 |
Example Calculation
If a study finds that a dose of 100 mg/kg in rats is effective, what is the equivalent dose for a 70 kg human?
- Step 1: Calculate HED in mg/kg.
100 mg/kg × (6 / 37) = 16.21 mg/kg. - Step 2: Calculate the total dose.
16.21 mg/kg × 70 kg = 1,134.7 mg.
Why use BSA instead of Weight?
Smaller animals have higher metabolic rates. Body Surface Area correlates better with several biological parameters, including basal metabolic rate, blood volume, and renal function. Using BSA-based conversion helps prevent toxicity when moving from preclinical animal models to Phase I clinical trials in humans.