University of Wisconsin-Madison, Research Animal Resources Center Calculating Injection Doses for Rodents Overview
The methodology for determining injection volume in rodent studies is dependent on how accurate each injection must be for the overall research design. For the greatest accuracy in dosing, each individual animal is weighed, and that result is used for the equation: Calculated injection volume (typically measured in "ml") = multiply animal's weight (kg) x dose (mg/kg) and divide by the concentration (mg/ml). Example:
Mouse: 25g body weight (0.025kg) Required dose of test substance: 10mg/kg Concentration of test substance: 1mg/ml Needed dose: 0.025kg x 10mg/kg = 0.25mg Needed volume: 0.25mg / 1mg/ml = 0.25ml test substance In other instances a dose range can be used when an exact dose is not required (e.g., some anesthetic dosing). To prevent the stress of unnecessary handling of each individual rodent when a dose range is acceptable, the following methods are recommended: For well-established rodent lines, a growth-curve chart supplied by the animal vendor can be used to estimate the weight of the rodents based on their age. It is often beneficial to double-check this information to ensure that study manipulations have not affected the growth curve of the study animals. alternatively On the day of dosing, weigh 3-4 representative animals from the group, and use the average weight for all dosing calculations. This method should only be used for animals of approximately the same age and body condition. Animals that appear bigger or smaller than the representative animals should be weighed individually.
Protocol and Record Requirements The method or methods that will be employed in your study must be adequately described in your protocol. Records of animal dosing must be readily available for review by IACUC inspectors. Example protocol language for dosing
Individual mice will be weighed and dosed with _____ at _____ mg/kg. Records of all dosing will be kept in a laboratory notebook. Mice will be dosed with _____ at a range of ____ to _____ mg/kg. Animal body weight will be estimated from an established strain-specific growth curve. Mice will be dosed with _____ at a range of ____ to _____ mg/kg. Animal body weights will be determined by an average weight of group conspecifics.
Calculating Injection Dose Rodent - Research Animal Resource Center
University of Wisconsin-Madison, Research Animal Resources Center Calculating Injection Doses for Rodents Overview
The methodology for determining in...