Dosage calculation and stock solution preparation of plant crude extract and drugs for
mice model:
In most researches involving experimental animals, dosages are usually calculated from stock
solution of the test drugs dissolved in appropriate volume of solvent (vehicle). According to the
OECD’s (organization of economic corporation and development’s) guidelines, dosage of drug
(mg) should be constituted in an appropriate volume not usually exceeding 10 ml/kg (1 ml/100g)
body weight of experimental animals (mice and rats) for non-aqueous solvent in oral route of
administration. However in the case of aqueous solvents, 20 ml/kg (2 ml/100g) body weight can
be considered (OECD, 2000). Large dose volumes (40 ml/kg body weight) can cause
unnecessary stress to animals and can also overload the stomach capacity and pass immediately
into the small bowel or can result in passive reflux in the stomach, aspiration pneumonia,
pharyngeal, esophageal, and gastric irritation or injury with stricture formation, esophageal and
gastric rupture and stress. Lower volume (5 ml/kg) can be considered to dissolve highly soluble
solute drugs. Such low volume would ease the administration of drug in solution. However,
highly viscous drug solution should be diluted, whenever possible, for ease of administration.
However, final dilution volume should not exceed 20 ml/kg.
Based on 10 ml/kg volume selection, required dose volume for a 30 g rat can be calculated as
follows;
30/1000× 10 ml = 0.3 ml
NB: 1kg = 1000 g
Based on 20 ml/kg volume selection, required dose volume for a 30 g rat can be calculated as
follows; 30/1000× 20 ml = 0.6 ml
Table 1: OECD’s Guideline on Volume Selection for 25–35 g Mice
Calculated Volume (mL)
Standard Volume Mouse Body Weight (g)
Based on Body Weight
10 mL/kg (Appropriate
25 g 0.25 mL
Volume)
26 g 0.26 mL
, 27 g 0.27 mL
28 g 0.28 mL
29 g 0.29 mL
30 g 0.30 mL
31 g 0.31 mL
32 g 0.32 mL
33 g 0.33 mL
34 g 0.34 mL
35 g 0.35 mL
20 mL/kg (Maximum
25 g 0.50 mL
Volume)
26 g 0.52 mL
27 g 0.54 mL
28 g 0.56 mL
29 g 0.58 mL
30 g 0.60 mL
31 g 0.62 mL
32 g 0.64 mL
33 g 0.66 mL
34 g 0.68 mL
35 g 0.70 mL
3. Dosage calculation and preparation of stock solution of crude plant extract for experimental
animals With reference to table 1 above, stock solutions and doses of a plant extract (With
selected doses, 150 mg/kg and 300 mg/kg) for a mice weighing 30 g be calculated as follows;
Step 1: Dosage calculation Body weight of animal =30 g
Dosage Calculation and Stock Solution Preparation for Crude Plant Extract
(For a 30 g Mouse, with Selected Doses of 150 mg/kg and 300 mg/kg)
Step 1: Dosage Calculation
The required dose (mg) is calculated using the formula:
Dosage (mg) = (Body Weight (g))/1000×Dose (mg/kg)
For a 30 g mouse:
At 150 mg/kg dose:
30/1000×150=4.5 mg
mice model:
In most researches involving experimental animals, dosages are usually calculated from stock
solution of the test drugs dissolved in appropriate volume of solvent (vehicle). According to the
OECD’s (organization of economic corporation and development’s) guidelines, dosage of drug
(mg) should be constituted in an appropriate volume not usually exceeding 10 ml/kg (1 ml/100g)
body weight of experimental animals (mice and rats) for non-aqueous solvent in oral route of
administration. However in the case of aqueous solvents, 20 ml/kg (2 ml/100g) body weight can
be considered (OECD, 2000). Large dose volumes (40 ml/kg body weight) can cause
unnecessary stress to animals and can also overload the stomach capacity and pass immediately
into the small bowel or can result in passive reflux in the stomach, aspiration pneumonia,
pharyngeal, esophageal, and gastric irritation or injury with stricture formation, esophageal and
gastric rupture and stress. Lower volume (5 ml/kg) can be considered to dissolve highly soluble
solute drugs. Such low volume would ease the administration of drug in solution. However,
highly viscous drug solution should be diluted, whenever possible, for ease of administration.
However, final dilution volume should not exceed 20 ml/kg.
Based on 10 ml/kg volume selection, required dose volume for a 30 g rat can be calculated as
follows;
30/1000× 10 ml = 0.3 ml
NB: 1kg = 1000 g
Based on 20 ml/kg volume selection, required dose volume for a 30 g rat can be calculated as
follows; 30/1000× 20 ml = 0.6 ml
Table 1: OECD’s Guideline on Volume Selection for 25–35 g Mice
Calculated Volume (mL)
Standard Volume Mouse Body Weight (g)
Based on Body Weight
10 mL/kg (Appropriate
25 g 0.25 mL
Volume)
26 g 0.26 mL
, 27 g 0.27 mL
28 g 0.28 mL
29 g 0.29 mL
30 g 0.30 mL
31 g 0.31 mL
32 g 0.32 mL
33 g 0.33 mL
34 g 0.34 mL
35 g 0.35 mL
20 mL/kg (Maximum
25 g 0.50 mL
Volume)
26 g 0.52 mL
27 g 0.54 mL
28 g 0.56 mL
29 g 0.58 mL
30 g 0.60 mL
31 g 0.62 mL
32 g 0.64 mL
33 g 0.66 mL
34 g 0.68 mL
35 g 0.70 mL
3. Dosage calculation and preparation of stock solution of crude plant extract for experimental
animals With reference to table 1 above, stock solutions and doses of a plant extract (With
selected doses, 150 mg/kg and 300 mg/kg) for a mice weighing 30 g be calculated as follows;
Step 1: Dosage calculation Body weight of animal =30 g
Dosage Calculation and Stock Solution Preparation for Crude Plant Extract
(For a 30 g Mouse, with Selected Doses of 150 mg/kg and 300 mg/kg)
Step 1: Dosage Calculation
The required dose (mg) is calculated using the formula:
Dosage (mg) = (Body Weight (g))/1000×Dose (mg/kg)
For a 30 g mouse:
At 150 mg/kg dose:
30/1000×150=4.5 mg
