Aim: Study of Diuretic Activity of Drugs Using Rats/Mice
References
1. Schmid, B., & Schindler, C. (2003). Diuretic activity of drugs in rodents. Journal of Pharmacological Methods, 50(2), 123-129.
2. Vogel, H.G. (2008). Drug Discovery and Evaluation: Pharmacological Assays (3rd ed.). Springer.
3. Lipschitz, W.L., Haddian, Z., & Kerpcsar, A. (1943). Bioassay of diuretics. Journal of Pharmacology and Experimental Therapeutics, 79(1), 97-110.
Introduction
Diuretics are a class of drugs that promote the excretion of water and salts from the body through urine. This experiment aims to evaluate the diuretic activity of various drugs in rats or mice, providing insights into their efficacy and mechanism of action.
Objective
To determine the diuretic activity of test drugs in rats or mice by measuring the volume of urine output and electrolyte excretion.
Materials and Equipment: Rats or mice (male, 200-250 g for rats, 20-30 g for mice), Metabolic cages, Drugs to be tested (e.g., furosemide, hydrochlorothiazide, spironolactone), Normal saline (0.9% NaCl), Balance (for weighing animals and drugs), Measuring cylinders or graduated tubes, Test tubes, Electrolyte analyzer (optional, for Na⁺, K⁺, and Cl⁻ estimation), Water and food supply, Syringes and needles
Procedure
1. Animal Preparation: Acclimatize the animals to the laboratory environment for at least one week before the experiment.Fast the animals overnight (12-18 hours) with free access to water.
2. Baseline Measurement: Weigh the animals and record their body weight.Place each animal in a separate metabolic cage designed to separate urine from feces. Allow them to acclimatize for a couple of hours.
3. Drug Administration: Divide the animals into groups (e.g., control, standard diuretic, and test drug groups).Administer the drugs orally or intraperitoneally as per the experimental design:
Control group: Administer normal saline (10 mL/kg body weight).
Standard diuretic group: Administer a known diuretic (e.g., furosemide at 10 mg/kg body weight).
Test drug group: Administer the test drug at the required dosage.
4. Urine Collection: Collect urine samples at 1, 2, 4, and 6 hours after drug administration.Measure and record the volume of urine excreted at each time point.
5. Electrolyte Analysis (Optional): Analyze the urine samples for Na⁺, K⁺, and Cl⁻ concentrations using an electrolyte analyzer or flame photometry, if available.
6. Data Recording: Record the urine volume and electrolyte concentrations for each group.
Calculations
Diuretic Index:
The diuretic index can be calculated as the ratio of the urine volume produced by the test drug to that produced by the control group.
Diuretic Index =
Electrolyte Excretion:
Calculate the amount of electrolytes excreted using the concentration data and urine volume.
Sample Data Table
| Group | Body Weight (g) | Urine Volume (mL) | Na⁺ Concentration (mEq/L) | K⁺ Concentration (mEq/L) | Cl⁻ Concentration (mEq/L) |
| Control | 220 | 2.5 | 80 | 30 | 70 |
| Standard Diuretic | 230 | 5.8 | 150 | 50 | 130 |
| Test Drug 1 | 225 | 4.2 | 120 | 40 | 100 |
| Test Drug 2 | 215 | 3.0 | 90 | 35 | 80 |