Determining the Required Concentration
The primary objective in formulating the test solution is to concentrate the drug solution such that when loaded into a given pump, the animal will receive the desired dose. The information below will assist you in determining the concentration with which to load the pumps.
ALZET osmotic pumps are designed to deliver a fixed volume of test solution at a constant rate. The first step in formulating a test solution to be administered is to decide on the dose or hourly mass flow of test material you wish to deliver. To cut the mass flow rate in half, use half the concentration; to double the mass flow rate, use twice the concentration, etc. The highest mass flow of test material that the pump can deliver is set by the maximum solubility of the test agent in its vehicle (saturated solution) at the temperature of loading (usually room temperature, or about 23º C). The amount of agent (µg/hr) that a pump delivers can be adjusted by altering the concentration of agent in the test solution.