Use of the analogue computer to predict the distribution and excretion of drugs under conditions of fluctuating urinary pH

An analogue computer program, incorporating a previously established relation between urinary pH and amphetamine excretion, has been used to predict the quantitative excretion of the drug under normal conditions of fluctuating urinary pH. Under the same conditions, a comparison has been made of computer predicted body levels of amphetamine after administration of the drug in a single solution dose, three divided solution doses, and in various prolonged-release formulations. Advantages of sustained-release preparations are indicated and specifications for a theoretically ideal sustained-release formulation are suggested.