INTERSPECIES SCALING - PREDICTING CLEARANCE OF DRUGS IN HUMANS - 3 DIFFERENT APPROACHES

1. The interspecies scaling approach to predict clearance in humans fr om animal data was tested for a wide variety of drugs. 2. Three differ ent methods were utilized to generate plots to scale-up the clearance values: (i) method I, clearance versus body weight (simple allometric equation); (ii) method II, product of clearance and maximum life-span potential; (iii) method III, product of clearance and brain weight ver sus body weight. 3. The circumstances under which the three methods ca n be applied to predict clearance in humans were evaluated. 4. If the exponent lies between 0.55 to 0.7 then method I predicts clearance rea sonably well. 5. If the exponent lies between 0.71 to 1.0 clearance ca n be predicted reasonably well by method II. 6. If the exponent is > 1 .0 clearance can be predicted using method III.