Weight based dosing

Hi everyone, I am developing a POP PK model for an anti-infective drug, I am trying to determine if dosing should be weight based or not. The range of weight in the study was 40-100 kg. Weight was statistically significant for Cl/F but only explained 9% of the variability observed for Cl. I used allometric scaling to describe weights effect on Cl/F and slope effect of weight was 0.58, and scaled to 60 kg (the median). Based on the slope effect estimated, AUC is predicted to decrease by 15% for an 80 kg individual, and increase by 25% for an individual that weights 40 kg compared to a 60 kg individual. How much should I trust the slope effect determined by my study? and should I rely on it to develop the dosing regimen? if weight only explained 9% of variability observed with Cl/F, could that indicate that it is not clinically significant and weight based dosing is not required? Thanks, Abdullah Sultan, PhD candidate University of Florida