Add spaces: Forpharmacologicalstudies,addtherequiredchemicalatanappropriatefinalconcentrationtodevelopingzebrafishembryosataround26hrpostfertilization(hpf)withanappropriatevehicle-onlycontrol.
For pharmacological studies, add the required chemical at an appropriate final concentration to developing zebrafish embryos at around 26 hr post fertilization (hpf) with an appropriate vehicle-only control.