gama amino butyric acid [GABA] it appears can immobilize parasites and prevent scattering although not kill them.
Ivermectin's mechanism too results from an increased release of GABA.
If you check the link below and read [Scarface101] post dated 11/10/08 - this will give more info. Also read in same thread [10selection10] post dated 11/10/08 for added info.
I'm not sure it will affect hatchings and stages L2 or L3 larvae as I have not tried it yet but thinking of getting Valium to try it out along with the ABZ and Ivermectin. Ivermectin paste states that in Ascaris infections it treats stages L3 & L4 and not below L3. This could be one reason why I still get the hatching which ABZ should have treated, after 5 treatment cycles of the drug!