Why is colloidal gold used for intramuscular injection ?.

Colloidal solutions are heterogeneous solutions which contain particles of intermediate size between those of true solutions and suspensions. These particles do not settle under gravity but settle on centrifugation. These particles are found to have charge. We notice many applications of these in our day to day life. Answer the following question : Colloidal medicines are used for intramuscular injections. Why?

Why is great care is taken in intravenous injection to have comparable concentration of solutions to be injected to that of blood plasma /

Artificial gold Alloy is used for making-

Why is gold foil preffered on scattering object in rutherford's experiment?

What is intracytoplasmic sperm injection?

What is Tyndall effect? Why do colloidal solutions show Tyndall effect?

Why is a sea water not used for drinking?